fs/btrfs/inode.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/bio.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/file.h>
  23 #include <linux/fs.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/highmem.h>
  26 #include <linux/time.h>
  27 #include <linux/init.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mpage.h>
  31 #include <linux/swap.h>
  32 #include <linux/writeback.h>
  33 #include <linux/statfs.h>
  34 #include <linux/compat.h>
  35 #include <linux/bit_spinlock.h>
  36 #include <linux/xattr.h>
  37 #include <linux/posix_acl.h>
  38 #include <linux/falloc.h>
  39 #include <linux/slab.h>
  40 #include <linux/ratelimit.h>
  41 #include "compat.h"
  42 #include "ctree.h"
  43 #include "disk-io.h"
  44 #include "transaction.h"
  45 #include "btrfs_inode.h"
  46 #include "ioctl.h"
  47 #include "print-tree.h"
  48 #include "volumes.h"
  49 #include "ordered-data.h"
  50 #include "xattr.h"
  51 #include "tree-log.h"
  52 #include "compression.h"
  53 #include "locking.h"
  54 #include "free-space-cache.h"
  55 #include "inode-map.h"
  56
  57 struct btrfs_iget_args {
  58         u64 ino;
  59         struct btrfs_root *root;
  60 };
  61
  62 static const struct inode_operations btrfs_dir_inode_operations;
  63 static const struct inode_operations btrfs_symlink_inode_operations;
  64 static const struct inode_operations btrfs_dir_ro_inode_operations;
  65 static const struct inode_operations btrfs_special_inode_operations;
  66 static const struct inode_operations btrfs_file_inode_operations;
  67 static const struct address_space_operations btrfs_aops;
  68 static const struct address_space_operations btrfs_symlink_aops;
  69 static const struct file_operations btrfs_dir_file_operations;
  70 static struct extent_io_ops btrfs_extent_io_ops;
  71
  72 static struct kmem_cache *btrfs_inode_cachep;
  73 struct kmem_cache *btrfs_trans_handle_cachep;
  74 struct kmem_cache *btrfs_transaction_cachep;
  75 struct kmem_cache *btrfs_path_cachep;
  76 struct kmem_cache *btrfs_free_space_cachep;
  77
  78 #define S_SHIFT 12
  79 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  80         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  81         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  82         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  83         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  84         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  85         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
  86         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
  87 };
  88
  89 static int btrfs_setsize(struct inode *inode, loff_t newsize);
  90 static int btrfs_truncate(struct inode *inode);
  91 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end);
  92 static noinline int cow_file_range(struct inode *inode,
  93                                    struct page *locked_page,
  94                                    u64 start, u64 end, int *page_started,
  95                                    unsigned long *nr_written, int unlock);
  96
  97 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
  98                                      struct inode *inode,  struct inode *dir,
  99                                      const struct qstr *qstr)
 100 {
 101         int err;
 102
 103         err = btrfs_init_acl(trans, inode, dir);
 104         if (!err)
 105                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 106         return err;
 107 }
 108
 109 /*
 110  * this does all the hard work for inserting an inline extent into
 111  * the btree.  The caller should have done a btrfs_drop_extents so that
 112  * no overlapping inline items exist in the btree
 113  */
 114 static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
 115                                 struct btrfs_root *root, struct inode *inode,
 116                                 u64 start, size_t size, size_t compressed_size,
 117                                 int compress_type,
 118                                 struct page **compressed_pages)
 119 {
 120         struct btrfs_key key;
 121         struct btrfs_path *path;
 122         struct extent_buffer *leaf;
 123         struct page *page = NULL;
 124         char *kaddr;
 125         unsigned long ptr;
 126         struct btrfs_file_extent_item *ei;
 127         int err = 0;
 128         int ret;
 129         size_t cur_size = size;
 130         size_t datasize;
 131         unsigned long offset;
 132
 133         if (compressed_size && compressed_pages)
 134                 cur_size = compressed_size;
 135
 136         path = btrfs_alloc_path();
 137         if (!path)
 138                 return -ENOMEM;
 139
 140         path->leave_spinning = 1;
 141         btrfs_set_trans_block_group(trans, inode);
 142
 143         key.objectid = btrfs_ino(inode);
 144         key.offset = start;
 145         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
 146         datasize = btrfs_file_extent_calc_inline_size(cur_size);
 147
 148         inode_add_bytes(inode, size);
 149         ret = btrfs_insert_empty_item(trans, root, path, &key,
 150                                       datasize);
 151         BUG_ON(ret);
 152         if (ret) {
 153                 err = ret;
 154                 goto fail;
 155         }
 156         leaf = path->nodes[0];
 157         ei = btrfs_item_ptr(leaf, path->slots[0],
 158                             struct btrfs_file_extent_item);
 159         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 160         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 161         btrfs_set_file_extent_encryption(leaf, ei, 0);
 162         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 163         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 164         ptr = btrfs_file_extent_inline_start(ei);
 165
 166         if (compress_type != BTRFS_COMPRESS_NONE) {
 167                 struct page *cpage;
 168                 int i = 0;
 169                 while (compressed_size > 0) {
 170                         cpage = compressed_pages[i];
 171                         cur_size = min_t(unsigned long, compressed_size,
 172                                        PAGE_CACHE_SIZE);
 173
 174                         kaddr = kmap_atomic(cpage, KM_USER0);
 175                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 176                         kunmap_atomic(kaddr, KM_USER0);
 177
 178                         i++;
 179                         ptr += cur_size;
 180                         compressed_size -= cur_size;
 181                 }
 182                 btrfs_set_file_extent_compression(leaf, ei,
 183                                                   compress_type);
 184         } else {
 185                 page = find_get_page(inode->i_mapping,
 186                                      start >> PAGE_CACHE_SHIFT);
 187                 btrfs_set_file_extent_compression(leaf, ei, 0);
 188                 kaddr = kmap_atomic(page, KM_USER0);
 189                 offset = start & (PAGE_CACHE_SIZE - 1);
 190                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 191                 kunmap_atomic(kaddr, KM_USER0);
 192                 page_cache_release(page);
 193         }
 194         btrfs_mark_buffer_dirty(leaf);
 195         btrfs_free_path(path);
 196
 197         /*
 198          * we're an inline extent, so nobody can
 199          * extend the file past i_size without locking
 200          * a page we already have locked.
 201          *
 202          * We must do any isize and inode updates
 203          * before we unlock the pages.  Otherwise we
 204          * could end up racing with unlink.
 205          */
 206         BTRFS_I(inode)->disk_i_size = inode->i_size;
 207         btrfs_update_inode(trans, root, inode);
 208
 209         return 0;
 210 fail:
 211         btrfs_free_path(path);
 212         return err;
 213 }
 214
 215
 216 /*
 217  * conditionally insert an inline extent into the file.  This
 218  * does the checks required to make sure the data is small enough
 219  * to fit as an inline extent.
 220  */
 221 static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans,
 222                                  struct btrfs_root *root,
 223                                  struct inode *inode, u64 start, u64 end,
 224                                  size_t compressed_size, int compress_type,
 225                                  struct page **compressed_pages)
 226 {
 227         u64 isize = i_size_read(inode);
 228         u64 actual_end = min(end + 1, isize);
 229         u64 inline_len = actual_end - start;
 230         u64 aligned_end = (end + root->sectorsize - 1) &
 231                         ~((u64)root->sectorsize - 1);
 232         u64 hint_byte;
 233         u64 data_len = inline_len;
 234         int ret;
 235
 236         if (compressed_size)
 237                 data_len = compressed_size;
 238
 239         if (start > 0 ||
 240             actual_end >= PAGE_CACHE_SIZE ||
 241             data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 242             (!compressed_size &&
 243             (actual_end & (root->sectorsize - 1)) == 0) ||
 244             end + 1 < isize ||
 245             data_len > root->fs_info->max_inline) {
 246                 return 1;
 247         }
 248
 249         ret = btrfs_drop_extents(trans, inode, start, aligned_end,
 250                                  &hint_byte, 1);
 251         BUG_ON(ret);
 252
 253         if (isize > actual_end)
 254                 inline_len = min_t(u64, isize, actual_end);
 255         ret = insert_inline_extent(trans, root, inode, start,
 256                                    inline_len, compressed_size,
 257                                    compress_type, compressed_pages);
 258         BUG_ON(ret);
 259         btrfs_delalloc_release_metadata(inode, end + 1 - start);
 260         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 261         return 0;
 262 }
 263
 264 struct async_extent {
 265         u64 start;
 266         u64 ram_size;
 267         u64 compressed_size;
 268         struct page **pages;
 269         unsigned long nr_pages;
 270         int compress_type;
 271         struct list_head list;
 272 };
 273
 274 struct async_cow {
 275         struct inode *inode;
 276         struct btrfs_root *root;
 277         struct page *locked_page;
 278         u64 start;
 279         u64 end;
 280         struct list_head extents;
 281         struct btrfs_work work;
 282 };
 283
 284 static noinline int add_async_extent(struct async_cow *cow,
 285                                      u64 start, u64 ram_size,
 286                                      u64 compressed_size,
 287                                      struct page **pages,
 288                                      unsigned long nr_pages,
 289                                      int compress_type)
 290 {
 291         struct async_extent *async_extent;
 292
 293         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 294         BUG_ON(!async_extent);
 295         async_extent->start = start;
 296         async_extent->ram_size = ram_size;
 297         async_extent->compressed_size = compressed_size;
 298         async_extent->pages = pages;
 299         async_extent->nr_pages = nr_pages;
 300         async_extent->compress_type = compress_type;
 301         list_add_tail(&async_extent->list, &cow->extents);
 302         return 0;
 303 }
 304
 305 /*
 306  * we create compressed extents in two phases.  The first
 307  * phase compresses a range of pages that have already been
 308  * locked (both pages and state bits are locked).
 309  *
 310  * This is done inside an ordered work queue, and the compression
 311  * is spread across many cpus.  The actual IO submission is step
 312  * two, and the ordered work queue takes care of making sure that
 313  * happens in the same order things were put onto the queue by
 314  * writepages and friends.
 315  *
 316  * If this code finds it can't get good compression, it puts an
 317  * entry onto the work queue to write the uncompressed bytes.  This
 318  * makes sure that both compressed inodes and uncompressed inodes
 319  * are written in the same order that pdflush sent them down.
 320  */
 321 static noinline int compress_file_range(struct inode *inode,
 322                                         struct page *locked_page,
 323                                         u64 start, u64 end,
 324                                         struct async_cow *async_cow,
 325                                         int *num_added)
 326 {
 327         struct btrfs_root *root = BTRFS_I(inode)->root;
 328         struct btrfs_trans_handle *trans;
 329         u64 num_bytes;
 330         u64 blocksize = root->sectorsize;
 331         u64 actual_end;
 332         u64 isize = i_size_read(inode);
 333         int ret = 0;
 334         struct page **pages = NULL;
 335         unsigned long nr_pages;
 336         unsigned long nr_pages_ret = 0;
 337         unsigned long total_compressed = 0;
 338         unsigned long total_in = 0;
 339         unsigned long max_compressed = 128 * 1024;
 340         unsigned long max_uncompressed = 128 * 1024;
 341         int i;
 342         int will_compress;
 343         int compress_type = root->fs_info->compress_type;
 344
 345         actual_end = min_t(u64, isize, end + 1);
 346 again:
 347         will_compress = 0;
 348         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
 349         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
 350
 351         /*
 352          * we don't want to send crud past the end of i_size through
 353          * compression, that's just a waste of CPU time.  So, if the
 354          * end of the file is before the start of our current
 355          * requested range of bytes, we bail out to the uncompressed
 356          * cleanup code that can deal with all of this.
 357          *
 358          * It isn't really the fastest way to fix things, but this is a
 359          * very uncommon corner.
 360          */
 361         if (actual_end <= start)
 362                 goto cleanup_and_bail_uncompressed;
 363
 364         total_compressed = actual_end - start;
 365
 366         /* we want to make sure that amount of ram required to uncompress
 367          * an extent is reasonable, so we limit the total size in ram
 368          * of a compressed extent to 128k.  This is a crucial number
 369          * because it also controls how easily we can spread reads across
 370          * cpus for decompression.
 371          *
 372          * We also want to make sure the amount of IO required to do
 373          * a random read is reasonably small, so we limit the size of
 374          * a compressed extent to 128k.
 375          */
 376         total_compressed = min(total_compressed, max_uncompressed);
 377         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
 378         num_bytes = max(blocksize,  num_bytes);
 379         total_in = 0;
 380         ret = 0;
 381
 382         /*
 383          * we do compression for mount -o compress and when the
 384          * inode has not been flagged as nocompress.  This flag can
 385          * change at any time if we discover bad compression ratios.
 386          */
 387         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
 388             (btrfs_test_opt(root, COMPRESS) ||
 389              (BTRFS_I(inode)->force_compress) ||
 390              (BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))) {
 391                 WARN_ON(pages);
 392                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
 393                 BUG_ON(!pages);
 394
 395                 if (BTRFS_I(inode)->force_compress)
 396                         compress_type = BTRFS_I(inode)->force_compress;
 397
 398                 ret = btrfs_compress_pages(compress_type,
 399                                            inode->i_mapping, start,
 400                                            total_compressed, pages,
 401                                            nr_pages, &nr_pages_ret,
 402                                            &total_in,
 403                                            &total_compressed,
 404                                            max_compressed);
 405
 406                 if (!ret) {
 407                         unsigned long offset = total_compressed &
 408                                 (PAGE_CACHE_SIZE - 1);
 409                         struct page *page = pages[nr_pages_ret - 1];
 410                         char *kaddr;
 411
 412                         /* zero the tail end of the last page, we might be
 413                          * sending it down to disk
 414                          */
 415                         if (offset) {
 416                                 kaddr = kmap_atomic(page, KM_USER0);
 417                                 memset(kaddr + offset, 0,
 418                                        PAGE_CACHE_SIZE - offset);
 419                                 kunmap_atomic(kaddr, KM_USER0);
 420                         }
 421                         will_compress = 1;
 422                 }
 423         }
 424         if (start == 0) {
 425                 trans = btrfs_join_transaction(root, 1);
 426                 BUG_ON(IS_ERR(trans));
 427                 btrfs_set_trans_block_group(trans, inode);
 428                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 429
 430                 /* lets try to make an inline extent */
 431                 if (ret || total_in < (actual_end - start)) {
 432                         /* we didn't compress the entire range, try
 433                          * to make an uncompressed inline extent.
 434                          */
 435                         ret = cow_file_range_inline(trans, root, inode,
 436                                                     start, end, 0, 0, NULL);
 437                 } else {
 438                         /* try making a compressed inline extent */
 439                         ret = cow_file_range_inline(trans, root, inode,
 440                                                     start, end,
 441                                                     total_compressed,
 442                                                     compress_type, pages);
 443                 }
 444                 if (ret == 0) {
 445                         /*
 446                          * inline extent creation worked, we don't need
 447                          * to create any more async work items.  Unlock
 448                          * and free up our temp pages.
 449                          */
 450                         extent_clear_unlock_delalloc(inode,
 451                              &BTRFS_I(inode)->io_tree,
 452                              start, end, NULL,
 453                              EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
 454                              EXTENT_CLEAR_DELALLOC |
 455                              EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK);
 456
 457                         btrfs_end_transaction(trans, root);
 458                         goto free_pages_out;
 459                 }
 460                 btrfs_end_transaction(trans, root);
 461         }
 462
 463         if (will_compress) {
 464                 /*
 465                  * we aren't doing an inline extent round the compressed size
 466                  * up to a block size boundary so the allocator does sane
 467                  * things
 468                  */
 469                 total_compressed = (total_compressed + blocksize - 1) &
 470                         ~(blocksize - 1);
 471
 472                 /*
 473                  * one last check to make sure the compression is really a
 474                  * win, compare the page count read with the blocks on disk
 475                  */
 476                 total_in = (total_in + PAGE_CACHE_SIZE - 1) &
 477                         ~(PAGE_CACHE_SIZE - 1);
 478                 if (total_compressed >= total_in) {
 479                         will_compress = 0;
 480                 } else {
 481                         num_bytes = total_in;
 482                 }
 483         }
 484         if (!will_compress && pages) {
 485                 /*
 486                  * the compression code ran but failed to make things smaller,
 487                  * free any pages it allocated and our page pointer array
 488                  */
 489                 for (i = 0; i < nr_pages_ret; i++) {
 490                         WARN_ON(pages[i]->mapping);
 491                         page_cache_release(pages[i]);
 492                 }
 493                 kfree(pages);
 494                 pages = NULL;
 495                 total_compressed = 0;
 496                 nr_pages_ret = 0;
 497
 498                 /* flag the file so we don't compress in the future */
 499                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
 500                     !(BTRFS_I(inode)->force_compress)) {
 501                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 502                 }
 503         }
 504         if (will_compress) {
 505                 *num_added += 1;
 506
 507                 /* the async work queues will take care of doing actual
 508                  * allocation on disk for these compressed pages,
 509                  * and will submit them to the elevator.
 510                  */
 511                 add_async_extent(async_cow, start, num_bytes,
 512                                  total_compressed, pages, nr_pages_ret,
 513                                  compress_type);
 514
 515                 if (start + num_bytes < end) {
 516                         start += num_bytes;
 517                         pages = NULL;
 518                         cond_resched();
 519                         goto again;
 520                 }
 521         } else {
 522 cleanup_and_bail_uncompressed:
 523                 /*
 524                  * No compression, but we still need to write the pages in
 525                  * the file we've been given so far.  redirty the locked
 526                  * page if it corresponds to our extent and set things up
 527                  * for the async work queue to run cow_file_range to do
 528                  * the normal delalloc dance
 529                  */
 530                 if (page_offset(locked_page) >= start &&
 531                     page_offset(locked_page) <= end) {
 532                         __set_page_dirty_nobuffers(locked_page);
 533                         /* unlocked later on in the async handlers */
 534                 }
 535                 add_async_extent(async_cow, start, end - start + 1,
 536                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
 537                 *num_added += 1;
 538         }
 539
 540 out:
 541         return 0;
 542
 543 free_pages_out:
 544         for (i = 0; i < nr_pages_ret; i++) {
 545                 WARN_ON(pages[i]->mapping);
 546                 page_cache_release(pages[i]);
 547         }
 548         kfree(pages);
 549
 550         goto out;
 551 }
 552
 553 /*
 554  * phase two of compressed writeback.  This is the ordered portion
 555  * of the code, which only gets called in the order the work was
 556  * queued.  We walk all the async extents created by compress_file_range
 557  * and send them down to the disk.
 558  */
 559 static noinline int submit_compressed_extents(struct inode *inode,
 560                                               struct async_cow *async_cow)
 561 {
 562         struct async_extent *async_extent;
 563         u64 alloc_hint = 0;
 564         struct btrfs_trans_handle *trans;
 565         struct btrfs_key ins;
 566         struct extent_map *em;
 567         struct btrfs_root *root = BTRFS_I(inode)->root;
 568         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 569         struct extent_io_tree *io_tree;
 570         int ret = 0;
 571
 572         if (list_empty(&async_cow->extents))
 573                 return 0;
 574
 575
 576         while (!list_empty(&async_cow->extents)) {
 577                 async_extent = list_entry(async_cow->extents.next,
 578                                           struct async_extent, list);
 579                 list_del(&async_extent->list);
 580
 581                 io_tree = &BTRFS_I(inode)->io_tree;
 582
 583 retry:
 584                 /* did the compression code fall back to uncompressed IO? */
 585                 if (!async_extent->pages) {
 586                         int page_started = 0;
 587                         unsigned long nr_written = 0;
 588
 589                         lock_extent(io_tree, async_extent->start,
 590                                          async_extent->start +
 591                                          async_extent->ram_size - 1, GFP_NOFS);
 592
 593                         /* allocate blocks */
 594                         ret = cow_file_range(inode, async_cow->locked_page,
 595                                              async_extent->start,
 596                                              async_extent->start +
 597                                              async_extent->ram_size - 1,
 598                                              &page_started, &nr_written, 0);
 599
 600                         /*
 601                          * if page_started, cow_file_range inserted an
 602                          * inline extent and took care of all the unlocking
 603                          * and IO for us.  Otherwise, we need to submit
 604                          * all those pages down to the drive.
 605                          */
 606                         if (!page_started && !ret)
 607                                 extent_write_locked_range(io_tree,
 608                                                   inode, async_extent->start,
 609                                                   async_extent->start +
 610                                                   async_extent->ram_size - 1,
 611                                                   btrfs_get_extent,
 612                                                   WB_SYNC_ALL);
 613                         kfree(async_extent);
 614                         cond_resched();
 615                         continue;
 616                 }
 617
 618                 lock_extent(io_tree, async_extent->start,
 619                             async_extent->start + async_extent->ram_size - 1,
 620                             GFP_NOFS);
 621
 622                 trans = btrfs_join_transaction(root, 1);
 623                 BUG_ON(IS_ERR(trans));
 624                 ret = btrfs_reserve_extent(trans, root,
 625                                            async_extent->compressed_size,
 626                                            async_extent->compressed_size,
 627                                            0, alloc_hint,
 628                                            (u64)-1, &ins, 1);
 629                 btrfs_end_transaction(trans, root);
 630
 631                 if (ret) {
 632                         int i;
 633                         for (i = 0; i < async_extent->nr_pages; i++) {
 634                                 WARN_ON(async_extent->pages[i]->mapping);
 635                                 page_cache_release(async_extent->pages[i]);
 636                         }
 637                         kfree(async_extent->pages);
 638                         async_extent->nr_pages = 0;
 639                         async_extent->pages = NULL;
 640                         unlock_extent(io_tree, async_extent->start,
 641                                       async_extent->start +
 642                                       async_extent->ram_size - 1, GFP_NOFS);
 643                         goto retry;
 644                 }
 645
 646                 /*
 647                  * here we're doing allocation and writeback of the
 648                  * compressed pages
 649                  */
 650                 btrfs_drop_extent_cache(inode, async_extent->start,
 651                                         async_extent->start +
 652                                         async_extent->ram_size - 1, 0);
 653
 654                 em = alloc_extent_map();
 655                 BUG_ON(!em);
 656                 em->start = async_extent->start;
 657                 em->len = async_extent->ram_size;
 658                 em->orig_start = em->start;
 659
 660                 em->block_start = ins.objectid;
 661                 em->block_len = ins.offset;
 662                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 663                 em->compress_type = async_extent->compress_type;
 664                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 665                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 666
 667                 while (1) {
 668                         write_lock(&em_tree->lock);
 669                         ret = add_extent_mapping(em_tree, em);
 670                         write_unlock(&em_tree->lock);
 671                         if (ret != -EEXIST) {
 672                                 free_extent_map(em);
 673                                 break;
 674                         }
 675                         btrfs_drop_extent_cache(inode, async_extent->start,
 676                                                 async_extent->start +
 677                                                 async_extent->ram_size - 1, 0);
 678                 }
 679
 680                 ret = btrfs_add_ordered_extent_compress(inode,
 681                                                 async_extent->start,
 682                                                 ins.objectid,
 683                                                 async_extent->ram_size,
 684                                                 ins.offset,
 685                                                 BTRFS_ORDERED_COMPRESSED,
 686                                                 async_extent->compress_type);
 687                 BUG_ON(ret);
 688
 689                 /*
 690                  * clear dirty, set writeback and unlock the pages.
 691                  */
 692                 extent_clear_unlock_delalloc(inode,
 693                                 &BTRFS_I(inode)->io_tree,
 694                                 async_extent->start,
 695                                 async_extent->start +
 696                                 async_extent->ram_size - 1,
 697                                 NULL, EXTENT_CLEAR_UNLOCK_PAGE |
 698                                 EXTENT_CLEAR_UNLOCK |
 699                                 EXTENT_CLEAR_DELALLOC |
 700                                 EXTENT_CLEAR_DIRTY | EXTENT_SET_WRITEBACK);
 701
 702                 ret = btrfs_submit_compressed_write(inode,
 703                                     async_extent->start,
 704                                     async_extent->ram_size,
 705                                     ins.objectid,
 706                                     ins.offset, async_extent->pages,
 707                                     async_extent->nr_pages);
 708
 709                 BUG_ON(ret);
 710                 alloc_hint = ins.objectid + ins.offset;
 711                 kfree(async_extent);
 712                 cond_resched();
 713         }
 714
 715         return 0;
 716 }
 717
 718 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 719                                       u64 num_bytes)
 720 {
 721         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 722         struct extent_map *em;
 723         u64 alloc_hint = 0;
 724
 725         read_lock(&em_tree->lock);
 726         em = search_extent_mapping(em_tree, start, num_bytes);
 727         if (em) {
 728                 /*
 729                  * if block start isn't an actual block number then find the
 730                  * first block in this inode and use that as a hint.  If that
 731                  * block is also bogus then just don't worry about it.
 732                  */
 733                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 734                         free_extent_map(em);
 735                         em = search_extent_mapping(em_tree, 0, 0);
 736                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 737                                 alloc_hint = em->block_start;
 738                         if (em)
 739                                 free_extent_map(em);
 740                 } else {
 741                         alloc_hint = em->block_start;
 742                         free_extent_map(em);
 743                 }
 744         }
 745         read_unlock(&em_tree->lock);
 746
 747         return alloc_hint;
 748 }
 749
 750 static inline bool is_free_space_inode(struct btrfs_root *root,
 751                                        struct inode *inode)
 752 {
 753         if (root == root->fs_info->tree_root ||
 754             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID)
 755                 return true;
 756         return false;
 757 }
 758
 759 /*
 760  * when extent_io.c finds a delayed allocation range in the file,
 761  * the call backs end up in this code.  The basic idea is to
 762  * allocate extents on disk for the range, and create ordered data structs
 763  * in ram to track those extents.
 764  *
 765  * locked_page is the page that writepage had locked already.  We use
 766  * it to make sure we don't do extra locks or unlocks.
 767  *
 768  * *page_started is set to one if we unlock locked_page and do everything
 769  * required to start IO on it.  It may be clean and already done with
 770  * IO when we return.
 771  */
 772 static noinline int cow_file_range(struct inode *inode,
 773                                    struct page *locked_page,
 774                                    u64 start, u64 end, int *page_started,
 775                                    unsigned long *nr_written,
 776                                    int unlock)
 777 {
 778         struct btrfs_root *root = BTRFS_I(inode)->root;
 779         struct btrfs_trans_handle *trans;
 780         u64 alloc_hint = 0;
 781         u64 num_bytes;
 782         unsigned long ram_size;
 783         u64 disk_num_bytes;
 784         u64 cur_alloc_size;
 785         u64 blocksize = root->sectorsize;
 786         struct btrfs_key ins;
 787         struct extent_map *em;
 788         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 789         int ret = 0;
 790
 791         BUG_ON(is_free_space_inode(root, inode));
 792         trans = btrfs_join_transaction(root, 1);
 793         BUG_ON(IS_ERR(trans));
 794         btrfs_set_trans_block_group(trans, inode);
 795         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 796
 797         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
 798         num_bytes = max(blocksize,  num_bytes);
 799         disk_num_bytes = num_bytes;
 800         ret = 0;
 801
 802         if (start == 0) {
 803                 /* lets try to make an inline extent */
 804                 ret = cow_file_range_inline(trans, root, inode,
 805                                             start, end, 0, 0, NULL);
 806                 if (ret == 0) {
 807                         extent_clear_unlock_delalloc(inode,
 808                                      &BTRFS_I(inode)->io_tree,
 809                                      start, end, NULL,
 810                                      EXTENT_CLEAR_UNLOCK_PAGE |
 811                                      EXTENT_CLEAR_UNLOCK |
 812                                      EXTENT_CLEAR_DELALLOC |
 813                                      EXTENT_CLEAR_DIRTY |
 814                                      EXTENT_SET_WRITEBACK |
 815                                      EXTENT_END_WRITEBACK);
 816
 817                         *nr_written = *nr_written +
 818                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
 819                         *page_started = 1;
 820                         ret = 0;
 821                         goto out;
 822                 }
 823         }
 824
 825         BUG_ON(disk_num_bytes >
 826                btrfs_super_total_bytes(&root->fs_info->super_copy));
 827
 828         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 829         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 830
 831         while (disk_num_bytes > 0) {
 832                 unsigned long op;
 833
 834                 cur_alloc_size = disk_num_bytes;
 835                 ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
 836                                            root->sectorsize, 0, alloc_hint,
 837                                            (u64)-1, &ins, 1);
 838                 BUG_ON(ret);
 839
 840                 em = alloc_extent_map();
 841                 BUG_ON(!em);
 842                 em->start = start;
 843                 em->orig_start = em->start;
 844                 ram_size = ins.offset;
 845                 em->len = ins.offset;
 846
 847                 em->block_start = ins.objectid;
 848                 em->block_len = ins.offset;
 849                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 850                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 851
 852                 while (1) {
 853                         write_lock(&em_tree->lock);
 854                         ret = add_extent_mapping(em_tree, em);
 855                         write_unlock(&em_tree->lock);
 856                         if (ret != -EEXIST) {
 857                                 free_extent_map(em);
 858                                 break;
 859                         }
 860                         btrfs_drop_extent_cache(inode, start,
 861                                                 start + ram_size - 1, 0);
 862                 }
 863
 864                 cur_alloc_size = ins.offset;
 865                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
 866                                                ram_size, cur_alloc_size, 0);
 867                 BUG_ON(ret);
 868
 869                 if (root->root_key.objectid ==
 870                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
 871                         ret = btrfs_reloc_clone_csums(inode, start,
 872                                                       cur_alloc_size);
 873                         BUG_ON(ret);
 874                 }
 875
 876                 if (disk_num_bytes < cur_alloc_size)
 877                         break;
 878
 879                 /* we're not doing compressed IO, don't unlock the first
 880                  * page (which the caller expects to stay locked), don't
 881                  * clear any dirty bits and don't set any writeback bits
 882                  *
 883                  * Do set the Private2 bit so we know this page was properly
 884                  * setup for writepage
 885                  */
 886                 op = unlock ? EXTENT_CLEAR_UNLOCK_PAGE : 0;
 887                 op |= EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
 888                         EXTENT_SET_PRIVATE2;
 889
 890                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
 891                                              start, start + ram_size - 1,
 892                                              locked_page, op);
 893                 disk_num_bytes -= cur_alloc_size;
 894                 num_bytes -= cur_alloc_size;
 895                 alloc_hint = ins.objectid + ins.offset;
 896                 start += cur_alloc_size;
 897         }
 898 out:
 899         ret = 0;
 900         btrfs_end_transaction(trans, root);
 901
 902         return ret;
 903 }
 904
 905 /*
 906  * work queue call back to started compression on a file and pages
 907  */
 908 static noinline void async_cow_start(struct btrfs_work *work)
 909 {
 910         struct async_cow *async_cow;
 911         int num_added = 0;
 912         async_cow = container_of(work, struct async_cow, work);
 913
 914         compress_file_range(async_cow->inode, async_cow->locked_page,
 915                             async_cow->start, async_cow->end, async_cow,
 916                             &num_added);
 917         if (num_added == 0)
 918                 async_cow->inode = NULL;
 919 }
 920
 921 /*
 922  * work queue call back to submit previously compressed pages
 923  */
 924 static noinline void async_cow_submit(struct btrfs_work *work)
 925 {
 926         struct async_cow *async_cow;
 927         struct btrfs_root *root;
 928         unsigned long nr_pages;
 929
 930         async_cow = container_of(work, struct async_cow, work);
 931
 932         root = async_cow->root;
 933         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
 934                 PAGE_CACHE_SHIFT;
 935
 936         atomic_sub(nr_pages, &root->fs_info->async_delalloc_pages);
 937
 938         if (atomic_read(&root->fs_info->async_delalloc_pages) <
 939             5 * 1042 * 1024 &&
 940             waitqueue_active(&root->fs_info->async_submit_wait))
 941                 wake_up(&root->fs_info->async_submit_wait);
 942
 943         if (async_cow->inode)
 944                 submit_compressed_extents(async_cow->inode, async_cow);
 945 }
 946
 947 static noinline void async_cow_free(struct btrfs_work *work)
 948 {
 949         struct async_cow *async_cow;
 950         async_cow = container_of(work, struct async_cow, work);
 951         kfree(async_cow);
 952 }
 953
 954 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
 955                                 u64 start, u64 end, int *page_started,
 956                                 unsigned long *nr_written)
 957 {
 958         struct async_cow *async_cow;
 959         struct btrfs_root *root = BTRFS_I(inode)->root;
 960         unsigned long nr_pages;
 961         u64 cur_end;
 962         int limit = 10 * 1024 * 1042;
 963
 964         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
 965                          1, 0, NULL, GFP_NOFS);
 966         while (start < end) {
 967                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
 968                 BUG_ON(!async_cow);
 969                 async_cow->inode = inode;
 970                 async_cow->root = root;
 971                 async_cow->locked_page = locked_page;
 972                 async_cow->start = start;
 973
 974                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 975                         cur_end = end;
 976                 else
 977                         cur_end = min(end, start + 512 * 1024 - 1);
 978
 979                 async_cow->end = cur_end;
 980                 INIT_LIST_HEAD(&async_cow->extents);
 981
 982                 async_cow->work.func = async_cow_start;
 983                 async_cow->work.ordered_func = async_cow_submit;
 984                 async_cow->work.ordered_free = async_cow_free;
 985                 async_cow->work.flags = 0;
 986
 987                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
 988                         PAGE_CACHE_SHIFT;
 989                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
 990
 991                 btrfs_queue_worker(&root->fs_info->delalloc_workers,
 992                                    &async_cow->work);
 993
 994                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
 995                         wait_event(root->fs_info->async_submit_wait,
 996                            (atomic_read(&root->fs_info->async_delalloc_pages) <
 997                             limit));
 998                 }
 999
1000                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1001                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1002                         wait_event(root->fs_info->async_submit_wait,
1003                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1004                            0));
1005                 }
1006
1007                 *nr_written += nr_pages;
1008                 start = cur_end + 1;
1009         }
1010         *page_started = 1;
1011         return 0;
1012 }
1013
1014 static noinline int csum_exist_in_range(struct btrfs_root *root,
1015                                         u64 bytenr, u64 num_bytes)
1016 {
1017         int ret;
1018         struct btrfs_ordered_sum *sums;
1019         LIST_HEAD(list);
1020
1021         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1022                                        bytenr + num_bytes - 1, &list, 0);
1023         if (ret == 0 && list_empty(&list))
1024                 return 0;
1025
1026         while (!list_empty(&list)) {
1027                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1028                 list_del(&sums->list);
1029                 kfree(sums);
1030         }
1031         return 1;
1032 }
1033
1034 /*
1035  * when nowcow writeback call back.  This checks for snapshots or COW copies
1036  * of the extents that exist in the file, and COWs the file as required.
