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/smp_lock.h>
  30 #include <linux/backing-dev.h>
  31 #include <linux/mpage.h>
  32 #include <linux/swap.h>
  33 #include <linux/writeback.h>
  34 #include <linux/statfs.h>
  35 #include <linux/compat.h>
  36 #include <linux/bit_spinlock.h>
  37 #include <linux/xattr.h>
  38 #include <linux/posix_acl.h>
  39 #include <linux/falloc.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 "ref-cache.h"
  52 #include "compression.h"
  53 #include "locking.h"
  54
  55 struct btrfs_iget_args {
  56         u64 ino;
  57         struct btrfs_root *root;
  58 };
  59
  60 static struct inode_operations btrfs_dir_inode_operations;
  61 static struct inode_operations btrfs_symlink_inode_operations;
  62 static struct inode_operations btrfs_dir_ro_inode_operations;
  63 static struct inode_operations btrfs_special_inode_operations;
  64 static struct inode_operations btrfs_file_inode_operations;
  65 static struct address_space_operations btrfs_aops;
  66 static struct address_space_operations btrfs_symlink_aops;
  67 static struct file_operations btrfs_dir_file_operations;
  68 static struct extent_io_ops btrfs_extent_io_ops;
  69
  70 static struct kmem_cache *btrfs_inode_cachep;
  71 struct kmem_cache *btrfs_trans_handle_cachep;
  72 struct kmem_cache *btrfs_transaction_cachep;
  73 struct kmem_cache *btrfs_bit_radix_cachep;
  74 struct kmem_cache *btrfs_path_cachep;
  75
  76 #define S_SHIFT 12
  77 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  78         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  79         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  80         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  81         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  82         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  83         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
  84         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
  85 };
  86
  87 static void btrfs_truncate(struct inode *inode);
  88 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end);
  89 static noinline int cow_file_range(struct inode *inode,
  90                                    struct page *locked_page,
  91                                    u64 start, u64 end, int *page_started,
  92                                    unsigned long *nr_written, int unlock);
  93
  94 static int btrfs_init_inode_security(struct inode *inode,  struct inode *dir)
  95 {
  96         int err;
  97
  98         err = btrfs_init_acl(inode, dir);
  99         if (!err)
 100                 err = btrfs_xattr_security_init(inode, dir);
 101         return err;
 102 }
 103
 104 /*
 105  * this does all the hard work for inserting an inline extent into
 106  * the btree.  The caller should have done a btrfs_drop_extents so that
 107  * no overlapping inline items exist in the btree
 108  */
 109 static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
 110                                 struct btrfs_root *root, struct inode *inode,
 111                                 u64 start, size_t size, size_t compressed_size,
 112                                 struct page **compressed_pages)
 113 {
 114         struct btrfs_key key;
 115         struct btrfs_path *path;
 116         struct extent_buffer *leaf;
 117         struct page *page = NULL;
 118         char *kaddr;
 119         unsigned long ptr;
 120         struct btrfs_file_extent_item *ei;
 121         int err = 0;
 122         int ret;
 123         size_t cur_size = size;
 124         size_t datasize;
 125         unsigned long offset;
 126         int use_compress = 0;
 127
 128         if (compressed_size && compressed_pages) {
 129                 use_compress = 1;
 130                 cur_size = compressed_size;
 131         }
 132
 133         path = btrfs_alloc_path();
 134         if (!path)
 135                 return -ENOMEM;
 136
 137         path->leave_spinning = 1;
 138         btrfs_set_trans_block_group(trans, inode);
 139
 140         key.objectid = inode->i_ino;
 141         key.offset = start;
 142         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
 143         datasize = btrfs_file_extent_calc_inline_size(cur_size);
 144
 145         inode_add_bytes(inode, size);
 146         ret = btrfs_insert_empty_item(trans, root, path, &key,
 147                                       datasize);
 148         BUG_ON(ret);
 149         if (ret) {
 150                 err = ret;
 151                 goto fail;
 152         }
 153         leaf = path->nodes[0];
 154         ei = btrfs_item_ptr(leaf, path->slots[0],
 155                             struct btrfs_file_extent_item);
 156         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 157         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 158         btrfs_set_file_extent_encryption(leaf, ei, 0);
 159         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 160         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 161         ptr = btrfs_file_extent_inline_start(ei);
 162
 163         if (use_compress) {
 164                 struct page *cpage;
 165                 int i = 0;
 166                 while (compressed_size > 0) {
 167                         cpage = compressed_pages[i];
 168                         cur_size = min_t(unsigned long, compressed_size,
 169                                        PAGE_CACHE_SIZE);
 170
 171                         kaddr = kmap_atomic(cpage, KM_USER0);
 172                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 173                         kunmap_atomic(kaddr, KM_USER0);
 174
 175                         i++;
 176                         ptr += cur_size;
 177                         compressed_size -= cur_size;
 178                 }
 179                 btrfs_set_file_extent_compression(leaf, ei,
 180                                                   BTRFS_COMPRESS_ZLIB);
 181         } else {
 182                 page = find_get_page(inode->i_mapping,
 183                                      start >> PAGE_CACHE_SHIFT);
 184                 btrfs_set_file_extent_compression(leaf, ei, 0);
 185                 kaddr = kmap_atomic(page, KM_USER0);
 186                 offset = start & (PAGE_CACHE_SIZE - 1);
 187                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 188                 kunmap_atomic(kaddr, KM_USER0);
 189                 page_cache_release(page);
 190         }
 191         btrfs_mark_buffer_dirty(leaf);
 192         btrfs_free_path(path);
 193
 194         BTRFS_I(inode)->disk_i_size = inode->i_size;
 195         btrfs_update_inode(trans, root, inode);
 196         return 0;
 197 fail:
 198         btrfs_free_path(path);
 199         return err;
 200 }
 201
 202
 203 /*
 204  * conditionally insert an inline extent into the file.  This
 205  * does the checks required to make sure the data is small enough
 206  * to fit as an inline extent.
 207  */
 208 static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans,
 209                                  struct btrfs_root *root,
 210                                  struct inode *inode, u64 start, u64 end,
 211                                  size_t compressed_size,
 212                                  struct page **compressed_pages)
 213 {
 214         u64 isize = i_size_read(inode);
 215         u64 actual_end = min(end + 1, isize);
 216         u64 inline_len = actual_end - start;
 217         u64 aligned_end = (end + root->sectorsize - 1) &
 218                         ~((u64)root->sectorsize - 1);
 219         u64 hint_byte;
 220         u64 data_len = inline_len;
 221         int ret;
 222
 223         if (compressed_size)
 224                 data_len = compressed_size;
 225
 226         if (start > 0 ||
 227             actual_end >= PAGE_CACHE_SIZE ||
 228             data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 229             (!compressed_size &&
 230             (actual_end & (root->sectorsize - 1)) == 0) ||
 231             end + 1 < isize ||
 232             data_len > root->fs_info->max_inline) {
 233                 return 1;
 234         }
 235
 236         ret = btrfs_drop_extents(trans, root, inode, start,
 237                                  aligned_end, start, &hint_byte);
 238         BUG_ON(ret);
 239
 240         if (isize > actual_end)
 241                 inline_len = min_t(u64, isize, actual_end);
 242         ret = insert_inline_extent(trans, root, inode, start,
 243                                    inline_len, compressed_size,
 244                                    compressed_pages);
 245         BUG_ON(ret);
 246         btrfs_drop_extent_cache(inode, start, aligned_end, 0);
 247         return 0;
 248 }
 249
 250 struct async_extent {
 251         u64 start;
 252         u64 ram_size;
 253         u64 compressed_size;
 254         struct page **pages;
 255         unsigned long nr_pages;
 256         struct list_head list;
 257 };
 258
 259 struct async_cow {
 260         struct inode *inode;
 261         struct btrfs_root *root;
 262         struct page *locked_page;
 263         u64 start;
 264         u64 end;
 265         struct list_head extents;
 266         struct btrfs_work work;
 267 };
 268
 269 static noinline int add_async_extent(struct async_cow *cow,
 270                                      u64 start, u64 ram_size,
 271                                      u64 compressed_size,
 272                                      struct page **pages,
 273                                      unsigned long nr_pages)
 274 {
 275         struct async_extent *async_extent;
 276
 277         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 278         async_extent->start = start;
 279         async_extent->ram_size = ram_size;
 280         async_extent->compressed_size = compressed_size;
 281         async_extent->pages = pages;
 282         async_extent->nr_pages = nr_pages;
 283         list_add_tail(&async_extent->list, &cow->extents);
 284         return 0;
 285 }
 286
 287 /*
 288  * we create compressed extents in two phases.  The first
 289  * phase compresses a range of pages that have already been
 290  * locked (both pages and state bits are locked).
 291  *
 292  * This is done inside an ordered work queue, and the compression
 293  * is spread across many cpus.  The actual IO submission is step
 294  * two, and the ordered work queue takes care of making sure that
 295  * happens in the same order things were put onto the queue by
 296  * writepages and friends.
 297  *
 298  * If this code finds it can't get good compression, it puts an
 299  * entry onto the work queue to write the uncompressed bytes.  This
 300  * makes sure that both compressed inodes and uncompressed inodes
 301  * are written in the same order that pdflush sent them down.
 302  */
 303 static noinline int compress_file_range(struct inode *inode,
 304                                         struct page *locked_page,
 305                                         u64 start, u64 end,
 306                                         struct async_cow *async_cow,
 307                                         int *num_added)
 308 {
 309         struct btrfs_root *root = BTRFS_I(inode)->root;
 310         struct btrfs_trans_handle *trans;
 311         u64 num_bytes;
 312         u64 orig_start;
 313         u64 disk_num_bytes;
 314         u64 blocksize = root->sectorsize;
 315         u64 actual_end;
 316         u64 isize = i_size_read(inode);
 317         int ret = 0;
 318         struct page **pages = NULL;
 319         unsigned long nr_pages;
 320         unsigned long nr_pages_ret = 0;
 321         unsigned long total_compressed = 0;
 322         unsigned long total_in = 0;
 323         unsigned long max_compressed = 128 * 1024;
 324         unsigned long max_uncompressed = 128 * 1024;
 325         int i;
 326         int will_compress;
 327
 328         orig_start = start;
 329
 330         actual_end = min_t(u64, isize, end + 1);
 331 again:
 332         will_compress = 0;
 333         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
 334         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
 335
 336         /*
 337          * we don't want to send crud past the end of i_size through
 338          * compression, that's just a waste of CPU time.  So, if the
 339          * end of the file is before the start of our current
 340          * requested range of bytes, we bail out to the uncompressed
 341          * cleanup code that can deal with all of this.
 342          *
 343          * It isn't really the fastest way to fix things, but this is a
 344          * very uncommon corner.
 345          */
 346         if (actual_end <= start)
 347                 goto cleanup_and_bail_uncompressed;
 348
 349         total_compressed = actual_end - start;
 350
 351         /* we want to make sure that amount of ram required to uncompress
 352          * an extent is reasonable, so we limit the total size in ram
 353          * of a compressed extent to 128k.  This is a crucial number
 354          * because it also controls how easily we can spread reads across
 355          * cpus for decompression.
 356          *
 357          * We also want to make sure the amount of IO required to do
 358          * a random read is reasonably small, so we limit the size of
 359          * a compressed extent to 128k.
 360          */
 361         total_compressed = min(total_compressed, max_uncompressed);
 362         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
 363         num_bytes = max(blocksize,  num_bytes);
 364         disk_num_bytes = num_bytes;
 365         total_in = 0;
 366         ret = 0;
 367
 368         /*
 369          * we do compression for mount -o compress and when the
 370          * inode has not been flagged as nocompress.  This flag can
 371          * change at any time if we discover bad compression ratios.
 372          */
 373         if (!btrfs_test_flag(inode, NOCOMPRESS) &&
 374             btrfs_test_opt(root, COMPRESS)) {
 375                 WARN_ON(pages);
 376                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
 377
 378                 ret = btrfs_zlib_compress_pages(inode->i_mapping, start,
 379                                                 total_compressed, pages,
 380                                                 nr_pages, &nr_pages_ret,
 381                                                 &total_in,
 382                                                 &total_compressed,
 383                                                 max_compressed);
 384
 385                 if (!ret) {
 386                         unsigned long offset = total_compressed &
 387                                 (PAGE_CACHE_SIZE - 1);
 388                         struct page *page = pages[nr_pages_ret - 1];
 389                         char *kaddr;
 390
 391                         /* zero the tail end of the last page, we might be
 392                          * sending it down to disk
 393                          */
 394                         if (offset) {
 395                                 kaddr = kmap_atomic(page, KM_USER0);
 396                                 memset(kaddr + offset, 0,
 397                                        PAGE_CACHE_SIZE - offset);
 398                                 kunmap_atomic(kaddr, KM_USER0);
 399                         }
 400                         will_compress = 1;
 401                 }
 402         }
 403         if (start == 0) {
 404                 trans = btrfs_join_transaction(root, 1);
 405                 BUG_ON(!trans);
 406                 btrfs_set_trans_block_group(trans, inode);
 407
 408                 /* lets try to make an inline extent */
 409                 if (ret || total_in < (actual_end - start)) {
 410                         /* we didn't compress the entire range, try
 411                          * to make an uncompressed inline extent.
 412                          */
 413                         ret = cow_file_range_inline(trans, root, inode,
 414                                                     start, end, 0, NULL);
 415                 } else {
 416                         /* try making a compressed inline extent */
 417                         ret = cow_file_range_inline(trans, root, inode,
 418                                                     start, end,
 419                                                     total_compressed, pages);
 420                 }
 421                 btrfs_end_transaction(trans, root);
 422                 if (ret == 0) {
 423                         /*
 424                          * inline extent creation worked, we don't need
 425                          * to create any more async work items.  Unlock
 426                          * and free up our temp pages.
 427                          */
 428                         extent_clear_unlock_delalloc(inode,
 429                                                      &BTRFS_I(inode)->io_tree,
 430                                                      start, end, NULL, 1, 0,
 431                                                      0, 1, 1, 1);
 432                         ret = 0;
 433                         goto free_pages_out;
 434                 }
 435         }
 436
 437         if (will_compress) {
 438                 /*
 439                  * we aren't doing an inline extent round the compressed size
 440                  * up to a block size boundary so the allocator does sane
 441                  * things
 442                  */
 443                 total_compressed = (total_compressed + blocksize - 1) &
 444                         ~(blocksize - 1);
 445
 446                 /*
 447                  * one last check to make sure the compression is really a
 448                  * win, compare the page count read with the blocks on disk
 449                  */
 450                 total_in = (total_in + PAGE_CACHE_SIZE - 1) &
 451                         ~(PAGE_CACHE_SIZE - 1);
 452                 if (total_compressed >= total_in) {
 453                         will_compress = 0;
 454                 } else {
 455                         disk_num_bytes = total_compressed;
 456                         num_bytes = total_in;
 457                 }
 458         }
 459         if (!will_compress && pages) {
 460                 /*
 461                  * the compression code ran but failed to make things smaller,
 462                  * free any pages it allocated and our page pointer array
 463                  */
 464                 for (i = 0; i < nr_pages_ret; i++) {
 465                         WARN_ON(pages[i]->mapping);
 466                         page_cache_release(pages[i]);
 467                 }
 468                 kfree(pages);
 469                 pages = NULL;
 470                 total_compressed = 0;
 471                 nr_pages_ret = 0;
 472
 473                 /* flag the file so we don't compress in the future */
 474                 btrfs_set_flag(inode, NOCOMPRESS);
 475         }
 476         if (will_compress) {
 477                 *num_added += 1;
 478
 479                 /* the async work queues will take care of doing actual
 480                  * allocation on disk for these compressed pages,
 481                  * and will submit them to the elevator.
 482                  */
 483                 add_async_extent(async_cow, start, num_bytes,
 484                                  total_compressed, pages, nr_pages_ret);
 485
 486                 if (start + num_bytes < end && start + num_bytes < actual_end) {
 487                         start += num_bytes;
 488                         pages = NULL;
 489                         cond_resched();
 490                         goto again;
 491                 }
 492         } else {
 493 cleanup_and_bail_uncompressed:
 494                 /*
 495                  * No compression, but we still need to write the pages in
 496                  * the file we've been given so far.  redirty the locked
 497                  * page if it corresponds to our extent and set things up
 498                  * for the async work queue to run cow_file_range to do
 499                  * the normal delalloc dance
 500                  */
 501                 if (page_offset(locked_page) >= start &&
 502                     page_offset(locked_page) <= end) {
 503                         __set_page_dirty_nobuffers(locked_page);
 504                         /* unlocked later on in the async handlers */
 505                 }
 506                 add_async_extent(async_cow, start, end - start + 1, 0, NULL, 0);
 507                 *num_added += 1;
 508         }
 509
 510 out:
 511         return 0;
 512
 513 free_pages_out:
 514         for (i = 0; i < nr_pages_ret; i++) {
 515                 WARN_ON(pages[i]->mapping);
 516                 page_cache_release(pages[i]);
 517         }
 518         kfree(pages);
 519
 520         goto out;
 521 }
 522
 523 /*
 524  * phase two of compressed writeback.  This is the ordered portion
 525  * of the code, which only gets called in the order the work was
 526  * queued.  We walk all the async extents created by compress_file_range
 527  * and send them down to the disk.
 528  */
 529 static noinline int submit_compressed_extents(struct inode *inode,
 530                                               struct async_cow *async_cow)
 531 {
 532         struct async_extent *async_extent;
 533         u64 alloc_hint = 0;
 534         struct btrfs_trans_handle *trans;
 535         struct btrfs_key ins;
 536         struct extent_map *em;
 537         struct btrfs_root *root = BTRFS_I(inode)->root;
 538         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 539         struct extent_io_tree *io_tree;
 540         int ret;
 541
 542         if (list_empty(&async_cow->extents))
 543                 return 0;
 544
 545         trans = btrfs_join_transaction(root, 1);
 546
 547         while (!list_empty(&async_cow->extents)) {
 548                 async_extent = list_entry(async_cow->extents.next,
 549                                           struct async_extent, list);
 550                 list_del(&async_extent->list);
 551
 552                 io_tree = &BTRFS_I(inode)->io_tree;
 553
 554                 /* did the compression code fall back to uncompressed IO? */
 555                 if (!async_extent->pages) {
 556                         int page_started = 0;
 557                         unsigned long nr_written = 0;
 558
 559                         lock_extent(io_tree, async_extent->start,
 560                                     async_extent->start +
 561                                     async_extent->ram_size - 1, GFP_NOFS);
 562
 563                         /* allocate blocks */
 564                         cow_file_range(inode, async_cow->locked_page,
 565                                        async_extent->start,
 566                                        async_extent->start +
 567                                        async_extent->ram_size - 1,
 568                                        &page_started, &nr_written, 0);
 569
 570                         /*
 571                          * if page_started, cow_file_range inserted an
 572                          * inline extent and took care of all the unlocking
 573                          * and IO for us.  Otherwise, we need to submit
 574                          * all those pages down to the drive.
 575                          */
 576                         if (!page_started)
 577                                 extent_write_locked_range(io_tree,
 578                                                   inode, async_extent->start,
 579                                                   async_extent->start +
 580                                                   async_extent->ram_size - 1,
 581                                                   btrfs_get_extent,
 582                                                   WB_SYNC_ALL);
 583                         kfree(async_extent);
 584                         cond_resched();
 585                         continue;
 586                 }
 587
 588                 lock_extent(io_tree, async_extent->start,
 589                             async_extent->start + async_extent->ram_size - 1,
 590                             GFP_NOFS);
 591                 /*
 592                  * here we're doing allocation and writeback of the
 593                  * compressed pages
 594                  */
 595                 btrfs_drop_extent_cache(inode, async_extent->start,
 596                                         async_extent->start +
 597                                         async_extent->ram_size - 1, 0);
 598
 599                 ret = btrfs_reserve_extent(trans, root,
 600                                            async_extent->compressed_size,
 601                                            async_extent->compressed_size,
 602                                            0, alloc_hint,
 603                                            (u64)-1, &ins, 1);
 604                 BUG_ON(ret);
 605                 em = alloc_extent_map(GFP_NOFS);
 606                 em->start = async_extent->start;
 607                 em->len = async_extent->ram_size;
 608                 em->orig_start = em->start;
 609
 610                 em->block_start = ins.objectid;
 611                 em->block_len = ins.offset;
 612                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 613                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 614                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 615
 616                 while (1) {
 617                         spin_lock(&em_tree->lock);
 618                         ret = add_extent_mapping(em_tree, em);
 619                         spin_unlock(&em_tree->lock);
 620                         if (ret != -EEXIST) {
 621                                 free_extent_map(em);
 622                                 break;
 623                         }
 624                         btrfs_drop_extent_cache(inode, async_extent->start,
 625                                                 async_extent->start +
 626                                                 async_extent->ram_size - 1, 0);
 627                 }
 628
 629                 ret = btrfs_add_ordered_extent(inode, async_extent->start,
 630                                                ins.objectid,
 631                                                async_extent->ram_size,
 632                                                ins.offset,
 633                                                BTRFS_ORDERED_COMPRESSED);
 634                 BUG_ON(ret);
 635
 636                 btrfs_end_transaction(trans, root);
 637
 638                 /*
 639                  * clear dirty, set writeback and unlock the pages.
 640                  */
 641                 extent_clear_unlock_delalloc(inode,
 642                                              &BTRFS_I(inode)->io_tree,
 643                                              async_extent->start,
 644                                              async_extent->start +
 645                                              async_extent->ram_size - 1,
 646                                              NULL, 1, 1, 0, 1, 1, 0);
 647
 648                 ret = btrfs_submit_compressed_write(inode,
 649                                     async_extent->start,
 650                                     async_extent->ram_size,
 651                                     ins.objectid,
 652                                     ins.offset, async_extent->pages,
 653                                     async_extent->nr_pages);
 654
 655                 BUG_ON(ret);
 656                 trans = btrfs_join_transaction(root, 1);
 657                 alloc_hint = ins.objectid + ins.offset;
 658                 kfree(async_extent);
 659                 cond_resched();
 660         }
 661
 662         btrfs_end_transaction(trans, root);
 663         return 0;
 664 }
 665
 666 /*
 667  * when extent_io.c finds a delayed allocation range in the file,
 668  * the call backs end up in this code.  The basic idea is to
 669  * allocate extents on disk for the range, and create ordered data structs
 670  * in ram to track those extents.
 671  *
 672  * locked_page is the page that writepage had locked already.  We use
 673  * it to make sure we don't do extra locks or unlocks.
 674  *
 675  * *page_started is set to one if we unlock locked_page and do everything
 676  * required to start IO on it.  It may be clean and already done with
 677  * IO when we return.
