SAFE public projects git trees. - safe/jmp/linux-2.6/blob - fs/btrfs/file.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/fs.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/highmem.h>
  22 #include <linux/time.h>
  23 #include <linux/init.h>
  24 #include <linux/string.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/backing-dev.h>
  27 #include <linux/mpage.h>
  28 #include <linux/swap.h>
  29 #include <linux/writeback.h>
  30 #include <linux/statfs.h>
  31 #include <linux/compat.h>
  32 #include <linux/version.h>
  33 #include "ctree.h"
  34 #include "disk-io.h"
  35 #include "transaction.h"
  36 #include "btrfs_inode.h"
  37 #include "ioctl.h"
  38 #include "print-tree.h"
  39 #include "tree-log.h"
  40 #include "locking.h"
  41 #include "compat.h"
  42
  43
  44 /* simple helper to fault in pages and copy.  This should go away
  45  * and be replaced with calls into generic code.
  46  */
  47 static int noinline btrfs_copy_from_user(loff_t pos, int num_pages,
  48                                          int write_bytes,
  49                                          struct page **prepared_pages,
  50                                          const char __user * buf)
  51 {
  52         long page_fault = 0;
  53         int i;
  54         int offset = pos & (PAGE_CACHE_SIZE - 1);
  55
  56         for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
  57                 size_t count = min_t(size_t,
  58                                      PAGE_CACHE_SIZE - offset, write_bytes);
  59                 struct page *page = prepared_pages[i];
  60                 fault_in_pages_readable(buf, count);
  61
  62                 /* Copy data from userspace to the current page */
  63                 kmap(page);
  64                 page_fault = __copy_from_user(page_address(page) + offset,
  65                                               buf, count);
  66                 /* Flush processor's dcache for this page */
  67                 flush_dcache_page(page);
  68                 kunmap(page);
  69                 buf += count;
  70                 write_bytes -= count;
  71
  72                 if (page_fault)
  73                         break;
  74         }
  75         return page_fault ? -EFAULT : 0;
  76 }
  77
  78 /*
  79  * unlocks pages after btrfs_file_write is done with them
  80  */
  81 static void noinline btrfs_drop_pages(struct page **pages, size_t num_pages)
  82 {
  83         size_t i;
  84         for (i = 0; i < num_pages; i++) {
  85                 if (!pages[i])
  86                         break;
  87                 /* page checked is some magic around finding pages that
  88                  * have been modified without going through btrfs_set_page_dirty
  89                  * clear it here
  90                  */
  91                 ClearPageChecked(pages[i]);
  92                 unlock_page(pages[i]);
  93                 mark_page_accessed(pages[i]);
  94                 page_cache_release(pages[i]);
  95         }
  96 }
  97
  98 /*
  99  * after copy_from_user, pages need to be dirtied and we need to make
 100  * sure holes are created between the current EOF and the start of
 101  * any next extents (if required).
 102  *
 103  * this also makes the decision about creating an inline extent vs
 104  * doing real data extents, marking pages dirty and delalloc as required.
 105  */
 106 static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
 107                                    struct btrfs_root *root,
 108                                    struct file *file,
 109                                    struct page **pages,
 110                                    size_t num_pages,
 111                                    loff_t pos,
 112                                    size_t write_bytes)
 113 {
 114         int err = 0;
 115         int i;
 116         struct inode *inode = fdentry(file)->d_inode;
 117         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 118         u64 hint_byte;
 119         u64 num_bytes;
 120         u64 start_pos;
 121         u64 end_of_last_block;
 122         u64 end_pos = pos + write_bytes;
 123         loff_t isize = i_size_read(inode);
 124
 125         start_pos = pos & ~((u64)root->sectorsize - 1);
 126         num_bytes = (write_bytes + pos - start_pos +
 127                     root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
 128
 129         end_of_last_block = start_pos + num_bytes - 1;
 130
 131         lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 132         trans = btrfs_join_transaction(root, 1);
 133         if (!trans) {
 134                 err = -ENOMEM;
 135                 goto out_unlock;
 136         }
 137         btrfs_set_trans_block_group(trans, inode);
 138         hint_byte = 0;
 139
 140         if ((end_of_last_block & 4095) == 0) {
 141                 printk("strange end of last %Lu %zu %Lu\n", start_pos, write_bytes, end_of_last_block);
 142         }
 143         set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 144
 145         /* check for reserved extents on each page, we don't want
 146          * to reset the delalloc bit on things that already have
 147          * extents reserved.