1037  *
1038  * If no cow copies or snapshots exist, we write directly to the existing
1039  * blocks on disk
1040  */
1041 static noinline int run_delalloc_nocow(struct inode *inode,
1042                                        struct page *locked_page,
1043                               u64 start, u64 end, int *page_started, int force,
1044                               unsigned long *nr_written)
1045 {
1046         struct btrfs_root *root = BTRFS_I(inode)->root;
1047         struct btrfs_trans_handle *trans;
1048         struct extent_buffer *leaf;
1049         struct btrfs_path *path;
1050         struct btrfs_file_extent_item *fi;
1051         struct btrfs_key found_key;
1052         u64 cow_start;
1053         u64 cur_offset;
1054         u64 extent_end;
1055         u64 extent_offset;
1056         u64 disk_bytenr;
1057         u64 num_bytes;
1058         int extent_type;
1059         int ret;
1060         int type;
1061         int nocow;
1062         int check_prev = 1;
1063         bool nolock;
1064         u64 ino = btrfs_ino(inode);
1065
1066         path = btrfs_alloc_path();
1067         BUG_ON(!path);
1068
1069         nolock = is_free_space_inode(root, inode);
1070
1071         if (nolock)
1072                 trans = btrfs_join_transaction_nolock(root, 1);
1073         else
1074                 trans = btrfs_join_transaction(root, 1);
1075         BUG_ON(IS_ERR(trans));
1076
1077         cow_start = (u64)-1;
1078         cur_offset = start;
1079         while (1) {
1080                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1081                                                cur_offset, 0);
1082                 BUG_ON(ret < 0);
1083                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1084                         leaf = path->nodes[0];
1085                         btrfs_item_key_to_cpu(leaf, &found_key,
1086                                               path->slots[0] - 1);
1087                         if (found_key.objectid == ino &&
1088                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1089                                 path->slots[0]--;
1090                 }
1091                 check_prev = 0;
1092 next_slot:
1093                 leaf = path->nodes[0];
1094                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1095                         ret = btrfs_next_leaf(root, path);
1096                         if (ret < 0)
1097                                 BUG_ON(1);
1098                         if (ret > 0)
1099                                 break;
1100                         leaf = path->nodes[0];
1101                 }
1102
1103                 nocow = 0;
1104                 disk_bytenr = 0;
1105                 num_bytes = 0;
1106                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1107
1108                 if (found_key.objectid > ino ||
1109                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1110                     found_key.offset > end)
1111                         break;
1112
1113                 if (found_key.offset > cur_offset) {
1114                         extent_end = found_key.offset;
1115                         extent_type = 0;
1116                         goto out_check;
1117                 }
1118
1119                 fi = btrfs_item_ptr(leaf, path->slots[0],
1120                                     struct btrfs_file_extent_item);
1121                 extent_type = btrfs_file_extent_type(leaf, fi);
1122
1123                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1124                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1125                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1126                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1127                         extent_end = found_key.offset +
1128                                 btrfs_file_extent_num_bytes(leaf, fi);
1129                         if (extent_end <= start) {
1130                                 path->slots[0]++;
1131                                 goto next_slot;
1132                         }
1133                         if (disk_bytenr == 0)
1134                                 goto out_check;
1135                         if (btrfs_file_extent_compression(leaf, fi) ||
1136                             btrfs_file_extent_encryption(leaf, fi) ||
1137                             btrfs_file_extent_other_encoding(leaf, fi))
1138                                 goto out_check;
1139                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1140                                 goto out_check;
1141                         if (btrfs_extent_readonly(root, disk_bytenr))
1142                                 goto out_check;
1143                         if (btrfs_cross_ref_exist(trans, root, ino,
1144                                                   found_key.offset -
1145                                                   extent_offset, disk_bytenr))
1146                                 goto out_check;
1147                         disk_bytenr += extent_offset;
1148                         disk_bytenr += cur_offset - found_key.offset;
1149                         num_bytes = min(end + 1, extent_end) - cur_offset;
1150                         /*
1151                          * force cow if csum exists in the range.
1152                          * this ensure that csum for a given extent are
1153                          * either valid or do not exist.
1154                          */
1155                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1156                                 goto out_check;
1157                         nocow = 1;
1158                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1159                         extent_end = found_key.offset +
1160                                 btrfs_file_extent_inline_len(leaf, fi);
1161                         extent_end = ALIGN(extent_end, root->sectorsize);
1162                 } else {
1163                         BUG_ON(1);
1164                 }
1165 out_check:
1166                 if (extent_end <= start) {
1167                         path->slots[0]++;
1168                         goto next_slot;
1169                 }
1170                 if (!nocow) {
1171                         if (cow_start == (u64)-1)
1172                                 cow_start = cur_offset;
1173                         cur_offset = extent_end;
1174                         if (cur_offset > end)
1175                                 break;
1176                         path->slots[0]++;
1177                         goto next_slot;
1178                 }
1179
1180                 btrfs_release_path(path);
1181                 if (cow_start != (u64)-1) {
1182                         ret = cow_file_range(inode, locked_page, cow_start,
1183                                         found_key.offset - 1, page_started,
1184                                         nr_written, 1);
1185                         BUG_ON(ret);
1186                         cow_start = (u64)-1;
1187                 }
1188
1189                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1190                         struct extent_map *em;
1191                         struct extent_map_tree *em_tree;
1192                         em_tree = &BTRFS_I(inode)->extent_tree;
1193                         em = alloc_extent_map();
1194                         BUG_ON(!em);
1195                         em->start = cur_offset;
1196                         em->orig_start = em->start;
1197                         em->len = num_bytes;
1198                         em->block_len = num_bytes;
1199                         em->block_start = disk_bytenr;
1200                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1201                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1202                         while (1) {
1203                                 write_lock(&em_tree->lock);
1204                                 ret = add_extent_mapping(em_tree, em);
1205                                 write_unlock(&em_tree->lock);
1206                                 if (ret != -EEXIST) {
1207                                         free_extent_map(em);
1208                                         break;
1209                                 }
1210                                 btrfs_drop_extent_cache(inode, em->start,
1211                                                 em->start + em->len - 1, 0);
1212                         }
1213                         type = BTRFS_ORDERED_PREALLOC;
1214                 } else {
1215                         type = BTRFS_ORDERED_NOCOW;
1216                 }
1217
1218                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1219                                                num_bytes, num_bytes, type);
1220                 BUG_ON(ret);
1221
1222                 if (root->root_key.objectid ==
1223                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1224                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1225                                                       num_bytes);
1226                         BUG_ON(ret);
1227                 }
1228
1229                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
1230                                 cur_offset, cur_offset + num_bytes - 1,
1231                                 locked_page, EXTENT_CLEAR_UNLOCK_PAGE |
1232                                 EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
1233                                 EXTENT_SET_PRIVATE2);
1234                 cur_offset = extent_end;
1235                 if (cur_offset > end)
1236                         break;
1237         }
1238         btrfs_release_path(path);
1239
1240         if (cur_offset <= end && cow_start == (u64)-1)
1241                 cow_start = cur_offset;
1242         if (cow_start != (u64)-1) {
1243                 ret = cow_file_range(inode, locked_page, cow_start, end,
1244                                      page_started, nr_written, 1);
1245                 BUG_ON(ret);
1246         }
1247
1248         if (nolock) {
1249                 ret = btrfs_end_transaction_nolock(trans, root);
1250                 BUG_ON(ret);
1251         } else {
1252                 ret = btrfs_end_transaction(trans, root);
1253                 BUG_ON(ret);
1254         }
1255         btrfs_free_path(path);
1256         return 0;
1257 }
1258
1259 /*
1260  * extent_io.c call back to do delayed allocation processing
1261  */
1262 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1263                               u64 start, u64 end, int *page_started,
1264                               unsigned long *nr_written)
1265 {
1266         int ret;
1267         struct btrfs_root *root = BTRFS_I(inode)->root;
1268
1269         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW)
1270                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1271                                          page_started, 1, nr_written);
1272         else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC)
1273                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1274                                          page_started, 0, nr_written);
1275         else if (!btrfs_test_opt(root, COMPRESS) &&
1276                  !(BTRFS_I(inode)->force_compress) &&
1277                  !(BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))
1278                 ret = cow_file_range(inode, locked_page, start, end,
1279                                       page_started, nr_written, 1);
1280         else
1281                 ret = cow_file_range_async(inode, locked_page, start, end,
1282                                            page_started, nr_written);
1283         return ret;
1284 }
1285
1286 static int btrfs_split_extent_hook(struct inode *inode,
1287                                    struct extent_state *orig, u64 split)
1288 {
1289         /* not delalloc, ignore it */
1290         if (!(orig->state & EXTENT_DELALLOC))
1291                 return 0;
1292
1293         atomic_inc(&BTRFS_I(inode)->outstanding_extents);
1294         return 0;
1295 }
1296
1297 /*
1298  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1299  * extents so we can keep track of new extents that are just merged onto old
1300  * extents, such as when we are doing sequential writes, so we can properly
1301  * account for the metadata space we'll need.
1302  */
1303 static int btrfs_merge_extent_hook(struct inode *inode,
1304                                    struct extent_state *new,
1305                                    struct extent_state *other)
1306 {
1307         /* not delalloc, ignore it */
1308         if (!(other->state & EXTENT_DELALLOC))
1309                 return 0;
1310
1311         atomic_dec(&BTRFS_I(inode)->outstanding_extents);
1312         return 0;
1313 }
1314
1315 /*
1316  * extent_io.c set_bit_hook, used to track delayed allocation
1317  * bytes in this file, and to maintain the list of inodes that
1318  * have pending delalloc work to be done.
1319  */
1320 static int btrfs_set_bit_hook(struct inode *inode,
1321                               struct extent_state *state, int *bits)
1322 {
1323
1324         /*
1325          * set_bit and clear bit hooks normally require _irqsave/restore
1326          * but in this case, we are only testing for the DELALLOC
1327          * bit, which is only set or cleared with irqs on
1328          */
1329         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1330                 struct btrfs_root *root = BTRFS_I(inode)->root;
1331                 u64 len = state->end + 1 - state->start;
1332                 bool do_list = !is_free_space_inode(root, inode);
1333
1334                 if (*bits & EXTENT_FIRST_DELALLOC)
1335                         *bits &= ~EXTENT_FIRST_DELALLOC;
1336                 else
1337                         atomic_inc(&BTRFS_I(inode)->outstanding_extents);
1338
1339                 spin_lock(&root->fs_info->delalloc_lock);
1340                 BTRFS_I(inode)->delalloc_bytes += len;
1341                 root->fs_info->delalloc_bytes += len;
1342                 if (do_list && list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1343                         list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1344                                       &root->fs_info->delalloc_inodes);
1345                 }
1346                 spin_unlock(&root->fs_info->delalloc_lock);
1347         }
1348         return 0;
1349 }
1350
1351 /*
1352  * extent_io.c clear_bit_hook, see set_bit_hook for why
1353  */
1354 static int btrfs_clear_bit_hook(struct inode *inode,
1355                                 struct extent_state *state, int *bits)
1356 {
1357         /*
1358          * set_bit and clear bit hooks normally require _irqsave/restore
1359          * but in this case, we are only testing for the DELALLOC
1360          * bit, which is only set or cleared with irqs on
1361          */
1362         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1363                 struct btrfs_root *root = BTRFS_I(inode)->root;
1364                 u64 len = state->end + 1 - state->start;
1365                 bool do_list = !is_free_space_inode(root, inode);
1366
1367                 if (*bits & EXTENT_FIRST_DELALLOC)
1368                         *bits &= ~EXTENT_FIRST_DELALLOC;
1369                 else if (!(*bits & EXTENT_DO_ACCOUNTING))
1370                         atomic_dec(&BTRFS_I(inode)->outstanding_extents);
1371
1372                 if (*bits & EXTENT_DO_ACCOUNTING)
1373                         btrfs_delalloc_release_metadata(inode, len);
1374
1375                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1376                     && do_list)
1377                         btrfs_free_reserved_data_space(inode, len);
1378
1379                 spin_lock(&root->fs_info->delalloc_lock);
1380                 root->fs_info->delalloc_bytes -= len;
1381                 BTRFS_I(inode)->delalloc_bytes -= len;
1382
1383                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1384                     !list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1385                         list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1386                 }
1387                 spin_unlock(&root->fs_info->delalloc_lock);
1388         }
1389         return 0;
1390 }
1391
1392 /*
1393  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1394  * we don't create bios that span stripes or chunks
1395  */
1396 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1397                          size_t size, struct bio *bio,
1398                          unsigned long bio_flags)
1399 {
1400         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1401         struct btrfs_mapping_tree *map_tree;
1402         u64 logical = (u64)bio->bi_sector << 9;
1403         u64 length = 0;
1404         u64 map_length;
1405         int ret;
1406
1407         if (bio_flags & EXTENT_BIO_COMPRESSED)
1408                 return 0;
1409
1410         length = bio->bi_size;
1411         map_tree = &root->fs_info->mapping_tree;
1412         map_length = length;
1413         ret = btrfs_map_block(map_tree, READ, logical,
1414                               &map_length, NULL, 0);
1415
1416         if (map_length < length + size)
1417                 return 1;
1418         return ret;
1419 }
1420
1421 /*
1422  * in order to insert checksums into the metadata in large chunks,
1423  * we wait until bio submission time.   All the pages in the bio are
1424  * checksummed and sums are attached onto the ordered extent record.
1425  *
1426  * At IO completion time the cums attached on the ordered extent record
1427  * are inserted into the btree
1428  */
1429 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1430                                     struct bio *bio, int mirror_num,
1431                                     unsigned long bio_flags,
1432                                     u64 bio_offset)
1433 {
1434         struct btrfs_root *root = BTRFS_I(inode)->root;
1435         int ret = 0;
1436
1437         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1438         BUG_ON(ret);
1439         return 0;
1440 }
1441
1442 /*
1443  * in order to insert checksums into the metadata in large chunks,
1444  * we wait until bio submission time.   All the pages in the bio are
1445  * checksummed and sums are attached onto the ordered extent record.
1446  *
1447  * At IO completion time the cums attached on the ordered extent record
1448  * are inserted into the btree
1449  */
1450 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1451                           int mirror_num, unsigned long bio_flags,
1452                           u64 bio_offset)
1453 {
1454         struct btrfs_root *root = BTRFS_I(inode)->root;
1455         return btrfs_map_bio(root, rw, bio, mirror_num, 1);
1456 }
1457
1458 /*
1459  * extent_io.c submission hook. This does the right thing for csum calculation
1460  * on write, or reading the csums from the tree before a read
1461  */
1462 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1463                           int mirror_num, unsigned long bio_flags,
1464                           u64 bio_offset)
1465 {
1466         struct btrfs_root *root = BTRFS_I(inode)->root;
1467         int ret = 0;
1468         int skip_sum;
1469
1470         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1471
1472         if (is_free_space_inode(root, inode))
1473                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 2);
1474         else
1475                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
1476         BUG_ON(ret);
1477
1478         if (!(rw & REQ_WRITE)) {
1479                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1480                         return btrfs_submit_compressed_read(inode, bio,
1481                                                     mirror_num, bio_flags);
1482                 } else if (!skip_sum) {
1483                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1484                         if (ret)
1485                                 return ret;
1486                 }
1487                 goto mapit;
1488         } else if (!skip_sum) {
1489                 /* csum items have already been cloned */
1490                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1491                         goto mapit;
1492                 /* we're doing a write, do the async checksumming */
1493                 return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1494                                    inode, rw, bio, mirror_num,
1495                                    bio_flags, bio_offset,
1496                                    __btrfs_submit_bio_start,
1497                                    __btrfs_submit_bio_done);
1498         }
1499
1500 mapit:
1501         return btrfs_map_bio(root, rw, bio, mirror_num, 0);
1502 }
1503
1504 /*
1505  * given a list of ordered sums record them in the inode.  This happens
1506  * at IO completion time based on sums calculated at bio submission time.
1507  */
1508 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1509                              struct inode *inode, u64 file_offset,
1510                              struct list_head *list)
1511 {
1512         struct btrfs_ordered_sum *sum;
1513
1514         btrfs_set_trans_block_group(trans, inode);
1515
1516         list_for_each_entry(sum, list, list) {
1517                 btrfs_csum_file_blocks(trans,
1518                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1519         }
1520         return 0;
1521 }
1522
1523 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1524                               struct extent_state **cached_state)
1525 {
1526         if ((end & (PAGE_CACHE_SIZE - 1)) == 0)
1527                 WARN_ON(1);
1528         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1529                                    cached_state, GFP_NOFS);
1530 }
1531
1532 /* see btrfs_writepage_start_hook for details on why this is required */
1533 struct btrfs_writepage_fixup {
1534         struct page *page;
1535         struct btrfs_work work;
1536 };
1537
1538 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1539 {
1540         struct btrfs_writepage_fixup *fixup;
1541         struct btrfs_ordered_extent *ordered;
1542         struct extent_state *cached_state = NULL;
1543         struct page *page;
1544         struct inode *inode;
1545         u64 page_start;
1546         u64 page_end;
1547
1548         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1549         page = fixup->page;
1550 again:
1551         lock_page(page);
1552         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1553                 ClearPageChecked(page);
1554                 goto out_page;
1555         }
1556
1557         inode = page->mapping->host;
1558         page_start = page_offset(page);
1559         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1560
1561         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1562                          &cached_state, GFP_NOFS);
1563
1564         /* already ordered? We're done */
1565         if (PagePrivate2(page))
1566                 goto out;
1567
1568         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1569         if (ordered) {
1570                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1571                                      page_end, &cached_state, GFP_NOFS);
1572                 unlock_page(page);
1573                 btrfs_start_ordered_extent(inode, ordered, 1);
1574                 goto again;
1575         }
1576
1577         BUG();
1578         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1579         ClearPageChecked(page);
1580 out:
1581         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1582                              &cached_state, GFP_NOFS);
1583 out_page:
1584         unlock_page(page);
1585         page_cache_release(page);
1586         kfree(fixup);
1587 }
1588
1589 /*
1590  * There are a few paths in the higher layers of the kernel that directly
1591  * set the page dirty bit without asking the filesystem if it is a
1592  * good idea.  This causes problems because we want to make sure COW
1593  * properly happens and the data=ordered rules are followed.
1594  *
1595  * In our case any range that doesn't have the ORDERED bit set
1596  * hasn't been properly setup for IO.  We kick off an async process
1597  * to fix it up.  The async helper will wait for ordered extents, set
1598  * the delalloc bit and make it safe to write the page.
1599  */
1600 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1601 {
1602         struct inode *inode = page->mapping->host;
1603         struct btrfs_writepage_fixup *fixup;
1604         struct btrfs_root *root = BTRFS_I(inode)->root;
1605
1606         /* this page is properly in the ordered list */
1607         if (TestClearPagePrivate2(page))
1608                 return 0;
1609
1610         if (PageChecked(page))
1611                 return -EAGAIN;
1612
1613         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1614         if (!fixup)
1615                 return -EAGAIN;
1616
1617         SetPageChecked(page);
1618         page_cache_get(page);
1619         fixup->work.func = btrfs_writepage_fixup_worker;
1620         fixup->page = page;
1621         btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
1622         return -EAGAIN;
1623 }
1624
1625 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1626                                        struct inode *inode, u64 file_pos,
1627                                        u64 disk_bytenr, u64 disk_num_bytes,
1628                                        u64 num_bytes, u64 ram_bytes,
1629                                        u8 compression, u8 encryption,
1630                                        u16 other_encoding, int extent_type)
1631 {
1632         struct btrfs_root *root = BTRFS_I(inode)->root;
1633         struct btrfs_file_extent_item *fi;
1634         struct btrfs_path *path;
1635         struct extent_buffer *leaf;
1636         struct btrfs_key ins;
1637         u64 hint;
1638         int ret;
1639
1640         path = btrfs_alloc_path();
1641         BUG_ON(!path);
1642
1643         path->leave_spinning = 1;
1644
1645         /*
1646          * we may be replacing one extent in the tree with another.
1647          * The new extent is pinned in the extent map, and we don't want
1648          * to drop it from the cache until it is completely in the btree.
1649          *
1650          * So, tell btrfs_drop_extents to leave this extent in the cache.
1651          * the caller is expected to unpin it and allow it to be merged
1652          * with the others.
1653          */
1654         ret = btrfs_drop_extents(trans, inode, file_pos, file_pos + num_bytes,
1655                                  &hint, 0);
1656         BUG_ON(ret);
1657
1658         ins.objectid = btrfs_ino(inode);
1659         ins.offset = file_pos;
1660         ins.type = BTRFS_EXTENT_DATA_KEY;
1661         ret = btrfs_insert_empty_item(trans, root, path, &ins, sizeof(*fi));
1662         BUG_ON(ret);
1663         leaf = path->nodes[0];
1664         fi = btrfs_item_ptr(leaf, path->slots[0],
1665                             struct btrfs_file_extent_item);
1666         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1667         btrfs_set_file_extent_type(leaf, fi, extent_type);
1668         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1669         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1670         btrfs_set_file_extent_offset(leaf, fi, 0);
1671         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1672         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1673         btrfs_set_file_extent_compression(leaf, fi, compression);
1674         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1675         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1676
1677         btrfs_unlock_up_safe(path, 1);
1678         btrfs_set_lock_blocking(leaf);
1679
1680         btrfs_mark_buffer_dirty(leaf);
1681
1682         inode_add_bytes(inode, num_bytes);
1683
1684         ins.objectid = disk_bytenr;
1685         ins.offset = disk_num_bytes;
1686         ins.type = BTRFS_EXTENT_ITEM_KEY;
1687         ret = btrfs_alloc_reserved_file_extent(trans, root,
1688                                         root->root_key.objectid,
1689                                         btrfs_ino(inode), file_pos, &ins);
1690         BUG_ON(ret);
1691         btrfs_free_path(path);
1692
1693         return 0;
1694 }
1695
1696 /*
1697  * helper function for btrfs_finish_ordered_io, this
1698  * just reads in some of the csum leaves to prime them into ram
1699  * before we start the transaction.  It limits the amount of btree
1700  * reads required while inside the transaction.
1701  */
1702 /* as ordered data IO finishes, this gets called so we can finish
1703  * an ordered extent if the range of bytes in the file it covers are
1704  * fully written.
1705  */
1706 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
1707 {
1708         struct btrfs_root *root = BTRFS_I(inode)->root;
1709         struct btrfs_trans_handle *trans = NULL;
1710         struct btrfs_ordered_extent *ordered_extent = NULL;
1711         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1712         struct extent_state *cached_state = NULL;
1713         int compress_type = 0;
1714         int ret;
1715         bool nolock;
1716
1717         ret = btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
1718                                              end - start + 1);
1719         if (!ret)
1720                 return 0;
1721         BUG_ON(!ordered_extent);
1722
1723         nolock = is_free_space_inode(root, inode);
1724
1725         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
1726                 BUG_ON(!list_empty(&ordered_extent->list));
1727                 ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1728                 if (!ret) {
1729                         if (nolock)
1730                                 trans = btrfs_join_transaction_nolock(root, 1);
1731                         else
1732                                 trans = btrfs_join_transaction(root, 1);
1733                         BUG_ON(IS_ERR(trans));
1734                         btrfs_set_trans_block_group(trans, inode);
1735                         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1736                         ret = btrfs_update_inode(trans, root, inode);
1737                         BUG_ON(ret);
1738                 }
1739                 goto out;
1740         }
1741
1742         lock_extent_bits(io_tree, ordered_extent->file_offset,
1743                          ordered_extent->file_offset + ordered_extent->len - 1,
1744                          0, &cached_state, GFP_NOFS);
1745
1746         if (nolock)
1747                 trans = btrfs_join_transaction_nolock(root, 1);
1748         else
1749                 trans = btrfs_join_transaction(root, 1);
1750         BUG_ON(IS_ERR(trans));
1751         btrfs_set_trans_block_group(trans, inode);
1752         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1753
1754         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
1755                 compress_type = ordered_extent->compress_type;
1756         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
1757                 BUG_ON(compress_type);
1758                 ret = btrfs_mark_extent_written(trans, inode,
1759                                                 ordered_extent->file_offset,
1760                                                 ordered_extent->file_offset +
1761                                                 ordered_extent->len);
1762                 BUG_ON(ret);
1763         } else {
1764                 BUG_ON(root == root->fs_info->tree_root);
1765                 ret = insert_reserved_file_extent(trans, inode,
1766                                                 ordered_extent->file_offset,
1767                                                 ordered_extent->start,
1768                                                 ordered_extent->disk_len,
1769                                                 ordered_extent->len,
1770                                                 ordered_extent->len,
1771                                                 compress_type, 0, 0,
1772                                                 BTRFS_FILE_EXTENT_REG);
1773                 unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
1774                                    ordered_extent->file_offset,
1775                                    ordered_extent->len);
1776                 BUG_ON(ret);
1777         }
1778         unlock_extent_cached(io_tree, ordered_extent->file_offset,
1779                              ordered_extent->file_offset +
1780                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
1781
1782         add_pending_csums(trans, inode, ordered_extent->file_offset,
1783                           &ordered_extent->list);
1784
1785         ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1786         if (!ret) {
1787                 ret = btrfs_update_inode(trans, root, inode);
1788                 BUG_ON(ret);
1789         }
1790         ret = 0;
1791 out:
1792         if (nolock) {
1793                 if (trans)
1794                         btrfs_end_transaction_nolock(trans, root);
1795         } else {
1796                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
1797                 if (trans)
1798                         btrfs_end_transaction(trans, root);
1799         }
1800
1801         /* once for us */
1802         btrfs_put_ordered_extent(ordered_extent);
1803         /* once for the tree */
1804         btrfs_put_ordered_extent(ordered_extent);
1805
1806         return 0;
1807 }
1808
1809 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
1810                                 struct extent_state *state, int uptodate)
1811 {
1812         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
1813
1814         ClearPagePrivate2(page);
1815         return btrfs_finish_ordered_io(page->mapping->host, start, end);
1816 }
1817
1818 /*
1819  * When IO fails, either with EIO or csum verification fails, we
1820  * try other mirrors that might have a good copy of the data.  This
1821  * io_failure_record is used to record state as we go through all the
1822  * mirrors.  If another mirror has good data, the page is set up to date
1823  * and things continue.  If a good mirror can't be found, the original
1824  * bio end_io callback is called to indicate things have failed.