 678  */
 679 static noinline int cow_file_range(struct inode *inode,
 680                                    struct page *locked_page,
 681                                    u64 start, u64 end, int *page_started,
 682                                    unsigned long *nr_written,
 683                                    int unlock)
 684 {
 685         struct btrfs_root *root = BTRFS_I(inode)->root;
 686         struct btrfs_trans_handle *trans;
 687         u64 alloc_hint = 0;
 688         u64 num_bytes;
 689         unsigned long ram_size;
 690         u64 disk_num_bytes;
 691         u64 cur_alloc_size;
 692         u64 blocksize = root->sectorsize;
 693         u64 actual_end;
 694         u64 isize = i_size_read(inode);
 695         struct btrfs_key ins;
 696         struct extent_map *em;
 697         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 698         int ret = 0;
 699
 700         trans = btrfs_join_transaction(root, 1);
 701         BUG_ON(!trans);
 702         btrfs_set_trans_block_group(trans, inode);
 703
 704         actual_end = min_t(u64, isize, end + 1);
 705
 706         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
 707         num_bytes = max(blocksize,  num_bytes);
 708         disk_num_bytes = num_bytes;
 709         ret = 0;
 710
 711         if (start == 0) {
 712                 /* lets try to make an inline extent */
 713                 ret = cow_file_range_inline(trans, root, inode,
 714                                             start, end, 0, NULL);
 715                 if (ret == 0) {
 716                         extent_clear_unlock_delalloc(inode,
 717                                                      &BTRFS_I(inode)->io_tree,
 718                                                      start, end, NULL, 1, 1,
 719                                                      1, 1, 1, 1);
 720                         *nr_written = *nr_written +
 721                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
 722                         *page_started = 1;
 723                         ret = 0;
 724                         goto out;
 725                 }
 726         }
 727
 728         BUG_ON(disk_num_bytes >
 729                btrfs_super_total_bytes(&root->fs_info->super_copy));
 730
 731         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 732
 733         while (disk_num_bytes > 0) {
 734                 cur_alloc_size = min(disk_num_bytes, root->fs_info->max_extent);
 735                 ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
 736                                            root->sectorsize, 0, alloc_hint,
 737                                            (u64)-1, &ins, 1);
 738                 BUG_ON(ret);
 739
 740                 em = alloc_extent_map(GFP_NOFS);
 741                 em->start = start;
 742                 em->orig_start = em->start;
 743
 744                 ram_size = ins.offset;
 745                 em->len = ins.offset;
 746
 747                 em->block_start = ins.objectid;
 748                 em->block_len = ins.offset;
 749                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 750                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 751
 752                 while (1) {
 753                         spin_lock(&em_tree->lock);
 754                         ret = add_extent_mapping(em_tree, em);
 755                         spin_unlock(&em_tree->lock);
 756                         if (ret != -EEXIST) {
 757                                 free_extent_map(em);
 758                                 break;
 759                         }
 760                         btrfs_drop_extent_cache(inode, start,
 761                                                 start + ram_size - 1, 0);
 762                 }
 763
 764                 cur_alloc_size = ins.offset;
 765                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
 766                                                ram_size, cur_alloc_size, 0);
 767                 BUG_ON(ret);
 768
 769                 if (root->root_key.objectid ==
 770                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
 771                         ret = btrfs_reloc_clone_csums(inode, start,
 772                                                       cur_alloc_size);
 773                         BUG_ON(ret);
 774                 }
 775
 776                 if (disk_num_bytes < cur_alloc_size)
 777                         break;
 778
 779                 /* we're not doing compressed IO, don't unlock the first
 780                  * page (which the caller expects to stay locked), don't
 781                  * clear any dirty bits and don't set any writeback bits
 782                  */
 783                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
 784                                              start, start + ram_size - 1,
 785                                              locked_page, unlock, 1,
 786                                              1, 0, 0, 0);
 787                 disk_num_bytes -= cur_alloc_size;
 788                 num_bytes -= cur_alloc_size;
 789                 alloc_hint = ins.objectid + ins.offset;
 790                 start += cur_alloc_size;
 791         }
 792 out:
 793         ret = 0;
 794         btrfs_end_transaction(trans, root);
 795
 796         return ret;
 797 }
 798
 799 /*
 800  * work queue call back to started compression on a file and pages
 801  */
 802 static noinline void async_cow_start(struct btrfs_work *work)
 803 {
 804         struct async_cow *async_cow;
 805         int num_added = 0;
 806         async_cow = container_of(work, struct async_cow, work);
 807
 808         compress_file_range(async_cow->inode, async_cow->locked_page,
 809                             async_cow->start, async_cow->end, async_cow,
 810                             &num_added);
 811         if (num_added == 0)
 812                 async_cow->inode = NULL;
 813 }
 814
 815 /*
 816  * work queue call back to submit previously compressed pages
 817  */
 818 static noinline void async_cow_submit(struct btrfs_work *work)
 819 {
 820         struct async_cow *async_cow;
 821         struct btrfs_root *root;
 822         unsigned long nr_pages;
 823
 824         async_cow = container_of(work, struct async_cow, work);
 825
 826         root = async_cow->root;
 827         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
 828                 PAGE_CACHE_SHIFT;
 829
 830         atomic_sub(nr_pages, &root->fs_info->async_delalloc_pages);
 831
 832         if (atomic_read(&root->fs_info->async_delalloc_pages) <
 833             5 * 1042 * 1024 &&
 834             waitqueue_active(&root->fs_info->async_submit_wait))
 835                 wake_up(&root->fs_info->async_submit_wait);
 836
 837         if (async_cow->inode)
 838                 submit_compressed_extents(async_cow->inode, async_cow);
 839 }
 840
 841 static noinline void async_cow_free(struct btrfs_work *work)
 842 {
 843         struct async_cow *async_cow;
 844         async_cow = container_of(work, struct async_cow, work);
 845         kfree(async_cow);
 846 }
 847
 848 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
 849                                 u64 start, u64 end, int *page_started,
 850                                 unsigned long *nr_written)
 851 {
 852         struct async_cow *async_cow;
 853         struct btrfs_root *root = BTRFS_I(inode)->root;
 854         unsigned long nr_pages;
 855         u64 cur_end;
 856         int limit = 10 * 1024 * 1042;
 857
 858         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED |
 859                          EXTENT_DELALLOC, 1, 0, GFP_NOFS);
 860         while (start < end) {
 861                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
 862                 async_cow->inode = inode;
 863                 async_cow->root = root;
 864                 async_cow->locked_page = locked_page;
 865                 async_cow->start = start;
 866
 867                 if (btrfs_test_flag(inode, NOCOMPRESS))
 868                         cur_end = end;
 869                 else
 870                         cur_end = min(end, start + 512 * 1024 - 1);
 871
 872                 async_cow->end = cur_end;
 873                 INIT_LIST_HEAD(&async_cow->extents);
 874
 875                 async_cow->work.func = async_cow_start;
 876                 async_cow->work.ordered_func = async_cow_submit;
 877                 async_cow->work.ordered_free = async_cow_free;
 878                 async_cow->work.flags = 0;
 879
 880                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
 881                         PAGE_CACHE_SHIFT;
 882                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
 883
 884                 btrfs_queue_worker(&root->fs_info->delalloc_workers,
 885                                    &async_cow->work);
 886
 887                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
 888                         wait_event(root->fs_info->async_submit_wait,
 889                            (atomic_read(&root->fs_info->async_delalloc_pages) <
 890                             limit));
 891                 }
 892
 893                 while (atomic_read(&root->fs_info->async_submit_draining) &&
 894                       atomic_read(&root->fs_info->async_delalloc_pages)) {
 895                         wait_event(root->fs_info->async_submit_wait,
 896                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
 897                            0));
 898                 }
 899
 900                 *nr_written += nr_pages;
 901                 start = cur_end + 1;
 902         }
 903         *page_started = 1;
 904         return 0;
 905 }
 906
 907 static noinline int csum_exist_in_range(struct btrfs_root *root,
 908                                         u64 bytenr, u64 num_bytes)
 909 {
 910         int ret;
 911         struct btrfs_ordered_sum *sums;
 912         LIST_HEAD(list);
 913
 914         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
 915                                        bytenr + num_bytes - 1, &list);
 916         if (ret == 0 && list_empty(&list))
 917                 return 0;
 918
 919         while (!list_empty(&list)) {
 920                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
 921                 list_del(&sums->list);
 922                 kfree(sums);
 923         }
 924         return 1;
 925 }
 926
 927 /*
 928  * when nowcow writeback call back.  This checks for snapshots or COW copies
 929  * of the extents that exist in the file, and COWs the file as required.
 930  *
 931  * If no cow copies or snapshots exist, we write directly to the existing
 932  * blocks on disk
 933  */
 934 static noinline int run_delalloc_nocow(struct inode *inode,
 935                                        struct page *locked_page,
 936                               u64 start, u64 end, int *page_started, int force,
 937                               unsigned long *nr_written)
 938 {
 939         struct btrfs_root *root = BTRFS_I(inode)->root;
 940         struct btrfs_trans_handle *trans;
 941         struct extent_buffer *leaf;
 942         struct btrfs_path *path;
 943         struct btrfs_file_extent_item *fi;
 944         struct btrfs_key found_key;
 945         u64 cow_start;
 946         u64 cur_offset;
 947         u64 extent_end;
 948         u64 disk_bytenr;
 949         u64 num_bytes;
 950         int extent_type;
 951         int ret;
 952         int type;
 953         int nocow;
 954         int check_prev = 1;
 955
 956         path = btrfs_alloc_path();
 957         BUG_ON(!path);
 958         trans = btrfs_join_transaction(root, 1);
 959         BUG_ON(!trans);
 960
 961         cow_start = (u64)-1;
 962         cur_offset = start;
 963         while (1) {
 964                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
 965                                                cur_offset, 0);
 966                 BUG_ON(ret < 0);
 967                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
 968                         leaf = path->nodes[0];
 969                         btrfs_item_key_to_cpu(leaf, &found_key,
 970                                               path->slots[0] - 1);
 971                         if (found_key.objectid == inode->i_ino &&
 972                             found_key.type == BTRFS_EXTENT_DATA_KEY)
 973                                 path->slots[0]--;
 974                 }
 975                 check_prev = 0;
 976 next_slot:
 977                 leaf = path->nodes[0];
 978                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 979                         ret = btrfs_next_leaf(root, path);
 980                         if (ret < 0)
 981                                 BUG_ON(1);
 982                         if (ret > 0)
 983                                 break;
 984                         leaf = path->nodes[0];
 985                 }
 986
 987                 nocow = 0;
 988                 disk_bytenr = 0;
 989                 num_bytes = 0;
 990                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 991
 992                 if (found_key.objectid > inode->i_ino ||
 993                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
 994                     found_key.offset > end)
 995                         break;
 996
 997                 if (found_key.offset > cur_offset) {
 998                         extent_end = found_key.offset;
 999                         goto out_check;
1000                 }
1001
1002                 fi = btrfs_item_ptr(leaf, path->slots[0],
1003                                     struct btrfs_file_extent_item);
1004                 extent_type = btrfs_file_extent_type(leaf, fi);
1005
1006                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1007                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1008                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1009                         extent_end = found_key.offset +
1010                                 btrfs_file_extent_num_bytes(leaf, fi);
1011                         if (extent_end <= start) {
1012                                 path->slots[0]++;
1013                                 goto next_slot;
1014                         }
1015                         if (disk_bytenr == 0)
1016                                 goto out_check;
1017                         if (btrfs_file_extent_compression(leaf, fi) ||
1018                             btrfs_file_extent_encryption(leaf, fi) ||
1019                             btrfs_file_extent_other_encoding(leaf, fi))
1020                                 goto out_check;
1021                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1022                                 goto out_check;
1023                         if (btrfs_extent_readonly(root, disk_bytenr))
1024                                 goto out_check;
1025                         if (btrfs_cross_ref_exist(trans, root, inode->i_ino,
1026                                                   disk_bytenr))
1027                                 goto out_check;
1028                         disk_bytenr += btrfs_file_extent_offset(leaf, fi);
1029                         disk_bytenr += cur_offset - found_key.offset;
1030                         num_bytes = min(end + 1, extent_end) - cur_offset;
1031                         /*
1032                          * force cow if csum exists in the range.
1033                          * this ensure that csum for a given extent are
1034                          * either valid or do not exist.
1035                          */
1036                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1037                                 goto out_check;
1038                         nocow = 1;
1039                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1040                         extent_end = found_key.offset +
1041                                 btrfs_file_extent_inline_len(leaf, fi);
1042                         extent_end = ALIGN(extent_end, root->sectorsize);
1043                 } else {
1044                         BUG_ON(1);
1045                 }
1046 out_check:
1047                 if (extent_end <= start) {
1048                         path->slots[0]++;
1049                         goto next_slot;
1050                 }
1051                 if (!nocow) {
1052                         if (cow_start == (u64)-1)
1053                                 cow_start = cur_offset;
1054                         cur_offset = extent_end;
1055                         if (cur_offset > end)
1056                                 break;
1057                         path->slots[0]++;
1058                         goto next_slot;
1059                 }
1060
1061                 btrfs_release_path(root, path);
1062                 if (cow_start != (u64)-1) {
1063                         ret = cow_file_range(inode, locked_page, cow_start,
1064                                         found_key.offset - 1, page_started,
1065                                         nr_written, 1);
1066                         BUG_ON(ret);
1067                         cow_start = (u64)-1;
1068                 }
1069
1070                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1071                         struct extent_map *em;
1072                         struct extent_map_tree *em_tree;
1073                         em_tree = &BTRFS_I(inode)->extent_tree;
1074                         em = alloc_extent_map(GFP_NOFS);
1075                         em->start = cur_offset;
1076                         em->orig_start = em->start;
1077                         em->len = num_bytes;
1078                         em->block_len = num_bytes;
1079                         em->block_start = disk_bytenr;
1080                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1081                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1082                         while (1) {
1083                                 spin_lock(&em_tree->lock);
1084                                 ret = add_extent_mapping(em_tree, em);
1085                                 spin_unlock(&em_tree->lock);
1086                                 if (ret != -EEXIST) {
1087                                         free_extent_map(em);
1088                                         break;
1089                                 }
1090                                 btrfs_drop_extent_cache(inode, em->start,
1091                                                 em->start + em->len - 1, 0);
1092                         }
1093                         type = BTRFS_ORDERED_PREALLOC;
1094                 } else {
1095                         type = BTRFS_ORDERED_NOCOW;
1096                 }
1097
1098                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1099                                                num_bytes, num_bytes, type);
1100                 BUG_ON(ret);
1101
1102                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
1103                                         cur_offset, cur_offset + num_bytes - 1,
1104                                         locked_page, 1, 1, 1, 0, 0, 0);
1105                 cur_offset = extent_end;
1106                 if (cur_offset > end)
1107                         break;
1108         }
1109         btrfs_release_path(root, path);
1110
1111         if (cur_offset <= end && cow_start == (u64)-1)
1112                 cow_start = cur_offset;
1113         if (cow_start != (u64)-1) {
1114                 ret = cow_file_range(inode, locked_page, cow_start, end,
1115                                      page_started, nr_written, 1);
1116                 BUG_ON(ret);
1117         }
1118
1119         ret = btrfs_end_transaction(trans, root);
1120         BUG_ON(ret);
1121         btrfs_free_path(path);
1122         return 0;
1123 }
1124
1125 /*
1126  * extent_io.c call back to do delayed allocation processing
1127  */
1128 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1129                               u64 start, u64 end, int *page_started,
1130                               unsigned long *nr_written)
1131 {
1132         int ret;
1133         struct btrfs_root *root = BTRFS_I(inode)->root;
1134
1135         if (btrfs_test_flag(inode, NODATACOW))
1136                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1137                                          page_started, 1, nr_written);
1138         else if (btrfs_test_flag(inode, PREALLOC))
1139                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1140                                          page_started, 0, nr_written);
1141         else if (!btrfs_test_opt(root, COMPRESS))
1142                 ret = cow_file_range(inode, locked_page, start, end,
1143                                       page_started, nr_written, 1);
1144         else
1145                 ret = cow_file_range_async(inode, locked_page, start, end,
1146                                            page_started, nr_written);
1147         return ret;
1148 }
1149
1150 /*
1151  * extent_io.c set_bit_hook, used to track delayed allocation
1152  * bytes in this file, and to maintain the list of inodes that
1153  * have pending delalloc work to be done.
1154  */
1155 static int btrfs_set_bit_hook(struct inode *inode, u64 start, u64 end,
1156                        unsigned long old, unsigned long bits)
1157 {
1158         /*
1159          * set_bit and clear bit hooks normally require _irqsave/restore
1160          * but in this case, we are only testeing for the DELALLOC
1161          * bit, which is only set or cleared with irqs on
1162          */
1163         if (!(old & EXTENT_DELALLOC) && (bits & EXTENT_DELALLOC)) {
1164                 struct btrfs_root *root = BTRFS_I(inode)->root;
1165                 btrfs_delalloc_reserve_space(root, inode, end - start + 1);
1166                 spin_lock(&root->fs_info->delalloc_lock);
1167                 BTRFS_I(inode)->delalloc_bytes += end - start + 1;
1168                 root->fs_info->delalloc_bytes += end - start + 1;
1169                 if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1170                         list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1171                                       &root->fs_info->delalloc_inodes);
1172                 }
1173                 spin_unlock(&root->fs_info->delalloc_lock);
1174         }
1175         return 0;
1176 }
1177
1178 /*
1179  * extent_io.c clear_bit_hook, see set_bit_hook for why
1180  */
1181 static int btrfs_clear_bit_hook(struct inode *inode, u64 start, u64 end,
1182                          unsigned long old, unsigned long bits)
1183 {
1184         /*
1185          * set_bit and clear bit hooks normally require _irqsave/restore
1186          * but in this case, we are only testeing for the DELALLOC
1187          * bit, which is only set or cleared with irqs on
1188          */
1189         if ((old & EXTENT_DELALLOC) && (bits & EXTENT_DELALLOC)) {
1190                 struct btrfs_root *root = BTRFS_I(inode)->root;
1191
1192                 spin_lock(&root->fs_info->delalloc_lock);
1193                 if (end - start + 1 > root->fs_info->delalloc_bytes) {
1194                         printk(KERN_INFO "btrfs warning: delalloc account "
1195                                "%llu %llu\n",
1196                                (unsigned long long)end - start + 1,
1197                                (unsigned long long)
1198                                root->fs_info->delalloc_bytes);
1199                         btrfs_delalloc_free_space(root, inode, (u64)-1);
1200                         root->fs_info->delalloc_bytes = 0;
1201                         BTRFS_I(inode)->delalloc_bytes = 0;
1202                 } else {
1203                         btrfs_delalloc_free_space(root, inode,
1204                                                   end - start + 1);
1205                         root->fs_info->delalloc_bytes -= end - start + 1;
1206                         BTRFS_I(inode)->delalloc_bytes -= end - start + 1;
1207                 }
1208                 if (BTRFS_I(inode)->delalloc_bytes == 0 &&
1209                     !list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1210                         list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1211                 }
1212                 spin_unlock(&root->fs_info->delalloc_lock);
1213         }
1214         return 0;
1215 }
1216
1217 /*
1218  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1219  * we don't create bios that span stripes or chunks
1220  */
1221 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1222                          size_t size, struct bio *bio,
1223                          unsigned long bio_flags)
1224 {
1225         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1226         struct btrfs_mapping_tree *map_tree;
1227         u64 logical = (u64)bio->bi_sector << 9;
1228         u64 length = 0;
1229         u64 map_length;
1230         int ret;
1231
1232         if (bio_flags & EXTENT_BIO_COMPRESSED)
1233                 return 0;
1234
1235         length = bio->bi_size;
1236         map_tree = &root->fs_info->mapping_tree;
1237         map_length = length;
1238         ret = btrfs_map_block(map_tree, READ, logical,
1239                               &map_length, NULL, 0);
1240
1241         if (map_length < length + size)
1242                 return 1;
1243         return 0;
1244 }
1245
1246 /*
1247  * in order to insert checksums into the metadata in large chunks,
1248  * we wait until bio submission time.   All the pages in the bio are
1249  * checksummed and sums are attached onto the ordered extent record.
1250  *
1251  * At IO completion time the cums attached on the ordered extent record
1252  * are inserted into the btree
1253  */
1254 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1255                                     struct bio *bio, int mirror_num,
1256                                     unsigned long bio_flags)
1257 {
1258         struct btrfs_root *root = BTRFS_I(inode)->root;
1259         int ret = 0;
1260
1261         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1262         BUG_ON(ret);
1263         return 0;
1264 }
1265
1266 /*
1267  * in order to insert checksums into the metadata in large chunks,
1268  * we wait until bio submission time.   All the pages in the bio are
1269  * checksummed and sums are attached onto the ordered extent record.
1270  *
1271  * At IO completion time the cums attached on the ordered extent record
1272  * are inserted into the btree
1273  */
1274 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1275                           int mirror_num, unsigned long bio_flags)
1276 {
1277         struct btrfs_root *root = BTRFS_I(inode)->root;
1278         return btrfs_map_bio(root, rw, bio, mirror_num, 1);
1279 }
1280
1281 /*
1282  * extent_io.c submission hook. This does the right thing for csum calculation
1283  * on write, or reading the csums from the tree before a read
1284  */
1285 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1286                           int mirror_num, unsigned long bio_flags)
1287 {
1288         struct btrfs_root *root = BTRFS_I(inode)->root;
1289         int ret = 0;
1290         int skip_sum;
1291
1292         skip_sum = btrfs_test_flag(inode, NODATASUM);
1293
1294         ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
1295         BUG_ON(ret);
1296
1297         if (!(rw & (1 << BIO_RW))) {
1298                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1299                         return btrfs_submit_compressed_read(inode, bio,
1300                                                     mirror_num, bio_flags);
1301                 } else if (!skip_sum)
1302                         btrfs_lookup_bio_sums(root, inode, bio, NULL);
1303                 goto mapit;
1304         } else if (!skip_sum) {
1305                 /* csum items have already been cloned */
1306                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1307                         goto mapit;
1308                 /* we're doing a write, do the async checksumming */
1309                 return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1310                                    inode, rw, bio, mirror_num,
1311                                    bio_flags, __btrfs_submit_bio_start,
1312                                    __btrfs_submit_bio_done);
1313         }
1314
1315 mapit:
1316         return btrfs_map_bio(root, rw, bio, mirror_num, 0);
1317 }
1318
1319 /*
1320  * given a list of ordered sums record them in the inode.  This happens
1321  * at IO completion time based on sums calculated at bio submission time.