 148          */
 149         btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
 150         for (i = 0; i < num_pages; i++) {
 151                 struct page *p = pages[i];
 152                 SetPageUptodate(p);
 153                 ClearPageChecked(p);
 154                 set_page_dirty(p);
 155         }
 156         if (end_pos > isize) {
 157                 i_size_write(inode, end_pos);
 158                 btrfs_update_inode(trans, root, inode);
 159         }
 160         err = btrfs_end_transaction(trans, root);
 161 out_unlock:
 162         unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 163         return err;
 164 }
 165
 166 /*
 167  * this drops all the extents in the cache that intersect the range
 168  * [start, end].  Existing extents are split as required.
 169  */
 170 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
 171                             int skip_pinned)
 172 {
 173         struct extent_map *em;
 174         struct extent_map *split = NULL;
 175         struct extent_map *split2 = NULL;
 176         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 177         u64 len = end - start + 1;
 178         int ret;
 179         int testend = 1;
 180         unsigned long flags;
 181         int compressed = 0;
 182
 183         WARN_ON(end < start);
 184         if (end == (u64)-1) {
 185                 len = (u64)-1;
 186                 testend = 0;
 187         }
 188         while(1) {
 189                 if (!split)
 190                         split = alloc_extent_map(GFP_NOFS);
 191                 if (!split2)
 192                         split2 = alloc_extent_map(GFP_NOFS);
 193
 194                 spin_lock(&em_tree->lock);
 195                 em = lookup_extent_mapping(em_tree, start, len);
 196                 if (!em) {
 197                         spin_unlock(&em_tree->lock);
 198                         break;
 199                 }
 200                 flags = em->flags;
 201                 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
 202                         spin_unlock(&em_tree->lock);
 203                         if (em->start <= start &&
 204                             (!testend || em->start + em->len >= start + len)) {
 205                                 free_extent_map(em);
 206                                 break;
 207                         }
 208                         if (start < em->start) {
 209                                 len = em->start - start;
 210                         } else {
 211                                 len = start + len - (em->start + em->len);
 212                                 start = em->start + em->len;
 213                         }
 214                         free_extent_map(em);
 215                         continue;
 216                 }
 217                 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 218                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
 219                 remove_extent_mapping(em_tree, em);
 220
 221                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
 222                     em->start < start) {
 223                         split->start = em->start;
 224                         split->len = start - em->start;
 225                         split->orig_start = em->orig_start;
 226                         split->block_start = em->block_start;
 227
 228                         if (compressed)
 229                                 split->block_len = em->block_len;
 230                         else
 231                                 split->block_len = split->len;
 232
 233                         split->bdev = em->bdev;
 234                         split->flags = flags;
 235                         ret = add_extent_mapping(em_tree, split);
 236                         BUG_ON(ret);
 237                         free_extent_map(split);
 238                         split = split2;
 239                         split2 = NULL;
 240                 }
 241                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
 242                     testend && em->start + em->len > start + len) {
 243                         u64 diff = start + len - em->start;
 244
 245                         split->start = start + len;
 246                         split->len = em->start + em->len - (start + len);
 247                         split->orig_start = em->orig_start;
 248                         split->bdev = em->bdev;
 249                         split->flags = flags;
 250
 251                         if (compressed) {
 252                                 split->block_len = em->block_len;
 253                                 split->block_start = em->block_start;
 254                         } else {
 255                                 split->block_len = split->len;
 256                                 split->block_start = em->block_start + diff;
 257                         }
 258
 259                         ret = add_extent_mapping(em_tree, split);
 260                         BUG_ON(ret);
 261                         free_extent_map(split);
 262                         split = NULL;
 263                 }
 264                 spin_unlock(&em_tree->lock);
 265
 266                 /* once for us */
 267                 free_extent_map(em);
 268                 /* once for the tree*/
 269                 free_extent_map(em);
 270         }
 271         if (split)
 272                 free_extent_map(split);
 273         if (split2)
 274                 free_extent_map(split2);
 275         return 0;
 276 }
 277
 278 int btrfs_check_file(struct btrfs_root *root, struct inode *inode)