1825  */
1826 struct io_failure_record {
1827         struct page *page;
1828         u64 start;
1829         u64 len;
1830         u64 logical;
1831         unsigned long bio_flags;
1832         int last_mirror;
1833 };
1834
1835 static int btrfs_io_failed_hook(struct bio *failed_bio,
1836                          struct page *page, u64 start, u64 end,
1837                          struct extent_state *state)
1838 {
1839         struct io_failure_record *failrec = NULL;
1840         u64 private;
1841         struct extent_map *em;
1842         struct inode *inode = page->mapping->host;
1843         struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
1844         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1845         struct bio *bio;
1846         int num_copies;
1847         int ret;
1848         int rw;
1849         u64 logical;
1850
1851         ret = get_state_private(failure_tree, start, &private);
1852         if (ret) {
1853                 failrec = kmalloc(sizeof(*failrec), GFP_NOFS);
1854                 if (!failrec)
1855                         return -ENOMEM;
1856                 failrec->start = start;
1857                 failrec->len = end - start + 1;
1858                 failrec->last_mirror = 0;
1859                 failrec->bio_flags = 0;
1860
1861                 read_lock(&em_tree->lock);
1862                 em = lookup_extent_mapping(em_tree, start, failrec->len);
1863                 if (em->start > start || em->start + em->len < start) {
1864                         free_extent_map(em);
1865                         em = NULL;
1866                 }
1867                 read_unlock(&em_tree->lock);
1868
1869                 if (IS_ERR_OR_NULL(em)) {
1870                         kfree(failrec);
1871                         return -EIO;
1872                 }
1873                 logical = start - em->start;
1874                 logical = em->block_start + logical;
1875                 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
1876                         logical = em->block_start;
1877                         failrec->bio_flags = EXTENT_BIO_COMPRESSED;
1878                         extent_set_compress_type(&failrec->bio_flags,
1879                                                  em->compress_type);
1880                 }
1881                 failrec->logical = logical;
1882                 free_extent_map(em);
1883                 set_extent_bits(failure_tree, start, end, EXTENT_LOCKED |
1884                                 EXTENT_DIRTY, GFP_NOFS);
1885                 set_state_private(failure_tree, start,
1886                                  (u64)(unsigned long)failrec);
1887         } else {
1888                 failrec = (struct io_failure_record *)(unsigned long)private;
1889         }
1890         num_copies = btrfs_num_copies(
1891                               &BTRFS_I(inode)->root->fs_info->mapping_tree,
1892                               failrec->logical, failrec->len);
1893         failrec->last_mirror++;
1894         if (!state) {
1895                 spin_lock(&BTRFS_I(inode)->io_tree.lock);
1896                 state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
1897                                                     failrec->start,
1898                                                     EXTENT_LOCKED);
1899                 if (state && state->start != failrec->start)
1900                         state = NULL;
1901                 spin_unlock(&BTRFS_I(inode)->io_tree.lock);
1902         }
1903         if (!state || failrec->last_mirror > num_copies) {
1904                 set_state_private(failure_tree, failrec->start, 0);
1905                 clear_extent_bits(failure_tree, failrec->start,
1906                                   failrec->start + failrec->len - 1,
1907                                   EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
1908                 kfree(failrec);
1909                 return -EIO;
1910         }
1911         bio = bio_alloc(GFP_NOFS, 1);
1912         bio->bi_private = state;
1913         bio->bi_end_io = failed_bio->bi_end_io;
1914         bio->bi_sector = failrec->logical >> 9;
1915         bio->bi_bdev = failed_bio->bi_bdev;
1916         bio->bi_size = 0;
1917
1918         bio_add_page(bio, page, failrec->len, start - page_offset(page));
1919         if (failed_bio->bi_rw & REQ_WRITE)
1920                 rw = WRITE;
1921         else
1922                 rw = READ;
1923
1924         ret = BTRFS_I(inode)->io_tree.ops->submit_bio_hook(inode, rw, bio,
1925                                                       failrec->last_mirror,
1926                                                       failrec->bio_flags, 0);
1927         return ret;
1928 }
1929
1930 /*
1931  * each time an IO finishes, we do a fast check in the IO failure tree
1932  * to see if we need to process or clean up an io_failure_record
1933  */
1934 static int btrfs_clean_io_failures(struct inode *inode, u64 start)
1935 {
1936         u64 private;
1937         u64 private_failure;
1938         struct io_failure_record *failure;
1939         int ret;
1940
1941         private = 0;
1942         if (count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
1943                              (u64)-1, 1, EXTENT_DIRTY, 0)) {
1944                 ret = get_state_private(&BTRFS_I(inode)->io_failure_tree,
1945                                         start, &private_failure);
1946                 if (ret == 0) {
1947                         failure = (struct io_failure_record *)(unsigned long)
1948                                    private_failure;
1949                         set_state_private(&BTRFS_I(inode)->io_failure_tree,
1950                                           failure->start, 0);
1951                         clear_extent_bits(&BTRFS_I(inode)->io_failure_tree,
1952                                           failure->start,
1953                                           failure->start + failure->len - 1,
1954                                           EXTENT_DIRTY | EXTENT_LOCKED,
1955                                           GFP_NOFS);
1956                         kfree(failure);
1957                 }
1958         }
1959         return 0;
1960 }
1961
1962 /*
1963  * when reads are done, we need to check csums to verify the data is correct
1964  * if there's a match, we allow the bio to finish.  If not, we go through
1965  * the io_failure_record routines to find good copies
1966  */
1967 static int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
1968                                struct extent_state *state)
1969 {
1970         size_t offset = start - ((u64)page->index << PAGE_CACHE_SHIFT);
1971         struct inode *inode = page->mapping->host;
1972         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1973         char *kaddr;
1974         u64 private = ~(u32)0;
1975         int ret;
1976         struct btrfs_root *root = BTRFS_I(inode)->root;
1977         u32 csum = ~(u32)0;
1978
1979         if (PageChecked(page)) {
1980                 ClearPageChecked(page);
1981                 goto good;
1982         }
1983
1984         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
1985                 return 0;
1986
1987         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
1988             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
1989                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
1990                                   GFP_NOFS);
1991                 return 0;
1992         }
1993
1994         if (state && state->start == start) {
1995                 private = state->private;
1996                 ret = 0;
1997         } else {
1998                 ret = get_state_private(io_tree, start, &private);
1999         }
2000         kaddr = kmap_atomic(page, KM_USER0);
2001         if (ret)
2002                 goto zeroit;
2003
2004         csum = btrfs_csum_data(root, kaddr + offset, csum,  end - start + 1);
2005         btrfs_csum_final(csum, (char *)&csum);
2006         if (csum != private)
2007                 goto zeroit;
2008
2009         kunmap_atomic(kaddr, KM_USER0);
2010 good:
2011         /* if the io failure tree for this inode is non-empty,
2012          * check to see if we've recovered from a failed IO
2013          */
2014         btrfs_clean_io_failures(inode, start);
2015         return 0;
2016
2017 zeroit:
2018         printk_ratelimited(KERN_INFO "btrfs csum failed ino %llu off %llu csum %u "
2019                        "private %llu\n",
2020                        (unsigned long long)btrfs_ino(page->mapping->host),
2021                        (unsigned long long)start, csum,
2022                        (unsigned long long)private);
2023         memset(kaddr + offset, 1, end - start + 1);
2024         flush_dcache_page(page);
2025         kunmap_atomic(kaddr, KM_USER0);
2026         if (private == 0)
2027                 return 0;
2028         return -EIO;
2029 }
2030
2031 struct delayed_iput {
2032         struct list_head list;
2033         struct inode *inode;
2034 };
2035
2036 void btrfs_add_delayed_iput(struct inode *inode)
2037 {
2038         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2039         struct delayed_iput *delayed;
2040
2041         if (atomic_add_unless(&inode->i_count, -1, 1))
2042                 return;
2043
2044         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
2045         delayed->inode = inode;
2046
2047         spin_lock(&fs_info->delayed_iput_lock);
2048         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
2049         spin_unlock(&fs_info->delayed_iput_lock);
2050 }
2051
2052 void btrfs_run_delayed_iputs(struct btrfs_root *root)
2053 {
2054         LIST_HEAD(list);
2055         struct btrfs_fs_info *fs_info = root->fs_info;
2056         struct delayed_iput *delayed;
2057         int empty;
2058
2059         spin_lock(&fs_info->delayed_iput_lock);
2060         empty = list_empty(&fs_info->delayed_iputs);
2061         spin_unlock(&fs_info->delayed_iput_lock);
2062         if (empty)
2063                 return;
2064
2065         down_read(&root->fs_info->cleanup_work_sem);
2066         spin_lock(&fs_info->delayed_iput_lock);
2067         list_splice_init(&fs_info->delayed_iputs, &list);
2068         spin_unlock(&fs_info->delayed_iput_lock);
2069
2070         while (!list_empty(&list)) {
2071                 delayed = list_entry(list.next, struct delayed_iput, list);
2072                 list_del(&delayed->list);
2073                 iput(delayed->inode);
2074                 kfree(delayed);
2075         }
2076         up_read(&root->fs_info->cleanup_work_sem);
2077 }
2078
2079 /*
2080  * calculate extra metadata reservation when snapshotting a subvolume
2081  * contains orphan files.
2082  */
2083 void btrfs_orphan_pre_snapshot(struct btrfs_trans_handle *trans,
2084                                 struct btrfs_pending_snapshot *pending,
2085                                 u64 *bytes_to_reserve)
2086 {
2087         struct btrfs_root *root;
2088         struct btrfs_block_rsv *block_rsv;
2089         u64 num_bytes;
2090         int index;
2091
2092         root = pending->root;
2093         if (!root->orphan_block_rsv || list_empty(&root->orphan_list))
2094                 return;
2095
2096         block_rsv = root->orphan_block_rsv;
2097
2098         /* orphan block reservation for the snapshot */
2099         num_bytes = block_rsv->size;
2100
2101         /*
2102          * after the snapshot is created, COWing tree blocks may use more
2103          * space than it frees. So we should make sure there is enough
2104          * reserved space.
2105          */
2106         index = trans->transid & 0x1;
2107         if (block_rsv->reserved + block_rsv->freed[index] < block_rsv->size) {
2108                 num_bytes += block_rsv->size -
2109                              (block_rsv->reserved + block_rsv->freed[index]);
2110         }
2111
2112         *bytes_to_reserve += num_bytes;
2113 }
2114
2115 void btrfs_orphan_post_snapshot(struct btrfs_trans_handle *trans,
2116                                 struct btrfs_pending_snapshot *pending)
2117 {
2118         struct btrfs_root *root = pending->root;
2119         struct btrfs_root *snap = pending->snap;
2120         struct btrfs_block_rsv *block_rsv;
2121         u64 num_bytes;
2122         int index;
2123         int ret;
2124
2125         if (!root->orphan_block_rsv || list_empty(&root->orphan_list))
2126                 return;
2127
2128         /* refill source subvolume's orphan block reservation */
2129         block_rsv = root->orphan_block_rsv;
2130         index = trans->transid & 0x1;
2131         if (block_rsv->reserved + block_rsv->freed[index] < block_rsv->size) {
2132                 num_bytes = block_rsv->size -
2133                             (block_rsv->reserved + block_rsv->freed[index]);
2134                 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
2135                                               root->orphan_block_rsv,
2136                                               num_bytes);
2137                 BUG_ON(ret);
2138         }
2139
2140         /* setup orphan block reservation for the snapshot */
2141         block_rsv = btrfs_alloc_block_rsv(snap);
2142         BUG_ON(!block_rsv);
2143
2144         btrfs_add_durable_block_rsv(root->fs_info, block_rsv);
2145         snap->orphan_block_rsv = block_rsv;
2146
2147         num_bytes = root->orphan_block_rsv->size;
2148         ret = btrfs_block_rsv_migrate(&pending->block_rsv,
2149                                       block_rsv, num_bytes);
2150         BUG_ON(ret);
2151
2152 #if 0
2153         /* insert orphan item for the snapshot */
2154         WARN_ON(!root->orphan_item_inserted);
2155         ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
2156                                        snap->root_key.objectid);
2157         BUG_ON(ret);
2158         snap->orphan_item_inserted = 1;
2159 #endif
2160 }
2161
2162 enum btrfs_orphan_cleanup_state {
2163         ORPHAN_CLEANUP_STARTED  = 1,
2164         ORPHAN_CLEANUP_DONE     = 2,
2165 };
2166
2167 /*
2168  * This is called in transaction commmit time. If there are no orphan
2169  * files in the subvolume, it removes orphan item and frees block_rsv
2170  * structure.
2171  */
2172 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
2173                               struct btrfs_root *root)
2174 {
2175         int ret;
2176
2177         if (!list_empty(&root->orphan_list) ||
2178             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
2179                 return;
2180
2181         if (root->orphan_item_inserted &&
2182             btrfs_root_refs(&root->root_item) > 0) {
2183                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
2184                                             root->root_key.objectid);
2185                 BUG_ON(ret);
2186                 root->orphan_item_inserted = 0;
2187         }
2188
2189         if (root->orphan_block_rsv) {
2190                 WARN_ON(root->orphan_block_rsv->size > 0);
2191                 btrfs_free_block_rsv(root, root->orphan_block_rsv);
2192                 root->orphan_block_rsv = NULL;
2193         }
2194 }
2195
2196 /*
2197  * This creates an orphan entry for the given inode in case something goes
2198  * wrong in the middle of an unlink/truncate.
2199  *
2200  * NOTE: caller of this function should reserve 5 units of metadata for
2201  *       this function.
2202  */
2203 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
2204 {
2205         struct btrfs_root *root = BTRFS_I(inode)->root;
2206         struct btrfs_block_rsv *block_rsv = NULL;
2207         int reserve = 0;
2208         int insert = 0;
2209         int ret;
2210
2211         if (!root->orphan_block_rsv) {
2212                 block_rsv = btrfs_alloc_block_rsv(root);
2213                 BUG_ON(!block_rsv);
2214         }
2215
2216         spin_lock(&root->orphan_lock);
2217         if (!root->orphan_block_rsv) {
2218                 root->orphan_block_rsv = block_rsv;
2219         } else if (block_rsv) {
2220                 btrfs_free_block_rsv(root, block_rsv);
2221                 block_rsv = NULL;
2222         }
2223
2224         if (list_empty(&BTRFS_I(inode)->i_orphan)) {
2225                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2226 #if 0
2227                 /*
2228                  * For proper ENOSPC handling, we should do orphan
2229                  * cleanup when mounting. But this introduces backward
2230                  * compatibility issue.
2231                  */
2232                 if (!xchg(&root->orphan_item_inserted, 1))
2233                         insert = 2;
2234                 else
2235                         insert = 1;
2236 #endif
2237                 insert = 1;
2238         }
2239
2240         if (!BTRFS_I(inode)->orphan_meta_reserved) {
2241                 BTRFS_I(inode)->orphan_meta_reserved = 1;
2242                 reserve = 1;
2243         }
2244         spin_unlock(&root->orphan_lock);
2245
2246         if (block_rsv)
2247                 btrfs_add_durable_block_rsv(root->fs_info, block_rsv);
2248
2249         /* grab metadata reservation from transaction handle */
2250         if (reserve) {
2251                 ret = btrfs_orphan_reserve_metadata(trans, inode);
2252                 BUG_ON(ret);
2253         }
2254
2255         /* insert an orphan item to track this unlinked/truncated file */
2256         if (insert >= 1) {
2257                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
2258                 BUG_ON(ret);
2259         }
2260
2261         /* insert an orphan item to track subvolume contains orphan files */
2262         if (insert >= 2) {
2263                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
2264                                                root->root_key.objectid);
2265                 BUG_ON(ret);
2266         }
2267         return 0;
2268 }
2269
2270 /*
2271  * We have done the truncate/delete so we can go ahead and remove the orphan
2272  * item for this particular inode.
2273  */
2274 int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode)
2275 {
2276         struct btrfs_root *root = BTRFS_I(inode)->root;
2277         int delete_item = 0;
2278         int release_rsv = 0;
2279         int ret = 0;
2280
2281         spin_lock(&root->orphan_lock);
2282         if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
2283                 list_del_init(&BTRFS_I(inode)->i_orphan);
2284                 delete_item = 1;
2285         }
2286
2287         if (BTRFS_I(inode)->orphan_meta_reserved) {
2288                 BTRFS_I(inode)->orphan_meta_reserved = 0;
2289                 release_rsv = 1;
2290         }
2291         spin_unlock(&root->orphan_lock);
2292
2293         if (trans && delete_item) {
2294                 ret = btrfs_del_orphan_item(trans, root, btrfs_ino(inode));
2295                 BUG_ON(ret);
2296         }
2297
2298         if (release_rsv)
2299                 btrfs_orphan_release_metadata(inode);
2300
2301         return 0;
2302 }
2303
2304 /*
2305  * this cleans up any orphans that may be left on the list from the last use
2306  * of this root.
2307  */
2308 int btrfs_orphan_cleanup(struct btrfs_root *root)
2309 {
2310         struct btrfs_path *path;
2311         struct extent_buffer *leaf;
2312         struct btrfs_key key, found_key;
2313         struct btrfs_trans_handle *trans;
2314         struct inode *inode;
2315         int ret = 0, nr_unlink = 0, nr_truncate = 0;
2316
2317         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
2318                 return 0;
2319
2320         path = btrfs_alloc_path();
2321         if (!path) {
2322                 ret = -ENOMEM;
2323                 goto out;
2324         }
2325         path->reada = -1;
2326
2327         key.objectid = BTRFS_ORPHAN_OBJECTID;
2328         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
2329         key.offset = (u64)-1;
2330
2331         while (1) {
2332                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2333                 if (ret < 0)
2334                         goto out;
2335
2336                 /*
2337                  * if ret == 0 means we found what we were searching for, which
2338                  * is weird, but possible, so only screw with path if we didn't
2339                  * find the key and see if we have stuff that matches
2340                  */
2341                 if (ret > 0) {
2342                         ret = 0;
2343                         if (path->slots[0] == 0)
2344                                 break;
2345                         path->slots[0]--;
2346                 }
2347
2348                 /* pull out the item */
2349                 leaf = path->nodes[0];
2350                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2351
2352                 /* make sure the item matches what we want */
2353                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
2354                         break;
2355                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
2356                         break;
2357
2358                 /* release the path since we're done with it */
2359                 btrfs_release_path(path);
2360
2361                 /*
2362                  * this is where we are basically btrfs_lookup, without the
2363                  * crossing root thing.  we store the inode number in the
2364                  * offset of the orphan item.
2365                  */
2366                 found_key.objectid = found_key.offset;
2367                 found_key.type = BTRFS_INODE_ITEM_KEY;
2368                 found_key.offset = 0;
2369                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
2370                 if (IS_ERR(inode)) {
2371                         ret = PTR_ERR(inode);
2372                         goto out;
2373                 }
2374
2375                 /*
2376                  * add this inode to the orphan list so btrfs_orphan_del does
2377                  * the proper thing when we hit it
2378                  */
2379                 spin_lock(&root->orphan_lock);
2380                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2381                 spin_unlock(&root->orphan_lock);
2382
2383                 /*
2384                  * if this is a bad inode, means we actually succeeded in
2385                  * removing the inode, but not the orphan record, which means
2386                  * we need to manually delete the orphan since iput will just
2387                  * do a destroy_inode
2388                  */
2389                 if (is_bad_inode(inode)) {
2390                         trans = btrfs_start_transaction(root, 0);
2391                         if (IS_ERR(trans)) {
2392                                 ret = PTR_ERR(trans);
2393                                 goto out;
2394                         }
2395                         btrfs_orphan_del(trans, inode);
2396                         btrfs_end_transaction(trans, root);
2397                         iput(inode);
2398                         continue;
2399                 }
2400
2401                 /* if we have links, this was a truncate, lets do that */
2402                 if (inode->i_nlink) {
2403                         if (!S_ISREG(inode->i_mode)) {
2404                                 WARN_ON(1);
2405                                 iput(inode);
2406                                 continue;
2407                         }
2408                         nr_truncate++;
2409                         ret = btrfs_truncate(inode);
2410                 } else {
2411                         nr_unlink++;
2412                 }
2413
2414                 /* this will do delete_inode and everything for us */
2415                 iput(inode);
2416                 if (ret)
2417                         goto out;
2418         }
2419         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
2420
2421         if (root->orphan_block_rsv)
2422                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
2423                                         (u64)-1);
2424
2425         if (root->orphan_block_rsv || root->orphan_item_inserted) {
2426                 trans = btrfs_join_transaction(root, 1);
2427                 if (!IS_ERR(trans))
2428                         btrfs_end_transaction(trans, root);
2429         }
2430
2431         if (nr_unlink)
2432                 printk(KERN_INFO "btrfs: unlinked %d orphans\n", nr_unlink);
2433         if (nr_truncate)
2434                 printk(KERN_INFO "btrfs: truncated %d orphans\n", nr_truncate);
2435
2436 out:
2437         if (ret)
2438                 printk(KERN_CRIT "btrfs: could not do orphan cleanup %d\n", ret);
2439         btrfs_free_path(path);
2440         return ret;
2441 }
2442
2443 /*
2444  * very simple check to peek ahead in the leaf looking for xattrs.  If we
2445  * don't find any xattrs, we know there can't be any acls.
2446  *
2447  * slot is the slot the inode is in, objectid is the objectid of the inode
2448  */
2449 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
2450                                           int slot, u64 objectid)
2451 {
2452         u32 nritems = btrfs_header_nritems(leaf);
2453         struct btrfs_key found_key;
2454         int scanned = 0;
2455
2456         slot++;
2457         while (slot < nritems) {
2458                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2459
2460                 /* we found a different objectid, there must not be acls */
2461                 if (found_key.objectid != objectid)
2462                         return 0;
2463
2464                 /* we found an xattr, assume we've got an acl */
2465                 if (found_key.type == BTRFS_XATTR_ITEM_KEY)
2466                         return 1;
2467
2468                 /*
2469                  * we found a key greater than an xattr key, there can't
2470                  * be any acls later on
2471                  */
2472                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
2473                         return 0;
2474
2475                 slot++;
2476                 scanned++;
2477
2478                 /*
2479                  * it goes inode, inode backrefs, xattrs, extents,
2480                  * so if there are a ton of hard links to an inode there can
2481                  * be a lot of backrefs.  Don't waste time searching too hard,
2482                  * this is just an optimization
2483                  */
2484                 if (scanned >= 8)
2485                         break;
2486         }
2487         /* we hit the end of the leaf before we found an xattr or
2488          * something larger than an xattr.  We have to assume the inode
2489          * has acls
2490          */
2491         return 1;
2492 }
2493
2494 /*
2495  * read an inode from the btree into the in-memory inode
2496  */
2497 static void btrfs_read_locked_inode(struct inode *inode)
2498 {
2499         struct btrfs_path *path;
2500         struct extent_buffer *leaf;
2501         struct btrfs_inode_item *inode_item;
2502         struct btrfs_timespec *tspec;
2503         struct btrfs_root *root = BTRFS_I(inode)->root;
2504         struct btrfs_key location;
2505         int maybe_acls;
2506         u64 alloc_group_block;
2507         u32 rdev;
2508         int ret;
2509
2510         path = btrfs_alloc_path();
2511         BUG_ON(!path);
2512         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
2513
2514         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
2515         if (ret)
2516                 goto make_bad;
2517
2518         leaf = path->nodes[0];
2519         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2520                                     struct btrfs_inode_item);
2521
2522         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
2523         inode->i_nlink = btrfs_inode_nlink(leaf, inode_item);
2524         inode->i_uid = btrfs_inode_uid(leaf, inode_item);
2525         inode->i_gid = btrfs_inode_gid(leaf, inode_item);
2526         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
2527
2528         tspec = btrfs_inode_atime(inode_item);
2529         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2530         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2531
2532         tspec = btrfs_inode_mtime(inode_item);
2533         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2534         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2535
2536         tspec = btrfs_inode_ctime(inode_item);
2537         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2538         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2539
2540         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
2541         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
2542         BTRFS_I(inode)->sequence = btrfs_inode_sequence(leaf, inode_item);
2543         inode->i_generation = BTRFS_I(inode)->generation;
2544         inode->i_rdev = 0;
2545         rdev = btrfs_inode_rdev(leaf, inode_item);
2546
2547         BTRFS_I(inode)->index_cnt = (u64)-1;
2548         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
2549
2550         alloc_group_block = btrfs_inode_block_group(leaf, inode_item);
2551
2552         /*
2553          * try to precache a NULL acl entry for files that don't have
2554          * any xattrs or acls
2555          */
2556         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
2557                                            btrfs_ino(inode));
2558         if (!maybe_acls)
2559                 cache_no_acl(inode);
2560
2561         BTRFS_I(inode)->block_group = btrfs_find_block_group(root, 0,
2562                                                 alloc_group_block, 0);
2563         btrfs_free_path(path);
2564         inode_item = NULL;
2565
2566         switch (inode->i_mode & S_IFMT) {
2567         case S_IFREG:
2568                 inode->i_mapping->a_ops = &btrfs_aops;
2569                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2570                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
2571                 inode->i_fop = &btrfs_file_operations;
2572                 inode->i_op = &btrfs_file_inode_operations;
2573                 break;
2574         case S_IFDIR:
2575                 inode->i_fop = &btrfs_dir_file_operations;
2576                 if (root == root->fs_info->tree_root)
2577                         inode->i_op = &btrfs_dir_ro_inode_operations;
2578                 else
2579                         inode->i_op = &btrfs_dir_inode_operations;
2580                 break;
2581         case S_IFLNK:
2582                 inode->i_op = &btrfs_symlink_inode_operations;
2583                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
2584                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2585                 break;
2586         default:
2587                 inode->i_op = &btrfs_special_inode_operations;
2588                 init_special_inode(inode, inode->i_mode, rdev);
2589                 break;
2590         }
2591
2592         btrfs_update_iflags(inode);
2593         return;
2594
2595 make_bad:
2596         btrfs_free_path(path);
2597         make_bad_inode(inode);
2598 }
2599
2600 /*
2601  * given a leaf and an inode, copy the inode fields into the leaf
2602  */
2603 static void fill_inode_item(struct btrfs_trans_handle *trans,
2604                             struct extent_buffer *leaf,
2605                             struct btrfs_inode_item *item,
2606                             struct inode *inode)
2607 {
2608         if (!leaf->map_token)
2609                 map_private_extent_buffer(leaf, (unsigned long)item,
2610                                           sizeof(struct btrfs_inode_item),
2611                                           &leaf->map_token, &leaf->kaddr,
2612                                           &leaf->map_start, &leaf->map_len,
2613                                           KM_USER1);
2614
2615         btrfs_set_inode_uid(leaf, item, inode->i_uid);
2616         btrfs_set_inode_gid(leaf, item, inode->i_gid);
2617         btrfs_set_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size);
2618         btrfs_set_inode_mode(leaf, item, inode->i_mode);
2619         btrfs_set_inode_nlink(leaf, item, inode->i_nlink);
2620
2621         btrfs_set_timespec_sec(leaf, btrfs_inode_atime(item),
2622                                inode->i_atime.tv_sec);
2623         btrfs_set_timespec_nsec(leaf, btrfs_inode_atime(item),
2624                                 inode->i_atime.tv_nsec);
2625
2626         btrfs_set_timespec_sec(leaf, btrfs_inode_mtime(item),
2627                                inode->i_mtime.tv_sec);
2628         btrfs_set_timespec_nsec(leaf, btrfs_inode_mtime(item),
2629                                 inode->i_mtime.tv_nsec);
2630
2631         btrfs_set_timespec_sec(leaf, btrfs_inode_ctime(item),
2632                                inode->i_ctime.tv_sec);
2633         btrfs_set_timespec_nsec(leaf, btrfs_inode_ctime(item),
2634                                 inode->i_ctime.tv_nsec);
2635
2636         btrfs_set_inode_nbytes(leaf, item, inode_get_bytes(inode));
2637         btrfs_set_inode_generation(leaf, item, BTRFS_I(inode)->generation);
2638         btrfs_set_inode_sequence(leaf, item, BTRFS_I(inode)->sequence);
2639         btrfs_set_inode_transid(leaf, item, trans->transid);
2640         btrfs_set_inode_rdev(leaf, item, inode->i_rdev);
2641         btrfs_set_inode_flags(leaf, item, BTRFS_I(inode)->flags);
2642         btrfs_set_inode_block_group(leaf, item, BTRFS_I(inode)->block_group);
2643
2644         if (leaf->map_token) {
2645                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2646                 leaf->map_token = NULL;
2647         }
2648 }
2649
2650 /*
2651  * copy everything in the in-memory inode into the btree.
2652  */
2653 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
2654                                 struct btrfs_root *root, struct inode *inode)
2655 {
2656         struct btrfs_inode_item *inode_item;
2657         struct btrfs_path *path;
2658         struct extent_buffer *leaf;
2659         int ret;
2660
2661         /*
2662          * If root is tree root, it means this inode is used to
2663          * store free space information. And these inodes are updated
2664          * when committing the transaction, so they needn't delaye to
2665          * be updated, or deadlock will occured.
2666          */
2667         if (!is_free_space_inode(root, inode)) {
2668                 ret = btrfs_delayed_update_inode(trans, root, inode);
2669                 if (!ret)
2670                         btrfs_set_inode_last_trans(trans, inode);
2671                 return ret;
2672         }
2673
2674         path = btrfs_alloc_path();
2675         if (!path)
2676                 return -ENOMEM;
2677
2678         path->leave_spinning = 1;
2679         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
2680                                  1);
2681         if (ret) {
2682                 if (ret > 0)
2683                         ret = -ENOENT;
2684                 goto failed;
2685         }
2686
2687         btrfs_unlock_up_safe(path, 1);
2688         leaf = path->nodes[0];
2689         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2690                                     struct btrfs_inode_item);
2691
2692         fill_inode_item(trans, leaf, inode_item, inode);
2693         btrfs_mark_buffer_dirty(leaf);
2694         btrfs_set_inode_last_trans(trans, inode);
2695         ret = 0;
2696 failed:
2697         btrfs_free_path(path);
2698         return ret;
2699 }
2700
2701 /*
2702  * unlink helper that gets used here in inode.c and in the tree logging
2703  * recovery code.  It remove a link in a directory with a given name, and
2704  * also drops the back refs in the inode to the directory
2705  */
2706 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2707                                 struct btrfs_root *root,
2708                                 struct inode *dir, struct inode *inode,
2709                                 const char *name, int name_len)
2710 {
2711         struct btrfs_path *path;
2712         int ret = 0;
2713         struct extent_buffer *leaf;
2714         struct btrfs_dir_item *di;
2715         struct btrfs_key key;
2716         u64 index;
2717         u64 ino = btrfs_ino(inode);
2718         u64 dir_ino = btrfs_ino(dir);
2719
2720         path = btrfs_alloc_path();
2721         if (!path) {
2722                 ret = -ENOMEM;
2723                 goto out;
2724         }
2725
2726         path->leave_spinning = 1;
2727         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
2728                                     name, name_len, -1);
2729         if (IS_ERR(di)) {
2730                 ret = PTR_ERR(di);
2731                 goto err;
2732         }
2733         if (!di) {
2734                 ret = -ENOENT;
2735                 goto err;
2736         }
2737         leaf = path->nodes[0];
2738         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2739         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2740         if (ret)
2741                 goto err;
2742         btrfs_release_path(path);
2743
2744         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
2745                                   dir_ino, &index);
2746         if (ret) {
2747                 printk(KERN_INFO "btrfs failed to delete reference to %.*s, "
2748                        "inode %llu parent %llu\n", name_len, name,
2749                        (unsigned long long)ino, (unsigned long long)dir_ino);
2750                 goto err;
2751         }
2752
2753         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
2754         if (ret)
2755                 goto err;
2756
2757         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
2758                                          inode, dir_ino);
2759         BUG_ON(ret != 0 && ret != -ENOENT);
2760
2761         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
2762                                            dir, index);
2763         if (ret == -ENOENT)
2764                 ret = 0;
2765 err:
2766         btrfs_free_path(path);
2767         if (ret)
2768                 goto out;
2769
2770         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2771         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2772         btrfs_update_inode(trans, root, dir);
2773 out:
2774         return ret;
2775 }
2776
2777 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2778                        struct btrfs_root *root,
2779                        struct inode *dir, struct inode *inode,
2780                        const char *name, int name_len)
2781 {
2782         int ret;
2783         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
2784         if (!ret) {
2785                 btrfs_drop_nlink(inode);
2786                 ret = btrfs_update_inode(trans, root, inode);
2787         }
2788         return ret;
2789 }
2790
2791
2792 /* helper to check if there is any shared block in the path */
2793 static int check_path_shared(struct btrfs_root *root,
2794                              struct btrfs_path *path)
2795 {
2796         struct extent_buffer *eb;
2797         int level;
2798         u64 refs = 1;
2799
2800         for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2801                 int ret;
2802
2803                 if (!path->nodes[level])
2804                         break;
2805                 eb = path->nodes[level];
2806                 if (!btrfs_block_can_be_shared(root, eb))
2807                         continue;
2808                 ret = btrfs_lookup_extent_info(NULL, root, eb->start, eb->len,
2809                                                &refs, NULL);
2810                 if (refs > 1)
2811                         return 1;
2812         }
2813         return 0;
2814 }
2815
2816 /*
2817  * helper to start transaction for unlink and rmdir.