1322  */
1323 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1324                              struct inode *inode, u64 file_offset,
1325                              struct list_head *list)
1326 {
1327         struct btrfs_ordered_sum *sum;
1328
1329         btrfs_set_trans_block_group(trans, inode);
1330
1331         list_for_each_entry(sum, list, list) {
1332                 btrfs_csum_file_blocks(trans,
1333                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1334         }
1335         return 0;
1336 }
1337
1338 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end)
1339 {
1340         if ((end & (PAGE_CACHE_SIZE - 1)) == 0)
1341                 WARN_ON(1);
1342         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1343                                    GFP_NOFS);
1344 }
1345
1346 /* see btrfs_writepage_start_hook for details on why this is required */
1347 struct btrfs_writepage_fixup {
1348         struct page *page;
1349         struct btrfs_work work;
1350 };
1351
1352 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1353 {
1354         struct btrfs_writepage_fixup *fixup;
1355         struct btrfs_ordered_extent *ordered;
1356         struct page *page;
1357         struct inode *inode;
1358         u64 page_start;
1359         u64 page_end;
1360
1361         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1362         page = fixup->page;
1363 again:
1364         lock_page(page);
1365         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1366                 ClearPageChecked(page);
1367                 goto out_page;
1368         }
1369
1370         inode = page->mapping->host;
1371         page_start = page_offset(page);
1372         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1373
1374         lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end, GFP_NOFS);
1375
1376         /* already ordered? We're done */
1377         if (test_range_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
1378                              EXTENT_ORDERED, 0)) {
1379                 goto out;
1380         }
1381
1382         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1383         if (ordered) {
1384                 unlock_extent(&BTRFS_I(inode)->io_tree, page_start,
1385                               page_end, GFP_NOFS);
1386                 unlock_page(page);
1387                 btrfs_start_ordered_extent(inode, ordered, 1);
1388                 goto again;
1389         }
1390
1391         btrfs_set_extent_delalloc(inode, page_start, page_end);
1392         ClearPageChecked(page);
1393 out:
1394         unlock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end, GFP_NOFS);
1395 out_page:
1396         unlock_page(page);
1397         page_cache_release(page);
1398 }
1399
1400 /*
1401  * There are a few paths in the higher layers of the kernel that directly
1402  * set the page dirty bit without asking the filesystem if it is a
1403  * good idea.  This causes problems because we want to make sure COW
1404  * properly happens and the data=ordered rules are followed.
1405  *
1406  * In our case any range that doesn't have the ORDERED bit set
1407  * hasn't been properly setup for IO.  We kick off an async process
1408  * to fix it up.  The async helper will wait for ordered extents, set
1409  * the delalloc bit and make it safe to write the page.
1410  */
1411 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1412 {
1413         struct inode *inode = page->mapping->host;
1414         struct btrfs_writepage_fixup *fixup;
1415         struct btrfs_root *root = BTRFS_I(inode)->root;
1416         int ret;
1417
1418         ret = test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
1419                              EXTENT_ORDERED, 0);
1420         if (ret)
1421                 return 0;
1422
1423         if (PageChecked(page))
1424                 return -EAGAIN;
1425
1426         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1427         if (!fixup)
1428                 return -EAGAIN;
1429
1430         SetPageChecked(page);
1431         page_cache_get(page);
1432         fixup->work.func = btrfs_writepage_fixup_worker;
1433         fixup->page = page;
1434         btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
1435         return -EAGAIN;
1436 }
1437
1438 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1439                                        struct inode *inode, u64 file_pos,
1440                                        u64 disk_bytenr, u64 disk_num_bytes,
1441                                        u64 num_bytes, u64 ram_bytes,
1442                                        u8 compression, u8 encryption,
1443                                        u16 other_encoding, int extent_type)
1444 {
1445         struct btrfs_root *root = BTRFS_I(inode)->root;
1446         struct btrfs_file_extent_item *fi;
1447         struct btrfs_path *path;
1448         struct extent_buffer *leaf;
1449         struct btrfs_key ins;
1450         u64 hint;
1451         int ret;
1452
1453         path = btrfs_alloc_path();
1454         BUG_ON(!path);
1455
1456         path->leave_spinning = 1;
1457         ret = btrfs_drop_extents(trans, root, inode, file_pos,
1458                                  file_pos + num_bytes, file_pos, &hint);
1459         BUG_ON(ret);
1460
1461         ins.objectid = inode->i_ino;
1462         ins.offset = file_pos;
1463         ins.type = BTRFS_EXTENT_DATA_KEY;
1464         ret = btrfs_insert_empty_item(trans, root, path, &ins, sizeof(*fi));
1465         BUG_ON(ret);
1466         leaf = path->nodes[0];
1467         fi = btrfs_item_ptr(leaf, path->slots[0],
1468                             struct btrfs_file_extent_item);
1469         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1470         btrfs_set_file_extent_type(leaf, fi, extent_type);
1471         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1472         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1473         btrfs_set_file_extent_offset(leaf, fi, 0);
1474         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1475         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1476         btrfs_set_file_extent_compression(leaf, fi, compression);
1477         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1478         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1479
1480         btrfs_unlock_up_safe(path, 1);
1481         btrfs_set_lock_blocking(leaf);
1482
1483         btrfs_mark_buffer_dirty(leaf);
1484
1485         inode_add_bytes(inode, num_bytes);
1486         btrfs_drop_extent_cache(inode, file_pos, file_pos + num_bytes - 1, 0);
1487
1488         ins.objectid = disk_bytenr;
1489         ins.offset = disk_num_bytes;
1490         ins.type = BTRFS_EXTENT_ITEM_KEY;
1491         ret = btrfs_alloc_reserved_extent(trans, root, leaf->start,
1492                                           root->root_key.objectid,
1493                                           trans->transid, inode->i_ino, &ins);
1494         BUG_ON(ret);
1495         btrfs_free_path(path);
1496
1497         return 0;
1498 }
1499
1500 /*
1501  * helper function for btrfs_finish_ordered_io, this
1502  * just reads in some of the csum leaves to prime them into ram
1503  * before we start the transaction.  It limits the amount of btree
1504  * reads required while inside the transaction.
1505  */
1506 static noinline void reada_csum(struct btrfs_root *root,
1507                                 struct btrfs_path *path,
1508                                 struct btrfs_ordered_extent *ordered_extent)
1509 {
1510         struct btrfs_ordered_sum *sum;
1511         u64 bytenr;
1512
1513         sum = list_entry(ordered_extent->list.next, struct btrfs_ordered_sum,
1514                          list);
1515         bytenr = sum->sums[0].bytenr;
1516
1517         /*
1518          * we don't care about the results, the point of this search is
1519          * just to get the btree leaves into ram
1520          */
1521         btrfs_lookup_csum(NULL, root->fs_info->csum_root, path, bytenr, 0);
1522 }
1523
1524 /* as ordered data IO finishes, this gets called so we can finish
1525  * an ordered extent if the range of bytes in the file it covers are
1526  * fully written.
1527  */
1528 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
1529 {
1530         struct btrfs_root *root = BTRFS_I(inode)->root;
1531         struct btrfs_trans_handle *trans;
1532         struct btrfs_ordered_extent *ordered_extent = NULL;
1533         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1534         struct btrfs_path *path;
1535         int compressed = 0;
1536         int ret;
1537
1538         ret = btrfs_dec_test_ordered_pending(inode, start, end - start + 1);
1539         if (!ret)
1540                 return 0;
1541
1542         /*
1543          * before we join the transaction, try to do some of our IO.
1544          * This will limit the amount of IO that we have to do with
1545          * the transaction running.  We're unlikely to need to do any
1546          * IO if the file extents are new, the disk_i_size checks
1547          * covers the most common case.
1548          */
1549         if (start < BTRFS_I(inode)->disk_i_size) {
1550                 path = btrfs_alloc_path();
1551                 if (path) {
1552                         ret = btrfs_lookup_file_extent(NULL, root, path,
1553                                                        inode->i_ino,
1554                                                        start, 0);
1555                         ordered_extent = btrfs_lookup_ordered_extent(inode,
1556                                                                      start);
1557                         if (!list_empty(&ordered_extent->list)) {
1558                                 btrfs_release_path(root, path);
1559                                 reada_csum(root, path, ordered_extent);
1560                         }
1561                         btrfs_free_path(path);
1562                 }
1563         }
1564
1565         trans = btrfs_join_transaction(root, 1);
1566
1567         if (!ordered_extent)
1568                 ordered_extent = btrfs_lookup_ordered_extent(inode, start);
1569         BUG_ON(!ordered_extent);
1570         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags))
1571                 goto nocow;
1572
1573         lock_extent(io_tree, ordered_extent->file_offset,
1574                     ordered_extent->file_offset + ordered_extent->len - 1,
1575                     GFP_NOFS);
1576
1577         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
1578                 compressed = 1;
1579         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
1580                 BUG_ON(compressed);
1581                 ret = btrfs_mark_extent_written(trans, root, inode,
1582                                                 ordered_extent->file_offset,
1583                                                 ordered_extent->file_offset +
1584                                                 ordered_extent->len);
1585                 BUG_ON(ret);
1586         } else {
1587                 ret = insert_reserved_file_extent(trans, inode,
1588                                                 ordered_extent->file_offset,
1589                                                 ordered_extent->start,
1590                                                 ordered_extent->disk_len,
1591                                                 ordered_extent->len,
1592                                                 ordered_extent->len,
1593                                                 compressed, 0, 0,
1594                                                 BTRFS_FILE_EXTENT_REG);
1595                 BUG_ON(ret);
1596         }
1597         unlock_extent(io_tree, ordered_extent->file_offset,
1598                     ordered_extent->file_offset + ordered_extent->len - 1,
1599                     GFP_NOFS);
1600 nocow:
1601         add_pending_csums(trans, inode, ordered_extent->file_offset,
1602                           &ordered_extent->list);
1603
1604         mutex_lock(&BTRFS_I(inode)->extent_mutex);
1605         btrfs_ordered_update_i_size(inode, ordered_extent);
1606         btrfs_update_inode(trans, root, inode);
1607         btrfs_remove_ordered_extent(inode, ordered_extent);
1608         mutex_unlock(&BTRFS_I(inode)->extent_mutex);
1609
1610         /* once for us */
1611         btrfs_put_ordered_extent(ordered_extent);
1612         /* once for the tree */
1613         btrfs_put_ordered_extent(ordered_extent);
1614
1615         btrfs_end_transaction(trans, root);
1616         return 0;
1617 }
1618
1619 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
1620                                 struct extent_state *state, int uptodate)
1621 {
1622         return btrfs_finish_ordered_io(page->mapping->host, start, end);
1623 }
1624
1625 /*
1626  * When IO fails, either with EIO or csum verification fails, we
1627  * try other mirrors that might have a good copy of the data.  This
1628  * io_failure_record is used to record state as we go through all the
1629  * mirrors.  If another mirror has good data, the page is set up to date
1630  * and things continue.  If a good mirror can't be found, the original
1631  * bio end_io callback is called to indicate things have failed.
1632  */
1633 struct io_failure_record {
1634         struct page *page;
1635         u64 start;
1636         u64 len;
1637         u64 logical;
1638         unsigned long bio_flags;
1639         int last_mirror;
1640 };
1641
1642 static int btrfs_io_failed_hook(struct bio *failed_bio,
1643                          struct page *page, u64 start, u64 end,
1644                          struct extent_state *state)
1645 {
1646         struct io_failure_record *failrec = NULL;
1647         u64 private;
1648         struct extent_map *em;
1649         struct inode *inode = page->mapping->host;
1650         struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
1651         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1652         struct bio *bio;
1653         int num_copies;
1654         int ret;
1655         int rw;
1656         u64 logical;
1657
1658         ret = get_state_private(failure_tree, start, &private);
1659         if (ret) {
1660                 failrec = kmalloc(sizeof(*failrec), GFP_NOFS);
1661                 if (!failrec)
1662                         return -ENOMEM;
1663                 failrec->start = start;
1664                 failrec->len = end - start + 1;
1665                 failrec->last_mirror = 0;
1666                 failrec->bio_flags = 0;
1667
1668                 spin_lock(&em_tree->lock);
1669                 em = lookup_extent_mapping(em_tree, start, failrec->len);
1670                 if (em->start > start || em->start + em->len < start) {
1671                         free_extent_map(em);
1672                         em = NULL;
1673                 }
1674                 spin_unlock(&em_tree->lock);
1675
1676                 if (!em || IS_ERR(em)) {
1677                         kfree(failrec);
1678                         return -EIO;
1679                 }
1680                 logical = start - em->start;
1681                 logical = em->block_start + logical;
1682                 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
1683                         logical = em->block_start;
1684                         failrec->bio_flags = EXTENT_BIO_COMPRESSED;
1685                 }
1686                 failrec->logical = logical;
1687                 free_extent_map(em);
1688                 set_extent_bits(failure_tree, start, end, EXTENT_LOCKED |
1689                                 EXTENT_DIRTY, GFP_NOFS);
1690                 set_state_private(failure_tree, start,
1691                                  (u64)(unsigned long)failrec);
1692         } else {
1693                 failrec = (struct io_failure_record *)(unsigned long)private;
1694         }
1695         num_copies = btrfs_num_copies(
1696                               &BTRFS_I(inode)->root->fs_info->mapping_tree,
1697                               failrec->logical, failrec->len);
1698         failrec->last_mirror++;
1699         if (!state) {
1700                 spin_lock(&BTRFS_I(inode)->io_tree.lock);
1701                 state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
1702                                                     failrec->start,
1703                                                     EXTENT_LOCKED);
1704                 if (state && state->start != failrec->start)
1705                         state = NULL;
1706                 spin_unlock(&BTRFS_I(inode)->io_tree.lock);
1707         }
1708         if (!state || failrec->last_mirror > num_copies) {
1709                 set_state_private(failure_tree, failrec->start, 0);
1710                 clear_extent_bits(failure_tree, failrec->start,
1711                                   failrec->start + failrec->len - 1,
1712                                   EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
1713                 kfree(failrec);
1714                 return -EIO;
1715         }
1716         bio = bio_alloc(GFP_NOFS, 1);
1717         bio->bi_private = state;
1718         bio->bi_end_io = failed_bio->bi_end_io;
1719         bio->bi_sector = failrec->logical >> 9;
1720         bio->bi_bdev = failed_bio->bi_bdev;
1721         bio->bi_size = 0;
1722
1723         bio_add_page(bio, page, failrec->len, start - page_offset(page));
1724         if (failed_bio->bi_rw & (1 << BIO_RW))
1725                 rw = WRITE;
1726         else
1727                 rw = READ;
1728
1729         BTRFS_I(inode)->io_tree.ops->submit_bio_hook(inode, rw, bio,
1730                                                       failrec->last_mirror,
1731                                                       failrec->bio_flags);
1732         return 0;
1733 }
1734
1735 /*
1736  * each time an IO finishes, we do a fast check in the IO failure tree
1737  * to see if we need to process or clean up an io_failure_record
1738  */
1739 static int btrfs_clean_io_failures(struct inode *inode, u64 start)
1740 {
1741         u64 private;
1742         u64 private_failure;
1743         struct io_failure_record *failure;
1744         int ret;
1745
1746         private = 0;
1747         if (count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
1748                              (u64)-1, 1, EXTENT_DIRTY)) {
1749                 ret = get_state_private(&BTRFS_I(inode)->io_failure_tree,
1750                                         start, &private_failure);
1751                 if (ret == 0) {
1752                         failure = (struct io_failure_record *)(unsigned long)
1753                                    private_failure;
1754                         set_state_private(&BTRFS_I(inode)->io_failure_tree,
1755                                           failure->start, 0);
1756                         clear_extent_bits(&BTRFS_I(inode)->io_failure_tree,
1757                                           failure->start,
1758                                           failure->start + failure->len - 1,
1759                                           EXTENT_DIRTY | EXTENT_LOCKED,
1760                                           GFP_NOFS);
1761                         kfree(failure);
1762                 }
1763         }
1764         return 0;
1765 }
1766
1767 /*
1768  * when reads are done, we need to check csums to verify the data is correct
1769  * if there's a match, we allow the bio to finish.  If not, we go through
1770  * the io_failure_record routines to find good copies
1771  */
1772 static int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
1773                                struct extent_state *state)
1774 {
1775         size_t offset = start - ((u64)page->index << PAGE_CACHE_SHIFT);
1776         struct inode *inode = page->mapping->host;
1777         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1778         char *kaddr;
1779         u64 private = ~(u32)0;
1780         int ret;
1781         struct btrfs_root *root = BTRFS_I(inode)->root;
1782         u32 csum = ~(u32)0;
1783
1784         if (PageChecked(page)) {
1785                 ClearPageChecked(page);
1786                 goto good;
1787         }
1788         if (btrfs_test_flag(inode, NODATASUM))
1789                 return 0;
1790
1791         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
1792             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1)) {
1793                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
1794                                   GFP_NOFS);
1795                 return 0;
1796         }
1797
1798         if (state && state->start == start) {
1799                 private = state->private;
1800                 ret = 0;
1801         } else {
1802                 ret = get_state_private(io_tree, start, &private);
1803         }
1804         kaddr = kmap_atomic(page, KM_USER0);
1805         if (ret)
1806                 goto zeroit;
1807
1808         csum = btrfs_csum_data(root, kaddr + offset, csum,  end - start + 1);
1809         btrfs_csum_final(csum, (char *)&csum);
1810         if (csum != private)
1811                 goto zeroit;
1812
1813         kunmap_atomic(kaddr, KM_USER0);
1814 good:
1815         /* if the io failure tree for this inode is non-empty,
1816          * check to see if we've recovered from a failed IO
1817          */
1818         btrfs_clean_io_failures(inode, start);
1819         return 0;
1820
1821 zeroit:
1822         printk(KERN_INFO "btrfs csum failed ino %lu off %llu csum %u "
1823                "private %llu\n", page->mapping->host->i_ino,
1824                (unsigned long long)start, csum,
1825                (unsigned long long)private);
1826         memset(kaddr + offset, 1, end - start + 1);
1827         flush_dcache_page(page);
1828         kunmap_atomic(kaddr, KM_USER0);
1829         if (private == 0)
1830                 return 0;
1831         return -EIO;
1832 }
1833
1834 /*
1835  * This creates an orphan entry for the given inode in case something goes
1836  * wrong in the middle of an unlink/truncate.
1837  */
1838 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
1839 {
1840         struct btrfs_root *root = BTRFS_I(inode)->root;
1841         int ret = 0;
1842
1843         spin_lock(&root->list_lock);
1844
1845         /* already on the orphan list, we're good */
1846         if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
1847                 spin_unlock(&root->list_lock);
1848                 return 0;
1849         }
1850
1851         list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
1852
1853         spin_unlock(&root->list_lock);
1854
1855         /*
1856          * insert an orphan item to track this unlinked/truncated file
1857          */
1858         ret = btrfs_insert_orphan_item(trans, root, inode->i_ino);
1859
1860         return ret;
1861 }
1862
1863 /*
1864  * We have done the truncate/delete so we can go ahead and remove the orphan
1865  * item for this particular inode.
1866  */
1867 int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode)
1868 {
1869         struct btrfs_root *root = BTRFS_I(inode)->root;
1870         int ret = 0;
1871
1872         spin_lock(&root->list_lock);
1873
1874         if (list_empty(&BTRFS_I(inode)->i_orphan)) {
1875                 spin_unlock(&root->list_lock);
1876                 return 0;
1877         }
1878
1879         list_del_init(&BTRFS_I(inode)->i_orphan);
1880         if (!trans) {
1881                 spin_unlock(&root->list_lock);
1882                 return 0;
1883         }
1884
1885         spin_unlock(&root->list_lock);
1886
1887         ret = btrfs_del_orphan_item(trans, root, inode->i_ino);
1888
1889         return ret;
1890 }
1891
1892 /*
1893  * this cleans up any orphans that may be left on the list from the last use
1894  * of this root.
1895  */
1896 void btrfs_orphan_cleanup(struct btrfs_root *root)
1897 {
1898         struct btrfs_path *path;
1899         struct extent_buffer *leaf;
1900         struct btrfs_item *item;
1901         struct btrfs_key key, found_key;
1902         struct btrfs_trans_handle *trans;
1903         struct inode *inode;
1904         int ret = 0, nr_unlink = 0, nr_truncate = 0;
1905
1906         path = btrfs_alloc_path();
1907         if (!path)
1908                 return;
1909         path->reada = -1;
1910
1911         key.objectid = BTRFS_ORPHAN_OBJECTID;
1912         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
1913         key.offset = (u64)-1;
1914
1915
1916         while (1) {
1917                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1918                 if (ret < 0) {
1919                         printk(KERN_ERR "Error searching slot for orphan: %d"
1920                                "\n", ret);
1921                         break;
1922                 }
1923
1924                 /*
1925                  * if ret == 0 means we found what we were searching for, which
1926                  * is weird, but possible, so only screw with path if we didnt
1927                  * find the key and see if we have stuff that matches
1928                  */
1929                 if (ret > 0) {
1930                         if (path->slots[0] == 0)
1931                                 break;
1932                         path->slots[0]--;
1933                 }
1934
1935                 /* pull out the item */
1936                 leaf = path->nodes[0];
1937                 item = btrfs_item_nr(leaf, path->slots[0]);
1938                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1939
1940                 /* make sure the item matches what we want */
1941                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
1942                         break;
1943                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
1944                         break;
1945
1946                 /* release the path since we're done with it */
1947                 btrfs_release_path(root, path);
1948
1949                 /*
1950                  * this is where we are basically btrfs_lookup, without the
1951                  * crossing root thing.  we store the inode number in the
1952                  * offset of the orphan item.