 279 {
 280         return 0;
 281 #if 0
 282         struct btrfs_path *path;
 283         struct btrfs_key found_key;
 284         struct extent_buffer *leaf;
 285         struct btrfs_file_extent_item *extent;
 286         u64 last_offset = 0;
 287         int nritems;
 288         int slot;
 289         int found_type;
 290         int ret;
 291         int err = 0;
 292         u64 extent_end = 0;
 293
 294         path = btrfs_alloc_path();
 295         ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,
 296                                        last_offset, 0);
 297         while(1) {
 298                 nritems = btrfs_header_nritems(path->nodes[0]);
 299                 if (path->slots[0] >= nritems) {
 300                         ret = btrfs_next_leaf(root, path);
 301                         if (ret)
 302                                 goto out;
 303                         nritems = btrfs_header_nritems(path->nodes[0]);
 304                 }
 305                 slot = path->slots[0];
 306                 leaf = path->nodes[0];
 307                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
 308                 if (found_key.objectid != inode->i_ino)
 309                         break;
 310                 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
 311                         goto out;
 312
 313                 if (found_key.offset < last_offset) {
 314                         WARN_ON(1);
 315                         btrfs_print_leaf(root, leaf);
 316                         printk("inode %lu found offset %Lu expected %Lu\n",
 317                                inode->i_ino, found_key.offset, last_offset);
 318                         err = 1;
 319                         goto out;
 320                 }
 321                 extent = btrfs_item_ptr(leaf, slot,
 322                                         struct btrfs_file_extent_item);
 323                 found_type = btrfs_file_extent_type(leaf, extent);
 324                 if (found_type == BTRFS_FILE_EXTENT_REG) {
 325                         extent_end = found_key.offset +
 326                              btrfs_file_extent_num_bytes(leaf, extent);
 327                 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 328                         struct btrfs_item *item;
 329                         item = btrfs_item_nr(leaf, slot);
 330                         extent_end = found_key.offset +
 331                              btrfs_file_extent_inline_len(leaf, extent);
 332                         extent_end = (extent_end + root->sectorsize - 1) &
 333                                 ~((u64)root->sectorsize -1 );
 334                 }
 335                 last_offset = extent_end;
 336                 path->slots[0]++;
 337         }
 338         if (0 && last_offset < inode->i_size) {
 339                 WARN_ON(1);
 340                 btrfs_print_leaf(root, leaf);
 341                 printk("inode %lu found offset %Lu size %Lu\n", inode->i_ino,
 342                        last_offset, inode->i_size);
 343                 err = 1;
 344
 345         }
 346 out:
 347         btrfs_free_path(path);
 348         return err;
 349 #endif
 350 }
 351
 352 /*
 353  * this is very complex, but the basic idea is to drop all extents
 354  * in the range start - end.  hint_block is filled in with a block number
 355  * that would be a good hint to the block allocator for this file.
 356  *
 357  * If an extent intersects the range but is not entirely inside the range
 358  * it is either truncated or split.  Anything entirely inside the range
 359  * is deleted from the tree.
 360  *
 361  * inline_limit is used to tell this code which offsets in the file to keep
 362  * if they contain inline extents.
 363  */
 364 int noinline btrfs_drop_extents(struct btrfs_trans_handle *trans,
 365                        struct btrfs_root *root, struct inode *inode,
 366                        u64 start, u64 end, u64 inline_limit, u64 *hint_byte)
 367 {
 368         u64 extent_end = 0;
 369         u64 locked_end = end;
 370         u64 search_start = start;
 371         u64 leaf_start;
 372         u64 ram_bytes = 0;
 373         u64 orig_parent = 0;
 374         u64 disk_bytenr = 0;
 375         u8 compression;
 376         u8 encryption;
 377         u16 other_encoding = 0;
 378         u64 root_gen;
 379         u64 root_owner;
 380         struct extent_buffer *leaf;
 381         struct btrfs_file_extent_item *extent;
 382         struct btrfs_path *path;
 383         struct btrfs_key key;
 384         struct btrfs_file_extent_item old;
 385         int keep;
 386         int slot;
 387         int bookend;
 388         int found_type = 0;
 389         int found_extent;
 390         int found_inline;
 391         int recow;
 392         int ret;
 393
 394         inline_limit = 0;
 395         btrfs_drop_extent_cache(inode, start, end - 1, 0);
 396
 397         path = btrfs_alloc_path();
 398         if (!path)
 399                 return -ENOMEM;
 400         while(1) {
 401                 recow = 0;
 402                 btrfs_release_path(root, path);
 403                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
 404                                                search_start, -1);
 405                 if (ret < 0)
 406                         goto out;
 407                 if (ret > 0) {
 408                         if (path->slots[0] == 0) {
 409                                 ret = 0;
 410                                 goto out;
 411                         }
 412                         path->slots[0]--;
 413                 }
 414 next_slot:
