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