1953                  */
1954                 inode = btrfs_iget_locked(root->fs_info->sb,
1955                                           found_key.offset, root);
1956                 if (!inode)
1957                         break;
1958
1959                 if (inode->i_state & I_NEW) {
1960                         BTRFS_I(inode)->root = root;
1961
1962                         /* have to set the location manually */
1963                         BTRFS_I(inode)->location.objectid = inode->i_ino;
1964                         BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
1965                         BTRFS_I(inode)->location.offset = 0;
1966
1967                         btrfs_read_locked_inode(inode);
1968                         unlock_new_inode(inode);
1969                 }
1970
1971                 /*
1972                  * add this inode to the orphan list so btrfs_orphan_del does
1973                  * the proper thing when we hit it
1974                  */
1975                 spin_lock(&root->list_lock);
1976                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
1977                 spin_unlock(&root->list_lock);
1978
1979                 /*
1980                  * if this is a bad inode, means we actually succeeded in
1981                  * removing the inode, but not the orphan record, which means
1982                  * we need to manually delete the orphan since iput will just
1983                  * do a destroy_inode
1984                  */
1985                 if (is_bad_inode(inode)) {
1986                         trans = btrfs_start_transaction(root, 1);
1987                         btrfs_orphan_del(trans, inode);
1988                         btrfs_end_transaction(trans, root);
1989                         iput(inode);
1990                         continue;
1991                 }
1992
1993                 /* if we have links, this was a truncate, lets do that */
1994                 if (inode->i_nlink) {
1995                         nr_truncate++;
1996                         btrfs_truncate(inode);
1997                 } else {
1998                         nr_unlink++;
1999                 }
2000
2001                 /* this will do delete_inode and everything for us */
2002                 iput(inode);
2003         }
2004
2005         if (nr_unlink)
2006                 printk(KERN_INFO "btrfs: unlinked %d orphans\n", nr_unlink);
2007         if (nr_truncate)
2008                 printk(KERN_INFO "btrfs: truncated %d orphans\n", nr_truncate);
2009
2010         btrfs_free_path(path);
2011 }
2012
2013 /*
2014  * read an inode from the btree into the in-memory inode
2015  */
2016 void btrfs_read_locked_inode(struct inode *inode)
2017 {
2018         struct btrfs_path *path;
2019         struct extent_buffer *leaf;
2020         struct btrfs_inode_item *inode_item;
2021         struct btrfs_timespec *tspec;
2022         struct btrfs_root *root = BTRFS_I(inode)->root;
2023         struct btrfs_key location;
2024         u64 alloc_group_block;
2025         u32 rdev;
2026         int ret;
2027
2028         path = btrfs_alloc_path();
2029         BUG_ON(!path);
2030         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
2031
2032         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
2033         if (ret)
2034                 goto make_bad;
2035
2036         leaf = path->nodes[0];
2037         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2038                                     struct btrfs_inode_item);
2039
2040         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
2041         inode->i_nlink = btrfs_inode_nlink(leaf, inode_item);
2042         inode->i_uid = btrfs_inode_uid(leaf, inode_item);
2043         inode->i_gid = btrfs_inode_gid(leaf, inode_item);
2044         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
2045
2046         tspec = btrfs_inode_atime(inode_item);
2047         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2048         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2049
2050         tspec = btrfs_inode_mtime(inode_item);
2051         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2052         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2053
2054         tspec = btrfs_inode_ctime(inode_item);
2055         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2056         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2057
2058         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
2059         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
2060         BTRFS_I(inode)->sequence = btrfs_inode_sequence(leaf, inode_item);
2061         inode->i_generation = BTRFS_I(inode)->generation;
2062         inode->i_rdev = 0;
2063         rdev = btrfs_inode_rdev(leaf, inode_item);
2064
2065         BTRFS_I(inode)->index_cnt = (u64)-1;
2066         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
2067
2068         alloc_group_block = btrfs_inode_block_group(leaf, inode_item);
2069
2070         BTRFS_I(inode)->block_group = btrfs_find_block_group(root, 0,
2071                                                 alloc_group_block, 0);
2072         btrfs_free_path(path);
2073         inode_item = NULL;
2074
2075         switch (inode->i_mode & S_IFMT) {
2076         case S_IFREG:
2077                 inode->i_mapping->a_ops = &btrfs_aops;
2078                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2079                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
2080                 inode->i_fop = &btrfs_file_operations;
2081                 inode->i_op = &btrfs_file_inode_operations;
2082                 break;
2083         case S_IFDIR:
2084                 inode->i_fop = &btrfs_dir_file_operations;
2085                 if (root == root->fs_info->tree_root)
2086                         inode->i_op = &btrfs_dir_ro_inode_operations;
2087                 else
2088                         inode->i_op = &btrfs_dir_inode_operations;
2089                 break;
2090         case S_IFLNK:
2091                 inode->i_op = &btrfs_symlink_inode_operations;
2092                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
2093                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2094                 break;
2095         default:
2096                 inode->i_op = &btrfs_special_inode_operations;
2097                 init_special_inode(inode, inode->i_mode, rdev);
2098                 break;
2099         }
2100         return;
2101
2102 make_bad:
2103         btrfs_free_path(path);
2104         make_bad_inode(inode);
2105 }
2106
2107 /*
2108  * given a leaf and an inode, copy the inode fields into the leaf
2109  */
2110 static void fill_inode_item(struct btrfs_trans_handle *trans,
2111                             struct extent_buffer *leaf,
2112                             struct btrfs_inode_item *item,
2113                             struct inode *inode)
2114 {
2115         btrfs_set_inode_uid(leaf, item, inode->i_uid);
2116         btrfs_set_inode_gid(leaf, item, inode->i_gid);
2117         btrfs_set_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size);
2118         btrfs_set_inode_mode(leaf, item, inode->i_mode);
2119         btrfs_set_inode_nlink(leaf, item, inode->i_nlink);
2120
2121         btrfs_set_timespec_sec(leaf, btrfs_inode_atime(item),
2122                                inode->i_atime.tv_sec);
2123         btrfs_set_timespec_nsec(leaf, btrfs_inode_atime(item),
2124                                 inode->i_atime.tv_nsec);
2125
2126         btrfs_set_timespec_sec(leaf, btrfs_inode_mtime(item),
2127                                inode->i_mtime.tv_sec);
2128         btrfs_set_timespec_nsec(leaf, btrfs_inode_mtime(item),
2129                                 inode->i_mtime.tv_nsec);
2130
2131         btrfs_set_timespec_sec(leaf, btrfs_inode_ctime(item),
2132                                inode->i_ctime.tv_sec);
2133         btrfs_set_timespec_nsec(leaf, btrfs_inode_ctime(item),
2134                                 inode->i_ctime.tv_nsec);
2135
2136         btrfs_set_inode_nbytes(leaf, item, inode_get_bytes(inode));
2137         btrfs_set_inode_generation(leaf, item, BTRFS_I(inode)->generation);
2138         btrfs_set_inode_sequence(leaf, item, BTRFS_I(inode)->sequence);
2139         btrfs_set_inode_transid(leaf, item, trans->transid);
2140         btrfs_set_inode_rdev(leaf, item, inode->i_rdev);
2141         btrfs_set_inode_flags(leaf, item, BTRFS_I(inode)->flags);
2142         btrfs_set_inode_block_group(leaf, item, BTRFS_I(inode)->block_group);
2143 }
2144
2145 /*
2146  * copy everything in the in-memory inode into the btree.
2147  */
2148 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
2149                                 struct btrfs_root *root, struct inode *inode)
2150 {
2151         struct btrfs_inode_item *inode_item;
2152         struct btrfs_path *path;
2153         struct extent_buffer *leaf;
2154         int ret;
2155
2156         path = btrfs_alloc_path();
2157         BUG_ON(!path);
2158         path->leave_spinning = 1;
2159         ret = btrfs_lookup_inode(trans, root, path,
2160                                  &BTRFS_I(inode)->location, 1);
2161         if (ret) {
2162                 if (ret > 0)
2163                         ret = -ENOENT;
2164                 goto failed;
2165         }
2166
2167         btrfs_unlock_up_safe(path, 1);
2168         leaf = path->nodes[0];
2169         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2170                                   struct btrfs_inode_item);
2171
2172         fill_inode_item(trans, leaf, inode_item, inode);
2173         btrfs_mark_buffer_dirty(leaf);
2174         btrfs_set_inode_last_trans(trans, inode);
2175         ret = 0;
2176 failed:
2177         btrfs_free_path(path);
2178         return ret;
2179 }
2180
2181
2182 /*
2183  * unlink helper that gets used here in inode.c and in the tree logging
2184  * recovery code.  It remove a link in a directory with a given name, and
2185  * also drops the back refs in the inode to the directory
2186  */
2187 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2188                        struct btrfs_root *root,
2189                        struct inode *dir, struct inode *inode,
2190                        const char *name, int name_len)
2191 {
2192         struct btrfs_path *path;
2193         int ret = 0;
2194         struct extent_buffer *leaf;
2195         struct btrfs_dir_item *di;
2196         struct btrfs_key key;
2197         u64 index;
2198
2199         path = btrfs_alloc_path();
2200         if (!path) {
2201                 ret = -ENOMEM;
2202                 goto err;
2203         }
2204
2205         path->leave_spinning = 1;
2206         di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
2207                                     name, name_len, -1);
2208         if (IS_ERR(di)) {
2209                 ret = PTR_ERR(di);
2210                 goto err;
2211         }
2212         if (!di) {
2213                 ret = -ENOENT;
2214                 goto err;
2215         }
2216         leaf = path->nodes[0];
2217         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2218         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2219         if (ret)
2220                 goto err;
2221         btrfs_release_path(root, path);
2222
2223         ret = btrfs_del_inode_ref(trans, root, name, name_len,
2224                                   inode->i_ino,
2225                                   dir->i_ino, &index);
2226         if (ret) {
2227                 printk(KERN_INFO "btrfs failed to delete reference to %.*s, "
2228                        "inode %lu parent %lu\n", name_len, name,
2229                        inode->i_ino, dir->i_ino);
2230                 goto err;
2231         }
2232
2233         di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
2234                                          index, name, name_len, -1);
2235         if (IS_ERR(di)) {
2236                 ret = PTR_ERR(di);
2237                 goto err;
2238         }
2239         if (!di) {
2240                 ret = -ENOENT;
2241                 goto err;
2242         }
2243         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2244         btrfs_release_path(root, path);
2245
2246         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
2247                                          inode, dir->i_ino);
2248         BUG_ON(ret != 0 && ret != -ENOENT);
2249
2250         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
2251                                            dir, index);
2252         BUG_ON(ret);
2253 err:
2254         btrfs_free_path(path);
2255         if (ret)
2256                 goto out;
2257
2258         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2259         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2260         btrfs_update_inode(trans, root, dir);
2261         btrfs_drop_nlink(inode);
2262         ret = btrfs_update_inode(trans, root, inode);
2263         dir->i_sb->s_dirt = 1;
2264 out:
2265         return ret;
2266 }
2267
2268 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
2269 {
2270         struct btrfs_root *root;
2271         struct btrfs_trans_handle *trans;
2272         struct inode *inode = dentry->d_inode;
2273         int ret;
2274         unsigned long nr = 0;
2275
2276         root = BTRFS_I(dir)->root;
2277
2278         trans = btrfs_start_transaction(root, 1);
2279
2280         btrfs_set_trans_block_group(trans, dir);
2281
2282         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
2283
2284         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
2285                                  dentry->d_name.name, dentry->d_name.len);
2286
2287         if (inode->i_nlink == 0)
2288                 ret = btrfs_orphan_add(trans, inode);
2289
2290         nr = trans->blocks_used;
2291
2292         btrfs_end_transaction_throttle(trans, root);
2293         btrfs_btree_balance_dirty(root, nr);
2294         return ret;
2295 }
2296
2297 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
2298 {
2299         struct inode *inode = dentry->d_inode;
2300         int err = 0;
2301         int ret;
2302         struct btrfs_root *root = BTRFS_I(dir)->root;
2303         struct btrfs_trans_handle *trans;
2304         unsigned long nr = 0;
2305
2306         /*
2307          * the FIRST_FREE_OBJECTID check makes sure we don't try to rmdir
2308          * the root of a subvolume or snapshot
2309          */
2310         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE ||
2311             inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) {
2312                 return -ENOTEMPTY;
2313         }
2314
2315         trans = btrfs_start_transaction(root, 1);
2316         btrfs_set_trans_block_group(trans, dir);
2317
2318         err = btrfs_orphan_add(trans, inode);
2319         if (err)
2320                 goto fail_trans;
2321
2322         /* now the directory is empty */
2323         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
2324                                  dentry->d_name.name, dentry->d_name.len);
2325         if (!err)
2326                 btrfs_i_size_write(inode, 0);
2327
2328 fail_trans:
2329         nr = trans->blocks_used;
2330         ret = btrfs_end_transaction_throttle(trans, root);
2331         btrfs_btree_balance_dirty(root, nr);
2332
2333         if (ret && !err)
2334                 err = ret;
2335         return err;
2336 }
2337
2338 #if 0
2339 /*
2340  * when truncating bytes in a file, it is possible to avoid reading
2341  * the leaves that contain only checksum items.  This can be the
2342  * majority of the IO required to delete a large file, but it must
2343  * be done carefully.
2344  *
2345  * The keys in the level just above the leaves are checked to make sure
2346  * the lowest key in a given leaf is a csum key, and starts at an offset
2347  * after the new  size.
2348  *
2349  * Then the key for the next leaf is checked to make sure it also has
2350  * a checksum item for the same file.  If it does, we know our target leaf
2351  * contains only checksum items, and it can be safely freed without reading
2352  * it.
2353  *
2354  * This is just an optimization targeted at large files.  It may do
2355  * nothing.  It will return 0 unless things went badly.
2356  */
2357 static noinline int drop_csum_leaves(struct btrfs_trans_handle *trans,
2358                                      struct btrfs_root *root,
2359                                      struct btrfs_path *path,
2360                                      struct inode *inode, u64 new_size)
2361 {
2362         struct btrfs_key key;
2363         int ret;
2364         int nritems;
2365         struct btrfs_key found_key;
2366         struct btrfs_key other_key;
2367         struct btrfs_leaf_ref *ref;
2368         u64 leaf_gen;
2369         u64 leaf_start;
2370
2371         path->lowest_level = 1;
2372         key.objectid = inode->i_ino;
2373         key.type = BTRFS_CSUM_ITEM_KEY;
2374         key.offset = new_size;
2375 again:
2376         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2377         if (ret < 0)
2378                 goto out;
2379
2380         if (path->nodes[1] == NULL) {
2381                 ret = 0;
2382                 goto out;
2383         }
2384         ret = 0;
2385         btrfs_node_key_to_cpu(path->nodes[1], &found_key, path->slots[1]);
2386         nritems = btrfs_header_nritems(path->nodes[1]);
2387
2388         if (!nritems)
2389                 goto out;
2390
2391         if (path->slots[1] >= nritems)
2392                 goto next_node;
2393
2394         /* did we find a key greater than anything we want to delete? */
2395         if (found_key.objectid > inode->i_ino ||
2396            (found_key.objectid == inode->i_ino && found_key.type > key.type))
2397                 goto out;
2398
2399         /* we check the next key in the node to make sure the leave contains
2400          * only checksum items.  This comparison doesn't work if our
2401          * leaf is the last one in the node
2402          */
2403         if (path->slots[1] + 1 >= nritems) {
2404 next_node:
2405                 /* search forward from the last key in the node, this
2406                  * will bring us into the next node in the tree
2407                  */
2408                 btrfs_node_key_to_cpu(path->nodes[1], &found_key, nritems - 1);
2409
2410                 /* unlikely, but we inc below, so check to be safe */
2411                 if (found_key.offset == (u64)-1)
2412                         goto out;
2413
2414                 /* search_forward needs a path with locks held, do the
2415                  * search again for the original key.  It is possible
2416                  * this will race with a balance and return a path that
2417                  * we could modify, but this drop is just an optimization
2418                  * and is allowed to miss some leaves.
2419                  */
2420                 btrfs_release_path(root, path);
2421                 found_key.offset++;
2422
2423                 /* setup a max key for search_forward */
2424                 other_key.offset = (u64)-1;
2425                 other_key.type = key.type;
2426                 other_key.objectid = key.objectid;
2427
2428                 path->keep_locks = 1;
2429                 ret = btrfs_search_forward(root, &found_key, &other_key,
2430                                            path, 0, 0);
2431                 path->keep_locks = 0;
2432                 if (ret || found_key.objectid != key.objectid ||
2433                     found_key.type != key.type) {
2434                         ret = 0;
2435                         goto out;
2436                 }
2437
2438                 key.offset = found_key.offset;
2439                 btrfs_release_path(root, path);
2440                 cond_resched();
2441                 goto again;
2442         }
2443
2444         /* we know there's one more slot after us in the tree,
2445          * read that key so we can verify it is also a checksum item
2446          */
2447         btrfs_node_key_to_cpu(path->nodes[1], &other_key, path->slots[1] + 1);
2448
2449         if (found_key.objectid < inode->i_ino)
2450                 goto next_key;
2451
2452         if (found_key.type != key.type || found_key.offset < new_size)
2453                 goto next_key;
2454
2455         /*
2456          * if the key for the next leaf isn't a csum key from this objectid,
2457          * we can't be sure there aren't good items inside this leaf.
2458          * Bail out
2459          */
2460         if (other_key.objectid != inode->i_ino || other_key.type != key.type)
2461                 goto out;
2462
2463         leaf_start = btrfs_node_blockptr(path->nodes[1], path->slots[1]);
2464         leaf_gen = btrfs_node_ptr_generation(path->nodes[1], path->slots[1]);
2465         /*
2466          * it is safe to delete this leaf, it contains only
2467          * csum items from this inode at an offset >= new_size
2468          */
2469         ret = btrfs_del_leaf(trans, root, path, leaf_start);
2470         BUG_ON(ret);
2471
2472         if (root->ref_cows && leaf_gen < trans->transid) {
2473                 ref = btrfs_alloc_leaf_ref(root, 0);
2474                 if (ref) {
2475                         ref->root_gen = root->root_key.offset;
2476                         ref->bytenr = leaf_start;
2477                         ref->owner = 0;
2478                         ref->generation = leaf_gen;
2479                         ref->nritems = 0;
2480
2481                         btrfs_sort_leaf_ref(ref);
2482
2483                         ret = btrfs_add_leaf_ref(root, ref, 0);
2484                         WARN_ON(ret);
2485                         btrfs_free_leaf_ref(root, ref);
2486                 } else {
2487                         WARN_ON(1);
2488                 }
2489         }
2490 next_key:
2491         btrfs_release_path(root, path);
2492
2493         if (other_key.objectid == inode->i_ino &&
2494             other_key.type == key.type && other_key.offset > key.offset) {
2495                 key.offset = other_key.offset;
2496                 cond_resched();
2497                 goto again;
2498         }
2499         ret = 0;
2500 out:
2501         /* fixup any changes we've made to the path */
2502         path->lowest_level = 0;
2503         path->keep_locks = 0;
2504         btrfs_release_path(root, path);
2505         return ret;
2506 }
2507
2508 #endif
2509
2510 /*
2511  * this can truncate away extent items, csum items and directory items.
2512  * It starts at a high offset and removes keys until it can't find
2513  * any higher than new_size
2514  *
2515  * csum items that cross the new i_size are truncated to the new size
2516  * as well.
2517  *
2518  * min_type is the minimum key type to truncate down to.  If set to 0, this
2519  * will kill all the items on this inode, including the INODE_ITEM_KEY.
2520  */
2521 noinline int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
2522                                         struct btrfs_root *root,
2523                                         struct inode *inode,
2524                                         u64 new_size, u32 min_type)
2525 {
2526         int ret;
2527         struct btrfs_path *path;
2528         struct btrfs_key key;
2529         struct btrfs_key found_key;
2530         u32 found_type = (u8)-1;
2531         struct extent_buffer *leaf;
2532         struct btrfs_file_extent_item *fi;
2533         u64 extent_start = 0;
2534         u64 extent_num_bytes = 0;
2535         u64 item_end = 0;
2536         u64 root_gen = 0;
2537         u64 root_owner = 0;
2538         int found_extent;
2539         int del_item;
2540         int pending_del_nr = 0;
2541         int pending_del_slot = 0;
2542         int extent_type = -1;
2543         int encoding;
2544         u64 mask = root->sectorsize - 1;
2545
2546         if (root->ref_cows)
2547                 btrfs_drop_extent_cache(inode, new_size & (~mask), (u64)-1, 0);
2548         path = btrfs_alloc_path();
2549         path->reada = -1;
2550         BUG_ON(!path);
2551
2552         /* FIXME, add redo link to tree so we don't leak on crash */
2553         key.objectid = inode->i_ino;
2554         key.offset = (u64)-1;
2555         key.type = (u8)-1;
2556
2557 search_again:
2558         path->leave_spinning = 1;
2559         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2560         if (ret < 0)
2561                 goto error;
2562
2563         if (ret > 0) {
2564                 /* there are no items in the tree for us to truncate, we're
2565                  * done
2566                  */
2567                 if (path->slots[0] == 0) {
2568                         ret = 0;
2569                         goto error;
2570                 }
2571                 path->slots[0]--;
2572         }
2573
2574         while (1) {
2575                 fi = NULL;
2576                 leaf = path->nodes[0];
2577                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2578                 found_type = btrfs_key_type(&found_key);
2579                 encoding = 0;
2580
2581                 if (found_key.objectid != inode->i_ino)
2582                         break;
2583
2584                 if (found_type < min_type)
2585                         break;
2586
2587                 item_end = found_key.offset;
2588                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
2589                         fi = btrfs_item_ptr(leaf, path->slots[0],
2590                                             struct btrfs_file_extent_item);
2591                         extent_type = btrfs_file_extent_type(leaf, fi);
2592                         encoding = btrfs_file_extent_compression(leaf, fi);
2593                         encoding |= btrfs_file_extent_encryption(leaf, fi);
2594                         encoding |= btrfs_file_extent_other_encoding(leaf, fi);
2595
2596                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
2597                                 item_end +=
2598                                     btrfs_file_extent_num_bytes(leaf, fi);
2599                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
2600                                 item_end += btrfs_file_extent_inline_len(leaf,
2601                                                                          fi);
2602                         }
2603                         item_end--;
2604                 }
2605                 if (item_end < new_size) {
2606                         if (found_type == BTRFS_DIR_ITEM_KEY)
2607                                 found_type = BTRFS_INODE_ITEM_KEY;
2608                         else if (found_type == BTRFS_EXTENT_ITEM_KEY)
2609                                 found_type = BTRFS_EXTENT_DATA_KEY;
2610                         else if (found_type == BTRFS_EXTENT_DATA_KEY)
2611                                 found_type = BTRFS_XATTR_ITEM_KEY;
2612                         else if (found_type == BTRFS_XATTR_ITEM_KEY)
2613                                 found_type = BTRFS_INODE_REF_KEY;
2614                         else if (found_type)
2615                                 found_type--;
2616                         else
2617                                 break;
2618                         btrfs_set_key_type(&key, found_type);
2619                         goto next;
2620                 }
2621                 if (found_key.offset >= new_size)
2622                         del_item = 1;
2623                 else
2624                         del_item = 0;
2625                 found_extent = 0;
2626
2627                 /* FIXME, shrink the extent if the ref count is only 1 */
2628                 if (found_type != BTRFS_EXTENT_DATA_KEY)
2629                         goto delete;
2630
2631                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
2632                         u64 num_dec;
2633                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
2634                         if (!del_item && !encoding) {
2635                                 u64 orig_num_bytes =
2636                                         btrfs_file_extent_num_bytes(leaf, fi);
2637                                 extent_num_bytes = new_size -
2638                                         found_key.offset + root->sectorsize - 1;
2639                                 extent_num_bytes = extent_num_bytes &
2640                                         ~((u64)root->sectorsize - 1);
2641                                 btrfs_set_file_extent_num_bytes(leaf, fi,
2642                                                          extent_num_bytes);
2643                                 num_dec = (orig_num_bytes -
2644                                            extent_num_bytes);
2645                                 if (root->ref_cows && extent_start != 0)
2646                                         inode_sub_bytes(inode, num_dec);
2647                                 btrfs_mark_buffer_dirty(leaf);
2648                         } else {
2649                                 extent_num_bytes =
2650                                         btrfs_file_extent_disk_num_bytes(leaf,
2651                                                                          fi);
2652                                 /* FIXME blocksize != 4096 */
2653                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
2654                                 if (extent_start != 0) {
2655                                         found_extent = 1;
2656                                         if (root->ref_cows)
2657                                                 inode_sub_bytes(inode, num_dec);
2658                                 }
2659                                 root_gen = btrfs_header_generation(leaf);
2660                                 root_owner = btrfs_header_owner(leaf);
2661                         }
2662                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
2663                         /*
2664                          * we can't truncate inline items that have had
2665                          * special encodings
2666                          */
2667                         if (!del_item &&
2668                             btrfs_file_extent_compression(leaf, fi) == 0 &&
2669                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
2670                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
2671                                 u32 size = new_size - found_key.offset;
2672
2673                                 if (root->ref_cows) {
2674                                         inode_sub_bytes(inode, item_end + 1 -
2675                                                         new_size);
2676                                 }
2677                                 size =
2678                                     btrfs_file_extent_calc_inline_size(size);
2679                                 ret = btrfs_truncate_item(trans, root, path,
2680                                                           size, 1);
2681                                 BUG_ON(ret);
2682                         } else if (root->ref_cows) {
2683                                 inode_sub_bytes(inode, item_end + 1 -
2684                                                 found_key.offset);
2685                         }
2686                 }
2687 delete:
2688                 if (del_item) {
2689                         if (!pending_del_nr) {
2690                                 /* no pending yet, add ourselves */
2691                                 pending_del_slot = path->slots[0];
2692                                 pending_del_nr = 1;
2693                         } else if (pending_del_nr &&
2694                                    path->slots[0] + 1 == pending_del_slot) {
2695                                 /* hop on the pending chunk */
2696                                 pending_del_nr++;
2697                                 pending_del_slot = path->slots[0];
2698                         } else {
2699                                 BUG();
2700                         }
2701                 } else {
2702                         break;
2703                 }
2704                 if (found_extent) {
2705                         btrfs_set_path_blocking(path);
2706                         ret = btrfs_free_extent(trans, root, extent_start,
2707                                                 extent_num_bytes,
2708                                                 leaf->start, root_owner,
2709                                                 root_gen, inode->i_ino, 0);
2710                         BUG_ON(ret);
2711                 }
2712 next:
2713                 if (path->slots[0] == 0) {
2714                         if (pending_del_nr)
2715                                 goto del_pending;
2716                         btrfs_release_path(root, path);
2717                         if (found_type == BTRFS_INODE_ITEM_KEY)
2718                                 break;
2719                         goto search_again;
2720                 }
2721
2722                 path->slots[0]--;
2723                 if (pending_del_nr &&
2724                     path->slots[0] + 1 != pending_del_slot) {
2725                         struct btrfs_key debug;
2726 del_pending:
2727                         btrfs_item_key_to_cpu(path->nodes[0], &debug,
2728                                               pending_del_slot);
2729                         ret = btrfs_del_items(trans, root, path,
2730                                               pending_del_slot,
2731                                               pending_del_nr);
2732                         BUG_ON(ret);
2733                         pending_del_nr = 0;
2734                         btrfs_release_path(root, path);
2735                         if (found_type == BTRFS_INODE_ITEM_KEY)
2736                                 break;
2737                         goto search_again;
2738                 }
2739         }
2740         ret = 0;
2741 error:
2742         if (pending_del_nr) {
2743                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
2744                                       pending_del_nr);
2745         }
2746         btrfs_free_path(path);
2747         inode->i_sb->s_dirt = 1;
2748         return ret;
2749 }
2750
2751 /*
2752  * taken from block_truncate_page, but does cow as it zeros out
2753  * any bytes left in the last page in the file.