2818  *
2819  * unlink and rmdir are special in btrfs, they do not always free space.
2820  * so in enospc case, we should make sure they will free space before
2821  * allowing them to use the global metadata reservation.
2822  */
2823 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
2824                                                        struct dentry *dentry)
2825 {
2826         struct btrfs_trans_handle *trans;
2827         struct btrfs_root *root = BTRFS_I(dir)->root;
2828         struct btrfs_path *path;
2829         struct btrfs_inode_ref *ref;
2830         struct btrfs_dir_item *di;
2831         struct inode *inode = dentry->d_inode;
2832         u64 index;
2833         int check_link = 1;
2834         int err = -ENOSPC;
2835         int ret;
2836         u64 ino = btrfs_ino(inode);
2837         u64 dir_ino = btrfs_ino(dir);
2838
2839         trans = btrfs_start_transaction(root, 10);
2840         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
2841                 return trans;
2842
2843         if (ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
2844                 return ERR_PTR(-ENOSPC);
2845
2846         /* check if there is someone else holds reference */
2847         if (S_ISDIR(inode->i_mode) && atomic_read(&inode->i_count) > 1)
2848                 return ERR_PTR(-ENOSPC);
2849
2850         if (atomic_read(&inode->i_count) > 2)
2851                 return ERR_PTR(-ENOSPC);
2852
2853         if (xchg(&root->fs_info->enospc_unlink, 1))
2854                 return ERR_PTR(-ENOSPC);
2855
2856         path = btrfs_alloc_path();
2857         if (!path) {
2858                 root->fs_info->enospc_unlink = 0;
2859                 return ERR_PTR(-ENOMEM);
2860         }
2861
2862         trans = btrfs_start_transaction(root, 0);
2863         if (IS_ERR(trans)) {
2864                 btrfs_free_path(path);
2865                 root->fs_info->enospc_unlink = 0;
2866                 return trans;
2867         }
2868
2869         path->skip_locking = 1;
2870         path->search_commit_root = 1;
2871
2872         ret = btrfs_lookup_inode(trans, root, path,
2873                                 &BTRFS_I(dir)->location, 0);
2874         if (ret < 0) {
2875                 err = ret;
2876                 goto out;
2877         }
2878         if (ret == 0) {
2879                 if (check_path_shared(root, path))
2880                         goto out;
2881         } else {
2882                 check_link = 0;
2883         }
2884         btrfs_release_path(path);
2885
2886         ret = btrfs_lookup_inode(trans, root, path,
2887                                 &BTRFS_I(inode)->location, 0);
2888         if (ret < 0) {
2889                 err = ret;
2890                 goto out;
2891         }
2892         if (ret == 0) {
2893                 if (check_path_shared(root, path))
2894                         goto out;
2895         } else {
2896                 check_link = 0;
2897         }
2898         btrfs_release_path(path);
2899
2900         if (ret == 0 && S_ISREG(inode->i_mode)) {
2901                 ret = btrfs_lookup_file_extent(trans, root, path,
2902                                                ino, (u64)-1, 0);
2903                 if (ret < 0) {
2904                         err = ret;
2905                         goto out;
2906                 }
2907                 BUG_ON(ret == 0);
2908                 if (check_path_shared(root, path))
2909                         goto out;
2910                 btrfs_release_path(path);
2911         }
2912
2913         if (!check_link) {
2914                 err = 0;
2915                 goto out;
2916         }
2917
2918         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
2919                                 dentry->d_name.name, dentry->d_name.len, 0);
2920         if (IS_ERR(di)) {
2921                 err = PTR_ERR(di);
2922                 goto out;
2923         }
2924         if (di) {
2925                 if (check_path_shared(root, path))
2926                         goto out;
2927         } else {
2928                 err = 0;
2929                 goto out;
2930         }
2931         btrfs_release_path(path);
2932
2933         ref = btrfs_lookup_inode_ref(trans, root, path,
2934                                 dentry->d_name.name, dentry->d_name.len,
2935                                 ino, dir_ino, 0);
2936         if (IS_ERR(ref)) {
2937                 err = PTR_ERR(ref);
2938                 goto out;
2939         }
2940         BUG_ON(!ref);
2941         if (check_path_shared(root, path))
2942                 goto out;
2943         index = btrfs_inode_ref_index(path->nodes[0], ref);
2944         btrfs_release_path(path);
2945
2946         /*
2947          * This is a commit root search, if we can lookup inode item and other
2948          * relative items in the commit root, it means the transaction of
2949          * dir/file creation has been committed, and the dir index item that we
2950          * delay to insert has also been inserted into the commit root. So
2951          * we needn't worry about the delayed insertion of the dir index item
2952          * here.
2953          */
2954         di = btrfs_lookup_dir_index_item(trans, root, path, dir_ino, index,
2955                                 dentry->d_name.name, dentry->d_name.len, 0);
2956         if (IS_ERR(di)) {
2957                 err = PTR_ERR(di);
2958                 goto out;
2959         }
2960         BUG_ON(ret == -ENOENT);
2961         if (check_path_shared(root, path))
2962                 goto out;
2963
2964         err = 0;
2965 out:
2966         btrfs_free_path(path);
2967         if (err) {
2968                 btrfs_end_transaction(trans, root);
2969                 root->fs_info->enospc_unlink = 0;
2970                 return ERR_PTR(err);
2971         }
2972
2973         trans->block_rsv = &root->fs_info->global_block_rsv;
2974         return trans;
2975 }
2976
2977 static void __unlink_end_trans(struct btrfs_trans_handle *trans,
2978                                struct btrfs_root *root)
2979 {
2980         if (trans->block_rsv == &root->fs_info->global_block_rsv) {
2981                 BUG_ON(!root->fs_info->enospc_unlink);
2982                 root->fs_info->enospc_unlink = 0;
2983         }
2984         btrfs_end_transaction_throttle(trans, root);
2985 }
2986
2987 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
2988 {
2989         struct btrfs_root *root = BTRFS_I(dir)->root;
2990         struct btrfs_trans_handle *trans;
2991         struct inode *inode = dentry->d_inode;
2992         int ret;
2993         unsigned long nr = 0;
2994
2995         trans = __unlink_start_trans(dir, dentry);
2996         if (IS_ERR(trans))
2997                 return PTR_ERR(trans);
2998
2999         btrfs_set_trans_block_group(trans, dir);
3000
3001         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
3002
3003         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3004                                  dentry->d_name.name, dentry->d_name.len);
3005         BUG_ON(ret);
3006
3007         if (inode->i_nlink == 0) {
3008                 ret = btrfs_orphan_add(trans, inode);
3009                 BUG_ON(ret);
3010         }
3011
3012         nr = trans->blocks_used;
3013         __unlink_end_trans(trans, root);
3014         btrfs_btree_balance_dirty(root, nr);
3015         return ret;
3016 }
3017
3018 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
3019                         struct btrfs_root *root,
3020                         struct inode *dir, u64 objectid,
3021                         const char *name, int name_len)
3022 {
3023         struct btrfs_path *path;
3024         struct extent_buffer *leaf;
3025         struct btrfs_dir_item *di;
3026         struct btrfs_key key;
3027         u64 index;
3028         int ret;
3029         u64 dir_ino = btrfs_ino(dir);
3030
3031         path = btrfs_alloc_path();
3032         if (!path)
3033                 return -ENOMEM;
3034
3035         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3036                                    name, name_len, -1);
3037         BUG_ON(IS_ERR_OR_NULL(di));
3038
3039         leaf = path->nodes[0];
3040         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3041         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3042         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3043         BUG_ON(ret);
3044         btrfs_release_path(path);
3045
3046         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
3047                                  objectid, root->root_key.objectid,
3048                                  dir_ino, &index, name, name_len);
3049         if (ret < 0) {
3050                 BUG_ON(ret != -ENOENT);
3051                 di = btrfs_search_dir_index_item(root, path, dir_ino,
3052                                                  name, name_len);
3053                 BUG_ON(IS_ERR_OR_NULL(di));
3054
3055                 leaf = path->nodes[0];
3056                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3057                 btrfs_release_path(path);
3058                 index = key.offset;
3059         }
3060         btrfs_release_path(path);
3061
3062         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3063         BUG_ON(ret);
3064
3065         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3066         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3067         ret = btrfs_update_inode(trans, root, dir);
3068         BUG_ON(ret);
3069
3070         return 0;
3071 }
3072
3073 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
3074 {
3075         struct inode *inode = dentry->d_inode;
3076         int err = 0;
3077         struct btrfs_root *root = BTRFS_I(dir)->root;
3078         struct btrfs_trans_handle *trans;
3079         unsigned long nr = 0;
3080
3081         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE ||
3082             btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
3083                 return -ENOTEMPTY;
3084
3085         trans = __unlink_start_trans(dir, dentry);
3086         if (IS_ERR(trans))
3087                 return PTR_ERR(trans);
3088
3089         btrfs_set_trans_block_group(trans, dir);
3090
3091         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
3092                 err = btrfs_unlink_subvol(trans, root, dir,
3093                                           BTRFS_I(inode)->location.objectid,
3094                                           dentry->d_name.name,
3095                                           dentry->d_name.len);
3096                 goto out;
3097         }
3098
3099         err = btrfs_orphan_add(trans, inode);
3100         if (err)
3101                 goto out;
3102
3103         /* now the directory is empty */
3104         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3105                                  dentry->d_name.name, dentry->d_name.len);
3106         if (!err)
3107                 btrfs_i_size_write(inode, 0);
3108 out:
3109         nr = trans->blocks_used;
3110         __unlink_end_trans(trans, root);
3111         btrfs_btree_balance_dirty(root, nr);
3112
3113         return err;
3114 }
3115
3116 /*
3117  * this can truncate away extent items, csum items and directory items.
3118  * It starts at a high offset and removes keys until it can't find
3119  * any higher than new_size
3120  *
3121  * csum items that cross the new i_size are truncated to the new size
3122  * as well.
3123  *
3124  * min_type is the minimum key type to truncate down to.  If set to 0, this
3125  * will kill all the items on this inode, including the INODE_ITEM_KEY.
3126  */
3127 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
3128                                struct btrfs_root *root,
3129                                struct inode *inode,
3130                                u64 new_size, u32 min_type)
3131 {
3132         struct btrfs_path *path;
3133         struct extent_buffer *leaf;
3134         struct btrfs_file_extent_item *fi;
3135         struct btrfs_key key;
3136         struct btrfs_key found_key;
3137         u64 extent_start = 0;
3138         u64 extent_num_bytes = 0;
3139         u64 extent_offset = 0;
3140         u64 item_end = 0;
3141         u64 mask = root->sectorsize - 1;
3142         u32 found_type = (u8)-1;
3143         int found_extent;
3144         int del_item;
3145         int pending_del_nr = 0;
3146         int pending_del_slot = 0;
3147         int extent_type = -1;
3148         int encoding;
3149         int ret;
3150         int err = 0;
3151         u64 ino = btrfs_ino(inode);
3152
3153         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
3154
3155         if (root->ref_cows || root == root->fs_info->tree_root)
3156                 btrfs_drop_extent_cache(inode, new_size & (~mask), (u64)-1, 0);
3157
3158         /*
3159          * This function is also used to drop the items in the log tree before
3160          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
3161          * it is used to drop the loged items. So we shouldn't kill the delayed
3162          * items.
3163          */
3164         if (min_type == 0 && root == BTRFS_I(inode)->root)
3165                 btrfs_kill_delayed_inode_items(inode);
3166
3167         path = btrfs_alloc_path();
3168         BUG_ON(!path);
3169         path->reada = -1;
3170
3171         key.objectid = ino;
3172         key.offset = (u64)-1;
3173         key.type = (u8)-1;
3174
3175 search_again:
3176         path->leave_spinning = 1;
3177         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3178         if (ret < 0) {
3179                 err = ret;
3180                 goto out;
3181         }
3182
3183         if (ret > 0) {
3184                 /* there are no items in the tree for us to truncate, we're
3185                  * done
3186                  */
3187                 if (path->slots[0] == 0)
3188                         goto out;
3189                 path->slots[0]--;
3190         }
3191
3192         while (1) {
3193                 fi = NULL;
3194                 leaf = path->nodes[0];
3195                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3196                 found_type = btrfs_key_type(&found_key);
3197                 encoding = 0;
3198
3199                 if (found_key.objectid != ino)
3200                         break;
3201
3202                 if (found_type < min_type)
3203                         break;
3204
3205                 item_end = found_key.offset;
3206                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
3207                         fi = btrfs_item_ptr(leaf, path->slots[0],
3208                                             struct btrfs_file_extent_item);
3209                         extent_type = btrfs_file_extent_type(leaf, fi);
3210                         encoding = btrfs_file_extent_compression(leaf, fi);
3211                         encoding |= btrfs_file_extent_encryption(leaf, fi);
3212                         encoding |= btrfs_file_extent_other_encoding(leaf, fi);
3213
3214                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3215                                 item_end +=
3216                                     btrfs_file_extent_num_bytes(leaf, fi);
3217                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3218                                 item_end += btrfs_file_extent_inline_len(leaf,
3219                                                                          fi);
3220                         }
3221                         item_end--;
3222                 }
3223                 if (found_type > min_type) {
3224                         del_item = 1;
3225                 } else {
3226                         if (item_end < new_size)
3227                                 break;
3228                         if (found_key.offset >= new_size)
3229                                 del_item = 1;
3230                         else
3231                                 del_item = 0;
3232                 }
3233                 found_extent = 0;
3234                 /* FIXME, shrink the extent if the ref count is only 1 */
3235                 if (found_type != BTRFS_EXTENT_DATA_KEY)
3236                         goto delete;
3237
3238                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3239                         u64 num_dec;
3240                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
3241                         if (!del_item && !encoding) {
3242                                 u64 orig_num_bytes =
3243                                         btrfs_file_extent_num_bytes(leaf, fi);
3244                                 extent_num_bytes = new_size -
3245                                         found_key.offset + root->sectorsize - 1;
3246                                 extent_num_bytes = extent_num_bytes &
3247                                         ~((u64)root->sectorsize - 1);
3248                                 btrfs_set_file_extent_num_bytes(leaf, fi,
3249                                                          extent_num_bytes);
3250                                 num_dec = (orig_num_bytes -
3251                                            extent_num_bytes);
3252                                 if (root->ref_cows && extent_start != 0)
3253                                         inode_sub_bytes(inode, num_dec);
3254                                 btrfs_mark_buffer_dirty(leaf);
3255                         } else {
3256                                 extent_num_bytes =
3257                                         btrfs_file_extent_disk_num_bytes(leaf,
3258                                                                          fi);
3259                                 extent_offset = found_key.offset -
3260                                         btrfs_file_extent_offset(leaf, fi);
3261
3262                                 /* FIXME blocksize != 4096 */
3263                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
3264                                 if (extent_start != 0) {
3265                                         found_extent = 1;
3266                                         if (root->ref_cows)
3267                                                 inode_sub_bytes(inode, num_dec);
3268                                 }
3269                         }
3270                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3271                         /*
3272                          * we can't truncate inline items that have had
3273                          * special encodings
3274                          */
3275                         if (!del_item &&
3276                             btrfs_file_extent_compression(leaf, fi) == 0 &&
3277                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
3278                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
3279                                 u32 size = new_size - found_key.offset;
3280
3281                                 if (root->ref_cows) {
3282                                         inode_sub_bytes(inode, item_end + 1 -
3283                                                         new_size);
3284                                 }
3285                                 size =
3286                                     btrfs_file_extent_calc_inline_size(size);
3287                                 ret = btrfs_truncate_item(trans, root, path,
3288                                                           size, 1);
3289                         } else if (root->ref_cows) {
3290                                 inode_sub_bytes(inode, item_end + 1 -
3291                                                 found_key.offset);
3292                         }
3293                 }
3294 delete:
3295                 if (del_item) {
3296                         if (!pending_del_nr) {
3297                                 /* no pending yet, add ourselves */
3298                                 pending_del_slot = path->slots[0];
3299                                 pending_del_nr = 1;
3300                         } else if (pending_del_nr &&
3301                                    path->slots[0] + 1 == pending_del_slot) {
3302                                 /* hop on the pending chunk */
3303                                 pending_del_nr++;
3304                                 pending_del_slot = path->slots[0];
3305                         } else {
3306                                 BUG();
3307                         }
3308                 } else {
3309                         break;
3310                 }
3311                 if (found_extent && (root->ref_cows ||
3312                                      root == root->fs_info->tree_root)) {
3313                         btrfs_set_path_blocking(path);
3314                         ret = btrfs_free_extent(trans, root, extent_start,
3315                                                 extent_num_bytes, 0,
3316                                                 btrfs_header_owner(leaf),
3317                                                 ino, extent_offset);
3318                         BUG_ON(ret);
3319                 }
3320
3321                 if (found_type == BTRFS_INODE_ITEM_KEY)
3322                         break;
3323
3324                 if (path->slots[0] == 0 ||
3325                     path->slots[0] != pending_del_slot) {
3326                         if (root->ref_cows &&
3327                             BTRFS_I(inode)->location.objectid !=
3328                                                 BTRFS_FREE_INO_OBJECTID) {
3329                                 err = -EAGAIN;
3330                                 goto out;
3331                         }
3332                         if (pending_del_nr) {
3333                                 ret = btrfs_del_items(trans, root, path,
3334                                                 pending_del_slot,
3335                                                 pending_del_nr);
3336                                 BUG_ON(ret);
3337                                 pending_del_nr = 0;
3338                         }
3339                         btrfs_release_path(path);
3340                         goto search_again;
3341                 } else {
3342                         path->slots[0]--;
3343                 }
3344         }
3345 out:
3346         if (pending_del_nr) {
3347                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
3348                                       pending_del_nr);
3349                 BUG_ON(ret);
3350         }
3351         btrfs_free_path(path);
3352         return err;
3353 }
3354
3355 /*
3356  * taken from block_truncate_page, but does cow as it zeros out
3357  * any bytes left in the last page in the file.
3358  */
3359 static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
3360 {
3361         struct inode *inode = mapping->host;
3362         struct btrfs_root *root = BTRFS_I(inode)->root;
3363         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3364         struct btrfs_ordered_extent *ordered;
3365         struct extent_state *cached_state = NULL;
3366         char *kaddr;
3367         u32 blocksize = root->sectorsize;
3368         pgoff_t index = from >> PAGE_CACHE_SHIFT;
3369         unsigned offset = from & (PAGE_CACHE_SIZE-1);
3370         struct page *page;
3371         int ret = 0;
3372         u64 page_start;
3373         u64 page_end;
3374
3375         if ((offset & (blocksize - 1)) == 0)
3376                 goto out;
3377         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
3378         if (ret)
3379                 goto out;
3380
3381         ret = -ENOMEM;
3382 again:
3383         page = grab_cache_page(mapping, index);
3384         if (!page) {
3385                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3386                 goto out;
3387         }
3388
3389         page_start = page_offset(page);
3390         page_end = page_start + PAGE_CACHE_SIZE - 1;
3391
3392         if (!PageUptodate(page)) {
3393                 ret = btrfs_readpage(NULL, page);
3394                 lock_page(page);
3395                 if (page->mapping != mapping) {
3396                         unlock_page(page);
3397                         page_cache_release(page);
3398                         goto again;
3399                 }
3400                 if (!PageUptodate(page)) {
3401                         ret = -EIO;
3402                         goto out_unlock;
3403                 }
3404         }
3405         wait_on_page_writeback(page);
3406
3407         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state,
3408                          GFP_NOFS);
3409         set_page_extent_mapped(page);
3410
3411         ordered = btrfs_lookup_ordered_extent(inode, page_start);
3412         if (ordered) {
3413                 unlock_extent_cached(io_tree, page_start, page_end,
3414                                      &cached_state, GFP_NOFS);
3415                 unlock_page(page);
3416                 page_cache_release(page);
3417                 btrfs_start_ordered_extent(inode, ordered, 1);
3418                 btrfs_put_ordered_extent(ordered);
3419                 goto again;
3420         }
3421
3422         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
3423                           EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING,
3424                           0, 0, &cached_state, GFP_NOFS);
3425
3426         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
3427                                         &cached_state);
3428         if (ret) {
3429                 unlock_extent_cached(io_tree, page_start, page_end,
3430                                      &cached_state, GFP_NOFS);
3431                 goto out_unlock;
3432         }
3433
3434         ret = 0;
3435         if (offset != PAGE_CACHE_SIZE) {
3436                 kaddr = kmap(page);
3437                 memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
3438                 flush_dcache_page(page);
3439                 kunmap(page);
3440         }
3441         ClearPageChecked(page);
3442         set_page_dirty(page);
3443         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
3444                              GFP_NOFS);
3445
3446 out_unlock:
3447         if (ret)
3448                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3449         unlock_page(page);
3450         page_cache_release(page);
3451 out:
3452         return ret;
3453 }
3454
3455 /*
3456  * This function puts in dummy file extents for the area we're creating a hole
3457  * for.  So if we are truncating this file to a larger size we need to insert
3458  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
3459  * the range between oldsize and size
3460  */
3461 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
3462 {
3463         struct btrfs_trans_handle *trans;
3464         struct btrfs_root *root = BTRFS_I(inode)->root;
3465         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3466         struct extent_map *em = NULL;
3467         struct extent_state *cached_state = NULL;
3468         u64 mask = root->sectorsize - 1;
3469         u64 hole_start = (oldsize + mask) & ~mask;
3470         u64 block_end = (size + mask) & ~mask;
3471         u64 last_byte;
3472         u64 cur_offset;
3473         u64 hole_size;
3474         int err = 0;
3475
3476         if (size <= hole_start)
3477                 return 0;
3478
3479         while (1) {
3480                 struct btrfs_ordered_extent *ordered;
3481                 btrfs_wait_ordered_range(inode, hole_start,
3482                                          block_end - hole_start);
3483                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
3484                                  &cached_state, GFP_NOFS);
3485                 ordered = btrfs_lookup_ordered_extent(inode, hole_start);
3486                 if (!ordered)
3487                         break;
3488                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
3489                                      &cached_state, GFP_NOFS);
3490                 btrfs_put_ordered_extent(ordered);
3491         }
3492
3493         cur_offset = hole_start;
3494         while (1) {
3495                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
3496                                 block_end - cur_offset, 0);
3497                 BUG_ON(IS_ERR_OR_NULL(em));
3498                 last_byte = min(extent_map_end(em), block_end);
3499                 last_byte = (last_byte + mask) & ~mask;
3500                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
3501                         u64 hint_byte = 0;
3502                         hole_size = last_byte - cur_offset;
3503
3504                         trans = btrfs_start_transaction(root, 2);
3505                         if (IS_ERR(trans)) {
3506                                 err = PTR_ERR(trans);
3507                                 break;
3508                         }
3509                         btrfs_set_trans_block_group(trans, inode);
3510
3511                         err = btrfs_drop_extents(trans, inode, cur_offset,
3512                                                  cur_offset + hole_size,
3513                                                  &hint_byte, 1);
3514                         if (err)
3515                                 break;
3516
3517                         err = btrfs_insert_file_extent(trans, root,
3518                                         btrfs_ino(inode), cur_offset, 0,
3519                                         0, hole_size, 0, hole_size,
3520                                         0, 0, 0);
3521                         if (err)
3522                                 break;
3523
3524                         btrfs_drop_extent_cache(inode, hole_start,
3525                                         last_byte - 1, 0);
3526
3527                         btrfs_end_transaction(trans, root);
3528                 }
3529                 free_extent_map(em);
3530                 em = NULL;
3531                 cur_offset = last_byte;
3532                 if (cur_offset >= block_end)
3533                         break;
3534         }
3535
3536         free_extent_map(em);
3537         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
3538                              GFP_NOFS);
3539         return err;
3540 }
3541
3542 static int btrfs_setsize(struct inode *inode, loff_t newsize)
3543 {
3544         loff_t oldsize = i_size_read(inode);
3545         int ret;
3546
3547         if (newsize == oldsize)
3548                 return 0;
3549
3550         if (newsize > oldsize) {
3551                 i_size_write(inode, newsize);
3552                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
3553                 truncate_pagecache(inode, oldsize, newsize);
3554                 ret = btrfs_cont_expand(inode, oldsize, newsize);
3555                 if (ret) {
3556                         btrfs_setsize(inode, oldsize);
3557                         return ret;
3558                 }
3559
3560                 mark_inode_dirty(inode);
3561         } else {
3562
3563                 /*
3564                  * We're truncating a file that used to have good data down to
3565                  * zero. Make sure it gets into the ordered flush list so that
3566                  * any new writes get down to disk quickly.
3567                  */
3568                 if (newsize == 0)
3569                         BTRFS_I(inode)->ordered_data_close = 1;
3570
3571                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
3572                 truncate_setsize(inode, newsize);
3573                 ret = btrfs_truncate(inode);
3574         }
3575
3576         return ret;
3577 }
3578
3579 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
3580 {
3581         struct inode *inode = dentry->d_inode;
3582         struct btrfs_root *root = BTRFS_I(inode)->root;
3583         int err;
3584
3585         if (btrfs_root_readonly(root))
3586                 return -EROFS;
3587
3588         err = inode_change_ok(inode, attr);
3589         if (err)
3590                 return err;
3591
3592         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
3593                 err = btrfs_setsize(inode, attr->ia_size);
3594                 if (err)
3595                         return err;
3596         }
3597
3598         if (attr->ia_valid) {
3599                 setattr_copy(inode, attr);
3600                 mark_inode_dirty(inode);
3601
3602                 if (attr->ia_valid & ATTR_MODE)
3603                         err = btrfs_acl_chmod(inode);
3604         }
3605
3606         return err;
3607 }
3608
3609 void btrfs_evict_inode(struct inode *inode)
3610 {
3611         struct btrfs_trans_handle *trans;
3612         struct btrfs_root *root = BTRFS_I(inode)->root;
3613         unsigned long nr;
3614         int ret;
3615
3616         trace_btrfs_inode_evict(inode);
3617
3618         truncate_inode_pages(&inode->i_data, 0);
3619         if (inode->i_nlink && (btrfs_root_refs(&root->root_item) != 0 ||
3620                                is_free_space_inode(root, inode)))
3621                 goto no_delete;
3622
3623         if (is_bad_inode(inode)) {
3624                 btrfs_orphan_del(NULL, inode);
3625                 goto no_delete;
3626         }
3627         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
3628         btrfs_wait_ordered_range(inode, 0, (u64)-1);
3629
3630         if (root->fs_info->log_root_recovering) {
3631                 BUG_ON(!list_empty(&BTRFS_I(inode)->i_orphan));
3632                 goto no_delete;
3633         }
3634
3635         if (inode->i_nlink > 0) {
3636                 BUG_ON(btrfs_root_refs(&root->root_item) != 0);
3637                 goto no_delete;
3638         }
3639
3640         btrfs_i_size_write(inode, 0);
3641
3642         while (1) {
3643                 trans = btrfs_start_transaction(root, 0);
3644                 BUG_ON(IS_ERR(trans));
3645                 btrfs_set_trans_block_group(trans, inode);
3646                 trans->block_rsv = root->orphan_block_rsv;
3647
3648                 ret = btrfs_block_rsv_check(trans, root,
3649                                             root->orphan_block_rsv, 0, 5);
3650                 if (ret) {
3651                         BUG_ON(ret != -EAGAIN);
3652                         ret = btrfs_commit_transaction(trans, root);
3653                         BUG_ON(ret);
3654                         continue;
3655                 }
3656
3657                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
3658                 if (ret != -EAGAIN)
3659                         break;
3660
3661                 nr = trans->blocks_used;
3662                 btrfs_end_transaction(trans, root);
3663                 trans = NULL;
3664                 btrfs_btree_balance_dirty(root, nr);
3665
3666         }
3667
3668         if (ret == 0) {
3669                 ret = btrfs_orphan_del(trans, inode);
3670                 BUG_ON(ret);
3671         }
3672
3673         if (!(root == root->fs_info->tree_root ||
3674               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
3675                 btrfs_return_ino(root, btrfs_ino(inode));
3676
3677         nr = trans->blocks_used;
3678         btrfs_end_transaction(trans, root);
3679         btrfs_btree_balance_dirty(root, nr);
3680 no_delete:
3681         end_writeback(inode);
3682         return;
3683 }
3684
3685 /*
3686  * this returns the key found in the dir entry in the location pointer.
3687  * If no dir entries were found, location->objectid is 0.
3688  */
3689 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
3690                                struct btrfs_key *location)
3691 {
3692         const char *name = dentry->d_name.name;
3693         int namelen = dentry->d_name.len;
3694         struct btrfs_dir_item *di;
3695         struct btrfs_path *path;
3696         struct btrfs_root *root = BTRFS_I(dir)->root;
3697         int ret = 0;
3698
3699         path = btrfs_alloc_path();
3700         BUG_ON(!path);
3701
3702         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
3703                                     namelen, 0);
3704         if (IS_ERR(di))
3705                 ret = PTR_ERR(di);
3706
3707         if (IS_ERR_OR_NULL(di))
3708                 goto out_err;
3709
3710         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
3711 out:
3712         btrfs_free_path(path);
3713         return ret;
3714 out_err:
3715         location->objectid = 0;
3716         goto out;
3717 }
3718
3719 /*
3720  * when we hit a tree root in a directory, the btrfs part of the inode
3721  * needs to be changed to reflect the root directory of the tree root.  This
3722  * is kind of like crossing a mount point.