 415                 keep = 0;
 416                 bookend = 0;
 417                 found_extent = 0;
 418                 found_inline = 0;
 419                 leaf_start = 0;
 420                 root_gen = 0;
 421                 root_owner = 0;
 422                 compression = 0;
 423                 encryption = 0;
 424                 extent = NULL;
 425                 leaf = path->nodes[0];
 426                 slot = path->slots[0];
 427                 ret = 0;
 428                 btrfs_item_key_to_cpu(leaf, &key, slot);
 429                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
 430                     key.offset >= end) {
 431                         goto out;
 432                 }
 433                 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
 434                     key.objectid != inode->i_ino) {
 435                         goto out;
 436                 }
 437                 if (recow) {
 438                         search_start = key.offset;
 439                         continue;
 440                 }
 441                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
 442                         extent = btrfs_item_ptr(leaf, slot,
 443                                                 struct btrfs_file_extent_item);
 444                         found_type = btrfs_file_extent_type(leaf, extent);
 445                         compression = btrfs_file_extent_compression(leaf,
 446                                                                     extent);
 447                         encryption = btrfs_file_extent_encryption(leaf,
 448                                                                   extent);
 449                         other_encoding = btrfs_file_extent_other_encoding(leaf,
 450                                                                   extent);
 451                         if (found_type == BTRFS_FILE_EXTENT_REG ||
 452                             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
 453                                 extent_end =
 454                                      btrfs_file_extent_disk_bytenr(leaf,
 455                                                                    extent);
 456                                 if (extent_end)
 457                                         *hint_byte = extent_end;
 458
 459                                 extent_end = key.offset +
 460                                      btrfs_file_extent_num_bytes(leaf, extent);
 461                                 ram_bytes = btrfs_file_extent_ram_bytes(leaf,
 462                                                                 extent);
 463                                 found_extent = 1;
 464                         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 465                                 found_inline = 1;
 466                                 extent_end = key.offset +
 467                                      btrfs_file_extent_inline_len(leaf, extent);
 468                         }
 469                 } else {
 470                         extent_end = search_start;
 471                 }
 472
 473                 /* we found nothing we can drop */
 474                 if ((!found_extent && !found_inline) ||
 475                     search_start >= extent_end) {
 476                         int nextret;
 477                         u32 nritems;
 478                         nritems = btrfs_header_nritems(leaf);
 479                         if (slot >= nritems - 1) {
 480                                 nextret = btrfs_next_leaf(root, path);
 481                                 if (nextret)
 482                                         goto out;
 483                                 recow = 1;
 484                         } else {
 485                                 path->slots[0]++;
 486                         }
 487                         goto next_slot;
 488                 }
 489
 490                 if (end <= extent_end && start >= key.offset && found_inline)
 491                         *hint_byte = EXTENT_MAP_INLINE;
 492
 493                 if (found_extent) {
 494                         read_extent_buffer(leaf, &old, (unsigned long)extent,
 495                                            sizeof(old));
 496                         root_gen = btrfs_header_generation(leaf);
 497                         root_owner = btrfs_header_owner(leaf);
 498                         leaf_start = leaf->start;
 499                 }
 500
 501                 if (end < extent_end && end >= key.offset) {
 502                         bookend = 1;
 503                         if (found_inline && start <= key.offset)
 504                                 keep = 1;
 505                 }
 506
 507                 if (bookend && found_extent) {
 508                         if (locked_end < extent_end) {
 509                                 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
 510                                                 locked_end, extent_end - 1,
 511                                                 GFP_NOFS);
 512                                 if (!ret) {
 513                                         btrfs_release_path(root, path);
 514                                         lock_extent(&BTRFS_I(inode)->io_tree,
 515                                                 locked_end, extent_end - 1,
 516                                                 GFP_NOFS);
 517                                         locked_end = extent_end;
 518                                         continue;
 519                                 }