2754  */
2755 static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
2756 {
2757         struct inode *inode = mapping->host;
2758         struct btrfs_root *root = BTRFS_I(inode)->root;
2759         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2760         struct btrfs_ordered_extent *ordered;
2761         char *kaddr;
2762         u32 blocksize = root->sectorsize;
2763         pgoff_t index = from >> PAGE_CACHE_SHIFT;
2764         unsigned offset = from & (PAGE_CACHE_SIZE-1);
2765         struct page *page;
2766         int ret = 0;
2767         u64 page_start;
2768         u64 page_end;
2769
2770         if ((offset & (blocksize - 1)) == 0)
2771                 goto out;
2772
2773         ret = -ENOMEM;
2774 again:
2775         page = grab_cache_page(mapping, index);
2776         if (!page)
2777                 goto out;
2778
2779         page_start = page_offset(page);
2780         page_end = page_start + PAGE_CACHE_SIZE - 1;
2781
2782         if (!PageUptodate(page)) {
2783                 ret = btrfs_readpage(NULL, page);
2784                 lock_page(page);
2785                 if (page->mapping != mapping) {
2786                         unlock_page(page);
2787                         page_cache_release(page);
2788                         goto again;
2789                 }
2790                 if (!PageUptodate(page)) {
2791                         ret = -EIO;
2792                         goto out_unlock;
2793                 }
2794         }
2795         wait_on_page_writeback(page);
2796
2797         lock_extent(io_tree, page_start, page_end, GFP_NOFS);
2798         set_page_extent_mapped(page);
2799
2800         ordered = btrfs_lookup_ordered_extent(inode, page_start);
2801         if (ordered) {
2802                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
2803                 unlock_page(page);
2804                 page_cache_release(page);
2805                 btrfs_start_ordered_extent(inode, ordered, 1);
2806                 btrfs_put_ordered_extent(ordered);
2807                 goto again;
2808         }
2809
2810         btrfs_set_extent_delalloc(inode, page_start, page_end);
2811         ret = 0;
2812         if (offset != PAGE_CACHE_SIZE) {
2813                 kaddr = kmap(page);
2814                 memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
2815                 flush_dcache_page(page);
2816                 kunmap(page);
2817         }
2818         ClearPageChecked(page);
2819         set_page_dirty(page);
2820         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
2821
2822 out_unlock:
2823         unlock_page(page);
2824         page_cache_release(page);
2825 out:
2826         return ret;
2827 }
2828
2829 int btrfs_cont_expand(struct inode *inode, loff_t size)
2830 {
2831         struct btrfs_trans_handle *trans;
2832         struct btrfs_root *root = BTRFS_I(inode)->root;
2833         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2834         struct extent_map *em;
2835         u64 mask = root->sectorsize - 1;
2836         u64 hole_start = (inode->i_size + mask) & ~mask;
2837         u64 block_end = (size + mask) & ~mask;
2838         u64 last_byte;
2839         u64 cur_offset;
2840         u64 hole_size;
2841         int err;
2842
2843         if (size <= hole_start)
2844                 return 0;
2845
2846         err = btrfs_check_metadata_free_space(root);
2847         if (err)
2848                 return err;
2849
2850         btrfs_truncate_page(inode->i_mapping, inode->i_size);
2851
2852         while (1) {
2853                 struct btrfs_ordered_extent *ordered;
2854                 btrfs_wait_ordered_range(inode, hole_start,
2855                                          block_end - hole_start);
2856                 lock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
2857                 ordered = btrfs_lookup_ordered_extent(inode, hole_start);
2858                 if (!ordered)
2859                         break;
2860                 unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
2861                 btrfs_put_ordered_extent(ordered);
2862         }
2863
2864         trans = btrfs_start_transaction(root, 1);
2865         btrfs_set_trans_block_group(trans, inode);
2866
2867         cur_offset = hole_start;
2868         while (1) {
2869                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
2870                                 block_end - cur_offset, 0);
2871                 BUG_ON(IS_ERR(em) || !em);
2872                 last_byte = min(extent_map_end(em), block_end);
2873                 last_byte = (last_byte + mask) & ~mask;
2874                 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
2875                         u64 hint_byte = 0;
2876                         hole_size = last_byte - cur_offset;
2877                         err = btrfs_drop_extents(trans, root, inode,
2878                                                  cur_offset,
2879                                                  cur_offset + hole_size,
2880                                                  cur_offset, &hint_byte);
2881                         if (err)
2882                                 break;
2883                         err = btrfs_insert_file_extent(trans, root,
2884                                         inode->i_ino, cur_offset, 0,
2885                                         0, hole_size, 0, hole_size,
2886                                         0, 0, 0);
2887                         btrfs_drop_extent_cache(inode, hole_start,
2888                                         last_byte - 1, 0);
2889                 }
2890                 free_extent_map(em);
2891                 cur_offset = last_byte;
2892                 if (err || cur_offset >= block_end)
2893                         break;
2894         }
2895
2896         btrfs_end_transaction(trans, root);
2897         unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
2898         return err;
2899 }
2900
2901 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
2902 {
2903         struct inode *inode = dentry->d_inode;
2904         int err;
2905
2906         err = inode_change_ok(inode, attr);
2907         if (err)
2908                 return err;
2909
2910         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
2911                 if (attr->ia_size > inode->i_size) {
2912                         err = btrfs_cont_expand(inode, attr->ia_size);
2913                         if (err)
2914                                 return err;
2915                 } else if (inode->i_size > 0 &&
2916                            attr->ia_size == 0) {
2917
2918                         /* we're truncating a file that used to have good
2919                          * data down to zero.  Make sure it gets into
2920                          * the ordered flush list so that any new writes
2921                          * get down to disk quickly.
2922                          */
2923                         BTRFS_I(inode)->ordered_data_close = 1;
2924                 }
2925         }
2926
2927         err = inode_setattr(inode, attr);
2928
2929         if (!err && ((attr->ia_valid & ATTR_MODE)))
2930                 err = btrfs_acl_chmod(inode);
2931         return err;
2932 }
2933
2934 void btrfs_delete_inode(struct inode *inode)
2935 {
2936         struct btrfs_trans_handle *trans;
2937         struct btrfs_root *root = BTRFS_I(inode)->root;
2938         unsigned long nr;
2939         int ret;
2940
2941         truncate_inode_pages(&inode->i_data, 0);
2942         if (is_bad_inode(inode)) {
2943                 btrfs_orphan_del(NULL, inode);
2944                 goto no_delete;
2945         }
2946         btrfs_wait_ordered_range(inode, 0, (u64)-1);
2947
2948         btrfs_i_size_write(inode, 0);
2949         trans = btrfs_join_transaction(root, 1);
2950
2951         btrfs_set_trans_block_group(trans, inode);
2952         ret = btrfs_truncate_inode_items(trans, root, inode, inode->i_size, 0);
2953         if (ret) {
2954                 btrfs_orphan_del(NULL, inode);
2955                 goto no_delete_lock;
2956         }
2957
2958         btrfs_orphan_del(trans, inode);
2959
2960         nr = trans->blocks_used;
2961         clear_inode(inode);
2962
2963         btrfs_end_transaction(trans, root);
2964         btrfs_btree_balance_dirty(root, nr);
2965         return;
2966
2967 no_delete_lock:
2968         nr = trans->blocks_used;
2969         btrfs_end_transaction(trans, root);
2970         btrfs_btree_balance_dirty(root, nr);
2971 no_delete:
2972         clear_inode(inode);
2973 }
2974
2975 /*
2976  * this returns the key found in the dir entry in the location pointer.
2977  * If no dir entries were found, location->objectid is 0.
2978  */
2979 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
2980                                struct btrfs_key *location)
2981 {
2982         const char *name = dentry->d_name.name;
2983         int namelen = dentry->d_name.len;
2984         struct btrfs_dir_item *di;
2985         struct btrfs_path *path;
2986         struct btrfs_root *root = BTRFS_I(dir)->root;
2987         int ret = 0;
2988
2989         path = btrfs_alloc_path();
2990         BUG_ON(!path);
2991
2992         di = btrfs_lookup_dir_item(NULL, root, path, dir->i_ino, name,
2993                                     namelen, 0);
2994         if (IS_ERR(di))
2995                 ret = PTR_ERR(di);
2996
2997         if (!di || IS_ERR(di))
2998                 goto out_err;
2999
3000         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
3001 out:
3002         btrfs_free_path(path);
3003         return ret;
3004 out_err:
3005         location->objectid = 0;
3006         goto out;
3007 }
3008
3009 /*
3010  * when we hit a tree root in a directory, the btrfs part of the inode
3011  * needs to be changed to reflect the root directory of the tree root.  This
3012  * is kind of like crossing a mount point.
3013  */
3014 static int fixup_tree_root_location(struct btrfs_root *root,
3015                              struct btrfs_key *location,
3016                              struct btrfs_root **sub_root,
3017                              struct dentry *dentry)
3018 {
3019         struct btrfs_root_item *ri;
3020
3021         if (btrfs_key_type(location) != BTRFS_ROOT_ITEM_KEY)
3022                 return 0;
3023         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
3024                 return 0;
3025
3026         *sub_root = btrfs_read_fs_root(root->fs_info, location,
3027                                         dentry->d_name.name,
3028                                         dentry->d_name.len);
3029         if (IS_ERR(*sub_root))
3030                 return PTR_ERR(*sub_root);
3031
3032         ri = &(*sub_root)->root_item;
3033         location->objectid = btrfs_root_dirid(ri);
3034         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
3035         location->offset = 0;
3036
3037         return 0;
3038 }
3039
3040 static noinline void init_btrfs_i(struct inode *inode)
3041 {
3042         struct btrfs_inode *bi = BTRFS_I(inode);
3043
3044         bi->i_acl = NULL;
3045         bi->i_default_acl = NULL;
3046
3047         bi->generation = 0;
3048         bi->sequence = 0;
3049         bi->last_trans = 0;
3050         bi->logged_trans = 0;
3051         bi->delalloc_bytes = 0;
3052         bi->reserved_bytes = 0;
3053         bi->disk_i_size = 0;
3054         bi->flags = 0;
3055         bi->index_cnt = (u64)-1;
3056         bi->last_unlink_trans = 0;
3057         extent_map_tree_init(&BTRFS_I(inode)->extent_tree, GFP_NOFS);
3058         extent_io_tree_init(&BTRFS_I(inode)->io_tree,
3059                              inode->i_mapping, GFP_NOFS);
3060         extent_io_tree_init(&BTRFS_I(inode)->io_failure_tree,
3061                              inode->i_mapping, GFP_NOFS);
3062         INIT_LIST_HEAD(&BTRFS_I(inode)->delalloc_inodes);
3063         INIT_LIST_HEAD(&BTRFS_I(inode)->ordered_operations);
3064         btrfs_ordered_inode_tree_init(&BTRFS_I(inode)->ordered_tree);
3065         mutex_init(&BTRFS_I(inode)->extent_mutex);
3066         mutex_init(&BTRFS_I(inode)->log_mutex);
3067 }
3068
3069 static int btrfs_init_locked_inode(struct inode *inode, void *p)
3070 {
3071         struct btrfs_iget_args *args = p;
3072         inode->i_ino = args->ino;
3073         init_btrfs_i(inode);
3074         BTRFS_I(inode)->root = args->root;
3075         btrfs_set_inode_space_info(args->root, inode);
3076         return 0;
3077 }
3078
3079 static int btrfs_find_actor(struct inode *inode, void *opaque)
3080 {
3081         struct btrfs_iget_args *args = opaque;
3082         return args->ino == inode->i_ino &&
3083                 args->root == BTRFS_I(inode)->root;
3084 }
3085
3086 struct inode *btrfs_ilookup(struct super_block *s, u64 objectid,
3087                             struct btrfs_root *root, int wait)
3088 {
3089         struct inode *inode;
3090         struct btrfs_iget_args args;
3091         args.ino = objectid;
3092         args.root = root;
3093
3094         if (wait) {
3095                 inode = ilookup5(s, objectid, btrfs_find_actor,
3096                                  (void *)&args);
3097         } else {
3098                 inode = ilookup5_nowait(s, objectid, btrfs_find_actor,
3099                                         (void *)&args);
3100         }
3101         return inode;
3102 }
3103
3104 struct inode *btrfs_iget_locked(struct super_block *s, u64 objectid,
3105                                 struct btrfs_root *root)
3106 {
3107         struct inode *inode;
3108         struct btrfs_iget_args args;
3109         args.ino = objectid;
3110         args.root = root;
3111
3112         inode = iget5_locked(s, objectid, btrfs_find_actor,
3113                              btrfs_init_locked_inode,
3114                              (void *)&args);
3115         return inode;
3116 }
3117
3118 /* Get an inode object given its location and corresponding root.
3119  * Returns in *is_new if the inode was read from disk
3120  */
3121 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
3122                          struct btrfs_root *root, int *is_new)
3123 {
3124         struct inode *inode;
3125
3126         inode = btrfs_iget_locked(s, location->objectid, root);
3127         if (!inode)
3128                 return ERR_PTR(-EACCES);
3129
3130         if (inode->i_state & I_NEW) {
3131                 BTRFS_I(inode)->root = root;
3132                 memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
3133                 btrfs_read_locked_inode(inode);
3134                 unlock_new_inode(inode);
3135                 if (is_new)
3136                         *is_new = 1;
3137         } else {
3138                 if (is_new)
3139                         *is_new = 0;
3140         }
3141
3142         return inode;
3143 }
3144
3145 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
3146 {
3147         struct inode *inode;
3148         struct btrfs_inode *bi = BTRFS_I(dir);
3149         struct btrfs_root *root = bi->root;
3150         struct btrfs_root *sub_root = root;
3151         struct btrfs_key location;
3152         int ret, new;
3153
3154         if (dentry->d_name.len > BTRFS_NAME_LEN)
3155                 return ERR_PTR(-ENAMETOOLONG);
3156
3157         ret = btrfs_inode_by_name(dir, dentry, &location);
3158
3159         if (ret < 0)
3160                 return ERR_PTR(ret);
3161
3162         inode = NULL;
3163         if (location.objectid) {
3164                 ret = fixup_tree_root_location(root, &location, &sub_root,
3165                                                 dentry);
3166                 if (ret < 0)
3167                         return ERR_PTR(ret);
3168                 if (ret > 0)
3169                         return ERR_PTR(-ENOENT);
3170                 inode = btrfs_iget(dir->i_sb, &location, sub_root, &new);
3171                 if (IS_ERR(inode))
3172                         return ERR_CAST(inode);
3173         }
3174         return inode;
3175 }
3176
3177 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
3178                                    struct nameidata *nd)
3179 {
3180         struct inode *inode;
3181
3182         if (dentry->d_name.len > BTRFS_NAME_LEN)
3183                 return ERR_PTR(-ENAMETOOLONG);
3184
3185         inode = btrfs_lookup_dentry(dir, dentry);
3186         if (IS_ERR(inode))
3187                 return ERR_CAST(inode);
3188
3189         return d_splice_alias(inode, dentry);
3190 }
3191
3192 static unsigned char btrfs_filetype_table[] = {
3193         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
3194 };
3195
3196 static int btrfs_real_readdir(struct file *filp, void *dirent,
3197                               filldir_t filldir)
3198 {
3199         struct inode *inode = filp->f_dentry->d_inode;
3200         struct btrfs_root *root = BTRFS_I(inode)->root;
3201         struct btrfs_item *item;
3202         struct btrfs_dir_item *di;
3203         struct btrfs_key key;
3204         struct btrfs_key found_key;
3205         struct btrfs_path *path;
3206         int ret;
3207         u32 nritems;
3208         struct extent_buffer *leaf;
3209         int slot;
3210         int advance;
3211         unsigned char d_type;
3212         int over = 0;
3213         u32 di_cur;
3214         u32 di_total;
3215         u32 di_len;
3216         int key_type = BTRFS_DIR_INDEX_KEY;
3217         char tmp_name[32];
3218         char *name_ptr;
3219         int name_len;
3220
3221         /* FIXME, use a real flag for deciding about the key type */
3222         if (root->fs_info->tree_root == root)
3223                 key_type = BTRFS_DIR_ITEM_KEY;
3224
3225         /* special case for "." */
3226         if (filp->f_pos == 0) {
3227                 over = filldir(dirent, ".", 1,
3228                                1, inode->i_ino,
3229                                DT_DIR);
3230                 if (over)
3231                         return 0;
3232                 filp->f_pos = 1;
3233         }
3234         /* special case for .., just use the back ref */
3235         if (filp->f_pos == 1) {
3236                 u64 pino = parent_ino(filp->f_path.dentry);
3237                 over = filldir(dirent, "..", 2,
3238                                2, pino, DT_DIR);
3239                 if (over)
3240                         return 0;
3241                 filp->f_pos = 2;
3242         }
3243         path = btrfs_alloc_path();
3244         path->reada = 2;
3245
3246         btrfs_set_key_type(&key, key_type);
3247         key.offset = filp->f_pos;
3248         key.objectid = inode->i_ino;
3249
3250         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3251         if (ret < 0)
3252                 goto err;
3253         advance = 0;
3254
3255         while (1) {
3256                 leaf = path->nodes[0];
3257                 nritems = btrfs_header_nritems(leaf);
3258                 slot = path->slots[0];
3259                 if (advance || slot >= nritems) {
3260                         if (slot >= nritems - 1) {
3261                                 ret = btrfs_next_leaf(root, path);
3262                                 if (ret)
3263                                         break;
3264                                 leaf = path->nodes[0];
3265                                 nritems = btrfs_header_nritems(leaf);
3266                                 slot = path->slots[0];
3267                         } else {
3268                                 slot++;
3269                                 path->slots[0]++;
3270                         }
3271                 }
3272
3273                 advance = 1;
3274                 item = btrfs_item_nr(leaf, slot);
3275                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3276
3277                 if (found_key.objectid != key.objectid)
3278                         break;
3279                 if (btrfs_key_type(&found_key) != key_type)
3280                         break;
3281                 if (found_key.offset < filp->f_pos)
3282                         continue;
3283
3284                 filp->f_pos = found_key.offset;
3285
3286                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
3287                 di_cur = 0;
3288                 di_total = btrfs_item_size(leaf, item);
3289
3290                 while (di_cur < di_total) {
3291                         struct btrfs_key location;
3292
3293                         name_len = btrfs_dir_name_len(leaf, di);
3294                         if (name_len <= sizeof(tmp_name)) {
3295                                 name_ptr = tmp_name;
3296                         } else {
3297                                 name_ptr = kmalloc(name_len, GFP_NOFS);
3298                                 if (!name_ptr) {
3299                                         ret = -ENOMEM;
3300                                         goto err;
3301                                 }
3302                         }
3303                         read_extent_buffer(leaf, name_ptr,
3304                                            (unsigned long)(di + 1), name_len);
3305
3306                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
3307                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
3308
3309                         /* is this a reference to our own snapshot? If so
3310                          * skip it
3311                          */
3312                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
3313                             location.objectid == root->root_key.objectid) {
3314                                 over = 0;
3315                                 goto skip;
3316                         }
3317                         over = filldir(dirent, name_ptr, name_len,
3318                                        found_key.offset, location.objectid,
3319                                        d_type);
3320
3321 skip:
3322                         if (name_ptr != tmp_name)
3323                                 kfree(name_ptr);
3324
3325                         if (over)
3326                                 goto nopos;
3327                         di_len = btrfs_dir_name_len(leaf, di) +
3328                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
3329                         di_cur += di_len;
3330                         di = (struct btrfs_dir_item *)((char *)di + di_len);
3331                 }
3332         }
3333
3334         /* Reached end of directory/root. Bump pos past the last item. */
3335         if (key_type == BTRFS_DIR_INDEX_KEY)
3336                 filp->f_pos = INT_LIMIT(off_t);
3337         else
3338                 filp->f_pos++;
3339 nopos:
3340         ret = 0;
3341 err:
3342         btrfs_free_path(path);
3343         return ret;
3344 }
3345
3346 int btrfs_write_inode(struct inode *inode, int wait)
3347 {
3348         struct btrfs_root *root = BTRFS_I(inode)->root;
3349         struct btrfs_trans_handle *trans;
3350         int ret = 0;
3351
3352         if (root->fs_info->btree_inode == inode)
3353                 return 0;
3354
3355         if (wait) {
3356                 trans = btrfs_join_transaction(root, 1);
3357                 btrfs_set_trans_block_group(trans, inode);
3358                 ret = btrfs_commit_transaction(trans, root);
3359         }
3360         return ret;
3361 }
3362
3363 /*
3364  * This is somewhat expensive, updating the tree every time the
3365  * inode changes.  But, it is most likely to find the inode in cache.