3723  */
3724 static int fixup_tree_root_location(struct btrfs_root *root,
3725                                     struct inode *dir,
3726                                     struct dentry *dentry,
3727                                     struct btrfs_key *location,
3728                                     struct btrfs_root **sub_root)
3729 {
3730         struct btrfs_path *path;
3731         struct btrfs_root *new_root;
3732         struct btrfs_root_ref *ref;
3733         struct extent_buffer *leaf;
3734         int ret;
3735         int err = 0;
3736
3737         path = btrfs_alloc_path();
3738         if (!path) {
3739                 err = -ENOMEM;
3740                 goto out;
3741         }
3742
3743         err = -ENOENT;
3744         ret = btrfs_find_root_ref(root->fs_info->tree_root, path,
3745                                   BTRFS_I(dir)->root->root_key.objectid,
3746                                   location->objectid);
3747         if (ret) {
3748                 if (ret < 0)
3749                         err = ret;
3750                 goto out;
3751         }
3752
3753         leaf = path->nodes[0];
3754         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
3755         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
3756             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
3757                 goto out;
3758
3759         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
3760                                    (unsigned long)(ref + 1),
3761                                    dentry->d_name.len);
3762         if (ret)
3763                 goto out;
3764
3765         btrfs_release_path(path);
3766
3767         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
3768         if (IS_ERR(new_root)) {
3769                 err = PTR_ERR(new_root);
3770                 goto out;
3771         }
3772
3773         if (btrfs_root_refs(&new_root->root_item) == 0) {
3774                 err = -ENOENT;
3775                 goto out;
3776         }
3777
3778         *sub_root = new_root;
3779         location->objectid = btrfs_root_dirid(&new_root->root_item);
3780         location->type = BTRFS_INODE_ITEM_KEY;
3781         location->offset = 0;
3782         err = 0;
3783 out:
3784         btrfs_free_path(path);
3785         return err;
3786 }
3787
3788 static void inode_tree_add(struct inode *inode)
3789 {
3790         struct btrfs_root *root = BTRFS_I(inode)->root;
3791         struct btrfs_inode *entry;
3792         struct rb_node **p;
3793         struct rb_node *parent;
3794         u64 ino = btrfs_ino(inode);
3795 again:
3796         p = &root->inode_tree.rb_node;
3797         parent = NULL;
3798
3799         if (inode_unhashed(inode))
3800                 return;
3801
3802         spin_lock(&root->inode_lock);
3803         while (*p) {
3804                 parent = *p;
3805                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
3806
3807                 if (ino < btrfs_ino(&entry->vfs_inode))
3808                         p = &parent->rb_left;
3809                 else if (ino > btrfs_ino(&entry->vfs_inode))
3810                         p = &parent->rb_right;
3811                 else {
3812                         WARN_ON(!(entry->vfs_inode.i_state &
3813                                   (I_WILL_FREE | I_FREEING)));
3814                         rb_erase(parent, &root->inode_tree);
3815                         RB_CLEAR_NODE(parent);
3816                         spin_unlock(&root->inode_lock);
3817                         goto again;
3818                 }
3819         }
3820         rb_link_node(&BTRFS_I(inode)->rb_node, parent, p);
3821         rb_insert_color(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3822         spin_unlock(&root->inode_lock);
3823 }
3824
3825 static void inode_tree_del(struct inode *inode)
3826 {
3827         struct btrfs_root *root = BTRFS_I(inode)->root;
3828         int empty = 0;
3829
3830         spin_lock(&root->inode_lock);
3831         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
3832                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3833                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
3834                 empty = RB_EMPTY_ROOT(&root->inode_tree);
3835         }
3836         spin_unlock(&root->inode_lock);
3837
3838         /*
3839          * Free space cache has inodes in the tree root, but the tree root has a
3840          * root_refs of 0, so this could end up dropping the tree root as a
3841          * snapshot, so we need the extra !root->fs_info->tree_root check to
3842          * make sure we don't drop it.
3843          */
3844         if (empty && btrfs_root_refs(&root->root_item) == 0 &&
3845             root != root->fs_info->tree_root) {
3846                 synchronize_srcu(&root->fs_info->subvol_srcu);
3847                 spin_lock(&root->inode_lock);
3848                 empty = RB_EMPTY_ROOT(&root->inode_tree);
3849                 spin_unlock(&root->inode_lock);
3850                 if (empty)
3851                         btrfs_add_dead_root(root);
3852         }
3853 }
3854
3855 int btrfs_invalidate_inodes(struct btrfs_root *root)
3856 {
3857         struct rb_node *node;
3858         struct rb_node *prev;
3859         struct btrfs_inode *entry;
3860         struct inode *inode;
3861         u64 objectid = 0;
3862
3863         WARN_ON(btrfs_root_refs(&root->root_item) != 0);
3864
3865         spin_lock(&root->inode_lock);
3866 again:
3867         node = root->inode_tree.rb_node;
3868         prev = NULL;
3869         while (node) {
3870                 prev = node;
3871                 entry = rb_entry(node, struct btrfs_inode, rb_node);
3872
3873                 if (objectid < btrfs_ino(&entry->vfs_inode))
3874                         node = node->rb_left;
3875                 else if (objectid > btrfs_ino(&entry->vfs_inode))
3876                         node = node->rb_right;
3877                 else
3878                         break;
3879         }
3880         if (!node) {
3881                 while (prev) {
3882                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
3883                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
3884                                 node = prev;
3885                                 break;
3886                         }
3887                         prev = rb_next(prev);
3888                 }
3889         }
3890         while (node) {
3891                 entry = rb_entry(node, struct btrfs_inode, rb_node);
3892                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
3893                 inode = igrab(&entry->vfs_inode);
3894                 if (inode) {
3895                         spin_unlock(&root->inode_lock);
3896                         if (atomic_read(&inode->i_count) > 1)
3897                                 d_prune_aliases(inode);
3898                         /*
3899                          * btrfs_drop_inode will have it removed from
3900                          * the inode cache when its usage count
3901                          * hits zero.
3902                          */
3903                         iput(inode);
3904                         cond_resched();
3905                         spin_lock(&root->inode_lock);
3906                         goto again;
3907                 }
3908
3909                 if (cond_resched_lock(&root->inode_lock))
3910                         goto again;
3911
3912                 node = rb_next(node);
3913         }
3914         spin_unlock(&root->inode_lock);
3915         return 0;
3916 }
3917
3918 static int btrfs_init_locked_inode(struct inode *inode, void *p)
3919 {
3920         struct btrfs_iget_args *args = p;
3921         inode->i_ino = args->ino;
3922         BTRFS_I(inode)->root = args->root;
3923         btrfs_set_inode_space_info(args->root, inode);
3924         return 0;
3925 }
3926
3927 static int btrfs_find_actor(struct inode *inode, void *opaque)
3928 {
3929         struct btrfs_iget_args *args = opaque;
3930         return args->ino == btrfs_ino(inode) &&
3931                 args->root == BTRFS_I(inode)->root;
3932 }
3933
3934 static struct inode *btrfs_iget_locked(struct super_block *s,
3935                                        u64 objectid,
3936                                        struct btrfs_root *root)
3937 {
3938         struct inode *inode;
3939         struct btrfs_iget_args args;
3940         args.ino = objectid;
3941         args.root = root;
3942
3943         inode = iget5_locked(s, objectid, btrfs_find_actor,
3944                              btrfs_init_locked_inode,
3945                              (void *)&args);
3946         return inode;
3947 }
3948
3949 /* Get an inode object given its location and corresponding root.
3950  * Returns in *is_new if the inode was read from disk
3951  */
3952 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
3953                          struct btrfs_root *root, int *new)
3954 {
3955         struct inode *inode;
3956
3957         inode = btrfs_iget_locked(s, location->objectid, root);
3958         if (!inode)
3959                 return ERR_PTR(-ENOMEM);
3960
3961         if (inode->i_state & I_NEW) {
3962                 BTRFS_I(inode)->root = root;
3963                 memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
3964                 btrfs_read_locked_inode(inode);
3965                 inode_tree_add(inode);
3966                 unlock_new_inode(inode);
3967                 if (new)
3968                         *new = 1;
3969         }
3970
3971         return inode;
3972 }
3973
3974 static struct inode *new_simple_dir(struct super_block *s,
3975                                     struct btrfs_key *key,
3976                                     struct btrfs_root *root)
3977 {
3978         struct inode *inode = new_inode(s);
3979
3980         if (!inode)
3981                 return ERR_PTR(-ENOMEM);
3982
3983         BTRFS_I(inode)->root = root;
3984         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
3985         BTRFS_I(inode)->dummy_inode = 1;
3986
3987         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
3988         inode->i_op = &simple_dir_inode_operations;
3989         inode->i_fop = &simple_dir_operations;
3990         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
3991         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
3992
3993         return inode;
3994 }
3995
3996 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
3997 {
3998         struct inode *inode;
3999         struct btrfs_root *root = BTRFS_I(dir)->root;
4000         struct btrfs_root *sub_root = root;
4001         struct btrfs_key location;
4002         int index;
4003         int ret;
4004
4005         if (dentry->d_name.len > BTRFS_NAME_LEN)
4006                 return ERR_PTR(-ENAMETOOLONG);
4007
4008         ret = btrfs_inode_by_name(dir, dentry, &location);
4009
4010         if (ret < 0)
4011                 return ERR_PTR(ret);
4012
4013         if (location.objectid == 0)
4014                 return NULL;
4015
4016         if (location.type == BTRFS_INODE_ITEM_KEY) {
4017                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
4018                 return inode;
4019         }
4020
4021         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
4022
4023         index = srcu_read_lock(&root->fs_info->subvol_srcu);
4024         ret = fixup_tree_root_location(root, dir, dentry,
4025                                        &location, &sub_root);
4026         if (ret < 0) {
4027                 if (ret != -ENOENT)
4028                         inode = ERR_PTR(ret);
4029                 else
4030                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
4031         } else {
4032                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
4033         }
4034         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
4035
4036         if (!IS_ERR(inode) && root != sub_root) {
4037                 down_read(&root->fs_info->cleanup_work_sem);
4038                 if (!(inode->i_sb->s_flags & MS_RDONLY))
4039                         ret = btrfs_orphan_cleanup(sub_root);
4040                 up_read(&root->fs_info->cleanup_work_sem);
4041                 if (ret)
4042                         inode = ERR_PTR(ret);
4043         }
4044
4045         return inode;
4046 }
4047
4048 static int btrfs_dentry_delete(const struct dentry *dentry)
4049 {
4050         struct btrfs_root *root;
4051
4052         if (!dentry->d_inode && !IS_ROOT(dentry))
4053                 dentry = dentry->d_parent;
4054
4055         if (dentry->d_inode) {
4056                 root = BTRFS_I(dentry->d_inode)->root;
4057                 if (btrfs_root_refs(&root->root_item) == 0)
4058                         return 1;
4059         }
4060         return 0;
4061 }
4062
4063 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
4064                                    struct nameidata *nd)
4065 {
4066         struct inode *inode;
4067
4068         inode = btrfs_lookup_dentry(dir, dentry);
4069         if (IS_ERR(inode))
4070                 return ERR_CAST(inode);
4071
4072         return d_splice_alias(inode, dentry);
4073 }
4074
4075 unsigned char btrfs_filetype_table[] = {
4076         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
4077 };
4078
4079 static int btrfs_real_readdir(struct file *filp, void *dirent,
4080                               filldir_t filldir)
4081 {
4082         struct inode *inode = filp->f_dentry->d_inode;
4083         struct btrfs_root *root = BTRFS_I(inode)->root;
4084         struct btrfs_item *item;
4085         struct btrfs_dir_item *di;
4086         struct btrfs_key key;
4087         struct btrfs_key found_key;
4088         struct btrfs_path *path;
4089         struct list_head ins_list;
4090         struct list_head del_list;
4091         int ret;
4092         struct extent_buffer *leaf;
4093         int slot;
4094         unsigned char d_type;
4095         int over = 0;
4096         u32 di_cur;
4097         u32 di_total;
4098         u32 di_len;
4099         int key_type = BTRFS_DIR_INDEX_KEY;
4100         char tmp_name[32];
4101         char *name_ptr;
4102         int name_len;
4103         int is_curr = 0;        /* filp->f_pos points to the current index? */
4104
4105         /* FIXME, use a real flag for deciding about the key type */
4106         if (root->fs_info->tree_root == root)
4107                 key_type = BTRFS_DIR_ITEM_KEY;
4108
4109         /* special case for "." */
4110         if (filp->f_pos == 0) {
4111                 over = filldir(dirent, ".", 1, 1, btrfs_ino(inode), DT_DIR);
4112                 if (over)
4113                         return 0;
4114                 filp->f_pos = 1;
4115         }
4116         /* special case for .., just use the back ref */
4117         if (filp->f_pos == 1) {
4118                 u64 pino = parent_ino(filp->f_path.dentry);
4119                 over = filldir(dirent, "..", 2,
4120                                2, pino, DT_DIR);
4121                 if (over)
4122                         return 0;
4123                 filp->f_pos = 2;
4124         }
4125         path = btrfs_alloc_path();
4126         if (!path)
4127                 return -ENOMEM;
4128         path->reada = 2;
4129
4130         if (key_type == BTRFS_DIR_INDEX_KEY) {
4131                 INIT_LIST_HEAD(&ins_list);
4132                 INIT_LIST_HEAD(&del_list);
4133                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
4134         }
4135
4136         btrfs_set_key_type(&key, key_type);
4137         key.offset = filp->f_pos;
4138         key.objectid = btrfs_ino(inode);
4139
4140         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4141         if (ret < 0)
4142                 goto err;
4143
4144         while (1) {
4145                 leaf = path->nodes[0];
4146                 slot = path->slots[0];
4147                 if (slot >= btrfs_header_nritems(leaf)) {
4148                         ret = btrfs_next_leaf(root, path);
4149                         if (ret < 0)
4150                                 goto err;
4151                         else if (ret > 0)
4152                                 break;
4153                         continue;
4154                 }
4155
4156                 item = btrfs_item_nr(leaf, slot);
4157                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
4158
4159                 if (found_key.objectid != key.objectid)
4160                         break;
4161                 if (btrfs_key_type(&found_key) != key_type)
4162                         break;
4163                 if (found_key.offset < filp->f_pos)
4164                         goto next;
4165                 if (key_type == BTRFS_DIR_INDEX_KEY &&
4166                     btrfs_should_delete_dir_index(&del_list,
4167                                                   found_key.offset))
4168                         goto next;
4169
4170                 filp->f_pos = found_key.offset;
4171                 is_curr = 1;
4172
4173                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
4174                 di_cur = 0;
4175                 di_total = btrfs_item_size(leaf, item);
4176
4177                 while (di_cur < di_total) {
4178                         struct btrfs_key location;
4179
4180                         if (verify_dir_item(root, leaf, di))
4181                                 break;
4182
4183                         name_len = btrfs_dir_name_len(leaf, di);
4184                         if (name_len <= sizeof(tmp_name)) {
4185                                 name_ptr = tmp_name;
4186                         } else {
4187                                 name_ptr = kmalloc(name_len, GFP_NOFS);
4188                                 if (!name_ptr) {
4189                                         ret = -ENOMEM;
4190                                         goto err;
4191                                 }
4192                         }
4193                         read_extent_buffer(leaf, name_ptr,
4194                                            (unsigned long)(di + 1), name_len);
4195
4196                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
4197                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
4198
4199                         /* is this a reference to our own snapshot? If so
4200                          * skip it
4201                          */
4202                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
4203                             location.objectid == root->root_key.objectid) {
4204                                 over = 0;
4205                                 goto skip;
4206                         }
4207                         over = filldir(dirent, name_ptr, name_len,
4208                                        found_key.offset, location.objectid,
4209                                        d_type);
4210
4211 skip:
4212                         if (name_ptr != tmp_name)
4213                                 kfree(name_ptr);
4214
4215                         if (over)
4216                                 goto nopos;
4217                         di_len = btrfs_dir_name_len(leaf, di) +
4218                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
4219                         di_cur += di_len;
4220                         di = (struct btrfs_dir_item *)((char *)di + di_len);
4221                 }
4222 next:
4223                 path->slots[0]++;
4224         }
4225
4226         if (key_type == BTRFS_DIR_INDEX_KEY) {
4227                 if (is_curr)
4228                         filp->f_pos++;
4229                 ret = btrfs_readdir_delayed_dir_index(filp, dirent, filldir,
4230                                                       &ins_list);
4231                 if (ret)
4232                         goto nopos;
4233         }
4234
4235         /* Reached end of directory/root. Bump pos past the last item. */
4236         if (key_type == BTRFS_DIR_INDEX_KEY)
4237                 /*
4238                  * 32-bit glibc will use getdents64, but then strtol -
4239                  * so the last number we can serve is this.
4240                  */
4241                 filp->f_pos = 0x7fffffff;
4242         else
4243                 filp->f_pos++;
4244 nopos:
4245         ret = 0;
4246 err:
4247         if (key_type == BTRFS_DIR_INDEX_KEY)
4248                 btrfs_put_delayed_items(&ins_list, &del_list);
4249         btrfs_free_path(path);
4250         return ret;
4251 }
4252
4253 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
4254 {
4255         struct btrfs_root *root = BTRFS_I(inode)->root;
4256         struct btrfs_trans_handle *trans;
4257         int ret = 0;
4258         bool nolock = false;
4259
4260         if (BTRFS_I(inode)->dummy_inode)
4261                 return 0;
4262
4263         smp_mb();
4264         if (root->fs_info->closing && is_free_space_inode(root, inode))
4265                 nolock = true;
4266
4267         if (wbc->sync_mode == WB_SYNC_ALL) {
4268                 if (nolock)
4269                         trans = btrfs_join_transaction_nolock(root, 1);
4270                 else
4271                         trans = btrfs_join_transaction(root, 1);
4272                 if (IS_ERR(trans))
4273                         return PTR_ERR(trans);
4274                 btrfs_set_trans_block_group(trans, inode);
4275                 if (nolock)
4276                         ret = btrfs_end_transaction_nolock(trans, root);
4277                 else
4278                         ret = btrfs_commit_transaction(trans, root);
4279         }
4280         return ret;
4281 }
4282
4283 /*
4284  * This is somewhat expensive, updating the tree every time the
4285  * inode changes.  But, it is most likely to find the inode in cache.
4286  * FIXME, needs more benchmarking...there are no reasons other than performance
4287  * to keep or drop this code.
4288  */
4289 void btrfs_dirty_inode(struct inode *inode)
4290 {
4291         struct btrfs_root *root = BTRFS_I(inode)->root;
4292         struct btrfs_trans_handle *trans;
4293         int ret;
4294
4295         if (BTRFS_I(inode)->dummy_inode)
4296                 return;
4297
4298         trans = btrfs_join_transaction(root, 1);
4299         BUG_ON(IS_ERR(trans));
4300         btrfs_set_trans_block_group(trans, inode);
4301
4302         ret = btrfs_update_inode(trans, root, inode);
4303         if (ret && ret == -ENOSPC) {
4304                 /* whoops, lets try again with the full transaction */
4305                 btrfs_end_transaction(trans, root);
4306                 trans = btrfs_start_transaction(root, 1);
4307                 if (IS_ERR(trans)) {
4308                         printk_ratelimited(KERN_ERR "btrfs: fail to "
4309                                        "dirty  inode %llu error %ld\n",
4310                                        (unsigned long long)btrfs_ino(inode),
4311                                        PTR_ERR(trans));
4312                         return;
4313                 }
4314                 btrfs_set_trans_block_group(trans, inode);
4315
4316                 ret = btrfs_update_inode(trans, root, inode);
4317                 if (ret) {
4318                         printk_ratelimited(KERN_ERR "btrfs: fail to "
4319                                        "dirty  inode %llu error %d\n",
4320                                        (unsigned long long)btrfs_ino(inode),
4321                                        ret);
4322                 }
4323         }
4324         btrfs_end_transaction(trans, root);
4325         if (BTRFS_I(inode)->delayed_node)
4326                 btrfs_balance_delayed_items(root);
4327 }
4328
4329 /*
4330  * find the highest existing sequence number in a directory
4331  * and then set the in-memory index_cnt variable to reflect
4332  * free sequence numbers
4333  */
4334 static int btrfs_set_inode_index_count(struct inode *inode)
4335 {
4336         struct btrfs_root *root = BTRFS_I(inode)->root;
4337         struct btrfs_key key, found_key;
4338         struct btrfs_path *path;
4339         struct extent_buffer *leaf;
4340         int ret;
4341
4342         key.objectid = btrfs_ino(inode);
4343         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
4344         key.offset = (u64)-1;
4345
4346         path = btrfs_alloc_path();
4347         if (!path)
4348                 return -ENOMEM;
4349
4350         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4351         if (ret < 0)
4352                 goto out;
4353         /* FIXME: we should be able to handle this */
4354         if (ret == 0)
4355                 goto out;
4356         ret = 0;
4357
4358         /*
4359          * MAGIC NUMBER EXPLANATION:
4360          * since we search a directory based on f_pos we have to start at 2
4361          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
4362          * else has to start at 2
4363          */
4364         if (path->slots[0] == 0) {
4365                 BTRFS_I(inode)->index_cnt = 2;
4366                 goto out;
4367         }
4368
4369         path->slots[0]--;
4370
4371         leaf = path->nodes[0];
4372         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4373
4374         if (found_key.objectid != btrfs_ino(inode) ||
4375             btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
4376                 BTRFS_I(inode)->index_cnt = 2;
4377                 goto out;
4378         }
4379
4380         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
4381 out:
4382         btrfs_free_path(path);
4383         return ret;
4384 }
4385
4386 /*
4387  * helper to find a free sequence number in a given directory.  This current
4388  * code is very simple, later versions will do smarter things in the btree
4389  */
4390 int btrfs_set_inode_index(struct inode *dir, u64 *index)
4391 {
4392         int ret = 0;
4393
4394         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
4395                 ret = btrfs_inode_delayed_dir_index_count(dir);
4396                 if (ret) {
4397                         ret = btrfs_set_inode_index_count(dir);
4398                         if (ret)
4399                                 return ret;
4400                 }
4401         }
4402
4403         *index = BTRFS_I(dir)->index_cnt;
4404         BTRFS_I(dir)->index_cnt++;
4405
4406         return ret;
4407 }
4408
4409 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
4410                                      struct btrfs_root *root,
4411                                      struct inode *dir,
4412                                      const char *name, int name_len,
4413                                      u64 ref_objectid, u64 objectid,
4414                                      u64 alloc_hint, int mode, u64 *index)
4415 {
4416         struct inode *inode;
4417         struct btrfs_inode_item *inode_item;
4418         struct btrfs_key *location;
4419         struct btrfs_path *path;
4420         struct btrfs_inode_ref *ref;
4421         struct btrfs_key key[2];
4422         u32 sizes[2];
4423         unsigned long ptr;
4424         int ret;
4425         int owner;
4426
4427         path = btrfs_alloc_path();
4428         BUG_ON(!path);
4429
4430         inode = new_inode(root->fs_info->sb);
4431         if (!inode) {
4432                 btrfs_free_path(path);
4433                 return ERR_PTR(-ENOMEM);
4434         }
4435
4436         /*
4437          * we have to initialize this early, so we can reclaim the inode
4438          * number if we fail afterwards in this function.
4439          */
4440         inode->i_ino = objectid;
4441
4442         if (dir) {
4443                 trace_btrfs_inode_request(dir);
4444
4445                 ret = btrfs_set_inode_index(dir, index);
4446                 if (ret) {
4447                         btrfs_free_path(path);
4448                         iput(inode);
4449                         return ERR_PTR(ret);
4450                 }
4451         }
4452         /*
4453          * index_cnt is ignored for everything but a dir,
4454          * btrfs_get_inode_index_count has an explanation for the magic
4455          * number
4456          */
4457         BTRFS_I(inode)->index_cnt = 2;
4458         BTRFS_I(inode)->root = root;
4459         BTRFS_I(inode)->generation = trans->transid;
4460         inode->i_generation = BTRFS_I(inode)->generation;
4461         btrfs_set_inode_space_info(root, inode);
4462
4463         if (mode & S_IFDIR)
4464                 owner = 0;
4465         else
4466                 owner = 1;
4467         BTRFS_I(inode)->block_group =
4468                         btrfs_find_block_group(root, 0, alloc_hint, owner);
4469
4470         key[0].objectid = objectid;
4471         btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
4472         key[0].offset = 0;
4473
4474         key[1].objectid = objectid;
4475         btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
4476         key[1].offset = ref_objectid;
4477
4478         sizes[0] = sizeof(struct btrfs_inode_item);
4479         sizes[1] = name_len + sizeof(*ref);
4480
4481         path->leave_spinning = 1;
4482         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, 2);
4483         if (ret != 0)
4484                 goto fail;
4485
4486         inode_init_owner(inode, dir, mode);
4487         inode_set_bytes(inode, 0);
4488         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
4489         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
4490                                   struct btrfs_inode_item);
4491         fill_inode_item(trans, path->nodes[0], inode_item, inode);
4492
4493         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
4494                              struct btrfs_inode_ref);
4495         btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
4496         btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
4497         ptr = (unsigned long)(ref + 1);
4498         write_extent_buffer(path->nodes[0], name, ptr, name_len);
4499
4500         btrfs_mark_buffer_dirty(path->nodes[0]);
4501         btrfs_free_path(path);
4502
4503         location = &BTRFS_I(inode)->location;
4504         location->objectid = objectid;
4505         location->offset = 0;
4506         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
4507
4508         btrfs_inherit_iflags(inode, dir);
4509
4510         if ((mode & S_IFREG)) {
4511                 if (btrfs_test_opt(root, NODATASUM))
4512                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
4513                 if (btrfs_test_opt(root, NODATACOW) ||
4514                     (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW))
4515                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
4516         }
4517
4518         insert_inode_hash(inode);
4519         inode_tree_add(inode);
4520
4521         trace_btrfs_inode_new(inode);
4522
4523         return inode;
4524 fail:
4525         if (dir)
4526                 BTRFS_I(dir)->index_cnt--;
4527         btrfs_free_path(path);
4528         iput(inode);
4529         return ERR_PTR(ret);
4530 }
4531
4532 static inline u8 btrfs_inode_type(struct inode *inode)
4533 {
4534         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
4535 }
4536
4537 /*
4538  * utility function to add 'inode' into 'parent_inode' with
4539  * a give name and a given sequence number.
4540  * if 'add_backref' is true, also insert a backref from the
4541  * inode to the parent directory.
4542  */
4543 int btrfs_add_link(struct btrfs_trans_handle *trans,
4544                    struct inode *parent_inode, struct inode *inode,
4545                    const char *name, int name_len, int add_backref, u64 index)
4546 {
4547         int ret = 0;
4548         struct btrfs_key key;
4549         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
4550         u64 ino = btrfs_ino(inode);
4551         u64 parent_ino = btrfs_ino(parent_inode);
4552
4553         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4554                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
4555         } else {
4556                 key.objectid = ino;
4557                 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
4558                 key.offset = 0;
4559         }
4560
4561         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4562                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
4563                                          key.objectid, root->root_key.objectid,
4564                                          parent_ino, index, name, name_len);
4565         } else if (add_backref) {
4566                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
4567                                              parent_ino, index);
4568         }
4569
4570         if (ret == 0) {
4571                 ret = btrfs_insert_dir_item(trans, root, name, name_len,
4572                                             parent_inode, &key,
4573                                             btrfs_inode_type(inode), index);
4574                 BUG_ON(ret);
4575
4576                 btrfs_i_size_write(parent_inode, parent_inode->i_size +
4577                                    name_len * 2);
4578                 parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
4579                 ret = btrfs_update_inode(trans, root, parent_inode);
4580         }
4581         return ret;
4582 }
4583
4584 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
4585                             struct inode *dir, struct dentry *dentry,
4586                             struct inode *inode, int backref, u64 index)
4587 {
4588         int err = btrfs_add_link(trans, dir, inode,
4589                                  dentry->d_name.name, dentry->d_name.len,
4590                                  backref, index);
4591         if (!err) {
4592                 d_instantiate(dentry, inode);
4593                 return 0;
4594         }
4595         if (err > 0)
4596                 err = -EEXIST;
4597         return err;
4598 }
4599
4600 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
4601                         int mode, dev_t rdev)
4602 {
4603         struct btrfs_trans_handle *trans;
4604         struct btrfs_root *root = BTRFS_I(dir)->root;
4605         struct inode *inode = NULL;
4606         int err;
4607         int drop_inode = 0;
4608         u64 objectid;
4609         unsigned long nr = 0;
4610         u64 index = 0;
4611
4612         if (!new_valid_dev(rdev))
4613                 return -EINVAL;
4614
4615         /*
4616          * 2 for inode item and ref
4617          * 2 for dir items
4618          * 1 for xattr if selinux is on
4619          */
4620         trans = btrfs_start_transaction(root, 5);
4621         if (IS_ERR(trans))
4622                 return PTR_ERR(trans);
4623
4624         btrfs_set_trans_block_group(trans, dir);
4625
4626         err = btrfs_find_free_ino(root, &objectid);
4627         if (err)
4628                 goto out_unlock;
4629
4630         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4631                                 dentry->d_name.len, btrfs_ino(dir), objectid,
4632                                 BTRFS_I(dir)->block_group, mode, &index);
4633         if (IS_ERR(inode)) {
4634                 err = PTR_ERR(inode);
4635                 goto out_unlock;
4636         }
4637
4638         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4639         if (err) {
4640                 drop_inode = 1;
4641                 goto out_unlock;
4642         }
4643
4644         btrfs_set_trans_block_group(trans, inode);
4645         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4646         if (err)
4647                 drop_inode = 1;
4648         else {
4649                 inode->i_op = &btrfs_special_inode_operations;
4650                 init_special_inode(inode, inode->i_mode, rdev);
4651                 btrfs_update_inode(trans, root, inode);
4652         }
4653         btrfs_update_inode_block_group(trans, inode);
4654         btrfs_update_inode_block_group(trans, dir);
4655 out_unlock:
4656         nr = trans->blocks_used;
4657         btrfs_end_transaction_throttle(trans, root);
4658         btrfs_btree_balance_dirty(root, nr);
4659         if (drop_inode) {
4660                 inode_dec_link_count(inode);
4661                 iput(inode);
4662         }
4663         return err;
4664 }
4665
4666 static int btrfs_create(struct inode *dir, struct dentry *dentry,
4667                         int mode, struct nameidata *nd)
4668 {
4669         struct btrfs_trans_handle *trans;
4670         struct btrfs_root *root = BTRFS_I(dir)->root;
4671         struct inode *inode = NULL;
4672         int drop_inode = 0;
4673         int err;
4674         unsigned long nr = 0;
4675         u64 objectid;
4676         u64 index = 0;
4677
4678         /*
4679          * 2 for inode item and ref
4680          * 2 for dir items
4681          * 1 for xattr if selinux is on
4682          */
4683         trans = btrfs_start_transaction(root, 5);
4684         if (IS_ERR(trans))
4685                 return PTR_ERR(trans);
4686
4687         btrfs_set_trans_block_group(trans, dir);
4688
4689         err = btrfs_find_free_ino(root, &objectid);
4690         if (err)
4691                 goto out_unlock;
4692
4693         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4694                                 dentry->d_name.len, btrfs_ino(dir), objectid,
4695                                 BTRFS_I(dir)->block_group, mode, &index);
4696         if (IS_ERR(inode)) {
4697                 err = PTR_ERR(inode);
4698                 goto out_unlock;
4699         }
4700
4701         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4702         if (err) {
4703                 drop_inode = 1;
4704                 goto out_unlock;
4705         }
4706
4707         btrfs_set_trans_block_group(trans, inode);
4708         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4709         if (err)
4710                 drop_inode = 1;
4711         else {
4712                 inode->i_mapping->a_ops = &btrfs_aops;
4713                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
4714                 inode->i_fop = &btrfs_file_operations;
4715                 inode->i_op = &btrfs_file_inode_operations;
4716                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
4717         }
4718         btrfs_update_inode_block_group(trans, inode);
4719         btrfs_update_inode_block_group(trans, dir);
4720 out_unlock:
4721         nr = trans->blocks_used;
4722         btrfs_end_transaction_throttle(trans, root);
4723         if (drop_inode) {
4724                 inode_dec_link_count(inode);
4725                 iput(inode);
4726         }
4727         btrfs_btree_balance_dirty(root, nr);
4728         return err;
4729 }
4730
4731 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
4732                       struct dentry *dentry)
4733 {
4734         struct btrfs_trans_handle *trans;
4735         struct btrfs_root *root = BTRFS_I(dir)->root;
4736         struct inode *inode = old_dentry->d_inode;
4737         u64 index;
4738         unsigned long nr = 0;
4739         int err;
4740         int drop_inode = 0;
4741
4742         /* do not allow sys_link's with other subvols of the same device */
4743         if (root->objectid != BTRFS_I(inode)->root->objectid)
4744                 return -EXDEV;
4745
4746         if (inode->i_nlink == ~0U)
4747                 return -EMLINK;
4748
4749         err = btrfs_set_inode_index(dir, &index);
4750         if (err)
4751                 goto fail;
4752
4753         /*
4754          * 2 items for inode and inode ref
4755          * 2 items for dir items
4756          * 1 item for parent inode
4757          */
4758         trans = btrfs_start_transaction(root, 5);
4759         if (IS_ERR(trans)) {
4760                 err = PTR_ERR(trans);
4761                 goto fail;
4762         }
4763
4764         btrfs_inc_nlink(inode);
4765         inode->i_ctime = CURRENT_TIME;
4766
4767         btrfs_set_trans_block_group(trans, dir);
4768         ihold(inode);
4769
4770         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
4771
4772         if (err) {
4773                 drop_inode = 1;
4774         } else {
4775                 struct dentry *parent = dget_parent(dentry);
4776                 btrfs_update_inode_block_group(trans, dir);
4777                 err = btrfs_update_inode(trans, root, inode);
4778                 BUG_ON(err);
4779                 btrfs_log_new_name(trans, inode, NULL, parent);
4780                 dput(parent);
4781         }
4782
4783         nr = trans->blocks_used;
4784         btrfs_end_transaction_throttle(trans, root);
4785 fail:
4786         if (drop_inode) {
4787                 inode_dec_link_count(inode);
4788                 iput(inode);
4789         }
4790         btrfs_btree_balance_dirty(root, nr);
4791         return err;
4792 }
4793
4794 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
4795 {
4796         struct inode *inode = NULL;
4797         struct btrfs_trans_handle *trans;
4798         struct btrfs_root *root = BTRFS_I(dir)->root;
4799         int err = 0;
4800         int drop_on_err = 0;
4801         u64 objectid = 0;
4802         u64 index = 0;
4803         unsigned long nr = 1;
4804
4805         /*
4806          * 2 items for inode and ref
4807          * 2 items for dir items
4808          * 1 for xattr if selinux is on
4809          */
4810         trans = btrfs_start_transaction(root, 5);
4811         if (IS_ERR(trans))
4812                 return PTR_ERR(trans);
4813         btrfs_set_trans_block_group(trans, dir);
4814
4815         err = btrfs_find_free_ino(root, &objectid);
4816         if (err)
4817                 goto out_fail;
4818
4819         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4820                                 dentry->d_name.len, btrfs_ino(dir), objectid,
4821                                 BTRFS_I(dir)->block_group, S_IFDIR | mode,
4822                                 &index);
4823         if (IS_ERR(inode)) {
4824                 err = PTR_ERR(inode);
4825                 goto out_fail;
4826         }
4827
4828         drop_on_err = 1;
4829
4830         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4831         if (err)
4832                 goto out_fail;
4833
4834         inode->i_op = &btrfs_dir_inode_operations;
4835         inode->i_fop = &btrfs_dir_file_operations;
4836         btrfs_set_trans_block_group(trans, inode);
4837
4838         btrfs_i_size_write(inode, 0);
4839         err = btrfs_update_inode(trans, root, inode);
4840         if (err)
4841                 goto out_fail;
4842
4843         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
4844                              dentry->d_name.len, 0, index);
4845         if (err)
4846                 goto out_fail;
4847
4848         d_instantiate(dentry, inode);
4849         drop_on_err = 0;
4850         btrfs_update_inode_block_group(trans, inode);
4851         btrfs_update_inode_block_group(trans, dir);
4852
4853 out_fail:
4854         nr = trans->blocks_used;
4855         btrfs_end_transaction_throttle(trans, root);
4856         if (drop_on_err)
4857                 iput(inode);
4858         btrfs_btree_balance_dirty(root, nr);
4859         return err;
4860 }
4861
4862 /* helper for btfs_get_extent.  Given an existing extent in the tree,
4863  * and an extent that you want to insert, deal with overlap and insert
4864  * the new extent into the tree.