 520                                 locked_end = extent_end;
 521                         }
 522                         orig_parent = path->nodes[0]->start;
 523                         disk_bytenr = le64_to_cpu(old.disk_bytenr);
 524                         if (disk_bytenr != 0) {
 525                                 ret = btrfs_inc_extent_ref(trans, root,
 526                                            disk_bytenr,
 527                                            le64_to_cpu(old.disk_num_bytes),
 528                                            orig_parent, root->root_key.objectid,
 529                                            trans->transid, inode->i_ino);
 530                                 BUG_ON(ret);
 531                         }
 532                 }
 533
 534                 if (found_inline) {
 535                         u64 mask = root->sectorsize - 1;
 536                         search_start = (extent_end + mask) & ~mask;
 537                 } else
 538                         search_start = extent_end;
 539
 540                 /* truncate existing extent */
 541                 if (start > key.offset) {
 542                         u64 new_num;
 543                         u64 old_num;
 544                         keep = 1;
 545                         WARN_ON(start & (root->sectorsize - 1));
 546                         if (found_extent) {
 547                                 new_num = start - key.offset;
 548                                 old_num = btrfs_file_extent_num_bytes(leaf,
 549                                                                       extent);
 550                                 *hint_byte =
 551                                         btrfs_file_extent_disk_bytenr(leaf,
 552                                                                       extent);
 553                                 if (btrfs_file_extent_disk_bytenr(leaf,
 554                                                                   extent)) {
 555                                         inode_sub_bytes(inode, old_num -
 556                                                         new_num);
 557                                 }
 558                                 if (!compression && !encryption) {
 559                                         btrfs_set_file_extent_ram_bytes(leaf,
 560                                                         extent, new_num);
 561                                 }
 562                                 btrfs_set_file_extent_num_bytes(leaf,
 563                                                         extent, new_num);
 564                                 btrfs_mark_buffer_dirty(leaf);
 565                         } else if (key.offset < inline_limit &&
 566                                    (end > extent_end) &&
 567                                    (inline_limit < extent_end)) {
 568                                 u32 new_size;
 569                                 new_size = btrfs_file_extent_calc_inline_size(
 570                                                    inline_limit - key.offset);
 571                                 inode_sub_bytes(inode, extent_end -
 572                                                 inline_limit);
 573                                 btrfs_set_file_extent_ram_bytes(leaf, extent,
 574                                                         new_size);
 575                                 if (!compression && !encryption) {
 576                                         btrfs_truncate_item(trans, root, path,
 577                                                             new_size, 1);
 578                                 }
 579                         }
 580                 }
 581                 /* delete the entire extent */
 582                 if (!keep) {
 583                         if (found_inline)
 584                                 inode_sub_bytes(inode, extent_end -
 585                                                 key.offset);
 586                         ret = btrfs_del_item(trans, root, path);
 587                         /* TODO update progress marker and return */
 588                         BUG_ON(ret);
 589                         extent = NULL;
 590                         btrfs_release_path(root, path);
 591                         /* the extent will be freed later */
 592                 }
 593                 if (bookend && found_inline && start <= key.offset) {
 594                         u32 new_size;
 595                         new_size = btrfs_file_extent_calc_inline_size(
 596                                                    extent_end - end);
 597                         inode_sub_bytes(inode, end - key.offset);
 598                         btrfs_set_file_extent_ram_bytes(leaf, extent,
 599                                                         new_size);
 600                         if (!compression && !encryption)
 601                                 ret = btrfs_truncate_item(trans, root, path,
 602                                                           new_size, 0);
 603                         BUG_ON(ret);
 604                 }
 605                 /* create bookend, splitting the extent in two */
 606                 if (bookend && found_extent) {
 607                         struct btrfs_key ins;
 608                         ins.objectid = inode->i_ino;
 609                         ins.offset = end;
 610                         btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
 611
 612                         btrfs_release_path(root, path);
 613                         ret = btrfs_insert_empty_item(trans, root, path, &ins,