3366  * FIXME, needs more benchmarking...there are no reasons other than performance
3367  * to keep or drop this code.
3368  */
3369 void btrfs_dirty_inode(struct inode *inode)
3370 {
3371         struct btrfs_root *root = BTRFS_I(inode)->root;
3372         struct btrfs_trans_handle *trans;
3373
3374         trans = btrfs_join_transaction(root, 1);
3375         btrfs_set_trans_block_group(trans, inode);
3376         btrfs_update_inode(trans, root, inode);
3377         btrfs_end_transaction(trans, root);
3378 }
3379
3380 /*
3381  * find the highest existing sequence number in a directory
3382  * and then set the in-memory index_cnt variable to reflect
3383  * free sequence numbers
3384  */
3385 static int btrfs_set_inode_index_count(struct inode *inode)
3386 {
3387         struct btrfs_root *root = BTRFS_I(inode)->root;
3388         struct btrfs_key key, found_key;
3389         struct btrfs_path *path;
3390         struct extent_buffer *leaf;
3391         int ret;
3392
3393         key.objectid = inode->i_ino;
3394         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
3395         key.offset = (u64)-1;
3396
3397         path = btrfs_alloc_path();
3398         if (!path)
3399                 return -ENOMEM;
3400
3401         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3402         if (ret < 0)
3403                 goto out;
3404         /* FIXME: we should be able to handle this */
3405         if (ret == 0)
3406                 goto out;
3407         ret = 0;
3408
3409         /*
3410          * MAGIC NUMBER EXPLANATION:
3411          * since we search a directory based on f_pos we have to start at 2
3412          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
3413          * else has to start at 2
3414          */
3415         if (path->slots[0] == 0) {
3416                 BTRFS_I(inode)->index_cnt = 2;
3417                 goto out;
3418         }
3419
3420         path->slots[0]--;
3421
3422         leaf = path->nodes[0];
3423         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3424
3425         if (found_key.objectid != inode->i_ino ||
3426             btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
3427                 BTRFS_I(inode)->index_cnt = 2;
3428                 goto out;
3429         }
3430
3431         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
3432 out:
3433         btrfs_free_path(path);
3434         return ret;
3435 }
3436
3437 /*
3438  * helper to find a free sequence number in a given directory.  This current
3439  * code is very simple, later versions will do smarter things in the btree
3440  */
3441 int btrfs_set_inode_index(struct inode *dir, u64 *index)
3442 {
3443         int ret = 0;
3444
3445         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
3446                 ret = btrfs_set_inode_index_count(dir);
3447                 if (ret)
3448                         return ret;
3449         }
3450
3451         *index = BTRFS_I(dir)->index_cnt;
3452         BTRFS_I(dir)->index_cnt++;
3453
3454         return ret;
3455 }
3456
3457 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
3458                                      struct btrfs_root *root,
3459                                      struct inode *dir,
3460                                      const char *name, int name_len,
3461                                      u64 ref_objectid, u64 objectid,
3462                                      u64 alloc_hint, int mode, u64 *index)
3463 {
3464         struct inode *inode;
3465         struct btrfs_inode_item *inode_item;
3466         struct btrfs_key *location;
3467         struct btrfs_path *path;
3468         struct btrfs_inode_ref *ref;
3469         struct btrfs_key key[2];
3470         u32 sizes[2];
3471         unsigned long ptr;
3472         int ret;
3473         int owner;
3474
3475         path = btrfs_alloc_path();
3476         BUG_ON(!path);
3477
3478         inode = new_inode(root->fs_info->sb);
3479         if (!inode)
3480                 return ERR_PTR(-ENOMEM);
3481
3482         if (dir) {
3483                 ret = btrfs_set_inode_index(dir, index);
3484                 if (ret)
3485                         return ERR_PTR(ret);
3486         }
3487         /*
3488          * index_cnt is ignored for everything but a dir,
3489          * btrfs_get_inode_index_count has an explanation for the magic
3490          * number
3491          */
3492         init_btrfs_i(inode);
3493         BTRFS_I(inode)->index_cnt = 2;
3494         BTRFS_I(inode)->root = root;
3495         BTRFS_I(inode)->generation = trans->transid;
3496         btrfs_set_inode_space_info(root, inode);
3497
3498         if (mode & S_IFDIR)
3499                 owner = 0;
3500         else
3501                 owner = 1;
3502         BTRFS_I(inode)->block_group =
3503                         btrfs_find_block_group(root, 0, alloc_hint, owner);
3504         if ((mode & S_IFREG)) {
3505                 if (btrfs_test_opt(root, NODATASUM))
3506                         btrfs_set_flag(inode, NODATASUM);
3507                 if (btrfs_test_opt(root, NODATACOW))
3508                         btrfs_set_flag(inode, NODATACOW);
3509         }
3510
3511         key[0].objectid = objectid;
3512         btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
3513         key[0].offset = 0;
3514
3515         key[1].objectid = objectid;
3516         btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
3517         key[1].offset = ref_objectid;
3518
3519         sizes[0] = sizeof(struct btrfs_inode_item);
3520         sizes[1] = name_len + sizeof(*ref);
3521
3522         path->leave_spinning = 1;
3523         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, 2);
3524         if (ret != 0)
3525                 goto fail;
3526
3527         if (objectid > root->highest_inode)
3528                 root->highest_inode = objectid;
3529
3530         inode->i_uid = current_fsuid();
3531
3532         if (dir && (dir->i_mode & S_ISGID)) {
3533                 inode->i_gid = dir->i_gid;
3534                 if (S_ISDIR(mode))
3535                         mode |= S_ISGID;
3536         } else
3537                 inode->i_gid = current_fsgid();
3538
3539         inode->i_mode = mode;
3540         inode->i_ino = objectid;
3541         inode_set_bytes(inode, 0);
3542         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
3543         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
3544                                   struct btrfs_inode_item);
3545         fill_inode_item(trans, path->nodes[0], inode_item, inode);
3546
3547         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
3548                              struct btrfs_inode_ref);
3549         btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
3550         btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
3551         ptr = (unsigned long)(ref + 1);
3552         write_extent_buffer(path->nodes[0], name, ptr, name_len);
3553
3554         btrfs_mark_buffer_dirty(path->nodes[0]);
3555         btrfs_free_path(path);
3556
3557         location = &BTRFS_I(inode)->location;
3558         location->objectid = objectid;
3559         location->offset = 0;
3560         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
3561
3562         insert_inode_hash(inode);
3563         return inode;
3564 fail:
3565         if (dir)
3566                 BTRFS_I(dir)->index_cnt--;
3567         btrfs_free_path(path);
3568         return ERR_PTR(ret);
3569 }
3570
3571 static inline u8 btrfs_inode_type(struct inode *inode)
3572 {
3573         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
3574 }
3575
3576 /*
3577  * utility function to add 'inode' into 'parent_inode' with
3578  * a give name and a given sequence number.
3579  * if 'add_backref' is true, also insert a backref from the
3580  * inode to the parent directory.
3581  */
3582 int btrfs_add_link(struct btrfs_trans_handle *trans,
3583                    struct inode *parent_inode, struct inode *inode,
3584                    const char *name, int name_len, int add_backref, u64 index)
3585 {
3586         int ret;
3587         struct btrfs_key key;
3588         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
3589
3590         key.objectid = inode->i_ino;
3591         btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
3592         key.offset = 0;
3593
3594         ret = btrfs_insert_dir_item(trans, root, name, name_len,
3595                                     parent_inode->i_ino,
3596                                     &key, btrfs_inode_type(inode),
3597                                     index);
3598         if (ret == 0) {
3599                 if (add_backref) {
3600                         ret = btrfs_insert_inode_ref(trans, root,
3601                                                      name, name_len,
3602                                                      inode->i_ino,
3603                                                      parent_inode->i_ino,
3604                                                      index);
3605                 }
3606                 btrfs_i_size_write(parent_inode, parent_inode->i_size +
3607                                    name_len * 2);
3608                 parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
3609                 ret = btrfs_update_inode(trans, root, parent_inode);
3610         }
3611         return ret;
3612 }
3613
3614 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
3615                             struct dentry *dentry, struct inode *inode,
3616                             int backref, u64 index)
3617 {
3618         int err = btrfs_add_link(trans, dentry->d_parent->d_inode,
3619                                  inode, dentry->d_name.name,
3620                                  dentry->d_name.len, backref, index);
3621         if (!err) {
3622                 d_instantiate(dentry, inode);
3623                 return 0;
3624         }
3625         if (err > 0)
3626                 err = -EEXIST;
3627         return err;
3628 }
3629
3630 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
3631                         int mode, dev_t rdev)
3632 {
3633         struct btrfs_trans_handle *trans;
3634         struct btrfs_root *root = BTRFS_I(dir)->root;
3635         struct inode *inode = NULL;
3636         int err;
3637         int drop_inode = 0;
3638         u64 objectid;
3639         unsigned long nr = 0;
3640         u64 index = 0;
3641
3642         if (!new_valid_dev(rdev))
3643                 return -EINVAL;
3644
3645         err = btrfs_check_metadata_free_space(root);
3646         if (err)
3647                 goto fail;
3648
3649         trans = btrfs_start_transaction(root, 1);
3650         btrfs_set_trans_block_group(trans, dir);
3651
3652         err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
3653         if (err) {
3654                 err = -ENOSPC;
3655                 goto out_unlock;
3656         }
3657
3658         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
3659                                 dentry->d_name.len,
3660                                 dentry->d_parent->d_inode->i_ino, objectid,
3661                                 BTRFS_I(dir)->block_group, mode, &index);
3662         err = PTR_ERR(inode);
3663         if (IS_ERR(inode))
3664                 goto out_unlock;
3665
3666         err = btrfs_init_inode_security(inode, dir);
3667         if (err) {
3668                 drop_inode = 1;
3669                 goto out_unlock;
3670         }
3671
3672         btrfs_set_trans_block_group(trans, inode);
3673         err = btrfs_add_nondir(trans, dentry, inode, 0, index);
3674         if (err)
3675                 drop_inode = 1;
3676         else {
3677                 inode->i_op = &btrfs_special_inode_operations;
3678                 init_special_inode(inode, inode->i_mode, rdev);
3679                 btrfs_update_inode(trans, root, inode);
3680         }
3681         dir->i_sb->s_dirt = 1;
3682         btrfs_update_inode_block_group(trans, inode);
3683         btrfs_update_inode_block_group(trans, dir);
3684 out_unlock:
3685         nr = trans->blocks_used;
3686         btrfs_end_transaction_throttle(trans, root);
3687 fail:
3688         if (drop_inode) {
3689                 inode_dec_link_count(inode);
3690                 iput(inode);
3691         }
3692         btrfs_btree_balance_dirty(root, nr);
3693         return err;
3694 }
3695
3696 static int btrfs_create(struct inode *dir, struct dentry *dentry,
3697                         int mode, struct nameidata *nd)
3698 {
3699         struct btrfs_trans_handle *trans;
3700         struct btrfs_root *root = BTRFS_I(dir)->root;
3701         struct inode *inode = NULL;
3702         int err;
3703         int drop_inode = 0;
3704         unsigned long nr = 0;
3705         u64 objectid;
3706         u64 index = 0;
3707
3708         err = btrfs_check_metadata_free_space(root);
3709         if (err)
3710                 goto fail;
3711         trans = btrfs_start_transaction(root, 1);
3712         btrfs_set_trans_block_group(trans, dir);
3713
3714         err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
3715         if (err) {
3716                 err = -ENOSPC;
3717                 goto out_unlock;
3718         }
3719
3720         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
3721                                 dentry->d_name.len,
3722                                 dentry->d_parent->d_inode->i_ino,
3723                                 objectid, BTRFS_I(dir)->block_group, mode,
3724                                 &index);
3725         err = PTR_ERR(inode);
3726         if (IS_ERR(inode))
3727                 goto out_unlock;
3728
3729         err = btrfs_init_inode_security(inode, dir);
3730         if (err) {
3731                 drop_inode = 1;
3732                 goto out_unlock;
3733         }
3734
3735         btrfs_set_trans_block_group(trans, inode);
3736         err = btrfs_add_nondir(trans, dentry, inode, 0, index);
3737         if (err)
3738                 drop_inode = 1;
3739         else {
3740                 inode->i_mapping->a_ops = &btrfs_aops;
3741                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3742                 inode->i_fop = &btrfs_file_operations;
3743                 inode->i_op = &btrfs_file_inode_operations;
3744                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3745         }
3746         dir->i_sb->s_dirt = 1;
3747         btrfs_update_inode_block_group(trans, inode);
3748         btrfs_update_inode_block_group(trans, dir);
3749 out_unlock:
3750         nr = trans->blocks_used;
3751         btrfs_end_transaction_throttle(trans, root);
3752 fail:
3753         if (drop_inode) {
3754                 inode_dec_link_count(inode);
3755                 iput(inode);
3756         }
3757         btrfs_btree_balance_dirty(root, nr);
3758         return err;
3759 }
3760
3761 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
3762                       struct dentry *dentry)
3763 {
3764         struct btrfs_trans_handle *trans;
3765         struct btrfs_root *root = BTRFS_I(dir)->root;
3766         struct inode *inode = old_dentry->d_inode;
3767         u64 index;
3768         unsigned long nr = 0;
3769         int err;
3770         int drop_inode = 0;
3771
3772         if (inode->i_nlink == 0)
3773                 return -ENOENT;
3774
3775         btrfs_inc_nlink(inode);
3776         err = btrfs_check_metadata_free_space(root);
3777         if (err)
3778                 goto fail;
3779         err = btrfs_set_inode_index(dir, &index);
3780         if (err)
3781                 goto fail;
3782
3783         trans = btrfs_start_transaction(root, 1);
3784
3785         btrfs_set_trans_block_group(trans, dir);
3786         atomic_inc(&inode->i_count);
3787
3788         err = btrfs_add_nondir(trans, dentry, inode, 1, index);
3789
3790         if (err)
3791                 drop_inode = 1;
3792
3793         dir->i_sb->s_dirt = 1;
3794         btrfs_update_inode_block_group(trans, dir);
3795         err = btrfs_update_inode(trans, root, inode);
3796
3797         if (err)
3798                 drop_inode = 1;
3799
3800         nr = trans->blocks_used;
3801
3802         btrfs_log_new_name(trans, inode, NULL, dentry->d_parent);
3803         btrfs_end_transaction_throttle(trans, root);
3804 fail:
3805         if (drop_inode) {
3806                 inode_dec_link_count(inode);
3807                 iput(inode);
3808         }
3809         btrfs_btree_balance_dirty(root, nr);
3810         return err;
3811 }
3812
3813 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
3814 {
3815         struct inode *inode = NULL;
3816         struct btrfs_trans_handle *trans;
3817         struct btrfs_root *root = BTRFS_I(dir)->root;
3818         int err = 0;
3819         int drop_on_err = 0;
3820         u64 objectid = 0;
3821         u64 index = 0;
3822         unsigned long nr = 1;
3823
3824         err = btrfs_check_metadata_free_space(root);
3825         if (err)
3826                 goto out_unlock;
3827
3828         trans = btrfs_start_transaction(root, 1);
3829         btrfs_set_trans_block_group(trans, dir);
3830
3831         if (IS_ERR(trans)) {
3832                 err = PTR_ERR(trans);
3833                 goto out_unlock;
3834         }
3835
3836         err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
3837         if (err) {
3838                 err = -ENOSPC;
3839                 goto out_unlock;
3840         }
3841
3842         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
3843                                 dentry->d_name.len,
3844                                 dentry->d_parent->d_inode->i_ino, objectid,
3845                                 BTRFS_I(dir)->block_group, S_IFDIR | mode,
3846                                 &index);
3847         if (IS_ERR(inode)) {
3848                 err = PTR_ERR(inode);
3849                 goto out_fail;
3850         }
3851
3852         drop_on_err = 1;
3853
3854         err = btrfs_init_inode_security(inode, dir);
3855         if (err)
3856                 goto out_fail;
3857
3858         inode->i_op = &btrfs_dir_inode_operations;
3859         inode->i_fop = &btrfs_dir_file_operations;
3860         btrfs_set_trans_block_group(trans, inode);
3861
3862         btrfs_i_size_write(inode, 0);
3863         err = btrfs_update_inode(trans, root, inode);
3864         if (err)
3865                 goto out_fail;
3866
3867         err = btrfs_add_link(trans, dentry->d_parent->d_inode,
3868                                  inode, dentry->d_name.name,
3869                                  dentry->d_name.len, 0, index);
3870         if (err)
3871                 goto out_fail;
3872
3873         d_instantiate(dentry, inode);
3874         drop_on_err = 0;
3875         dir->i_sb->s_dirt = 1;
3876         btrfs_update_inode_block_group(trans, inode);
3877         btrfs_update_inode_block_group(trans, dir);
3878
3879 out_fail:
3880         nr = trans->blocks_used;
3881         btrfs_end_transaction_throttle(trans, root);
3882
3883 out_unlock:
3884         if (drop_on_err)
3885                 iput(inode);
3886         btrfs_btree_balance_dirty(root, nr);
3887         return err;
3888 }
3889
3890 /* helper for btfs_get_extent.  Given an existing extent in the tree,
3891  * and an extent that you want to insert, deal with overlap and insert
3892  * the new extent into the tree.
3893  */
3894 static int merge_extent_mapping(struct extent_map_tree *em_tree,
3895                                 struct extent_map *existing,
3896                                 struct extent_map *em,
3897                                 u64 map_start, u64 map_len)
3898 {
3899         u64 start_diff;
3900
3901         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
3902         start_diff = map_start - em->start;
3903         em->start = map_start;
3904         em->len = map_len;
3905         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
3906             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
3907                 em->block_start += start_diff;
3908                 em->block_len -= start_diff;
3909         }
3910         return add_extent_mapping(em_tree, em);
3911 }
3912
3913 static noinline int uncompress_inline(struct btrfs_path *path,
3914                                       struct inode *inode, struct page *page,
3915                                       size_t pg_offset, u64 extent_offset,
3916                                       struct btrfs_file_extent_item *item)
3917 {
3918         int ret;
3919         struct extent_buffer *leaf = path->nodes[0];
3920         char *tmp;
3921         size_t max_size;
3922         unsigned long inline_size;
3923         unsigned long ptr;
3924
3925         WARN_ON(pg_offset != 0);
3926         max_size = btrfs_file_extent_ram_bytes(leaf, item);
3927         inline_size = btrfs_file_extent_inline_item_len(leaf,
3928                                         btrfs_item_nr(leaf, path->slots[0]));
3929         tmp = kmalloc(inline_size, GFP_NOFS);
3930         ptr = btrfs_file_extent_inline_start(item);
3931
3932         read_extent_buffer(leaf, tmp, ptr, inline_size);
3933
3934         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
3935         ret = btrfs_zlib_decompress(tmp, page, extent_offset,
3936                                     inline_size, max_size);
3937         if (ret) {
3938                 char *kaddr = kmap_atomic(page, KM_USER0);
3939                 unsigned long copy_size = min_t(u64,
3940                                   PAGE_CACHE_SIZE - pg_offset,
3941                                   max_size - extent_offset);
3942                 memset(kaddr + pg_offset, 0, copy_size);
3943                 kunmap_atomic(kaddr, KM_USER0);
3944         }
3945         kfree(tmp);
3946         return 0;
3947 }
3948
3949 /*
3950  * a bit scary, this does extent mapping from logical file offset to the disk.
3951  * the ugly parts come from merging extents from the disk with the in-ram
3952  * representation.  This gets more complex because of the data=ordered code,
3953  * where the in-ram extents might be locked pending data=ordered completion.
3954  *
3955  * This also copies inline extents directly into the page.