4865  */
4866 static int merge_extent_mapping(struct extent_map_tree *em_tree,
4867                                 struct extent_map *existing,
4868                                 struct extent_map *em,
4869                                 u64 map_start, u64 map_len)
4870 {
4871         u64 start_diff;
4872
4873         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
4874         start_diff = map_start - em->start;
4875         em->start = map_start;
4876         em->len = map_len;
4877         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
4878             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
4879                 em->block_start += start_diff;
4880                 em->block_len -= start_diff;
4881         }
4882         return add_extent_mapping(em_tree, em);
4883 }
4884
4885 static noinline int uncompress_inline(struct btrfs_path *path,
4886                                       struct inode *inode, struct page *page,
4887                                       size_t pg_offset, u64 extent_offset,
4888                                       struct btrfs_file_extent_item *item)
4889 {
4890         int ret;
4891         struct extent_buffer *leaf = path->nodes[0];
4892         char *tmp;
4893         size_t max_size;
4894         unsigned long inline_size;
4895         unsigned long ptr;
4896         int compress_type;
4897
4898         WARN_ON(pg_offset != 0);
4899         compress_type = btrfs_file_extent_compression(leaf, item);
4900         max_size = btrfs_file_extent_ram_bytes(leaf, item);
4901         inline_size = btrfs_file_extent_inline_item_len(leaf,
4902                                         btrfs_item_nr(leaf, path->slots[0]));
4903         tmp = kmalloc(inline_size, GFP_NOFS);
4904         if (!tmp)
4905                 return -ENOMEM;
4906         ptr = btrfs_file_extent_inline_start(item);
4907
4908         read_extent_buffer(leaf, tmp, ptr, inline_size);
4909
4910         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
4911         ret = btrfs_decompress(compress_type, tmp, page,
4912                                extent_offset, inline_size, max_size);
4913         if (ret) {
4914                 char *kaddr = kmap_atomic(page, KM_USER0);
4915                 unsigned long copy_size = min_t(u64,
4916                                   PAGE_CACHE_SIZE - pg_offset,
4917                                   max_size - extent_offset);
4918                 memset(kaddr + pg_offset, 0, copy_size);
4919                 kunmap_atomic(kaddr, KM_USER0);
4920         }
4921         kfree(tmp);
4922         return 0;
4923 }
4924
4925 /*
4926  * a bit scary, this does extent mapping from logical file offset to the disk.
4927  * the ugly parts come from merging extents from the disk with the in-ram
4928  * representation.  This gets more complex because of the data=ordered code,
4929  * where the in-ram extents might be locked pending data=ordered completion.
4930  *
4931  * This also copies inline extents directly into the page.
4932  */
4933
4934 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
4935                                     size_t pg_offset, u64 start, u64 len,
4936                                     int create)
4937 {
4938         int ret;
4939         int err = 0;
4940         u64 bytenr;
4941         u64 extent_start = 0;
4942         u64 extent_end = 0;
4943         u64 objectid = btrfs_ino(inode);
4944         u32 found_type;
4945         struct btrfs_path *path = NULL;
4946         struct btrfs_root *root = BTRFS_I(inode)->root;
4947         struct btrfs_file_extent_item *item;
4948         struct extent_buffer *leaf;
4949         struct btrfs_key found_key;
4950         struct extent_map *em = NULL;
4951         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4952         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4953         struct btrfs_trans_handle *trans = NULL;
4954         int compress_type;
4955
4956 again:
4957         read_lock(&em_tree->lock);
4958         em = lookup_extent_mapping(em_tree, start, len);
4959         if (em)
4960                 em->bdev = root->fs_info->fs_devices->latest_bdev;
4961         read_unlock(&em_tree->lock);
4962
4963         if (em) {
4964                 if (em->start > start || em->start + em->len <= start)
4965                         free_extent_map(em);
4966                 else if (em->block_start == EXTENT_MAP_INLINE && page)
4967                         free_extent_map(em);
4968                 else
4969                         goto out;
4970         }
4971         em = alloc_extent_map();
4972         if (!em) {
4973                 err = -ENOMEM;
4974                 goto out;
4975         }
4976         em->bdev = root->fs_info->fs_devices->latest_bdev;
4977         em->start = EXTENT_MAP_HOLE;
4978         em->orig_start = EXTENT_MAP_HOLE;
4979         em->len = (u64)-1;
4980         em->block_len = (u64)-1;
4981
4982         if (!path) {
4983                 path = btrfs_alloc_path();
4984                 BUG_ON(!path);
4985         }
4986
4987         ret = btrfs_lookup_file_extent(trans, root, path,
4988                                        objectid, start, trans != NULL);
4989         if (ret < 0) {
4990                 err = ret;
4991                 goto out;
4992         }
4993
4994         if (ret != 0) {
4995                 if (path->slots[0] == 0)
4996                         goto not_found;
4997                 path->slots[0]--;
4998         }
4999
5000         leaf = path->nodes[0];
5001         item = btrfs_item_ptr(leaf, path->slots[0],
5002                               struct btrfs_file_extent_item);
5003         /* are we inside the extent that was found? */
5004         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5005         found_type = btrfs_key_type(&found_key);
5006         if (found_key.objectid != objectid ||
5007             found_type != BTRFS_EXTENT_DATA_KEY) {
5008                 goto not_found;
5009         }
5010
5011         found_type = btrfs_file_extent_type(leaf, item);
5012         extent_start = found_key.offset;
5013         compress_type = btrfs_file_extent_compression(leaf, item);
5014         if (found_type == BTRFS_FILE_EXTENT_REG ||
5015             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
5016                 extent_end = extent_start +
5017                        btrfs_file_extent_num_bytes(leaf, item);
5018         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
5019                 size_t size;
5020                 size = btrfs_file_extent_inline_len(leaf, item);
5021                 extent_end = (extent_start + size + root->sectorsize - 1) &
5022                         ~((u64)root->sectorsize - 1);
5023         }
5024
5025         if (start >= extent_end) {
5026                 path->slots[0]++;
5027                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
5028                         ret = btrfs_next_leaf(root, path);
5029                         if (ret < 0) {
5030                                 err = ret;
5031                                 goto out;
5032                         }
5033                         if (ret > 0)
5034                                 goto not_found;
5035                         leaf = path->nodes[0];
5036                 }
5037                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5038                 if (found_key.objectid != objectid ||
5039                     found_key.type != BTRFS_EXTENT_DATA_KEY)
5040                         goto not_found;
5041                 if (start + len <= found_key.offset)
5042                         goto not_found;
5043                 em->start = start;
5044                 em->len = found_key.offset - start;
5045                 goto not_found_em;
5046         }
5047
5048         if (found_type == BTRFS_FILE_EXTENT_REG ||
5049             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
5050                 em->start = extent_start;
5051                 em->len = extent_end - extent_start;
5052                 em->orig_start = extent_start -
5053                                  btrfs_file_extent_offset(leaf, item);
5054                 bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
5055                 if (bytenr == 0) {
5056                         em->block_start = EXTENT_MAP_HOLE;
5057                         goto insert;
5058                 }
5059                 if (compress_type != BTRFS_COMPRESS_NONE) {
5060                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
5061                         em->compress_type = compress_type;
5062                         em->block_start = bytenr;
5063                         em->block_len = btrfs_file_extent_disk_num_bytes(leaf,
5064                                                                          item);
5065                 } else {
5066                         bytenr += btrfs_file_extent_offset(leaf, item);
5067                         em->block_start = bytenr;
5068                         em->block_len = em->len;
5069                         if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
5070                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
5071                 }
5072                 goto insert;
5073         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
5074                 unsigned long ptr;
5075                 char *map;
5076                 size_t size;
5077                 size_t extent_offset;
5078                 size_t copy_size;
5079
5080                 em->block_start = EXTENT_MAP_INLINE;
5081                 if (!page || create) {
5082                         em->start = extent_start;
5083                         em->len = extent_end - extent_start;
5084                         goto out;
5085                 }
5086
5087                 size = btrfs_file_extent_inline_len(leaf, item);
5088                 extent_offset = page_offset(page) + pg_offset - extent_start;
5089                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
5090                                 size - extent_offset);
5091                 em->start = extent_start + extent_offset;
5092                 em->len = (copy_size + root->sectorsize - 1) &
5093                         ~((u64)root->sectorsize - 1);
5094                 em->orig_start = EXTENT_MAP_INLINE;
5095                 if (compress_type) {
5096                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
5097                         em->compress_type = compress_type;
5098                 }
5099                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
5100                 if (create == 0 && !PageUptodate(page)) {
5101                         if (btrfs_file_extent_compression(leaf, item) !=
5102                             BTRFS_COMPRESS_NONE) {
5103                                 ret = uncompress_inline(path, inode, page,
5104                                                         pg_offset,
5105                                                         extent_offset, item);
5106                                 BUG_ON(ret);
5107                         } else {
5108                                 map = kmap(page);
5109                                 read_extent_buffer(leaf, map + pg_offset, ptr,
5110                                                    copy_size);
5111                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
5112                                         memset(map + pg_offset + copy_size, 0,
5113                                                PAGE_CACHE_SIZE - pg_offset -
5114                                                copy_size);
5115                                 }
5116                                 kunmap(page);
5117                         }
5118                         flush_dcache_page(page);
5119                 } else if (create && PageUptodate(page)) {
5120                         WARN_ON(1);
5121                         if (!trans) {
5122                                 kunmap(page);
5123                                 free_extent_map(em);
5124                                 em = NULL;
5125                                 btrfs_release_path(path);
5126                                 trans = btrfs_join_transaction(root, 1);
5127                                 if (IS_ERR(trans))
5128                                         return ERR_CAST(trans);
5129                                 goto again;
5130                         }
5131                         map = kmap(page);
5132                         write_extent_buffer(leaf, map + pg_offset, ptr,
5133                                             copy_size);
5134                         kunmap(page);
5135                         btrfs_mark_buffer_dirty(leaf);
5136                 }
5137                 set_extent_uptodate(io_tree, em->start,
5138                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
5139                 goto insert;
5140         } else {
5141                 printk(KERN_ERR "btrfs unknown found_type %d\n", found_type);
5142                 WARN_ON(1);
5143         }
5144 not_found:
5145         em->start = start;
5146         em->len = len;
5147 not_found_em:
5148         em->block_start = EXTENT_MAP_HOLE;
5149         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
5150 insert:
5151         btrfs_release_path(path);
5152         if (em->start > start || extent_map_end(em) <= start) {
5153                 printk(KERN_ERR "Btrfs: bad extent! em: [%llu %llu] passed "
5154                        "[%llu %llu]\n", (unsigned long long)em->start,
5155                        (unsigned long long)em->len,
5156                        (unsigned long long)start,
5157                        (unsigned long long)len);
5158                 err = -EIO;
5159                 goto out;
5160         }
5161
5162         err = 0;
5163         write_lock(&em_tree->lock);
5164         ret = add_extent_mapping(em_tree, em);
5165         /* it is possible that someone inserted the extent into the tree
5166          * while we had the lock dropped.  It is also possible that
5167          * an overlapping map exists in the tree
5168          */
5169         if (ret == -EEXIST) {
5170                 struct extent_map *existing;
5171
5172                 ret = 0;
5173
5174                 existing = lookup_extent_mapping(em_tree, start, len);
5175                 if (existing && (existing->start > start ||
5176                     existing->start + existing->len <= start)) {
5177                         free_extent_map(existing);
5178                         existing = NULL;
5179                 }
5180                 if (!existing) {
5181                         existing = lookup_extent_mapping(em_tree, em->start,
5182                                                          em->len);
5183                         if (existing) {
5184                                 err = merge_extent_mapping(em_tree, existing,
5185                                                            em, start,
5186                                                            root->sectorsize);
5187                                 free_extent_map(existing);
5188                                 if (err) {
5189                                         free_extent_map(em);
5190                                         em = NULL;
5191                                 }
5192                         } else {
5193                                 err = -EIO;
5194                                 free_extent_map(em);
5195                                 em = NULL;
5196                         }
5197                 } else {
5198                         free_extent_map(em);
5199                         em = existing;
5200                         err = 0;
5201                 }
5202         }
5203         write_unlock(&em_tree->lock);
5204 out:
5205
5206         trace_btrfs_get_extent(root, em);
5207
5208         if (path)
5209                 btrfs_free_path(path);
5210         if (trans) {
5211                 ret = btrfs_end_transaction(trans, root);
5212                 if (!err)
5213                         err = ret;
5214         }
5215         if (err) {
5216                 free_extent_map(em);
5217                 return ERR_PTR(err);
5218         }
5219         return em;
5220 }
5221
5222 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
5223                                            size_t pg_offset, u64 start, u64 len,
5224                                            int create)
5225 {
5226         struct extent_map *em;
5227         struct extent_map *hole_em = NULL;
5228         u64 range_start = start;
5229         u64 end;
5230         u64 found;
5231         u64 found_end;
5232         int err = 0;
5233
5234         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
5235         if (IS_ERR(em))
5236                 return em;
5237         if (em) {
5238                 /*
5239                  * if our em maps to a hole, there might
5240                  * actually be delalloc bytes behind it
5241                  */
5242                 if (em->block_start != EXTENT_MAP_HOLE)
5243                         return em;
5244                 else
5245                         hole_em = em;
5246         }
5247
5248         /* check to see if we've wrapped (len == -1 or similar) */
5249         end = start + len;
5250         if (end < start)
5251                 end = (u64)-1;
5252         else
5253                 end -= 1;
5254
5255         em = NULL;
5256
5257         /* ok, we didn't find anything, lets look for delalloc */
5258         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
5259                                  end, len, EXTENT_DELALLOC, 1);
5260         found_end = range_start + found;
5261         if (found_end < range_start)
5262                 found_end = (u64)-1;
5263
5264         /*
5265          * we didn't find anything useful, return
5266          * the original results from get_extent()
5267          */
5268         if (range_start > end || found_end <= start) {
5269                 em = hole_em;
5270                 hole_em = NULL;
5271                 goto out;
5272         }
5273
5274         /* adjust the range_start to make sure it doesn't
5275          * go backwards from the start they passed in
5276          */
5277         range_start = max(start,range_start);
5278         found = found_end - range_start;
5279
5280         if (found > 0) {
5281                 u64 hole_start = start;
5282                 u64 hole_len = len;
5283
5284                 em = alloc_extent_map();
5285                 if (!em) {
5286                         err = -ENOMEM;
5287                         goto out;
5288                 }
5289                 /*
5290                  * when btrfs_get_extent can't find anything it
5291                  * returns one huge hole
5292                  *
5293                  * make sure what it found really fits our range, and
5294                  * adjust to make sure it is based on the start from
5295                  * the caller
5296                  */
5297                 if (hole_em) {
5298                         u64 calc_end = extent_map_end(hole_em);
5299
5300                         if (calc_end <= start || (hole_em->start > end)) {
5301                                 free_extent_map(hole_em);
5302                                 hole_em = NULL;
5303                         } else {
5304                                 hole_start = max(hole_em->start, start);
5305                                 hole_len = calc_end - hole_start;
5306                         }
5307                 }
5308                 em->bdev = NULL;
5309                 if (hole_em && range_start > hole_start) {
5310                         /* our hole starts before our delalloc, so we
5311                          * have to return just the parts of the hole
5312                          * that go until  the delalloc starts
5313                          */
5314                         em->len = min(hole_len,
5315                                       range_start - hole_start);
5316                         em->start = hole_start;
5317                         em->orig_start = hole_start;
5318                         /*
5319                          * don't adjust block start at all,
5320                          * it is fixed at EXTENT_MAP_HOLE
5321                          */
5322                         em->block_start = hole_em->block_start;
5323                         em->block_len = hole_len;
5324                 } else {
5325                         em->start = range_start;
5326                         em->len = found;
5327                         em->orig_start = range_start;
5328                         em->block_start = EXTENT_MAP_DELALLOC;
5329                         em->block_len = found;
5330                 }
5331         } else if (hole_em) {
5332                 return hole_em;
5333         }
5334 out:
5335
5336         free_extent_map(hole_em);
5337         if (err) {
5338                 free_extent_map(em);
5339                 return ERR_PTR(err);
5340         }
5341         return em;
5342 }
5343
5344 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
5345                                                   struct extent_map *em,
5346                                                   u64 start, u64 len)
5347 {
5348         struct btrfs_root *root = BTRFS_I(inode)->root;
5349         struct btrfs_trans_handle *trans;
5350         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
5351         struct btrfs_key ins;
5352         u64 alloc_hint;
5353         int ret;
5354         bool insert = false;
5355
5356         /*
5357          * Ok if the extent map we looked up is a hole and is for the exact
5358          * range we want, there is no reason to allocate a new one, however if
5359          * it is not right then we need to free this one and drop the cache for
5360          * our range.
5361          */
5362         if (em->block_start != EXTENT_MAP_HOLE || em->start != start ||
5363             em->len != len) {
5364                 free_extent_map(em);
5365                 em = NULL;
5366                 insert = true;
5367                 btrfs_drop_extent_cache(inode, start, start + len - 1, 0);
5368         }
5369
5370         trans = btrfs_join_transaction(root, 0);
5371         if (IS_ERR(trans))
5372                 return ERR_CAST(trans);
5373
5374         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
5375
5376         alloc_hint = get_extent_allocation_hint(inode, start, len);
5377         ret = btrfs_reserve_extent(trans, root, len, root->sectorsize, 0,
5378                                    alloc_hint, (u64)-1, &ins, 1);
5379         if (ret) {
5380                 em = ERR_PTR(ret);
5381                 goto out;
5382         }
5383
5384         if (!em) {
5385                 em = alloc_extent_map();
5386                 if (!em) {
5387                         em = ERR_PTR(-ENOMEM);
5388                         goto out;
5389                 }
5390         }
5391
5392         em->start = start;
5393         em->orig_start = em->start;
5394         em->len = ins.offset;
5395
5396         em->block_start = ins.objectid;
5397         em->block_len = ins.offset;
5398         em->bdev = root->fs_info->fs_devices->latest_bdev;
5399
5400         /*
5401          * We need to do this because if we're using the original em we searched
5402          * for, we could have EXTENT_FLAG_VACANCY set, and we don't want that.
5403          */
5404         em->flags = 0;
5405         set_bit(EXTENT_FLAG_PINNED, &em->flags);
5406
5407         while (insert) {
5408                 write_lock(&em_tree->lock);
5409                 ret = add_extent_mapping(em_tree, em);
5410                 write_unlock(&em_tree->lock);
5411                 if (ret != -EEXIST)
5412                         break;
5413                 btrfs_drop_extent_cache(inode, start, start + em->len - 1, 0);
5414         }
5415
5416         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
5417                                            ins.offset, ins.offset, 0);
5418         if (ret) {
5419                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
5420                 em = ERR_PTR(ret);
5421         }
5422 out:
5423         btrfs_end_transaction(trans, root);
5424         return em;
5425 }
5426
5427 /*
5428  * returns 1 when the nocow is safe, < 1 on error, 0 if the
5429  * block must be cow'd
5430  */
5431 static noinline int can_nocow_odirect(struct btrfs_trans_handle *trans,
5432                                       struct inode *inode, u64 offset, u64 len)
5433 {
5434         struct btrfs_path *path;
5435         int ret;
5436         struct extent_buffer *leaf;
5437         struct btrfs_root *root = BTRFS_I(inode)->root;
5438         struct btrfs_file_extent_item *fi;
5439         struct btrfs_key key;
5440         u64 disk_bytenr;
5441         u64 backref_offset;
5442         u64 extent_end;
5443         u64 num_bytes;
5444         int slot;
5445         int found_type;
5446
5447         path = btrfs_alloc_path();
5448         if (!path)
5449                 return -ENOMEM;
5450
5451         ret = btrfs_lookup_file_extent(trans, root, path, btrfs_ino(inode),
5452                                        offset, 0);
5453         if (ret < 0)
5454                 goto out;
5455
5456         slot = path->slots[0];
5457         if (ret == 1) {
5458                 if (slot == 0) {
5459                         /* can't find the item, must cow */
5460                         ret = 0;
5461                         goto out;
5462                 }
5463                 slot--;
5464         }
5465         ret = 0;
5466         leaf = path->nodes[0];
5467         btrfs_item_key_to_cpu(leaf, &key, slot);
5468         if (key.objectid != btrfs_ino(inode) ||
5469             key.type != BTRFS_EXTENT_DATA_KEY) {
5470                 /* not our file or wrong item type, must cow */
5471                 goto out;
5472         }
5473
5474         if (key.offset > offset) {
5475                 /* Wrong offset, must cow */
5476                 goto out;
5477         }
5478
5479         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
5480         found_type = btrfs_file_extent_type(leaf, fi);
5481         if (found_type != BTRFS_FILE_EXTENT_REG &&
5482             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
5483                 /* not a regular extent, must cow */
5484                 goto out;
5485         }
5486         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
5487         backref_offset = btrfs_file_extent_offset(leaf, fi);
5488
5489         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
5490         if (extent_end < offset + len) {
5491                 /* extent doesn't include our full range, must cow */
5492                 goto out;
5493         }
5494
5495         if (btrfs_extent_readonly(root, disk_bytenr))
5496                 goto out;
5497
5498         /*
5499          * look for other files referencing this extent, if we
5500          * find any we must cow
5501          */
5502         if (btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
5503                                   key.offset - backref_offset, disk_bytenr))
5504                 goto out;
5505
5506         /*
5507          * adjust disk_bytenr and num_bytes to cover just the bytes
5508          * in this extent we are about to write.  If there
5509          * are any csums in that range we have to cow in order
5510          * to keep the csums correct
5511          */
5512         disk_bytenr += backref_offset;
5513         disk_bytenr += offset - key.offset;
5514         num_bytes = min(offset + len, extent_end) - offset;
5515         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
5516                                 goto out;
5517         /*
5518          * all of the above have passed, it is safe to overwrite this extent
5519          * without cow
5520          */
5521         ret = 1;
5522 out:
5523         btrfs_free_path(path);
5524         return ret;
5525 }
5526
5527 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
5528                                    struct buffer_head *bh_result, int create)
5529 {
5530         struct extent_map *em;
5531         struct btrfs_root *root = BTRFS_I(inode)->root;
5532         u64 start = iblock << inode->i_blkbits;
5533         u64 len = bh_result->b_size;
5534         struct btrfs_trans_handle *trans;
5535
5536         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
5537         if (IS_ERR(em))
5538                 return PTR_ERR(em);
5539
5540         /*
5541          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
5542          * io.  INLINE is special, and we could probably kludge it in here, but
5543          * it's still buffered so for safety lets just fall back to the generic
5544          * buffered path.
5545          *
5546          * For COMPRESSED we _have_ to read the entire extent in so we can
5547          * decompress it, so there will be buffering required no matter what we
5548          * do, so go ahead and fallback to buffered.
5549          *
5550          * We return -ENOTBLK because thats what makes DIO go ahead and go back
5551          * to buffered IO.  Don't blame me, this is the price we pay for using
5552          * the generic code.
5553          */
5554         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
5555             em->block_start == EXTENT_MAP_INLINE) {
5556                 free_extent_map(em);
5557                 return -ENOTBLK;
5558         }
5559
5560         /* Just a good old fashioned hole, return */
5561         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
5562                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
5563                 free_extent_map(em);
5564                 /* DIO will do one hole at a time, so just unlock a sector */
5565                 unlock_extent(&BTRFS_I(inode)->io_tree, start,
5566                               start + root->sectorsize - 1, GFP_NOFS);
5567                 return 0;
5568         }
5569
5570         /*
5571          * We don't allocate a new extent in the following cases
5572          *
5573          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
5574          * existing extent.
5575          * 2) The extent is marked as PREALLOC.  We're good to go here and can
5576          * just use the extent.