 614                                                       sizeof(*extent));
 615                         BUG_ON(ret);
 616
 617                         leaf = path->nodes[0];
 618                         extent = btrfs_item_ptr(leaf, path->slots[0],
 619                                                 struct btrfs_file_extent_item);
 620                         write_extent_buffer(leaf, &old,
 621                                             (unsigned long)extent, sizeof(old));
 622
 623                         btrfs_set_file_extent_compression(leaf, extent,
 624                                                           compression);
 625                         btrfs_set_file_extent_encryption(leaf, extent,
 626                                                          encryption);
 627                         btrfs_set_file_extent_other_encoding(leaf, extent,
 628                                                              other_encoding);
 629                         btrfs_set_file_extent_offset(leaf, extent,
 630                                     le64_to_cpu(old.offset) + end - key.offset);
 631                         WARN_ON(le64_to_cpu(old.num_bytes) <
 632                                 (extent_end - end));
 633                         btrfs_set_file_extent_num_bytes(leaf, extent,
 634                                                         extent_end - end);
 635
 636                         /*
 637                          * set the ram bytes to the size of the full extent
 638                          * before splitting.  This is a worst case flag,
 639                          * but its the best we can do because we don't know
 640                          * how splitting affects compression
 641                          */
 642                         btrfs_set_file_extent_ram_bytes(leaf, extent,
 643                                                         ram_bytes);
 644                         btrfs_set_file_extent_type(leaf, extent, found_type);
 645
 646                         btrfs_mark_buffer_dirty(path->nodes[0]);
 647
 648                         if (disk_bytenr != 0) {
 649                                 ret = btrfs_update_extent_ref(trans, root,
 650                                                 disk_bytenr, orig_parent,
 651                                                 leaf->start,
 652                                                 root->root_key.objectid,
 653                                                 trans->transid, ins.objectid);
 654
 655                                 BUG_ON(ret);
 656                         }
 657                         btrfs_release_path(root, path);
 658                         if (disk_bytenr != 0) {
 659                                 inode_add_bytes(inode, extent_end - end);
 660                         }
 661                 }
 662
 663                 if (found_extent && !keep) {
 664                         u64 disk_bytenr = le64_to_cpu(old.disk_bytenr);
 665
 666                         if (disk_bytenr != 0) {
 667                                 inode_sub_bytes(inode,
 668                                                 le64_to_cpu(old.num_bytes));
 669                                 ret = btrfs_free_extent(trans, root,
 670                                                 disk_bytenr,
 671                                                 le64_to_cpu(old.disk_num_bytes),
 672                                                 leaf_start, root_owner,
 673                                                 root_gen, key.objectid, 0);
 674                                 BUG_ON(ret);
 675                                 *hint_byte = disk_bytenr;
 676                         }
 677                 }
 678
 679                 if (search_start >= end) {
 680                         ret = 0;
 681                         goto out;
 682                 }
 683         }
 684 out:
 685         btrfs_free_path(path);
 686         if (locked_end > end) {
 687                 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
 688                               GFP_NOFS);
 689         }
 690         btrfs_check_file(root, inode);
 691         return ret;
 692 }
 693
 694 static int extent_mergeable(struct extent_buffer *leaf, int slot,
 695                             u64 objectid, u64 bytenr, u64 *start, u64 *end)
 696 {
 697         struct btrfs_file_extent_item *fi;
 698         struct btrfs_key key;
 699         u64 extent_end;
 700
 701         if (slot < 0 || slot >= btrfs_header_nritems(leaf))
 702                 return 0;
 703
 704         btrfs_item_key_to_cpu(leaf, &key, slot);
 705         if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
 706                 return 0;
 707
 708         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
 709         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
 710             btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
 711             btrfs_file_extent_compression(leaf, fi) ||
 712             btrfs_file_extent_encryption(leaf, fi) ||
 713             btrfs_file_extent_other_encoding(leaf, fi))
 714                 return 0;
 715
 716         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
 717         if ((*start && *start != key.offset) || (*end && *end != extent_end))
 718                 return 0;
 719
 720         *start = key.offset;
 721         *end = extent_end;
 722         return 1;
 723 }
 724
 725 /*
 726  * Mark extent in the range start - end as written.
 727  *
 728  * This changes extent type from 'pre-allocated' to 'regular'. If only
 729  * part of extent is marked as written, the extent will be split into
 730  * two or three.