3956  */
3957
3958 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
3959                                     size_t pg_offset, u64 start, u64 len,
3960                                     int create)
3961 {
3962         int ret;
3963         int err = 0;
3964         u64 bytenr;
3965         u64 extent_start = 0;
3966         u64 extent_end = 0;
3967         u64 objectid = inode->i_ino;
3968         u32 found_type;
3969         struct btrfs_path *path = NULL;
3970         struct btrfs_root *root = BTRFS_I(inode)->root;
3971         struct btrfs_file_extent_item *item;
3972         struct extent_buffer *leaf;
3973         struct btrfs_key found_key;
3974         struct extent_map *em = NULL;
3975         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3976         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3977         struct btrfs_trans_handle *trans = NULL;
3978         int compressed;
3979
3980 again:
3981         spin_lock(&em_tree->lock);
3982         em = lookup_extent_mapping(em_tree, start, len);
3983         if (em)
3984                 em->bdev = root->fs_info->fs_devices->latest_bdev;
3985         spin_unlock(&em_tree->lock);
3986
3987         if (em) {
3988                 if (em->start > start || em->start + em->len <= start)
3989                         free_extent_map(em);
3990                 else if (em->block_start == EXTENT_MAP_INLINE && page)
3991                         free_extent_map(em);
3992                 else
3993                         goto out;
3994         }
3995         em = alloc_extent_map(GFP_NOFS);
3996         if (!em) {
3997                 err = -ENOMEM;
3998                 goto out;
3999         }
4000         em->bdev = root->fs_info->fs_devices->latest_bdev;
4001         em->start = EXTENT_MAP_HOLE;
4002         em->orig_start = EXTENT_MAP_HOLE;
4003         em->len = (u64)-1;
4004         em->block_len = (u64)-1;
4005
4006         if (!path) {
4007                 path = btrfs_alloc_path();
4008                 BUG_ON(!path);
4009         }
4010
4011         ret = btrfs_lookup_file_extent(trans, root, path,
4012                                        objectid, start, trans != NULL);
4013         if (ret < 0) {
4014                 err = ret;
4015                 goto out;
4016         }
4017
4018         if (ret != 0) {
4019                 if (path->slots[0] == 0)
4020                         goto not_found;
4021                 path->slots[0]--;
4022         }
4023
4024         leaf = path->nodes[0];
4025         item = btrfs_item_ptr(leaf, path->slots[0],
4026                               struct btrfs_file_extent_item);
4027         /* are we inside the extent that was found? */
4028         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4029         found_type = btrfs_key_type(&found_key);
4030         if (found_key.objectid != objectid ||
4031             found_type != BTRFS_EXTENT_DATA_KEY) {
4032                 goto not_found;
4033         }
4034
4035         found_type = btrfs_file_extent_type(leaf, item);
4036         extent_start = found_key.offset;
4037         compressed = btrfs_file_extent_compression(leaf, item);
4038         if (found_type == BTRFS_FILE_EXTENT_REG ||
4039             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
4040                 extent_end = extent_start +
4041                        btrfs_file_extent_num_bytes(leaf, item);
4042         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
4043                 size_t size;
4044                 size = btrfs_file_extent_inline_len(leaf, item);
4045                 extent_end = (extent_start + size + root->sectorsize - 1) &
4046                         ~((u64)root->sectorsize - 1);
4047         }
4048
4049         if (start >= extent_end) {
4050                 path->slots[0]++;
4051                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
4052                         ret = btrfs_next_leaf(root, path);
4053                         if (ret < 0) {
4054                                 err = ret;
4055                                 goto out;
4056                         }
4057                         if (ret > 0)
4058                                 goto not_found;
4059                         leaf = path->nodes[0];
4060                 }
4061                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4062                 if (found_key.objectid != objectid ||
4063                     found_key.type != BTRFS_EXTENT_DATA_KEY)
4064                         goto not_found;
4065                 if (start + len <= found_key.offset)
4066                         goto not_found;
4067                 em->start = start;
4068                 em->len = found_key.offset - start;
4069                 goto not_found_em;
4070         }
4071
4072         if (found_type == BTRFS_FILE_EXTENT_REG ||
4073             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
4074                 em->start = extent_start;
4075                 em->len = extent_end - extent_start;
4076                 em->orig_start = extent_start -
4077                                  btrfs_file_extent_offset(leaf, item);
4078                 bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
4079                 if (bytenr == 0) {
4080                         em->block_start = EXTENT_MAP_HOLE;
4081                         goto insert;
4082                 }
4083                 if (compressed) {
4084                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
4085                         em->block_start = bytenr;
4086                         em->block_len = btrfs_file_extent_disk_num_bytes(leaf,
4087                                                                          item);
4088                 } else {
4089                         bytenr += btrfs_file_extent_offset(leaf, item);
4090                         em->block_start = bytenr;
4091                         em->block_len = em->len;
4092                         if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
4093                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
4094                 }
4095                 goto insert;
4096         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
4097                 unsigned long ptr;
4098                 char *map;
4099                 size_t size;
4100                 size_t extent_offset;
4101                 size_t copy_size;
4102
4103                 em->block_start = EXTENT_MAP_INLINE;
4104                 if (!page || create) {
4105                         em->start = extent_start;
4106                         em->len = extent_end - extent_start;
4107                         goto out;
4108                 }
4109
4110                 size = btrfs_file_extent_inline_len(leaf, item);
4111                 extent_offset = page_offset(page) + pg_offset - extent_start;
4112                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
4113                                 size - extent_offset);
4114                 em->start = extent_start + extent_offset;
4115                 em->len = (copy_size + root->sectorsize - 1) &
4116                         ~((u64)root->sectorsize - 1);
4117                 em->orig_start = EXTENT_MAP_INLINE;
4118                 if (compressed)
4119                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
4120                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
4121                 if (create == 0 && !PageUptodate(page)) {
4122                         if (btrfs_file_extent_compression(leaf, item) ==
4123                             BTRFS_COMPRESS_ZLIB) {
4124                                 ret = uncompress_inline(path, inode, page,
4125                                                         pg_offset,
4126                                                         extent_offset, item);
4127                                 BUG_ON(ret);
4128                         } else {
4129                                 map = kmap(page);
4130                                 read_extent_buffer(leaf, map + pg_offset, ptr,
4131                                                    copy_size);
4132                                 kunmap(page);
4133                         }
4134                         flush_dcache_page(page);
4135                 } else if (create && PageUptodate(page)) {
4136                         if (!trans) {
4137                                 kunmap(page);
4138                                 free_extent_map(em);
4139                                 em = NULL;
4140                                 btrfs_release_path(root, path);
4141                                 trans = btrfs_join_transaction(root, 1);
4142                                 goto again;
4143                         }
4144                         map = kmap(page);
4145                         write_extent_buffer(leaf, map + pg_offset, ptr,
4146                                             copy_size);
4147                         kunmap(page);
4148                         btrfs_mark_buffer_dirty(leaf);
4149                 }
4150                 set_extent_uptodate(io_tree, em->start,
4151                                     extent_map_end(em) - 1, GFP_NOFS);
4152                 goto insert;
4153         } else {
4154                 printk(KERN_ERR "btrfs unknown found_type %d\n", found_type);
4155                 WARN_ON(1);
4156         }
4157 not_found:
4158         em->start = start;
4159         em->len = len;
4160 not_found_em:
4161         em->block_start = EXTENT_MAP_HOLE;
4162         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
4163 insert:
4164         btrfs_release_path(root, path);
4165         if (em->start > start || extent_map_end(em) <= start) {
4166                 printk(KERN_ERR "Btrfs: bad extent! em: [%llu %llu] passed "
4167                        "[%llu %llu]\n", (unsigned long long)em->start,
4168                        (unsigned long long)em->len,
4169                        (unsigned long long)start,
4170                        (unsigned long long)len);
4171                 err = -EIO;
4172                 goto out;
4173         }
4174
4175         err = 0;
4176         spin_lock(&em_tree->lock);
4177         ret = add_extent_mapping(em_tree, em);
4178         /* it is possible that someone inserted the extent into the tree
4179          * while we had the lock dropped.  It is also possible that
4180          * an overlapping map exists in the tree
4181          */
4182         if (ret == -EEXIST) {
4183                 struct extent_map *existing;
4184
4185                 ret = 0;
4186
4187                 existing = lookup_extent_mapping(em_tree, start, len);
4188                 if (existing && (existing->start > start ||
4189                     existing->start + existing->len <= start)) {
4190                         free_extent_map(existing);
4191                         existing = NULL;
4192                 }
4193                 if (!existing) {
4194                         existing = lookup_extent_mapping(em_tree, em->start,
4195                                                          em->len);
4196                         if (existing) {
4197                                 err = merge_extent_mapping(em_tree, existing,
4198                                                            em, start,
4199                                                            root->sectorsize);
4200                                 free_extent_map(existing);
4201                                 if (err) {
4202                                         free_extent_map(em);
4203                                         em = NULL;
4204                                 }
4205                         } else {
4206                                 err = -EIO;
4207                                 free_extent_map(em);
4208                                 em = NULL;
4209                         }
4210                 } else {
4211                         free_extent_map(em);
4212                         em = existing;
4213                         err = 0;
4214                 }
4215         }
4216         spin_unlock(&em_tree->lock);
4217 out:
4218         if (path)
4219                 btrfs_free_path(path);
4220         if (trans) {
4221                 ret = btrfs_end_transaction(trans, root);
4222                 if (!err)
4223                         err = ret;
4224         }
4225         if (err) {
4226                 free_extent_map(em);
4227                 WARN_ON(1);
4228                 return ERR_PTR(err);
4229         }
4230         return em;
4231 }
4232
4233 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
4234                         const struct iovec *iov, loff_t offset,
4235                         unsigned long nr_segs)
4236 {
4237         return -EINVAL;
4238 }
4239
4240 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4241                 __u64 start, __u64 len)
4242 {
4243         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent);
4244 }
4245
4246 int btrfs_readpage(struct file *file, struct page *page)
4247 {
4248         struct extent_io_tree *tree;
4249         tree = &BTRFS_I(page->mapping->host)->io_tree;
4250         return extent_read_full_page(tree, page, btrfs_get_extent);
4251 }
4252
4253 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
4254 {
4255         struct extent_io_tree *tree;
4256
4257
4258         if (current->flags & PF_MEMALLOC) {
4259                 redirty_page_for_writepage(wbc, page);
4260                 unlock_page(page);
4261                 return 0;
4262         }
4263         tree = &BTRFS_I(page->mapping->host)->io_tree;
4264         return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
4265 }
4266
4267 int btrfs_writepages(struct address_space *mapping,
4268                      struct writeback_control *wbc)
4269 {
4270         struct extent_io_tree *tree;
4271
4272         tree = &BTRFS_I(mapping->host)->io_tree;
4273         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
4274 }
4275
4276 static int
4277 btrfs_readpages(struct file *file, struct address_space *mapping,
4278                 struct list_head *pages, unsigned nr_pages)
4279 {
4280         struct extent_io_tree *tree;
4281         tree = &BTRFS_I(mapping->host)->io_tree;
4282         return extent_readpages(tree, mapping, pages, nr_pages,
4283                                 btrfs_get_extent);
4284 }
4285 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
4286 {
4287         struct extent_io_tree *tree;
4288         struct extent_map_tree *map;
4289         int ret;
4290
4291         tree = &BTRFS_I(page->mapping->host)->io_tree;
4292         map = &BTRFS_I(page->mapping->host)->extent_tree;
4293         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
4294         if (ret == 1) {
4295                 ClearPagePrivate(page);
4296                 set_page_private(page, 0);
4297                 page_cache_release(page);
4298         }
4299         return ret;
4300 }
4301
4302 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
4303 {
4304         if (PageWriteback(page) || PageDirty(page))
4305                 return 0;
4306         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
4307 }
4308
4309 static void btrfs_invalidatepage(struct page *page, unsigned long offset)
4310 {
4311         struct extent_io_tree *tree;
4312         struct btrfs_ordered_extent *ordered;
4313         u64 page_start = page_offset(page);
4314         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
4315
4316         wait_on_page_writeback(page);
4317         tree = &BTRFS_I(page->mapping->host)->io_tree;
4318         if (offset) {
4319                 btrfs_releasepage(page, GFP_NOFS);
4320                 return;
4321         }
4322
4323         lock_extent(tree, page_start, page_end, GFP_NOFS);
4324         ordered = btrfs_lookup_ordered_extent(page->mapping->host,
4325                                            page_offset(page));
4326         if (ordered) {
4327                 /*
4328                  * IO on this page will never be started, so we need
4329                  * to account for any ordered extents now
4330                  */
4331                 clear_extent_bit(tree, page_start, page_end,
4332                                  EXTENT_DIRTY | EXTENT_DELALLOC |
4333                                  EXTENT_LOCKED, 1, 0, GFP_NOFS);
4334                 btrfs_finish_ordered_io(page->mapping->host,
4335                                         page_start, page_end);
4336                 btrfs_put_ordered_extent(ordered);
4337                 lock_extent(tree, page_start, page_end, GFP_NOFS);
4338         }
4339         clear_extent_bit(tree, page_start, page_end,
4340                  EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
4341                  EXTENT_ORDERED,
4342                  1, 1, GFP_NOFS);
4343         __btrfs_releasepage(page, GFP_NOFS);
4344
4345         ClearPageChecked(page);
4346         if (PagePrivate(page)) {
4347                 ClearPagePrivate(page);
4348                 set_page_private(page, 0);
4349                 page_cache_release(page);
4350         }
4351 }
4352
4353 /*
4354  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
4355  * called from a page fault handler when a page is first dirtied. Hence we must
4356  * be careful to check for EOF conditions here. We set the page up correctly
4357  * for a written page which means we get ENOSPC checking when writing into
4358  * holes and correct delalloc and unwritten extent mapping on filesystems that
4359  * support these features.
4360  *
4361  * We are not allowed to take the i_mutex here so we have to play games to
4362  * protect against truncate races as the page could now be beyond EOF.  Because
4363  * vmtruncate() writes the inode size before removing pages, once we have the
4364  * page lock we can determine safely if the page is beyond EOF. If it is not
4365  * beyond EOF, then the page is guaranteed safe against truncation until we
4366  * unlock the page.
4367  */
4368 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
4369 {
4370         struct page *page = vmf->page;
4371         struct inode *inode = fdentry(vma->vm_file)->d_inode;
4372         struct btrfs_root *root = BTRFS_I(inode)->root;
4373         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4374         struct btrfs_ordered_extent *ordered;
4375         char *kaddr;
4376         unsigned long zero_start;
4377         loff_t size;
4378         int ret;
4379         u64 page_start;
4380         u64 page_end;
4381
4382         ret = btrfs_check_data_free_space(root, inode, PAGE_CACHE_SIZE);
4383         if (ret) {
4384                 if (ret == -ENOMEM)
4385                         ret = VM_FAULT_OOM;
4386                 else /* -ENOSPC, -EIO, etc */
4387                         ret = VM_FAULT_SIGBUS;
4388                 goto out;
4389         }
4390
4391         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
4392 again:
4393         lock_page(page);
4394         size = i_size_read(inode);
4395         page_start = page_offset(page);
4396         page_end = page_start + PAGE_CACHE_SIZE - 1;
4397
4398         if ((page->mapping != inode->i_mapping) ||
4399             (page_start >= size)) {
4400                 btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE);
4401                 /* page got truncated out from underneath us */
4402                 goto out_unlock;
4403         }
4404         wait_on_page_writeback(page);
4405
4406         lock_extent(io_tree, page_start, page_end, GFP_NOFS);
4407         set_page_extent_mapped(page);
4408
4409         /*
4410          * we can't set the delalloc bits if there are pending ordered
4411          * extents.  Drop our locks and wait for them to finish
4412          */
4413         ordered = btrfs_lookup_ordered_extent(inode, page_start);
4414         if (ordered) {
4415                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
4416                 unlock_page(page);
4417                 btrfs_start_ordered_extent(inode, ordered, 1);
4418                 btrfs_put_ordered_extent(ordered);
4419                 goto again;
4420         }
4421
4422         btrfs_set_extent_delalloc(inode, page_start, page_end);
4423         ret = 0;
4424
4425         /* page is wholly or partially inside EOF */
4426         if (page_start + PAGE_CACHE_SIZE > size)
4427                 zero_start = size & ~PAGE_CACHE_MASK;
4428         else
4429                 zero_start = PAGE_CACHE_SIZE;
4430
4431         if (zero_start != PAGE_CACHE_SIZE) {
4432                 kaddr = kmap(page);
4433                 memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
4434                 flush_dcache_page(page);
4435                 kunmap(page);
4436         }
4437         ClearPageChecked(page);
4438         set_page_dirty(page);
4439
4440         BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
4441         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
4442
4443 out_unlock:
4444         unlock_page(page);
4445 out:
4446         return ret;
4447 }
4448
4449 static void btrfs_truncate(struct inode *inode)
4450 {
4451         struct btrfs_root *root = BTRFS_I(inode)->root;
4452         int ret;
4453         struct btrfs_trans_handle *trans;
4454         unsigned long nr;
4455         u64 mask = root->sectorsize - 1;
4456
4457         if (!S_ISREG(inode->i_mode))
4458                 return;
4459         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
4460                 return;
4461
4462         btrfs_truncate_page(inode->i_mapping, inode->i_size);
4463         btrfs_wait_ordered_range(inode, inode->i_size & (~mask), (u64)-1);
4464
4465         trans = btrfs_start_transaction(root, 1);
4466
4467         /*
4468          * setattr is responsible for setting the ordered_data_close flag,
4469          * but that is only tested during the last file release.  That
4470          * could happen well after the next commit, leaving a great big
4471          * window where new writes may get lost if someone chooses to write
4472          * to this file after truncating to zero
4473          *
4474          * The inode doesn't have any dirty data here, and so if we commit
4475          * this is a noop.  If someone immediately starts writing to the inode
4476          * it is very likely we'll catch some of their writes in this
4477          * transaction, and the commit will find this file on the ordered
4478          * data list with good things to send down.
4479          *
4480          * This is a best effort solution, there is still a window where
4481          * using truncate to replace the contents of the file will
4482          * end up with a zero length file after a crash.
4483          */
4484         if (inode->i_size == 0 && BTRFS_I(inode)->ordered_data_close)
4485                 btrfs_add_ordered_operation(trans, root, inode);
4486
4487         btrfs_set_trans_block_group(trans, inode);
4488         btrfs_i_size_write(inode, inode->i_size);
4489
4490         ret = btrfs_orphan_add(trans, inode);
4491         if (ret)
4492                 goto out;
4493         /* FIXME, add redo link to tree so we don't leak on crash */
4494         ret = btrfs_truncate_inode_items(trans, root, inode, inode->i_size,
4495                                       BTRFS_EXTENT_DATA_KEY);
4496         btrfs_update_inode(trans, root, inode);
4497
4498         ret = btrfs_orphan_del(trans, inode);
4499         BUG_ON(ret);
4500
4501 out:
4502         nr = trans->blocks_used;
4503         ret = btrfs_end_transaction_throttle(trans, root);
4504         BUG_ON(ret);
4505         btrfs_btree_balance_dirty(root, nr);
4506 }
4507
4508 /*
4509  * create a new subvolume directory/inode (helper for the ioctl).
4510  */
4511 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
4512                              struct btrfs_root *new_root, struct dentry *dentry,
4513                              u64 new_dirid, u64 alloc_hint)
4514 {
4515         struct inode *inode;
4516         int error;
4517         u64 index = 0;
4518
4519         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2, new_dirid,
4520                                 new_dirid, alloc_hint, S_IFDIR | 0700, &index);
4521         if (IS_ERR(inode))
4522                 return PTR_ERR(inode);
4523         inode->i_op = &btrfs_dir_inode_operations;
4524         inode->i_fop = &btrfs_dir_file_operations;
4525
4526         inode->i_nlink = 1;
4527         btrfs_i_size_write(inode, 0);
4528
4529         error = btrfs_update_inode(trans, new_root, inode);
4530         if (error)
4531                 return error;
4532
4533         d_instantiate(dentry, inode);
4534         return 0;
4535 }
4536
4537 /* helper function for file defrag and space balancing.  This
4538  * forces readahead on a given range of bytes in an inode
4539  */
4540 unsigned long btrfs_force_ra(struct address_space *mapping,
4541                               struct file_ra_state *ra, struct file *file,
4542                               pgoff_t offset, pgoff_t last_index)
4543 {
4544         pgoff_t req_size = last_index - offset + 1;
4545
4546         page_cache_sync_readahead(mapping, ra, file, offset, req_size);
4547         return offset + req_size;
4548 }
4549
4550 struct inode *btrfs_alloc_inode(struct super_block *sb)
4551 {
4552         struct btrfs_inode *ei;
4553
4554         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
4555         if (!ei)
4556                 return NULL;
4557         ei->last_trans = 0;
4558         ei->logged_trans = 0;
4559         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
4560         ei->i_acl = BTRFS_ACL_NOT_CACHED;
4561         ei->i_default_acl = BTRFS_ACL_NOT_CACHED;
4562         INIT_LIST_HEAD(&ei->i_orphan);
4563         INIT_LIST_HEAD(&ei->ordered_operations);
4564         return &ei->vfs_inode;
4565 }
4566
4567 void btrfs_destroy_inode(struct inode *inode)
4568 {
4569         struct btrfs_ordered_extent *ordered;
4570         struct btrfs_root *root = BTRFS_I(inode)->root;
4571
4572         WARN_ON(!list_empty(&inode->i_dentry));
4573         WARN_ON(inode->i_data.nrpages);
4574
4575         if (BTRFS_I(inode)->i_acl &&
4576             BTRFS_I(inode)->i_acl != BTRFS_ACL_NOT_CACHED)
4577                 posix_acl_release(BTRFS_I(inode)->i_acl);
4578         if (BTRFS_I(inode)->i_default_acl &&
4579             BTRFS_I(inode)->i_default_acl != BTRFS_ACL_NOT_CACHED)
4580                 posix_acl_release(BTRFS_I(inode)->i_default_acl);
4581
4582         /*
4583          * Make sure we're properly removed from the ordered operation
4584          * lists.