5577          *
5578          */
5579         if (!create) {
5580                 len = em->len - (start - em->start);
5581                 goto map;
5582         }
5583
5584         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
5585             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
5586              em->block_start != EXTENT_MAP_HOLE)) {
5587                 int type;
5588                 int ret;
5589                 u64 block_start;
5590
5591                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
5592                         type = BTRFS_ORDERED_PREALLOC;
5593                 else
5594                         type = BTRFS_ORDERED_NOCOW;
5595                 len = min(len, em->len - (start - em->start));
5596                 block_start = em->block_start + (start - em->start);
5597
5598                 /*
5599                  * we're not going to log anything, but we do need
5600                  * to make sure the current transaction stays open
5601                  * while we look for nocow cross refs
5602                  */
5603                 trans = btrfs_join_transaction(root, 0);
5604                 if (IS_ERR(trans))
5605                         goto must_cow;
5606
5607                 if (can_nocow_odirect(trans, inode, start, len) == 1) {
5608                         ret = btrfs_add_ordered_extent_dio(inode, start,
5609                                            block_start, len, len, type);
5610                         btrfs_end_transaction(trans, root);
5611                         if (ret) {
5612                                 free_extent_map(em);
5613                                 return ret;
5614                         }
5615                         goto unlock;
5616                 }
5617                 btrfs_end_transaction(trans, root);
5618         }
5619 must_cow:
5620         /*
5621          * this will cow the extent, reset the len in case we changed
5622          * it above
5623          */
5624         len = bh_result->b_size;
5625         em = btrfs_new_extent_direct(inode, em, start, len);
5626         if (IS_ERR(em))
5627                 return PTR_ERR(em);
5628         len = min(len, em->len - (start - em->start));
5629 unlock:
5630         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, start + len - 1,
5631                           EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DIRTY, 1,
5632                           0, NULL, GFP_NOFS);
5633 map:
5634         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
5635                 inode->i_blkbits;
5636         bh_result->b_size = len;
5637         bh_result->b_bdev = em->bdev;
5638         set_buffer_mapped(bh_result);
5639         if (create && !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
5640                 set_buffer_new(bh_result);
5641
5642         free_extent_map(em);
5643
5644         return 0;
5645 }
5646
5647 struct btrfs_dio_private {
5648         struct inode *inode;
5649         u64 logical_offset;
5650         u64 disk_bytenr;
5651         u64 bytes;
5652         u32 *csums;
5653         void *private;
5654
5655         /* number of bios pending for this dio */
5656         atomic_t pending_bios;
5657
5658         /* IO errors */
5659         int errors;
5660
5661         struct bio *orig_bio;
5662 };
5663
5664 static void btrfs_endio_direct_read(struct bio *bio, int err)
5665 {
5666         struct btrfs_dio_private *dip = bio->bi_private;
5667         struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
5668         struct bio_vec *bvec = bio->bi_io_vec;
5669         struct inode *inode = dip->inode;
5670         struct btrfs_root *root = BTRFS_I(inode)->root;
5671         u64 start;
5672         u32 *private = dip->csums;
5673
5674         start = dip->logical_offset;
5675         do {
5676                 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
5677                         struct page *page = bvec->bv_page;
5678                         char *kaddr;
5679                         u32 csum = ~(u32)0;
5680                         unsigned long flags;
5681
5682                         local_irq_save(flags);
5683                         kaddr = kmap_atomic(page, KM_IRQ0);
5684                         csum = btrfs_csum_data(root, kaddr + bvec->bv_offset,
5685                                                csum, bvec->bv_len);
5686                         btrfs_csum_final(csum, (char *)&csum);
5687                         kunmap_atomic(kaddr, KM_IRQ0);
5688                         local_irq_restore(flags);
5689
5690                         flush_dcache_page(bvec->bv_page);
5691                         if (csum != *private) {
5692                                 printk(KERN_ERR "btrfs csum failed ino %llu off"
5693                                       " %llu csum %u private %u\n",
5694                                       (unsigned long long)btrfs_ino(inode),
5695                                       (unsigned long long)start,
5696                                       csum, *private);
5697                                 err = -EIO;
5698                         }
5699                 }
5700
5701                 start += bvec->bv_len;
5702                 private++;
5703                 bvec++;
5704         } while (bvec <= bvec_end);
5705
5706         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
5707                       dip->logical_offset + dip->bytes - 1, GFP_NOFS);
5708         bio->bi_private = dip->private;
5709
5710         kfree(dip->csums);
5711         kfree(dip);
5712
5713         /* If we had a csum failure make sure to clear the uptodate flag */
5714         if (err)
5715                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
5716         dio_end_io(bio, err);
5717 }
5718
5719 static void btrfs_endio_direct_write(struct bio *bio, int err)
5720 {
5721         struct btrfs_dio_private *dip = bio->bi_private;
5722         struct inode *inode = dip->inode;
5723         struct btrfs_root *root = BTRFS_I(inode)->root;
5724         struct btrfs_trans_handle *trans;
5725         struct btrfs_ordered_extent *ordered = NULL;
5726         struct extent_state *cached_state = NULL;
5727         u64 ordered_offset = dip->logical_offset;
5728         u64 ordered_bytes = dip->bytes;
5729         int ret;
5730
5731         if (err)
5732                 goto out_done;
5733 again:
5734         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
5735                                                    &ordered_offset,
5736                                                    ordered_bytes);
5737         if (!ret)
5738                 goto out_test;
5739
5740         BUG_ON(!ordered);
5741
5742         trans = btrfs_join_transaction(root, 1);
5743         if (IS_ERR(trans)) {
5744                 err = -ENOMEM;
5745                 goto out;
5746         }
5747         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
5748
5749         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags)) {
5750                 ret = btrfs_ordered_update_i_size(inode, 0, ordered);
5751                 if (!ret)
5752                         ret = btrfs_update_inode(trans, root, inode);
5753                 err = ret;
5754                 goto out;
5755         }
5756
5757         lock_extent_bits(&BTRFS_I(inode)->io_tree, ordered->file_offset,
5758                          ordered->file_offset + ordered->len - 1, 0,
5759                          &cached_state, GFP_NOFS);
5760
5761         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags)) {
5762                 ret = btrfs_mark_extent_written(trans, inode,
5763                                                 ordered->file_offset,
5764                                                 ordered->file_offset +
5765                                                 ordered->len);
5766                 if (ret) {
5767                         err = ret;
5768                         goto out_unlock;
5769                 }
5770         } else {
5771                 ret = insert_reserved_file_extent(trans, inode,
5772                                                   ordered->file_offset,
5773                                                   ordered->start,
5774                                                   ordered->disk_len,
5775                                                   ordered->len,
5776                                                   ordered->len,
5777                                                   0, 0, 0,
5778                                                   BTRFS_FILE_EXTENT_REG);
5779                 unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
5780                                    ordered->file_offset, ordered->len);
5781                 if (ret) {
5782                         err = ret;
5783                         WARN_ON(1);
5784                         goto out_unlock;
5785                 }
5786         }
5787
5788         add_pending_csums(trans, inode, ordered->file_offset, &ordered->list);
5789         ret = btrfs_ordered_update_i_size(inode, 0, ordered);
5790         if (!ret)
5791                 btrfs_update_inode(trans, root, inode);
5792         ret = 0;
5793 out_unlock:
5794         unlock_extent_cached(&BTRFS_I(inode)->io_tree, ordered->file_offset,
5795                              ordered->file_offset + ordered->len - 1,
5796                              &cached_state, GFP_NOFS);
5797 out:
5798         btrfs_delalloc_release_metadata(inode, ordered->len);
5799         btrfs_end_transaction(trans, root);
5800         ordered_offset = ordered->file_offset + ordered->len;
5801         btrfs_put_ordered_extent(ordered);
5802         btrfs_put_ordered_extent(ordered);
5803
5804 out_test:
5805         /*
5806          * our bio might span multiple ordered extents.  If we haven't
5807          * completed the accounting for the whole dio, go back and try again
5808          */
5809         if (ordered_offset < dip->logical_offset + dip->bytes) {
5810                 ordered_bytes = dip->logical_offset + dip->bytes -
5811                         ordered_offset;
5812                 goto again;
5813         }
5814 out_done:
5815         bio->bi_private = dip->private;
5816
5817         kfree(dip->csums);
5818         kfree(dip);
5819
5820         /* If we had an error make sure to clear the uptodate flag */
5821         if (err)
5822                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
5823         dio_end_io(bio, err);
5824 }
5825
5826 static int __btrfs_submit_bio_start_direct_io(struct inode *inode, int rw,
5827                                     struct bio *bio, int mirror_num,
5828                                     unsigned long bio_flags, u64 offset)
5829 {
5830         int ret;
5831         struct btrfs_root *root = BTRFS_I(inode)->root;
5832         ret = btrfs_csum_one_bio(root, inode, bio, offset, 1);
5833         BUG_ON(ret);
5834         return 0;
5835 }
5836
5837 static void btrfs_end_dio_bio(struct bio *bio, int err)
5838 {
5839         struct btrfs_dio_private *dip = bio->bi_private;
5840
5841         if (err) {
5842                 printk(KERN_ERR "btrfs direct IO failed ino %llu rw %lu "
5843                       "sector %#Lx len %u err no %d\n",
5844                       (unsigned long long)btrfs_ino(dip->inode), bio->bi_rw,
5845                       (unsigned long long)bio->bi_sector, bio->bi_size, err);
5846                 dip->errors = 1;
5847
5848                 /*
5849                  * before atomic variable goto zero, we must make sure
5850                  * dip->errors is perceived to be set.
5851                  */
5852                 smp_mb__before_atomic_dec();
5853         }
5854
5855         /* if there are more bios still pending for this dio, just exit */
5856         if (!atomic_dec_and_test(&dip->pending_bios))
5857                 goto out;
5858
5859         if (dip->errors)
5860                 bio_io_error(dip->orig_bio);
5861         else {
5862                 set_bit(BIO_UPTODATE, &dip->orig_bio->bi_flags);
5863                 bio_endio(dip->orig_bio, 0);
5864         }
5865 out:
5866         bio_put(bio);
5867 }
5868
5869 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
5870                                        u64 first_sector, gfp_t gfp_flags)
5871 {
5872         int nr_vecs = bio_get_nr_vecs(bdev);
5873         return btrfs_bio_alloc(bdev, first_sector, nr_vecs, gfp_flags);
5874 }
5875
5876 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
5877                                          int rw, u64 file_offset, int skip_sum,
5878                                          u32 *csums, int async_submit)
5879 {
5880         int write = rw & REQ_WRITE;
5881         struct btrfs_root *root = BTRFS_I(inode)->root;
5882         int ret;
5883
5884         bio_get(bio);
5885         ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
5886         if (ret)
5887                 goto err;
5888
5889         if (skip_sum)
5890                 goto map;
5891
5892         if (write && async_submit) {
5893                 ret = btrfs_wq_submit_bio(root->fs_info,
5894                                    inode, rw, bio, 0, 0,
5895                                    file_offset,
5896                                    __btrfs_submit_bio_start_direct_io,
5897                                    __btrfs_submit_bio_done);
5898                 goto err;
5899         } else if (write) {
5900                 /*
5901                  * If we aren't doing async submit, calculate the csum of the
5902                  * bio now.
5903                  */
5904                 ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
5905                 if (ret)
5906                         goto err;
5907         } else if (!skip_sum) {
5908                 ret = btrfs_lookup_bio_sums_dio(root, inode, bio,
5909                                           file_offset, csums);
5910                 if (ret)
5911                         goto err;
5912         }
5913
5914 map:
5915         ret = btrfs_map_bio(root, rw, bio, 0, async_submit);
5916 err:
5917         bio_put(bio);
5918         return ret;
5919 }
5920
5921 static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
5922                                     int skip_sum)
5923 {
5924         struct inode *inode = dip->inode;
5925         struct btrfs_root *root = BTRFS_I(inode)->root;
5926         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
5927         struct bio *bio;
5928         struct bio *orig_bio = dip->orig_bio;
5929         struct bio_vec *bvec = orig_bio->bi_io_vec;
5930         u64 start_sector = orig_bio->bi_sector;
5931         u64 file_offset = dip->logical_offset;
5932         u64 submit_len = 0;
5933         u64 map_length;
5934         int nr_pages = 0;
5935         u32 *csums = dip->csums;
5936         int ret = 0;
5937         int async_submit = 0;
5938         int write = rw & REQ_WRITE;
5939
5940         map_length = orig_bio->bi_size;
5941         ret = btrfs_map_block(map_tree, READ, start_sector << 9,
5942                               &map_length, NULL, 0);
5943         if (ret) {
5944                 bio_put(orig_bio);
5945                 return -EIO;
5946         }
5947
5948         if (map_length >= orig_bio->bi_size) {
5949                 bio = orig_bio;
5950                 goto submit;
5951         }
5952
5953         async_submit = 1;
5954         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
5955         if (!bio)
5956                 return -ENOMEM;
5957         bio->bi_private = dip;
5958         bio->bi_end_io = btrfs_end_dio_bio;
5959         atomic_inc(&dip->pending_bios);
5960
5961         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
5962                 if (unlikely(map_length < submit_len + bvec->bv_len ||
5963                     bio_add_page(bio, bvec->bv_page, bvec->bv_len,
5964                                  bvec->bv_offset) < bvec->bv_len)) {
5965                         /*
5966                          * inc the count before we submit the bio so
5967                          * we know the end IO handler won't happen before
5968                          * we inc the count. Otherwise, the dip might get freed
5969                          * before we're done setting it up
5970                          */
5971                         atomic_inc(&dip->pending_bios);
5972                         ret = __btrfs_submit_dio_bio(bio, inode, rw,
5973                                                      file_offset, skip_sum,
5974                                                      csums, async_submit);
5975                         if (ret) {
5976                                 bio_put(bio);
5977                                 atomic_dec(&dip->pending_bios);
5978                                 goto out_err;
5979                         }
5980
5981                         /* Write's use the ordered csums */
5982                         if (!write && !skip_sum)
5983                                 csums = csums + nr_pages;
5984                         start_sector += submit_len >> 9;
5985                         file_offset += submit_len;
5986
5987                         submit_len = 0;
5988                         nr_pages = 0;
5989
5990                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
5991                                                   start_sector, GFP_NOFS);
5992                         if (!bio)
5993                                 goto out_err;
5994                         bio->bi_private = dip;
5995                         bio->bi_end_io = btrfs_end_dio_bio;
5996
5997                         map_length = orig_bio->bi_size;
5998                         ret = btrfs_map_block(map_tree, READ, start_sector << 9,
5999                                               &map_length, NULL, 0);
6000                         if (ret) {
6001                                 bio_put(bio);
6002                                 goto out_err;
6003                         }
6004                 } else {
6005                         submit_len += bvec->bv_len;
6006                         nr_pages ++;
6007                         bvec++;
6008                 }
6009         }
6010
6011 submit:
6012         ret = __btrfs_submit_dio_bio(bio, inode, rw, file_offset, skip_sum,
6013                                      csums, async_submit);
6014         if (!ret)
6015                 return 0;
6016
6017         bio_put(bio);
6018 out_err:
6019         dip->errors = 1;
6020         /*
6021          * before atomic variable goto zero, we must
6022          * make sure dip->errors is perceived to be set.
6023          */
6024         smp_mb__before_atomic_dec();
6025         if (atomic_dec_and_test(&dip->pending_bios))
6026                 bio_io_error(dip->orig_bio);
6027
6028         /* bio_end_io() will handle error, so we needn't return it */
6029         return 0;
6030 }
6031
6032 static void btrfs_submit_direct(int rw, struct bio *bio, struct inode *inode,
6033                                 loff_t file_offset)
6034 {
6035         struct btrfs_root *root = BTRFS_I(inode)->root;
6036         struct btrfs_dio_private *dip;
6037         struct bio_vec *bvec = bio->bi_io_vec;
6038         int skip_sum;
6039         int write = rw & REQ_WRITE;
6040         int ret = 0;
6041
6042         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
6043
6044         dip = kmalloc(sizeof(*dip), GFP_NOFS);
6045         if (!dip) {
6046                 ret = -ENOMEM;
6047                 goto free_ordered;
6048         }
6049         dip->csums = NULL;
6050
6051         /* Write's use the ordered csum stuff, so we don't need dip->csums */
6052         if (!write && !skip_sum) {
6053                 dip->csums = kmalloc(sizeof(u32) * bio->bi_vcnt, GFP_NOFS);
6054                 if (!dip->csums) {
6055                         kfree(dip);
6056                         ret = -ENOMEM;
6057                         goto free_ordered;
6058                 }
6059         }
6060
6061         dip->private = bio->bi_private;
6062         dip->inode = inode;
6063         dip->logical_offset = file_offset;
6064
6065         dip->bytes = 0;
6066         do {
6067                 dip->bytes += bvec->bv_len;
6068                 bvec++;
6069         } while (bvec <= (bio->bi_io_vec + bio->bi_vcnt - 1));
6070
6071         dip->disk_bytenr = (u64)bio->bi_sector << 9;
6072         bio->bi_private = dip;
6073         dip->errors = 0;
6074         dip->orig_bio = bio;
6075         atomic_set(&dip->pending_bios, 0);
6076
6077         if (write)
6078                 bio->bi_end_io = btrfs_endio_direct_write;
6079         else
6080                 bio->bi_end_io = btrfs_endio_direct_read;
6081
6082         ret = btrfs_submit_direct_hook(rw, dip, skip_sum);
6083         if (!ret)
6084                 return;
6085 free_ordered:
6086         /*
6087          * If this is a write, we need to clean up the reserved space and kill
6088          * the ordered extent.
6089          */
6090         if (write) {
6091                 struct btrfs_ordered_extent *ordered;
6092                 ordered = btrfs_lookup_ordered_extent(inode, file_offset);
6093                 if (!test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags) &&
6094                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags))
6095                         btrfs_free_reserved_extent(root, ordered->start,
6096                                                    ordered->disk_len);
6097                 btrfs_put_ordered_extent(ordered);
6098                 btrfs_put_ordered_extent(ordered);
6099         }
6100         bio_endio(bio, ret);
6101 }
6102
6103 static ssize_t check_direct_IO(struct btrfs_root *root, int rw, struct kiocb *iocb,
6104                         const struct iovec *iov, loff_t offset,
6105                         unsigned long nr_segs)
6106 {
6107         int seg;
6108         int i;
6109         size_t size;
6110         unsigned long addr;
6111         unsigned blocksize_mask = root->sectorsize - 1;
6112         ssize_t retval = -EINVAL;
6113         loff_t end = offset;
6114
6115         if (offset & blocksize_mask)
6116                 goto out;
6117
6118         /* Check the memory alignment.  Blocks cannot straddle pages */
6119         for (seg = 0; seg < nr_segs; seg++) {
6120                 addr = (unsigned long)iov[seg].iov_base;
6121                 size = iov[seg].iov_len;
6122                 end += size;
6123                 if ((addr & blocksize_mask) || (size & blocksize_mask))
6124                         goto out;
6125
6126                 /* If this is a write we don't need to check anymore */
6127                 if (rw & WRITE)
6128                         continue;
6129
6130                 /*
6131                  * Check to make sure we don't have duplicate iov_base's in this
6132                  * iovec, if so return EINVAL, otherwise we'll get csum errors
6133                  * when reading back.
6134                  */
6135                 for (i = seg + 1; i < nr_segs; i++) {
6136                         if (iov[seg].iov_base == iov[i].iov_base)
6137                                 goto out;
6138                 }
6139         }
6140         retval = 0;
6141 out:
6142         return retval;
6143 }
6144 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
6145                         const struct iovec *iov, loff_t offset,
6146                         unsigned long nr_segs)
6147 {
6148         struct file *file = iocb->ki_filp;
6149         struct inode *inode = file->f_mapping->host;
6150         struct btrfs_ordered_extent *ordered;
6151         struct extent_state *cached_state = NULL;
6152         u64 lockstart, lockend;
6153         ssize_t ret;
6154         int writing = rw & WRITE;
6155         int write_bits = 0;
6156         size_t count = iov_length(iov, nr_segs);
6157
6158         if (check_direct_IO(BTRFS_I(inode)->root, rw, iocb, iov,
6159                             offset, nr_segs)) {
6160                 return 0;
6161         }
6162
6163         lockstart = offset;
6164         lockend = offset + count - 1;
6165
6166         if (writing) {
6167                 ret = btrfs_delalloc_reserve_space(inode, count);
6168                 if (ret)
6169                         goto out;
6170         }
6171
6172         while (1) {
6173                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6174                                  0, &cached_state, GFP_NOFS);
6175                 /*
6176                  * We're concerned with the entire range that we're going to be
6177                  * doing DIO to, so we need to make sure theres no ordered
6178                  * extents in this range.
6179                  */
6180                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
6181                                                      lockend - lockstart + 1);
6182                 if (!ordered)
6183                         break;
6184                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6185                                      &cached_state, GFP_NOFS);
6186                 btrfs_start_ordered_extent(inode, ordered, 1);
6187                 btrfs_put_ordered_extent(ordered);
6188                 cond_resched();
6189         }
6190
6191         /*
6192          * we don't use btrfs_set_extent_delalloc because we don't want
6193          * the dirty or uptodate bits
6194          */
6195         if (writing) {
6196                 write_bits = EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING;
6197                 ret = set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6198                                      EXTENT_DELALLOC, 0, NULL, &cached_state,
6199                                      GFP_NOFS);
6200                 if (ret) {
6201                         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
6202                                          lockend, EXTENT_LOCKED | write_bits,
6203                                          1, 0, &cached_state, GFP_NOFS);
6204                         goto out;
6205                 }
6206         }
6207
6208         free_extent_state(cached_state);
6209         cached_state = NULL;
6210
6211         ret = __blockdev_direct_IO(rw, iocb, inode,
6212                    BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
6213                    iov, offset, nr_segs, btrfs_get_blocks_direct, NULL,
6214                    btrfs_submit_direct, 0);
6215
6216         if (ret < 0 && ret != -EIOCBQUEUED) {
6217                 clear_extent_bit(&BTRFS_I(inode)->io_tree, offset,
6218                               offset + iov_length(iov, nr_segs) - 1,
6219                               EXTENT_LOCKED | write_bits, 1, 0,
6220                               &cached_state, GFP_NOFS);
6221         } else if (ret >= 0 && ret < iov_length(iov, nr_segs)) {
6222                 /*
6223                  * We're falling back to buffered, unlock the section we didn't
6224                  * do IO on.
6225                  */
6226                 clear_extent_bit(&BTRFS_I(inode)->io_tree, offset + ret,
6227                               offset + iov_length(iov, nr_segs) - 1,
6228                               EXTENT_LOCKED | write_bits, 1, 0,
6229                               &cached_state, GFP_NOFS);
6230         }
6231 out:
6232         free_extent_state(cached_state);
6233         return ret;
6234 }
6235
6236 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
6237                 __u64 start, __u64 len)
6238 {
6239         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
6240 }
6241
6242 int btrfs_readpage(struct file *file, struct page *page)
6243 {
6244         struct extent_io_tree *tree;
6245         tree = &BTRFS_I(page->mapping->host)->io_tree;
6246         return extent_read_full_page(tree, page, btrfs_get_extent);
6247 }
6248
6249 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
6250 {
6251         struct extent_io_tree *tree;
6252
6253
6254         if (current->flags & PF_MEMALLOC) {
6255                 redirty_page_for_writepage(wbc, page);
6256                 unlock_page(page);
6257                 return 0;
6258         }
6259         tree = &BTRFS_I(page->mapping->host)->io_tree;
6260         return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
6261 }
6262
6263 int btrfs_writepages(struct address_space *mapping,
6264                      struct writeback_control *wbc)
6265 {
6266         struct extent_io_tree *tree;
6267
6268         tree = &BTRFS_I(mapping->host)->io_tree;
6269         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
6270 }
6271
6272 static int
6273 btrfs_readpages(struct file *file, struct address_space *mapping,
6274                 struct list_head *pages, unsigned nr_pages)
6275 {
6276         struct extent_io_tree *tree;
6277         tree = &BTRFS_I(mapping->host)->io_tree;
6278         return extent_readpages(tree, mapping, pages, nr_pages,
6279                                 btrfs_get_extent);
6280 }
6281 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
6282 {
6283         struct extent_io_tree *tree;
6284         struct extent_map_tree *map;
6285         int ret;
6286
6287         tree = &BTRFS_I(page->mapping->host)->io_tree;
6288         map = &BTRFS_I(page->mapping->host)->extent_tree;
6289         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
6290         if (ret == 1) {
6291                 ClearPagePrivate(page);
6292                 set_page_private(page, 0);
6293                 page_cache_release(page);
6294         }
6295         return ret;
6296 }
6297
6298 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
6299 {
6300         if (PageWriteback(page) || PageDirty(page))
6301                 return 0;
6302         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
6303 }
6304
6305 static void btrfs_invalidatepage(struct page *page, unsigned long offset)
6306 {
6307         struct extent_io_tree *tree;
6308         struct btrfs_ordered_extent *ordered;
6309         struct extent_state *cached_state = NULL;
6310         u64 page_start = page_offset(page);
6311         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
6312
6313
6314         /*
6315          * we have the page locked, so new writeback can't start,
6316          * and the dirty bit won't be cleared while we are here.
6317          *
6318          * Wait for IO on this page so that we can safely clear
6319          * the PagePrivate2 bit and do ordered accounting
6320          */
6321         wait_on_page_writeback(page);
6322
6323         tree = &BTRFS_I(page->mapping->host)->io_tree;
6324         if (offset) {
6325                 btrfs_releasepage(page, GFP_NOFS);
6326                 return;
6327         }
6328         lock_extent_bits(tree, page_start, page_end, 0, &cached_state,
6329                          GFP_NOFS);
6330         ordered = btrfs_lookup_ordered_extent(page->mapping->host,
6331                                            page_offset(page));
6332         if (ordered) {
6333                 /*
6334                  * IO on this page will never be started, so we need
6335                  * to account for any ordered extents now
6336                  */
6337                 clear_extent_bit(tree, page_start, page_end,
6338                                  EXTENT_DIRTY | EXTENT_DELALLOC |
6339                                  EXTENT_LOCKED | EXTENT_DO_ACCOUNTING, 1, 0,
6340                                  &cached_state, GFP_NOFS);
6341                 /*
6342                  * whoever cleared the private bit is responsible
6343                  * for the finish_ordered_io
6344                  */
6345                 if (TestClearPagePrivate2(page)) {
6346                         btrfs_finish_ordered_io(page->mapping->host,
6347                                                 page_start, page_end);
6348                 }
6349                 btrfs_put_ordered_extent(ordered);
6350                 cached_state = NULL;
6351                 lock_extent_bits(tree, page_start, page_end, 0, &cached_state,
6352                                  GFP_NOFS);
6353         }
6354         clear_extent_bit(tree, page_start, page_end,
6355                  EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
6356                  EXTENT_DO_ACCOUNTING, 1, 1, &cached_state, GFP_NOFS);
6357         __btrfs_releasepage(page, GFP_NOFS);
6358
6359         ClearPageChecked(page);
6360         if (PagePrivate(page)) {
6361                 ClearPagePrivate(page);
6362                 set_page_private(page, 0);
6363                 page_cache_release(page);
6364         }
6365 }
6366
6367 /*
6368  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
6369  * called from a page fault handler when a page is first dirtied. Hence we must
6370  * be careful to check for EOF conditions here. We set the page up correctly
6371  * for a written page which means we get ENOSPC checking when writing into
6372  * holes and correct delalloc and unwritten extent mapping on filesystems that
6373  * support these features.
6374  *
6375  * We are not allowed to take the i_mutex here so we have to play games to
6376  * protect against truncate races as the page could now be beyond EOF.  Because
6377  * vmtruncate() writes the inode size before removing pages, once we have the
6378  * page lock we can determine safely if the page is beyond EOF. If it is not
6379  * beyond EOF, then the page is guaranteed safe against truncation until we
6380  * unlock the page.
6381  */
6382 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
6383 {
6384         struct page *page = vmf->page;
6385         struct inode *inode = fdentry(vma->vm_file)->d_inode;
6386         struct btrfs_root *root = BTRFS_I(inode)->root;
6387         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6388         struct btrfs_ordered_extent *ordered;
6389         struct extent_state *cached_state = NULL;
6390         char *kaddr;
6391         unsigned long zero_start;
6392         loff_t size;
6393         int ret;
6394         u64 page_start;
6395         u64 page_end;
6396
6397         ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
6398         if (ret) {
6399                 if (ret == -ENOMEM)
6400                         ret = VM_FAULT_OOM;
6401                 else /* -ENOSPC, -EIO, etc */
6402                         ret = VM_FAULT_SIGBUS;
6403                 goto out;
6404         }
6405
6406         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
6407 again:
6408         lock_page(page);
6409         size = i_size_read(inode);
6410         page_start = page_offset(page);
6411         page_end = page_start + PAGE_CACHE_SIZE - 1;
6412
6413         if ((page->mapping != inode->i_mapping) ||
6414             (page_start >= size)) {
6415                 /* page got truncated out from underneath us */
6416                 goto out_unlock;
6417         }
6418         wait_on_page_writeback(page);
6419
6420         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state,
6421                          GFP_NOFS);
6422         set_page_extent_mapped(page);
6423
6424         /*
6425          * we can't set the delalloc bits if there are pending ordered
6426          * extents.  Drop our locks and wait for them to finish
6427          */
6428         ordered = btrfs_lookup_ordered_extent(inode, page_start);
6429         if (ordered) {
6430                 unlock_extent_cached(io_tree, page_start, page_end,
6431                                      &cached_state, GFP_NOFS);
6432                 unlock_page(page);
6433                 btrfs_start_ordered_extent(inode, ordered, 1);
6434                 btrfs_put_ordered_extent(ordered);
6435                 goto again;
6436         }
6437
6438         /*
6439          * XXX - page_mkwrite gets called every time the page is dirtied, even
6440          * if it was already dirty, so for space accounting reasons we need to
6441          * clear any delalloc bits for the range we are fixing to save.  There
6442          * is probably a better way to do this, but for now keep consistent with
6443          * prepare_pages in the normal write path.
6444          */
6445         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
6446                           EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING,
6447                           0, 0, &cached_state, GFP_NOFS);
6448
6449         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
6450                                         &cached_state);
6451         if (ret) {
6452                 unlock_extent_cached(io_tree, page_start, page_end,
6453                                      &cached_state, GFP_NOFS);
6454                 ret = VM_FAULT_SIGBUS;
6455                 goto out_unlock;
6456         }
6457         ret = 0;
6458
6459         /* page is wholly or partially inside EOF */
6460         if (page_start + PAGE_CACHE_SIZE > size)
6461                 zero_start = size & ~PAGE_CACHE_MASK;
6462         else
6463                 zero_start = PAGE_CACHE_SIZE;
6464
6465         if (zero_start != PAGE_CACHE_SIZE) {
6466                 kaddr = kmap(page);
6467                 memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
6468                 flush_dcache_page(page);
6469                 kunmap(page);
6470         }
6471         ClearPageChecked(page);
6472         set_page_dirty(page);
6473         SetPageUptodate(page);
6474
6475         BTRFS_I(inode)->last_trans = root->fs_info->generation;
6476         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
6477
6478         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
6479
6480 out_unlock:
6481         if (!ret)
6482                 return VM_FAULT_LOCKED;
6483         unlock_page(page);
6484         btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
6485 out:
6486         return ret;
6487 }
6488
6489 static int btrfs_truncate(struct inode *inode)
6490 {
6491         struct btrfs_root *root = BTRFS_I(inode)->root;
6492         int ret;
6493         int err = 0;
6494         struct btrfs_trans_handle *trans;
6495         unsigned long nr;
6496         u64 mask = root->sectorsize - 1;
6497
6498         ret = btrfs_truncate_page(inode->i_mapping, inode->i_size);
6499         if (ret)
6500                 return ret;
6501
6502         btrfs_wait_ordered_range(inode, inode->i_size & (~mask), (u64)-1);
6503         btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
6504
6505         trans = btrfs_start_transaction(root, 5);
6506         if (IS_ERR(trans))
6507                 return PTR_ERR(trans);
6508
6509         btrfs_set_trans_block_group(trans, inode);
6510
6511         ret = btrfs_orphan_add(trans, inode);
6512         if (ret) {
6513                 btrfs_end_transaction(trans, root);
6514                 return ret;
6515         }
6516
6517         nr = trans->blocks_used;
6518         btrfs_end_transaction(trans, root);
6519         btrfs_btree_balance_dirty(root, nr);
6520
6521         /* Now start a transaction for the truncate */
6522         trans = btrfs_start_transaction(root, 0);
6523         if (IS_ERR(trans))
6524                 return PTR_ERR(trans);
6525         btrfs_set_trans_block_group(trans, inode);
6526         trans->block_rsv = root->orphan_block_rsv;
6527
6528         /*
6529          * setattr is responsible for setting the ordered_data_close flag,
6530          * but that is only tested during the last file release.  That
6531          * could happen well after the next commit, leaving a great big
6532          * window where new writes may get lost if someone chooses to write
6533          * to this file after truncating to zero
6534          *
6535          * The inode doesn't have any dirty data here, and so if we commit
6536          * this is a noop.  If someone immediately starts writing to the inode
6537          * it is very likely we'll catch some of their writes in this
6538          * transaction, and the commit will find this file on the ordered
6539          * data list with good things to send down.
6540          *
6541          * This is a best effort solution, there is still a window where
6542          * using truncate to replace the contents of the file will
6543          * end up with a zero length file after a crash.
6544          */
6545         if (inode->i_size == 0 && BTRFS_I(inode)->ordered_data_close)
6546                 btrfs_add_ordered_operation(trans, root, inode);
6547
6548         while (1) {
6549                 if (!trans) {
6550                         trans = btrfs_start_transaction(root, 0);
6551                         if (IS_ERR(trans))
6552                                 return PTR_ERR(trans);
6553                         btrfs_set_trans_block_group(trans, inode);
6554                         trans->block_rsv = root->orphan_block_rsv;
6555                 }
6556
6557                 ret = btrfs_block_rsv_check(trans, root,
6558                                             root->orphan_block_rsv, 0, 5);
6559                 if (ret == -EAGAIN) {
6560                         ret = btrfs_commit_transaction(trans, root);
6561                         if (ret)
6562                                 return ret;
6563                         trans = NULL;
6564                         continue;
6565                 } else if (ret) {
6566                         err = ret;
6567                         break;
6568                 }
6569
6570                 ret = btrfs_truncate_inode_items(trans, root, inode,
6571                                                  inode->i_size,
6572                                                  BTRFS_EXTENT_DATA_KEY);
6573                 if (ret != -EAGAIN) {
6574                         err = ret;
6575                         break;
6576                 }
6577
6578                 ret = btrfs_update_inode(trans, root, inode);
6579                 if (ret) {
6580                         err = ret;
6581                         break;
6582                 }
6583
6584                 nr = trans->blocks_used;
6585                 btrfs_end_transaction(trans, root);
6586                 trans = NULL;
6587                 btrfs_btree_balance_dirty(root, nr);
6588         }
6589
6590         if (ret == 0 && inode->i_nlink > 0) {
6591                 ret = btrfs_orphan_del(trans, inode);
6592                 if (ret)
6593                         err = ret;
6594         } else if (ret && inode->i_nlink > 0) {
6595                 /*
6596                  * Failed to do the truncate, remove us from the in memory
6597                  * orphan list.