 731  */
 732 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
 733                               struct btrfs_root *root,
 734                               struct inode *inode, u64 start, u64 end)
 735 {
 736         struct extent_buffer *leaf;
 737         struct btrfs_path *path;
 738         struct btrfs_file_extent_item *fi;
 739         struct btrfs_key key;
 740         u64 bytenr;
 741         u64 num_bytes;
 742         u64 extent_end;
 743         u64 extent_offset;
 744         u64 other_start;
 745         u64 other_end;
 746         u64 split = start;
 747         u64 locked_end = end;
 748         int extent_type;
 749         int split_end = 1;
 750         int ret;
 751
 752         btrfs_drop_extent_cache(inode, start, end - 1, 0);
 753
 754         path = btrfs_alloc_path();
 755         BUG_ON(!path);
 756 again:
 757         key.objectid = inode->i_ino;
 758         key.type = BTRFS_EXTENT_DATA_KEY;
 759         if (split == start)
 760                 key.offset = split;
 761         else
 762                 key.offset = split - 1;
 763
 764         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 765         if (ret > 0 && path->slots[0] > 0)
 766                 path->slots[0]--;
 767
 768         leaf = path->nodes[0];
 769         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 770         BUG_ON(key.objectid != inode->i_ino ||
 771                key.type != BTRFS_EXTENT_DATA_KEY);
 772         fi = btrfs_item_ptr(leaf, path->slots[0],
 773                             struct btrfs_file_extent_item);
 774         extent_type = btrfs_file_extent_type(leaf, fi);
 775         BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC);
 776         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
 777         BUG_ON(key.offset > start || extent_end < end);
 778
 779         bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
 780         num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
 781         extent_offset = btrfs_file_extent_offset(leaf, fi);
 782
 783         if (key.offset == start)
 784                 split = end;
 785
 786         if (key.offset == start && extent_end == end) {
 787                 int del_nr = 0;
 788                 int del_slot = 0;
 789                 u64 leaf_owner = btrfs_header_owner(leaf);
 790                 u64 leaf_gen = btrfs_header_generation(leaf);
 791                 other_start = end;
 792                 other_end = 0;
 793                 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
 794                                      bytenr, &other_start, &other_end)) {
 795                         extent_end = other_end;
 796                         del_slot = path->slots[0] + 1;
 797                         del_nr++;
 798                         ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
 799                                                 leaf->start, leaf_owner,
 800                                                 leaf_gen, inode->i_ino, 0);
 801                         BUG_ON(ret);
 802                 }
 803                 other_start = 0;
 804                 other_end = start;
 805                 if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino,
 806                                      bytenr, &other_start, &other_end)) {
 807                         key.offset = other_start;
 808                         del_slot = path->slots[0];
 809                         del_nr++;
 810                         ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
 811                                                 leaf->start, leaf_owner,
 812                                                 leaf_gen, inode->i_ino, 0);
 813                         BUG_ON(ret);
 814                 }
 815                 split_end = 0;
 816                 if (del_nr == 0) {
 817                         btrfs_set_file_extent_type(leaf, fi,
 818                                                    BTRFS_FILE_EXTENT_REG);
 819                         goto done;
 820                 }
 821
 822                 fi = btrfs_item_ptr(leaf, del_slot - 1,
 823                                     struct btrfs_file_extent_item);
 824                 btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
 825                 btrfs_set_file_extent_num_bytes(leaf, fi,
 826                                                 extent_end - key.offset);
 827                 btrfs_mark_buffer_dirty(leaf);
 828
 829                 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
 830                 BUG_ON(ret);
 831                 goto done;
 832         } else if (split == start) {
 833                 if (locked_end < extent_end) {
 834                         ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
 835                                         locked_end, extent_end - 1, GFP_NOFS);
 836                         if (!ret) {
 837                                 btrfs_release_path(root, path);
 838                                 lock_extent(&BTRFS_I(inode)->io_tree,
 839                                         locked_end, extent_end - 1, GFP_NOFS);
 840                                 locked_end = extent_end;
 841                                 goto again;
 842                         }
 843                         locked_end = extent_end;
 844                 }
 845                 btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset);
 846                 extent_offset += split - key.offset;
 847         } else  {
 848                 BUG_ON(key.offset != start);
 849                 btrfs_set_file_extent_offset(leaf, fi, extent_offset +
 850                                              split - key.offset);
 851                 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split);
 852                 key.offset = split;
 853                 btrfs_set_item_key_safe(trans, root, path, &key);
 854                 extent_end = split;
 855         }
 856
 857         if (extent_end == end) {
 858                 split_end = 0;
 859                 extent_type = BTRFS_FILE_EXTENT_REG;
 860         }
 861         if (extent_end == end && split == start) {
 862                 other_start = end;
 863                 other_end = 0;