4585          */
4586         smp_mb();
4587         if (!list_empty(&BTRFS_I(inode)->ordered_operations)) {
4588                 spin_lock(&root->fs_info->ordered_extent_lock);
4589                 list_del_init(&BTRFS_I(inode)->ordered_operations);
4590                 spin_unlock(&root->fs_info->ordered_extent_lock);
4591         }
4592
4593         spin_lock(&root->list_lock);
4594         if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
4595                 printk(KERN_ERR "BTRFS: inode %lu: inode still on the orphan"
4596                        " list\n", inode->i_ino);
4597                 dump_stack();
4598         }
4599         spin_unlock(&root->list_lock);
4600
4601         while (1) {
4602                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
4603                 if (!ordered)
4604                         break;
4605                 else {
4606                         printk(KERN_ERR "btrfs found ordered "
4607                                "extent %llu %llu on inode cleanup\n",
4608                                (unsigned long long)ordered->file_offset,
4609                                (unsigned long long)ordered->len);
4610                         btrfs_remove_ordered_extent(inode, ordered);
4611                         btrfs_put_ordered_extent(ordered);
4612                         btrfs_put_ordered_extent(ordered);
4613                 }
4614         }
4615         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
4616         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
4617 }
4618
4619 static void init_once(void *foo)
4620 {
4621         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
4622
4623         inode_init_once(&ei->vfs_inode);
4624 }
4625
4626 void btrfs_destroy_cachep(void)
4627 {
4628         if (btrfs_inode_cachep)
4629                 kmem_cache_destroy(btrfs_inode_cachep);
4630         if (btrfs_trans_handle_cachep)
4631                 kmem_cache_destroy(btrfs_trans_handle_cachep);
4632         if (btrfs_transaction_cachep)
4633                 kmem_cache_destroy(btrfs_transaction_cachep);
4634         if (btrfs_bit_radix_cachep)
4635                 kmem_cache_destroy(btrfs_bit_radix_cachep);
4636         if (btrfs_path_cachep)
4637                 kmem_cache_destroy(btrfs_path_cachep);
4638 }
4639
4640 struct kmem_cache *btrfs_cache_create(const char *name, size_t size,
4641                                        unsigned long extra_flags,
4642                                        void (*ctor)(void *))
4643 {
4644         return kmem_cache_create(name, size, 0, (SLAB_RECLAIM_ACCOUNT |
4645                                  SLAB_MEM_SPREAD | extra_flags), ctor);
4646 }
4647
4648 int btrfs_init_cachep(void)
4649 {
4650         btrfs_inode_cachep = btrfs_cache_create("btrfs_inode_cache",
4651                                           sizeof(struct btrfs_inode),
4652                                           0, init_once);
4653         if (!btrfs_inode_cachep)
4654                 goto fail;
4655         btrfs_trans_handle_cachep =
4656                         btrfs_cache_create("btrfs_trans_handle_cache",
4657                                            sizeof(struct btrfs_trans_handle),
4658                                            0, NULL);
4659         if (!btrfs_trans_handle_cachep)
4660                 goto fail;
4661         btrfs_transaction_cachep = btrfs_cache_create("btrfs_transaction_cache",
4662                                              sizeof(struct btrfs_transaction),
4663                                              0, NULL);
4664         if (!btrfs_transaction_cachep)
4665                 goto fail;
4666         btrfs_path_cachep = btrfs_cache_create("btrfs_path_cache",
4667                                          sizeof(struct btrfs_path),
4668                                          0, NULL);
4669         if (!btrfs_path_cachep)
4670                 goto fail;
4671         btrfs_bit_radix_cachep = btrfs_cache_create("btrfs_radix", 256,
4672                                               SLAB_DESTROY_BY_RCU, NULL);
4673         if (!btrfs_bit_radix_cachep)
4674                 goto fail;
4675         return 0;
4676 fail:
4677         btrfs_destroy_cachep();
4678         return -ENOMEM;
4679 }
4680
4681 static int btrfs_getattr(struct vfsmount *mnt,
4682                          struct dentry *dentry, struct kstat *stat)
4683 {
4684         struct inode *inode = dentry->d_inode;
4685         generic_fillattr(inode, stat);
4686         stat->dev = BTRFS_I(inode)->root->anon_super.s_dev;
4687         stat->blksize = PAGE_CACHE_SIZE;
4688         stat->blocks = (inode_get_bytes(inode) +
4689                         BTRFS_I(inode)->delalloc_bytes) >> 9;
4690         return 0;
4691 }
4692
4693 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
4694                            struct inode *new_dir, struct dentry *new_dentry)
4695 {
4696         struct btrfs_trans_handle *trans;
4697         struct btrfs_root *root = BTRFS_I(old_dir)->root;
4698         struct inode *new_inode = new_dentry->d_inode;
4699         struct inode *old_inode = old_dentry->d_inode;
4700         struct timespec ctime = CURRENT_TIME;
4701         u64 index = 0;
4702         int ret;
4703
4704         /* we're not allowed to rename between subvolumes */
4705         if (BTRFS_I(old_inode)->root->root_key.objectid !=
4706             BTRFS_I(new_dir)->root->root_key.objectid)
4707                 return -EXDEV;
4708
4709         if (S_ISDIR(old_inode->i_mode) && new_inode &&
4710             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE) {
4711                 return -ENOTEMPTY;
4712         }
4713
4714         /* to rename a snapshot or subvolume, we need to juggle the
4715          * backrefs.  This isn't coded yet
4716          */
4717         if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
4718                 return -EXDEV;
4719
4720         ret = btrfs_check_metadata_free_space(root);
4721         if (ret)
4722                 goto out_unlock;
4723
4724         /*
4725          * we're using rename to replace one file with another.
4726          * and the replacement file is large.  Start IO on it now so
4727          * we don't add too much work to the end of the transaction
4728          */
4729         if (new_inode && old_inode && S_ISREG(old_inode->i_mode) &&
4730             new_inode->i_size &&
4731             old_inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
4732                 filemap_flush(old_inode->i_mapping);
4733
4734         trans = btrfs_start_transaction(root, 1);
4735
4736         /*
4737          * make sure the inode gets flushed if it is replacing
4738          * something.
4739          */
4740         if (new_inode && new_inode->i_size &&
4741             old_inode && S_ISREG(old_inode->i_mode)) {
4742                 btrfs_add_ordered_operation(trans, root, old_inode);
4743         }
4744
4745         /*
4746          * this is an ugly little race, but the rename is required to make
4747          * sure that if we crash, the inode is either at the old name
4748          * or the new one.  pinning the log transaction lets us make sure
4749          * we don't allow a log commit to come in after we unlink the
4750          * name but before we add the new name back in.
4751          */
4752         btrfs_pin_log_trans(root);
4753
4754         btrfs_set_trans_block_group(trans, new_dir);
4755
4756         btrfs_inc_nlink(old_dentry->d_inode);
4757         old_dir->i_ctime = old_dir->i_mtime = ctime;
4758         new_dir->i_ctime = new_dir->i_mtime = ctime;
4759         old_inode->i_ctime = ctime;
4760
4761         if (old_dentry->d_parent != new_dentry->d_parent)
4762                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
4763
4764         ret = btrfs_unlink_inode(trans, root, old_dir, old_dentry->d_inode,
4765                                  old_dentry->d_name.name,
4766                                  old_dentry->d_name.len);
4767         if (ret)
4768                 goto out_fail;
4769
4770         if (new_inode) {
4771                 new_inode->i_ctime = CURRENT_TIME;
4772                 ret = btrfs_unlink_inode(trans, root, new_dir,
4773                                          new_dentry->d_inode,
4774                                          new_dentry->d_name.name,
4775                                          new_dentry->d_name.len);
4776                 if (ret)
4777                         goto out_fail;
4778                 if (new_inode->i_nlink == 0) {
4779                         ret = btrfs_orphan_add(trans, new_dentry->d_inode);
4780                         if (ret)
4781                                 goto out_fail;
4782                 }
4783
4784         }
4785         ret = btrfs_set_inode_index(new_dir, &index);
4786         if (ret)
4787                 goto out_fail;
4788
4789         ret = btrfs_add_link(trans, new_dentry->d_parent->d_inode,
4790                              old_inode, new_dentry->d_name.name,
4791                              new_dentry->d_name.len, 1, index);
4792         if (ret)
4793                 goto out_fail;
4794
4795         btrfs_log_new_name(trans, old_inode, old_dir,
4796                                        new_dentry->d_parent);
4797 out_fail:
4798
4799         /* this btrfs_end_log_trans just allows the current
4800          * log-sub transaction to complete
4801          */
4802         btrfs_end_log_trans(root);
4803         btrfs_end_transaction_throttle(trans, root);
4804 out_unlock:
4805         return ret;
4806 }
4807
4808 /*
4809  * some fairly slow code that needs optimization. This walks the list
4810  * of all the inodes with pending delalloc and forces them to disk.
4811  */
4812 int btrfs_start_delalloc_inodes(struct btrfs_root *root)
4813 {
4814         struct list_head *head = &root->fs_info->delalloc_inodes;
4815         struct btrfs_inode *binode;
4816         struct inode *inode;
4817
4818         if (root->fs_info->sb->s_flags & MS_RDONLY)
4819                 return -EROFS;
4820
4821         spin_lock(&root->fs_info->delalloc_lock);
4822         while (!list_empty(head)) {
4823                 binode = list_entry(head->next, struct btrfs_inode,
4824                                     delalloc_inodes);
4825                 inode = igrab(&binode->vfs_inode);
4826                 if (!inode)
4827                         list_del_init(&binode->delalloc_inodes);
4828                 spin_unlock(&root->fs_info->delalloc_lock);
4829                 if (inode) {
4830                         filemap_flush(inode->i_mapping);
4831                         iput(inode);
4832                 }
4833                 cond_resched();
4834                 spin_lock(&root->fs_info->delalloc_lock);
4835         }
4836         spin_unlock(&root->fs_info->delalloc_lock);
4837
4838         /* the filemap_flush will queue IO into the worker threads, but
4839          * we have to make sure the IO is actually started and that
4840          * ordered extents get created before we return
4841          */
4842         atomic_inc(&root->fs_info->async_submit_draining);
4843         while (atomic_read(&root->fs_info->nr_async_submits) ||
4844               atomic_read(&root->fs_info->async_delalloc_pages)) {
4845                 wait_event(root->fs_info->async_submit_wait,
4846                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
4847                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
4848         }
4849         atomic_dec(&root->fs_info->async_submit_draining);
4850         return 0;
4851 }
4852
4853 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
4854                          const char *symname)
4855 {
4856         struct btrfs_trans_handle *trans;
4857         struct btrfs_root *root = BTRFS_I(dir)->root;
4858         struct btrfs_path *path;
4859         struct btrfs_key key;
4860         struct inode *inode = NULL;
4861         int err;
4862         int drop_inode = 0;
4863         u64 objectid;
4864         u64 index = 0 ;
4865         int name_len;
4866         int datasize;
4867         unsigned long ptr;
4868         struct btrfs_file_extent_item *ei;
4869         struct extent_buffer *leaf;
4870         unsigned long nr = 0;
4871
4872         name_len = strlen(symname) + 1;
4873         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
4874                 return -ENAMETOOLONG;
4875
4876         err = btrfs_check_metadata_free_space(root);
4877         if (err)
4878                 goto out_fail;
4879
4880         trans = btrfs_start_transaction(root, 1);
4881         btrfs_set_trans_block_group(trans, dir);
4882
4883         err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
4884         if (err) {
4885                 err = -ENOSPC;
4886                 goto out_unlock;
4887         }
4888
4889         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4890                                 dentry->d_name.len,
4891                                 dentry->d_parent->d_inode->i_ino, objectid,
4892                                 BTRFS_I(dir)->block_group, S_IFLNK|S_IRWXUGO,
4893                                 &index);
4894         err = PTR_ERR(inode);
4895         if (IS_ERR(inode))
4896                 goto out_unlock;
4897
4898         err = btrfs_init_inode_security(inode, dir);
4899         if (err) {
4900                 drop_inode = 1;
4901                 goto out_unlock;
4902         }
4903
4904         btrfs_set_trans_block_group(trans, inode);
4905         err = btrfs_add_nondir(trans, dentry, inode, 0, index);
4906         if (err)
4907                 drop_inode = 1;
4908         else {
4909                 inode->i_mapping->a_ops = &btrfs_aops;
4910                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
4911                 inode->i_fop = &btrfs_file_operations;
4912                 inode->i_op = &btrfs_file_inode_operations;
4913                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
4914         }
4915         dir->i_sb->s_dirt = 1;
4916         btrfs_update_inode_block_group(trans, inode);
4917         btrfs_update_inode_block_group(trans, dir);
4918         if (drop_inode)
4919                 goto out_unlock;
4920
4921         path = btrfs_alloc_path();
4922         BUG_ON(!path);
4923         key.objectid = inode->i_ino;
4924         key.offset = 0;
4925         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
4926         datasize = btrfs_file_extent_calc_inline_size(name_len);
4927         err = btrfs_insert_empty_item(trans, root, path, &key,
4928                                       datasize);
4929         if (err) {
4930                 drop_inode = 1;
4931                 goto out_unlock;
4932         }
4933         leaf = path->nodes[0];
4934         ei = btrfs_item_ptr(leaf, path->slots[0],
4935                             struct btrfs_file_extent_item);
4936         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
4937         btrfs_set_file_extent_type(leaf, ei,
4938                                    BTRFS_FILE_EXTENT_INLINE);
4939         btrfs_set_file_extent_encryption(leaf, ei, 0);
4940         btrfs_set_file_extent_compression(leaf, ei, 0);
4941         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
4942         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
4943
4944         ptr = btrfs_file_extent_inline_start(ei);
4945         write_extent_buffer(leaf, symname, ptr, name_len);
4946         btrfs_mark_buffer_dirty(leaf);
4947         btrfs_free_path(path);
4948
4949         inode->i_op = &btrfs_symlink_inode_operations;
4950         inode->i_mapping->a_ops = &btrfs_symlink_aops;
4951         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
4952         inode_set_bytes(inode, name_len);
4953         btrfs_i_size_write(inode, name_len - 1);
4954         err = btrfs_update_inode(trans, root, inode);
4955         if (err)
4956                 drop_inode = 1;
4957
4958 out_unlock:
4959         nr = trans->blocks_used;
4960         btrfs_end_transaction_throttle(trans, root);
4961 out_fail:
4962         if (drop_inode) {
4963                 inode_dec_link_count(inode);
4964                 iput(inode);
4965         }
4966         btrfs_btree_balance_dirty(root, nr);
4967         return err;
4968 }
4969
4970 static int prealloc_file_range(struct inode *inode, u64 start, u64 end,
4971                                u64 alloc_hint, int mode)
4972 {
4973         struct btrfs_trans_handle *trans;
4974         struct btrfs_root *root = BTRFS_I(inode)->root;
4975         struct btrfs_key ins;
4976         u64 alloc_size;
4977         u64 cur_offset = start;
4978         u64 num_bytes = end - start;
4979         int ret = 0;
4980
4981         trans = btrfs_join_transaction(root, 1);
4982         BUG_ON(!trans);
4983         btrfs_set_trans_block_group(trans, inode);
4984
4985         while (num_bytes > 0) {
4986                 alloc_size = min(num_bytes, root->fs_info->max_extent);
4987                 ret = btrfs_reserve_extent(trans, root, alloc_size,
4988                                            root->sectorsize, 0, alloc_hint,
4989                                            (u64)-1, &ins, 1);
4990                 if (ret) {
4991                         WARN_ON(1);
4992                         goto out;
4993                 }
4994                 ret = insert_reserved_file_extent(trans, inode,
4995                                                   cur_offset, ins.objectid,
4996                                                   ins.offset, ins.offset,
4997                                                   ins.offset, 0, 0, 0,
4998                                                   BTRFS_FILE_EXTENT_PREALLOC);
4999                 BUG_ON(ret);
5000                 num_bytes -= ins.offset;
5001                 cur_offset += ins.offset;
5002                 alloc_hint = ins.objectid + ins.offset;
5003         }
5004 out:
5005         if (cur_offset > start) {
5006                 inode->i_ctime = CURRENT_TIME;
5007                 btrfs_set_flag(inode, PREALLOC);
5008                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
5009                     cur_offset > i_size_read(inode))
5010                         btrfs_i_size_write(inode, cur_offset);
5011                 ret = btrfs_update_inode(trans, root, inode);
5012                 BUG_ON(ret);
5013         }
5014
5015         btrfs_end_transaction(trans, root);
5016         return ret;
5017 }
5018
5019 static long btrfs_fallocate(struct inode *inode, int mode,
5020                             loff_t offset, loff_t len)
5021 {
5022         u64 cur_offset;
5023         u64 last_byte;
5024         u64 alloc_start;
5025         u64 alloc_end;
5026         u64 alloc_hint = 0;
5027         u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
5028         struct extent_map *em;
5029         int ret;
5030
5031         alloc_start = offset & ~mask;
5032         alloc_end =  (offset + len + mask) & ~mask;
5033
5034         mutex_lock(&inode->i_mutex);
5035         if (alloc_start > inode->i_size) {
5036                 ret = btrfs_cont_expand(inode, alloc_start);
5037                 if (ret)
5038                         goto out;
5039         }
5040
5041         while (1) {
5042                 struct btrfs_ordered_extent *ordered;
5043                 lock_extent(&BTRFS_I(inode)->io_tree, alloc_start,
5044                             alloc_end - 1, GFP_NOFS);
5045                 ordered = btrfs_lookup_first_ordered_extent(inode,
5046                                                             alloc_end - 1);
5047                 if (ordered &&
5048                     ordered->file_offset + ordered->len > alloc_start &&
5049                     ordered->file_offset < alloc_end) {
5050                         btrfs_put_ordered_extent(ordered);
5051                         unlock_extent(&BTRFS_I(inode)->io_tree,
5052                                       alloc_start, alloc_end - 1, GFP_NOFS);
5053                         btrfs_wait_ordered_range(inode, alloc_start,
5054                                                  alloc_end - alloc_start);
5055                 } else {
5056                         if (ordered)
5057                                 btrfs_put_ordered_extent(ordered);
5058                         break;
5059                 }
5060         }
5061
5062         cur_offset = alloc_start;
5063         while (1) {
5064                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
5065                                       alloc_end - cur_offset, 0);
5066                 BUG_ON(IS_ERR(em) || !em);
5067                 last_byte = min(extent_map_end(em), alloc_end);
5068                 last_byte = (last_byte + mask) & ~mask;
5069                 if (em->block_start == EXTENT_MAP_HOLE) {
5070                         ret = prealloc_file_range(inode, cur_offset,
5071                                         last_byte, alloc_hint, mode);
5072                         if (ret < 0) {
5073                                 free_extent_map(em);
5074                                 break;
5075                         }
5076                 }
5077                 if (em->block_start <= EXTENT_MAP_LAST_BYTE)
5078                         alloc_hint = em->block_start;
5079                 free_extent_map(em);
5080
5081                 cur_offset = last_byte;
5082                 if (cur_offset >= alloc_end) {
5083                         ret = 0;
5084                         break;
5085                 }
5086         }
5087         unlock_extent(&BTRFS_I(inode)->io_tree, alloc_start, alloc_end - 1,
5088                       GFP_NOFS);
5089 out:
5090         mutex_unlock(&inode->i_mutex);
5091         return ret;
5092 }
5093
5094 static int btrfs_set_page_dirty(struct page *page)
5095 {
5096         return __set_page_dirty_nobuffers(page);
5097 }
5098
5099 static int btrfs_permission(struct inode *inode, int mask)
5100 {
5101         if (btrfs_test_flag(inode, READONLY) && (mask & MAY_WRITE))
5102                 return -EACCES;
5103         return generic_permission(inode, mask, btrfs_check_acl);
5104 }
5105
5106 static struct inode_operations btrfs_dir_inode_operations = {
5107         .getattr        = btrfs_getattr,
5108         .lookup         = btrfs_lookup,
5109         .create         = btrfs_create,
5110         .unlink         = btrfs_unlink,
5111         .link           = btrfs_link,
5112         .mkdir          = btrfs_mkdir,
5113         .rmdir          = btrfs_rmdir,
5114         .rename         = btrfs_rename,
5115         .symlink        = btrfs_symlink,
5116         .setattr        = btrfs_setattr,
5117         .mknod          = btrfs_mknod,
5118         .setxattr       = btrfs_setxattr,
5119         .getxattr       = btrfs_getxattr,
5120         .listxattr      = btrfs_listxattr,
5121         .removexattr    = btrfs_removexattr,
5122         .permission     = btrfs_permission,
5123 };
5124 static struct inode_operations btrfs_dir_ro_inode_operations = {
5125         .lookup         = btrfs_lookup,
5126         .permission     = btrfs_permission,
5127 };
5128 static struct file_operations btrfs_dir_file_operations = {
5129         .llseek         = generic_file_llseek,
5130         .read           = generic_read_dir,
5131         .readdir        = btrfs_real_readdir,
5132         .unlocked_ioctl = btrfs_ioctl,
5133 #ifdef CONFIG_COMPAT
5134         .compat_ioctl   = btrfs_ioctl,
5135 #endif
5136         .release        = btrfs_release_file,
5137         .fsync          = btrfs_sync_file,
5138 };
5139
5140 static struct extent_io_ops btrfs_extent_io_ops = {
5141         .fill_delalloc = run_delalloc_range,
5142         .submit_bio_hook = btrfs_submit_bio_hook,
5143         .merge_bio_hook = btrfs_merge_bio_hook,
5144         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
5145         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
5146         .writepage_start_hook = btrfs_writepage_start_hook,
5147         .readpage_io_failed_hook = btrfs_io_failed_hook,
5148         .set_bit_hook = btrfs_set_bit_hook,
5149         .clear_bit_hook = btrfs_clear_bit_hook,
5150 };
5151
5152 /*
5153  * btrfs doesn't support the bmap operation because swapfiles
5154  * use bmap to make a mapping of extents in the file.  They assume
5155  * these extents won't change over the life of the file and they
5156  * use the bmap result to do IO directly to the drive.
5157  *
5158  * the btrfs bmap call would return logical addresses that aren't
5159  * suitable for IO and they also will change frequently as COW
5160  * operations happen.  So, swapfile + btrfs == corruption.
5161  *
5162  * For now we're avoiding this by dropping bmap.
5163  */
5164 static struct address_space_operations btrfs_aops = {
5165         .readpage       = btrfs_readpage,
5166         .writepage      = btrfs_writepage,
5167         .writepages     = btrfs_writepages,
5168         .readpages      = btrfs_readpages,
5169         .sync_page      = block_sync_page,
5170         .direct_IO      = btrfs_direct_IO,
5171         .invalidatepage = btrfs_invalidatepage,
5172         .releasepage    = btrfs_releasepage,
5173         .set_page_dirty = btrfs_set_page_dirty,
5174 };
5175
5176 static struct address_space_operations btrfs_symlink_aops = {
5177         .readpage       = btrfs_readpage,
5178         .writepage      = btrfs_writepage,
5179         .invalidatepage = btrfs_invalidatepage,
5180         .releasepage    = btrfs_releasepage,
5181 };
5182
5183 static struct inode_operations btrfs_file_inode_operations = {
5184         .truncate       = btrfs_truncate,
5185         .getattr        = btrfs_getattr,
5186         .setattr        = btrfs_setattr,
5187         .setxattr       = btrfs_setxattr,
5188         .getxattr       = btrfs_getxattr,
5189         .listxattr      = btrfs_listxattr,
5190         .removexattr    = btrfs_removexattr,
5191         .permission     = btrfs_permission,
5192         .fallocate      = btrfs_fallocate,
5193         .fiemap         = btrfs_fiemap,
5194 };
5195 static struct inode_operations btrfs_special_inode_operations = {
5196         .getattr        = btrfs_getattr,
5197         .setattr        = btrfs_setattr,
5198         .permission     = btrfs_permission,
5199         .setxattr       = btrfs_setxattr,
5200         .getxattr       = btrfs_getxattr,
5201         .listxattr      = btrfs_listxattr,
5202         .removexattr    = btrfs_removexattr,
5203 };
5204 static struct inode_operations btrfs_symlink_inode_operations = {
5205         .readlink       = generic_readlink,
5206         .follow_link    = page_follow_link_light,
5207         .put_link       = page_put_link,
5208         .permission     = btrfs_permission,
5209         .setxattr       = btrfs_setxattr,
5210         .getxattr       = btrfs_getxattr,
5211         .listxattr      = btrfs_listxattr,
5212         .removexattr    = btrfs_removexattr,
5213 };