6598                  */
6599                 ret = btrfs_orphan_del(NULL, inode);
6600         }
6601
6602         ret = btrfs_update_inode(trans, root, inode);
6603         if (ret && !err)
6604                 err = ret;
6605
6606         nr = trans->blocks_used;
6607         ret = btrfs_end_transaction_throttle(trans, root);
6608         if (ret && !err)
6609                 err = ret;
6610         btrfs_btree_balance_dirty(root, nr);
6611
6612         return err;
6613 }
6614
6615 /*
6616  * create a new subvolume directory/inode (helper for the ioctl).
6617  */
6618 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
6619                              struct btrfs_root *new_root,
6620                              u64 new_dirid, u64 alloc_hint)
6621 {
6622         struct inode *inode;
6623         int err;
6624         u64 index = 0;
6625
6626         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2, new_dirid,
6627                                 new_dirid, alloc_hint, S_IFDIR | 0700, &index);
6628         if (IS_ERR(inode))
6629                 return PTR_ERR(inode);
6630         inode->i_op = &btrfs_dir_inode_operations;
6631         inode->i_fop = &btrfs_dir_file_operations;
6632
6633         inode->i_nlink = 1;
6634         btrfs_i_size_write(inode, 0);
6635
6636         err = btrfs_update_inode(trans, new_root, inode);
6637         BUG_ON(err);
6638
6639         iput(inode);
6640         return 0;
6641 }
6642
6643 /* helper function for file defrag and space balancing.  This
6644  * forces readahead on a given range of bytes in an inode
6645  */
6646 unsigned long btrfs_force_ra(struct address_space *mapping,
6647                               struct file_ra_state *ra, struct file *file,
6648                               pgoff_t offset, pgoff_t last_index)
6649 {
6650         pgoff_t req_size = last_index - offset + 1;
6651
6652         page_cache_sync_readahead(mapping, ra, file, offset, req_size);
6653         return offset + req_size;
6654 }
6655
6656 struct inode *btrfs_alloc_inode(struct super_block *sb)
6657 {
6658         struct btrfs_inode *ei;
6659         struct inode *inode;
6660
6661         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
6662         if (!ei)
6663                 return NULL;
6664
6665         ei->root = NULL;
6666         ei->space_info = NULL;
6667         ei->generation = 0;
6668         ei->sequence = 0;
6669         ei->last_trans = 0;
6670         ei->last_sub_trans = 0;
6671         ei->logged_trans = 0;
6672         ei->delalloc_bytes = 0;
6673         ei->reserved_bytes = 0;
6674         ei->disk_i_size = 0;
6675         ei->flags = 0;
6676         ei->index_cnt = (u64)-1;
6677         ei->last_unlink_trans = 0;
6678
6679         atomic_set(&ei->outstanding_extents, 0);
6680         atomic_set(&ei->reserved_extents, 0);
6681
6682         ei->ordered_data_close = 0;
6683         ei->orphan_meta_reserved = 0;
6684         ei->dummy_inode = 0;
6685         ei->force_compress = BTRFS_COMPRESS_NONE;
6686
6687         ei->delayed_node = NULL;
6688
6689         inode = &ei->vfs_inode;
6690         extent_map_tree_init(&ei->extent_tree);
6691         extent_io_tree_init(&ei->io_tree, &inode->i_data);
6692         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
6693         mutex_init(&ei->log_mutex);
6694         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
6695         INIT_LIST_HEAD(&ei->i_orphan);
6696         INIT_LIST_HEAD(&ei->delalloc_inodes);
6697         INIT_LIST_HEAD(&ei->ordered_operations);
6698         RB_CLEAR_NODE(&ei->rb_node);
6699
6700         return inode;
6701 }
6702
6703 static void btrfs_i_callback(struct rcu_head *head)
6704 {
6705         struct inode *inode = container_of(head, struct inode, i_rcu);
6706         INIT_LIST_HEAD(&inode->i_dentry);
6707         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
6708 }
6709
6710 void btrfs_destroy_inode(struct inode *inode)
6711 {
6712         struct btrfs_ordered_extent *ordered;
6713         struct btrfs_root *root = BTRFS_I(inode)->root;
6714
6715         WARN_ON(!list_empty(&inode->i_dentry));
6716         WARN_ON(inode->i_data.nrpages);
6717         WARN_ON(atomic_read(&BTRFS_I(inode)->outstanding_extents));
6718         WARN_ON(atomic_read(&BTRFS_I(inode)->reserved_extents));
6719
6720         /*
6721          * This can happen where we create an inode, but somebody else also
6722          * created the same inode and we need to destroy the one we already
6723          * created.
6724          */
6725         if (!root)
6726                 goto free;
6727
6728         /*
6729          * Make sure we're properly removed from the ordered operation
6730          * lists.
6731          */
6732         smp_mb();
6733         if (!list_empty(&BTRFS_I(inode)->ordered_operations)) {
6734                 spin_lock(&root->fs_info->ordered_extent_lock);
6735                 list_del_init(&BTRFS_I(inode)->ordered_operations);
6736                 spin_unlock(&root->fs_info->ordered_extent_lock);
6737         }
6738
6739         if (root == root->fs_info->tree_root) {
6740                 struct btrfs_block_group_cache *block_group;
6741
6742                 block_group = btrfs_lookup_block_group(root->fs_info,
6743                                                 BTRFS_I(inode)->block_group);
6744                 if (block_group && block_group->inode == inode) {
6745                         spin_lock(&block_group->lock);
6746                         block_group->inode = NULL;
6747                         spin_unlock(&block_group->lock);
6748                         btrfs_put_block_group(block_group);
6749                 } else if (block_group) {
6750                         btrfs_put_block_group(block_group);
6751                 }
6752         }
6753
6754         spin_lock(&root->orphan_lock);
6755         if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
6756                 printk(KERN_INFO "BTRFS: inode %llu still on the orphan list\n",
6757                        (unsigned long long)btrfs_ino(inode));
6758                 list_del_init(&BTRFS_I(inode)->i_orphan);
6759         }
6760         spin_unlock(&root->orphan_lock);
6761
6762         while (1) {
6763                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
6764                 if (!ordered)
6765                         break;
6766                 else {
6767                         printk(KERN_ERR "btrfs found ordered "
6768                                "extent %llu %llu on inode cleanup\n",
6769                                (unsigned long long)ordered->file_offset,
6770                                (unsigned long long)ordered->len);
6771                         btrfs_remove_ordered_extent(inode, ordered);
6772                         btrfs_put_ordered_extent(ordered);
6773                         btrfs_put_ordered_extent(ordered);
6774                 }
6775         }
6776         inode_tree_del(inode);
6777         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
6778 free:
6779         btrfs_remove_delayed_node(inode);
6780         call_rcu(&inode->i_rcu, btrfs_i_callback);
6781 }
6782
6783 int btrfs_drop_inode(struct inode *inode)
6784 {
6785         struct btrfs_root *root = BTRFS_I(inode)->root;
6786
6787         if (btrfs_root_refs(&root->root_item) == 0 &&
6788             !is_free_space_inode(root, inode))
6789                 return 1;
6790         else
6791                 return generic_drop_inode(inode);
6792 }
6793
6794 static void init_once(void *foo)
6795 {
6796         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
6797
6798         inode_init_once(&ei->vfs_inode);
6799 }
6800
6801 void btrfs_destroy_cachep(void)
6802 {
6803         if (btrfs_inode_cachep)
6804                 kmem_cache_destroy(btrfs_inode_cachep);
6805         if (btrfs_trans_handle_cachep)
6806                 kmem_cache_destroy(btrfs_trans_handle_cachep);
6807         if (btrfs_transaction_cachep)
6808                 kmem_cache_destroy(btrfs_transaction_cachep);
6809         if (btrfs_path_cachep)
6810                 kmem_cache_destroy(btrfs_path_cachep);
6811         if (btrfs_free_space_cachep)
6812                 kmem_cache_destroy(btrfs_free_space_cachep);
6813 }
6814
6815 int btrfs_init_cachep(void)
6816 {
6817         btrfs_inode_cachep = kmem_cache_create("btrfs_inode_cache",
6818                         sizeof(struct btrfs_inode), 0,
6819                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, init_once);
6820         if (!btrfs_inode_cachep)
6821                 goto fail;
6822
6823         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle_cache",
6824                         sizeof(struct btrfs_trans_handle), 0,
6825                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
6826         if (!btrfs_trans_handle_cachep)
6827                 goto fail;
6828
6829         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction_cache",
6830                         sizeof(struct btrfs_transaction), 0,
6831                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
6832         if (!btrfs_transaction_cachep)
6833                 goto fail;
6834
6835         btrfs_path_cachep = kmem_cache_create("btrfs_path_cache",
6836                         sizeof(struct btrfs_path), 0,
6837                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
6838         if (!btrfs_path_cachep)
6839                 goto fail;
6840
6841         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space_cache",
6842                         sizeof(struct btrfs_free_space), 0,
6843                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
6844         if (!btrfs_free_space_cachep)
6845                 goto fail;
6846
6847         return 0;
6848 fail:
6849         btrfs_destroy_cachep();
6850         return -ENOMEM;
6851 }
6852
6853 static int btrfs_getattr(struct vfsmount *mnt,
6854                          struct dentry *dentry, struct kstat *stat)
6855 {
6856         struct inode *inode = dentry->d_inode;
6857         generic_fillattr(inode, stat);
6858         stat->dev = BTRFS_I(inode)->root->anon_super.s_dev;
6859         stat->blksize = PAGE_CACHE_SIZE;
6860         stat->blocks = (inode_get_bytes(inode) +
6861                         BTRFS_I(inode)->delalloc_bytes) >> 9;
6862         return 0;
6863 }
6864
6865 /*
6866  * If a file is moved, it will inherit the cow and compression flags of the new
6867  * directory.
6868  */
6869 static void fixup_inode_flags(struct inode *dir, struct inode *inode)
6870 {
6871         struct btrfs_inode *b_dir = BTRFS_I(dir);
6872         struct btrfs_inode *b_inode = BTRFS_I(inode);
6873
6874         if (b_dir->flags & BTRFS_INODE_NODATACOW)
6875                 b_inode->flags |= BTRFS_INODE_NODATACOW;
6876         else
6877                 b_inode->flags &= ~BTRFS_INODE_NODATACOW;
6878
6879         if (b_dir->flags & BTRFS_INODE_COMPRESS)
6880                 b_inode->flags |= BTRFS_INODE_COMPRESS;
6881         else
6882                 b_inode->flags &= ~BTRFS_INODE_COMPRESS;
6883 }
6884
6885 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
6886                            struct inode *new_dir, struct dentry *new_dentry)
6887 {
6888         struct btrfs_trans_handle *trans;
6889         struct btrfs_root *root = BTRFS_I(old_dir)->root;
6890         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
6891         struct inode *new_inode = new_dentry->d_inode;
6892         struct inode *old_inode = old_dentry->d_inode;
6893         struct timespec ctime = CURRENT_TIME;
6894         u64 index = 0;
6895         u64 root_objectid;
6896         int ret;
6897         u64 old_ino = btrfs_ino(old_inode);
6898
6899         if (btrfs_ino(new_dir) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
6900                 return -EPERM;
6901
6902         /* we only allow rename subvolume link between subvolumes */
6903         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
6904                 return -EXDEV;
6905
6906         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
6907             (new_inode && btrfs_ino(new_inode) == BTRFS_FIRST_FREE_OBJECTID))
6908                 return -ENOTEMPTY;
6909
6910         if (S_ISDIR(old_inode->i_mode) && new_inode &&
6911             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
6912                 return -ENOTEMPTY;
6913         /*
6914          * we're using rename to replace one file with another.
6915          * and the replacement file is large.  Start IO on it now so
6916          * we don't add too much work to the end of the transaction
6917          */
6918         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size &&
6919             old_inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
6920                 filemap_flush(old_inode->i_mapping);
6921
6922         /* close the racy window with snapshot create/destroy ioctl */
6923         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
6924                 down_read(&root->fs_info->subvol_sem);
6925         /*
6926          * We want to reserve the absolute worst case amount of items.  So if
6927          * both inodes are subvols and we need to unlink them then that would
6928          * require 4 item modifications, but if they are both normal inodes it
6929          * would require 5 item modifications, so we'll assume their normal
6930          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
6931          * should cover the worst case number of items we'll modify.
6932          */
6933         trans = btrfs_start_transaction(root, 20);
6934         if (IS_ERR(trans)) {
6935                 ret = PTR_ERR(trans);
6936                 goto out_notrans;
6937         }
6938
6939         btrfs_set_trans_block_group(trans, new_dir);
6940
6941         if (dest != root)
6942                 btrfs_record_root_in_trans(trans, dest);
6943
6944         ret = btrfs_set_inode_index(new_dir, &index);
6945         if (ret)
6946                 goto out_fail;
6947
6948         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
6949                 /* force full log commit if subvolume involved. */
6950                 root->fs_info->last_trans_log_full_commit = trans->transid;
6951         } else {
6952                 ret = btrfs_insert_inode_ref(trans, dest,
6953                                              new_dentry->d_name.name,
6954                                              new_dentry->d_name.len,
6955                                              old_ino,
6956                                              btrfs_ino(new_dir), index);
6957                 if (ret)
6958                         goto out_fail;
6959                 /*
6960                  * this is an ugly little race, but the rename is required
6961                  * to make sure that if we crash, the inode is either at the
6962                  * old name or the new one.  pinning the log transaction lets
6963                  * us make sure we don't allow a log commit to come in after
6964                  * we unlink the name but before we add the new name back in.
6965                  */
6966                 btrfs_pin_log_trans(root);
6967         }
6968         /*
6969          * make sure the inode gets flushed if it is replacing
6970          * something.
6971          */
6972         if (new_inode && new_inode->i_size && S_ISREG(old_inode->i_mode))
6973                 btrfs_add_ordered_operation(trans, root, old_inode);
6974
6975         old_dir->i_ctime = old_dir->i_mtime = ctime;
6976         new_dir->i_ctime = new_dir->i_mtime = ctime;
6977         old_inode->i_ctime = ctime;
6978
6979         if (old_dentry->d_parent != new_dentry->d_parent)
6980                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
6981
6982         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
6983                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
6984                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
6985                                         old_dentry->d_name.name,
6986                                         old_dentry->d_name.len);
6987         } else {
6988                 ret = __btrfs_unlink_inode(trans, root, old_dir,
6989                                         old_dentry->d_inode,
6990                                         old_dentry->d_name.name,
6991                                         old_dentry->d_name.len);
6992                 if (!ret)
6993                         ret = btrfs_update_inode(trans, root, old_inode);
6994         }
6995         BUG_ON(ret);
6996
6997         if (new_inode) {
6998                 new_inode->i_ctime = CURRENT_TIME;
6999                 if (unlikely(btrfs_ino(new_inode) ==
7000                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
7001                         root_objectid = BTRFS_I(new_inode)->location.objectid;
7002                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
7003                                                 root_objectid,
7004                                                 new_dentry->d_name.name,
7005                                                 new_dentry->d_name.len);
7006                         BUG_ON(new_inode->i_nlink == 0);
7007                 } else {
7008                         ret = btrfs_unlink_inode(trans, dest, new_dir,
7009                                                  new_dentry->d_inode,
7010                                                  new_dentry->d_name.name,
7011                                                  new_dentry->d_name.len);
7012                 }
7013                 BUG_ON(ret);
7014                 if (new_inode->i_nlink == 0) {
7015                         ret = btrfs_orphan_add(trans, new_dentry->d_inode);
7016                         BUG_ON(ret);
7017                 }
7018         }
7019
7020         fixup_inode_flags(new_dir, old_inode);
7021
7022         ret = btrfs_add_link(trans, new_dir, old_inode,
7023                              new_dentry->d_name.name,
7024                              new_dentry->d_name.len, 0, index);
7025         BUG_ON(ret);
7026
7027         if (old_ino != BTRFS_FIRST_FREE_OBJECTID) {
7028                 struct dentry *parent = dget_parent(new_dentry);
7029                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
7030                 dput(parent);
7031                 btrfs_end_log_trans(root);
7032         }
7033 out_fail:
7034         btrfs_end_transaction_throttle(trans, root);
7035 out_notrans:
7036         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
7037                 up_read(&root->fs_info->subvol_sem);
7038
7039         return ret;
7040 }
7041
7042 /*
7043  * some fairly slow code that needs optimization. This walks the list
7044  * of all the inodes with pending delalloc and forces them to disk.
7045  */
7046 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
7047 {
7048         struct list_head *head = &root->fs_info->delalloc_inodes;
7049         struct btrfs_inode *binode;
7050         struct inode *inode;
7051
7052         if (root->fs_info->sb->s_flags & MS_RDONLY)
7053                 return -EROFS;
7054
7055         spin_lock(&root->fs_info->delalloc_lock);
7056         while (!list_empty(head)) {
7057                 binode = list_entry(head->next, struct btrfs_inode,
7058                                     delalloc_inodes);
7059                 inode = igrab(&binode->vfs_inode);
7060                 if (!inode)
7061                         list_del_init(&binode->delalloc_inodes);
7062                 spin_unlock(&root->fs_info->delalloc_lock);
7063                 if (inode) {
7064                         filemap_flush(inode->i_mapping);
7065                         if (delay_iput)
7066                                 btrfs_add_delayed_iput(inode);
7067                         else
7068                                 iput(inode);
7069                 }
7070                 cond_resched();
7071                 spin_lock(&root->fs_info->delalloc_lock);
7072         }
7073         spin_unlock(&root->fs_info->delalloc_lock);
7074
7075         /* the filemap_flush will queue IO into the worker threads, but
7076          * we have to make sure the IO is actually started and that
7077          * ordered extents get created before we return
7078          */
7079         atomic_inc(&root->fs_info->async_submit_draining);
7080         while (atomic_read(&root->fs_info->nr_async_submits) ||
7081               atomic_read(&root->fs_info->async_delalloc_pages)) {
7082                 wait_event(root->fs_info->async_submit_wait,
7083                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
7084                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
7085         }
7086         atomic_dec(&root->fs_info->async_submit_draining);
7087         return 0;
7088 }
7089
7090 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
7091                          const char *symname)
7092 {
7093         struct btrfs_trans_handle *trans;
7094         struct btrfs_root *root = BTRFS_I(dir)->root;
7095         struct btrfs_path *path;
7096         struct btrfs_key key;
7097         struct inode *inode = NULL;
7098         int err;
7099         int drop_inode = 0;
7100         u64 objectid;
7101         u64 index = 0 ;
7102         int name_len;
7103         int datasize;
7104         unsigned long ptr;
7105         struct btrfs_file_extent_item *ei;
7106         struct extent_buffer *leaf;
7107         unsigned long nr = 0;
7108
7109         name_len = strlen(symname) + 1;
7110         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
7111                 return -ENAMETOOLONG;
7112
7113         /*
7114          * 2 items for inode item and ref
7115          * 2 items for dir items
7116          * 1 item for xattr if selinux is on
7117          */
7118         trans = btrfs_start_transaction(root, 5);
7119         if (IS_ERR(trans))
7120                 return PTR_ERR(trans);
7121
7122         btrfs_set_trans_block_group(trans, dir);
7123
7124         err = btrfs_find_free_ino(root, &objectid);
7125         if (err)
7126                 goto out_unlock;
7127
7128         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
7129                                 dentry->d_name.len, btrfs_ino(dir), objectid,
7130                                 BTRFS_I(dir)->block_group, S_IFLNK|S_IRWXUGO,
7131                                 &index);
7132         if (IS_ERR(inode)) {
7133                 err = PTR_ERR(inode);
7134                 goto out_unlock;
7135         }
7136
7137         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
7138         if (err) {
7139                 drop_inode = 1;
7140                 goto out_unlock;
7141         }
7142
7143         btrfs_set_trans_block_group(trans, inode);
7144         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
7145         if (err)
7146                 drop_inode = 1;
7147         else {
7148                 inode->i_mapping->a_ops = &btrfs_aops;
7149                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
7150                 inode->i_fop = &btrfs_file_operations;
7151                 inode->i_op = &btrfs_file_inode_operations;
7152                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
7153         }
7154         btrfs_update_inode_block_group(trans, inode);
7155         btrfs_update_inode_block_group(trans, dir);
7156         if (drop_inode)
7157                 goto out_unlock;
7158
7159         path = btrfs_alloc_path();
7160         BUG_ON(!path);
7161         key.objectid = btrfs_ino(inode);
7162         key.offset = 0;
7163         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
7164         datasize = btrfs_file_extent_calc_inline_size(name_len);
7165         err = btrfs_insert_empty_item(trans, root, path, &key,
7166                                       datasize);
7167         if (err) {
7168                 drop_inode = 1;
7169                 btrfs_free_path(path);
7170                 goto out_unlock;
7171         }
7172         leaf = path->nodes[0];
7173         ei = btrfs_item_ptr(leaf, path->slots[0],
7174                             struct btrfs_file_extent_item);
7175         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
7176         btrfs_set_file_extent_type(leaf, ei,
7177                                    BTRFS_FILE_EXTENT_INLINE);
7178         btrfs_set_file_extent_encryption(leaf, ei, 0);
7179         btrfs_set_file_extent_compression(leaf, ei, 0);
7180         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
7181         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
7182
7183         ptr = btrfs_file_extent_inline_start(ei);
7184         write_extent_buffer(leaf, symname, ptr, name_len);
7185         btrfs_mark_buffer_dirty(leaf);
7186         btrfs_free_path(path);
7187
7188         inode->i_op = &btrfs_symlink_inode_operations;
7189         inode->i_mapping->a_ops = &btrfs_symlink_aops;
7190         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
7191         inode_set_bytes(inode, name_len);
7192         btrfs_i_size_write(inode, name_len - 1);
7193         err = btrfs_update_inode(trans, root, inode);
7194         if (err)
7195                 drop_inode = 1;
7196
7197 out_unlock:
7198         nr = trans->blocks_used;
7199         btrfs_end_transaction_throttle(trans, root);
7200         if (drop_inode) {
7201                 inode_dec_link_count(inode);
7202                 iput(inode);
7203         }
7204         btrfs_btree_balance_dirty(root, nr);
7205         return err;
7206 }
7207
7208 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
7209                                        u64 start, u64 num_bytes, u64 min_size,
7210                                        loff_t actual_len, u64 *alloc_hint,
7211                                        struct btrfs_trans_handle *trans)
7212 {
7213         struct btrfs_root *root = BTRFS_I(inode)->root;
7214         struct btrfs_key ins;
7215         u64 cur_offset = start;
7216         u64 i_size;
7217         int ret = 0;
7218         bool own_trans = true;
7219
7220         if (trans)
7221                 own_trans = false;
7222         while (num_bytes > 0) {
7223                 if (own_trans) {
7224                         trans = btrfs_start_transaction(root, 3);
7225                         if (IS_ERR(trans)) {
7226                                 ret = PTR_ERR(trans);
7227                                 break;
7228                         }
7229                 }
7230
7231                 ret = btrfs_reserve_extent(trans, root, num_bytes, min_size,
7232                                            0, *alloc_hint, (u64)-1, &ins, 1);
7233                 if (ret) {
7234                         if (own_trans)
7235                                 btrfs_end_transaction(trans, root);
7236                         break;
7237                 }
7238
7239                 ret = insert_reserved_file_extent(trans, inode,
7240                                                   cur_offset, ins.objectid,
7241                                                   ins.offset, ins.offset,
7242                                                   ins.offset, 0, 0, 0,
7243                                                   BTRFS_FILE_EXTENT_PREALLOC);
7244                 BUG_ON(ret);
7245                 btrfs_drop_extent_cache(inode, cur_offset,
7246                                         cur_offset + ins.offset -1, 0);
7247
7248                 num_bytes -= ins.offset;
7249                 cur_offset += ins.offset;
7250                 *alloc_hint = ins.objectid + ins.offset;
7251
7252                 inode->i_ctime = CURRENT_TIME;
7253                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
7254                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
7255                     (actual_len > inode->i_size) &&
7256                     (cur_offset > inode->i_size)) {
7257                         if (cur_offset > actual_len)
7258                                 i_size = actual_len;
7259                         else
7260                                 i_size = cur_offset;
7261                         i_size_write(inode, i_size);
7262                         btrfs_ordered_update_i_size(inode, i_size, NULL);
7263                 }
7264
7265                 ret = btrfs_update_inode(trans, root, inode);
7266                 BUG_ON(ret);
7267
7268                 if (own_trans)
7269                         btrfs_end_transaction(trans, root);
7270         }
7271         return ret;
7272 }
7273
7274 int btrfs_prealloc_file_range(struct inode *inode, int mode,
7275                               u64 start, u64 num_bytes, u64 min_size,
7276                               loff_t actual_len, u64 *alloc_hint)
7277 {
7278         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
7279                                            min_size, actual_len, alloc_hint,
7280                                            NULL);
7281 }
7282
7283 int btrfs_prealloc_file_range_trans(struct inode *inode,
7284                                     struct btrfs_trans_handle *trans, int mode,
7285                                     u64 start, u64 num_bytes, u64 min_size,
7286                                     loff_t actual_len, u64 *alloc_hint)
7287 {
7288         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
7289                                            min_size, actual_len, alloc_hint, trans);
7290 }
7291
7292 static int btrfs_set_page_dirty(struct page *page)
7293 {
7294         return __set_page_dirty_nobuffers(page);
7295 }
7296
7297 static int btrfs_permission(struct inode *inode, int mask, unsigned int flags)
7298 {
7299         struct btrfs_root *root = BTRFS_I(inode)->root;
7300
7301         if (btrfs_root_readonly(root) && (mask & MAY_WRITE))
7302                 return -EROFS;
7303         if ((BTRFS_I(inode)->flags & BTRFS_INODE_READONLY) && (mask & MAY_WRITE))
7304                 return -EACCES;
7305         return generic_permission(inode, mask, flags, btrfs_check_acl);
7306 }
7307
7308 static const struct inode_operations btrfs_dir_inode_operations = {
7309         .getattr        = btrfs_getattr,
7310         .lookup         = btrfs_lookup,
7311         .create         = btrfs_create,
7312         .unlink         = btrfs_unlink,
7313         .link           = btrfs_link,
7314         .mkdir          = btrfs_mkdir,
7315         .rmdir          = btrfs_rmdir,
7316         .rename         = btrfs_rename,
7317         .symlink        = btrfs_symlink,
7318         .setattr        = btrfs_setattr,
7319         .mknod          = btrfs_mknod,
7320         .setxattr       = btrfs_setxattr,
7321         .getxattr       = btrfs_getxattr,
7322         .listxattr      = btrfs_listxattr,
7323         .removexattr    = btrfs_removexattr,
7324         .permission     = btrfs_permission,
7325 };
7326 static const struct inode_operations btrfs_dir_ro_inode_operations = {
7327         .lookup         = btrfs_lookup,
7328         .permission     = btrfs_permission,
7329 };
7330
7331 static const struct file_operations btrfs_dir_file_operations = {
7332         .llseek         = generic_file_llseek,
7333         .read           = generic_read_dir,
7334         .readdir        = btrfs_real_readdir,
7335         .unlocked_ioctl = btrfs_ioctl,
7336 #ifdef CONFIG_COMPAT
7337         .compat_ioctl   = btrfs_ioctl,
7338 #endif
7339         .release        = btrfs_release_file,
7340         .fsync          = btrfs_sync_file,
7341 };
7342
7343 static struct extent_io_ops btrfs_extent_io_ops = {
7344         .fill_delalloc = run_delalloc_range,
7345         .submit_bio_hook = btrfs_submit_bio_hook,
7346         .merge_bio_hook = btrfs_merge_bio_hook,
7347         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
7348         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
7349         .writepage_start_hook = btrfs_writepage_start_hook,
7350         .readpage_io_failed_hook = btrfs_io_failed_hook,
7351         .set_bit_hook = btrfs_set_bit_hook,
7352         .clear_bit_hook = btrfs_clear_bit_hook,
7353         .merge_extent_hook = btrfs_merge_extent_hook,
7354         .split_extent_hook = btrfs_split_extent_hook,
7355 };
7356
7357 /*
7358  * btrfs doesn't support the bmap operation because swapfiles
7359  * use bmap to make a mapping of extents in the file.  They assume
7360  * these extents won't change over the life of the file and they
7361  * use the bmap result to do IO directly to the drive.
7362  *
7363  * the btrfs bmap call would return logical addresses that aren't
7364  * suitable for IO and they also will change frequently as COW
7365  * operations happen.  So, swapfile + btrfs == corruption.
7366  *
7367  * For now we're avoiding this by dropping bmap.
7368  */
7369 static const struct address_space_operations btrfs_aops = {
7370         .readpage       = btrfs_readpage,
7371         .writepage      = btrfs_writepage,
7372         .writepages     = btrfs_writepages,
7373         .readpages      = btrfs_readpages,
7374         .direct_IO      = btrfs_direct_IO,
7375         .invalidatepage = btrfs_invalidatepage,
7376         .releasepage    = btrfs_releasepage,
7377         .set_page_dirty = btrfs_set_page_dirty,
7378         .error_remove_page = generic_error_remove_page,
7379 };
7380
7381 static const struct address_space_operations btrfs_symlink_aops = {
7382         .readpage       = btrfs_readpage,
7383         .writepage      = btrfs_writepage,
7384         .invalidatepage = btrfs_invalidatepage,
7385         .releasepage    = btrfs_releasepage,
7386 };
7387
7388 static const struct inode_operations btrfs_file_inode_operations = {
7389         .getattr        = btrfs_getattr,
7390         .setattr        = btrfs_setattr,
7391         .setxattr       = btrfs_setxattr,
7392         .getxattr       = btrfs_getxattr,
7393         .listxattr      = btrfs_listxattr,
7394         .removexattr    = btrfs_removexattr,
7395         .permission     = btrfs_permission,
7396         .fiemap         = btrfs_fiemap,
7397 };
7398 static const struct inode_operations btrfs_special_inode_operations = {
7399         .getattr        = btrfs_getattr,
7400         .setattr        = btrfs_setattr,
7401         .permission     = btrfs_permission,
7402         .setxattr       = btrfs_setxattr,
7403         .getxattr       = btrfs_getxattr,
7404         .listxattr      = btrfs_listxattr,
7405         .removexattr    = btrfs_removexattr,
7406 };
7407 static const struct inode_operations btrfs_symlink_inode_operations = {
7408         .readlink       = generic_readlink,
7409         .follow_link    = page_follow_link_light,
7410         .put_link       = page_put_link,
7411         .getattr        = btrfs_getattr,
7412         .permission     = btrfs_permission,
7413         .setxattr       = btrfs_setxattr,
7414         .getxattr       = btrfs_getxattr,
7415         .listxattr      = btrfs_listxattr,
7416         .removexattr    = btrfs_removexattr,
7417 };
7418
7419 const struct dentry_operations btrfs_dentry_operations = {
7420         .d_delete       = btrfs_dentry_delete,
7421 };