 864                 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
 865                                      bytenr, &other_start, &other_end)) {
 866                         path->slots[0]++;
 867                         fi = btrfs_item_ptr(leaf, path->slots[0],
 868                                             struct btrfs_file_extent_item);
 869                         key.offset = split;
 870                         btrfs_set_item_key_safe(trans, root, path, &key);
 871                         btrfs_set_file_extent_offset(leaf, fi, extent_offset);
 872                         btrfs_set_file_extent_num_bytes(leaf, fi,
 873                                                         other_end - split);
 874                         goto done;
 875                 }
 876         }
 877         if (extent_end == end && split == end) {
 878                 other_start = 0;
 879                 other_end = start;
 880                 if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino,
 881                                      bytenr, &other_start, &other_end)) {
 882                         path->slots[0]--;
 883                         fi = btrfs_item_ptr(leaf, path->slots[0],
 884                                             struct btrfs_file_extent_item);
 885                         btrfs_set_file_extent_num_bytes(leaf, fi, extent_end -
 886                                                         other_start);
 887                         goto done;
 888                 }
 889         }
 890
 891         btrfs_mark_buffer_dirty(leaf);
 892         btrfs_release_path(root, path);
 893
 894         key.offset = start;
 895         ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi));
 896         BUG_ON(ret);
 897
 898         leaf = path->nodes[0];
 899         fi = btrfs_item_ptr(leaf, path->slots[0],
 900                             struct btrfs_file_extent_item);
 901         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
 902         btrfs_set_file_extent_type(leaf, fi, extent_type);
 903         btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr);
 904         btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
 905         btrfs_set_file_extent_offset(leaf, fi, extent_offset);
 906         btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset);
 907         btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
 908         btrfs_set_file_extent_compression(leaf, fi, 0);
 909         btrfs_set_file_extent_encryption(leaf, fi, 0);
 910         btrfs_set_file_extent_other_encoding(leaf, fi, 0);
 911
 912         ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes,
 913                                    leaf->start, root->root_key.objectid,
 914                                    trans->transid, inode->i_ino);
 915         BUG_ON(ret);
 916 done:
 917         btrfs_mark_buffer_dirty(leaf);
 918         btrfs_release_path(root, path);
 919         if (split_end && split == start) {
 920                 split = end;
 921                 goto again;
 922         }
 923         if (locked_end > end) {
 924                 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
 925                               GFP_NOFS);
 926         }
 927         btrfs_free_path(path);
 928         return 0;
 929 }
 930
 931 /*
 932  * this gets pages into the page cache and locks them down, it also properly
 933  * waits for data=ordered extents to finish before allowing the pages to be
 934  * modified.
 935  */
 936 static int noinline prepare_pages(struct btrfs_root *root, struct file *file,
 937                          struct page **pages, size_t num_pages,
 938                          loff_t pos, unsigned long first_index,
 939                          unsigned long last_index, size_t write_bytes)
 940 {
 941         int i;
 942         unsigned long index = pos >> PAGE_CACHE_SHIFT;
 943         struct inode *inode = fdentry(file)->d_inode;
 944         int err = 0;
 945         u64 start_pos;
 946         u64 last_pos;
 947
 948         start_pos = pos & ~((u64)root->sectorsize - 1);
 949         last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
 950
 951         if (start_pos > inode->i_size) {
 952                 err = btrfs_cont_expand(inode, start_pos);
 953                 if (err)
 954                         return err;
 955         }
 956
 957         memset(pages, 0, num_pages * sizeof(struct page *));
 958 again:
 959         for (i = 0; i < num_pages; i++) {
 960                 pages[i] = grab_cache_page(inode->i_mapping, index + i);
 961                 if (!pages[i]) {
 962                         err = -ENOMEM;
 963                         BUG_ON(1);
 964                 }
 965                 wait_on_page_writeback(pages[i]);
 966         }
 967         if (start_pos < inode->i_size) {
 968                 struct btrfs_ordered_extent *ordered;
 969                 lock_extent(&BTRFS_I(inode)->io_tree,
 970                             start_pos, last_pos - 1, GFP_NOFS);
 971                 ordered = btrfs_lookup_first_ordered_extent(inode, last_pos -1);
 972                 if (ordered &&
 973                     ordered->file_offset + ordered->len > start_pos &&
 974                     ordered->file_offset < last_pos) {
 975                         btrfs_put_ordered_extent(ordered);
 976                         unlock_extent(&BTRFS_I(inode)->io_tree,
 977                                       start_pos, last_pos - 1, GFP_NOFS);
 978                         for (i = 0; i < num_pages; i++) {
 979                                 unlock_page(pages[i]);
 980                                 page_cache_release(pages[i]);
 981                         }
 982                         btrfs_wait_ordered_range(inode, start_pos,
 983                                                  last_pos - start_pos);
 984                         goto again;
 985                 }
 986                 if (ordered)
 987                         btrfs_put_ordered_extent(ordered);
 988
 989                 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
 990                                   last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
 991                                   GFP_NOFS);
 992                 unlock_extent(&BTRFS_I(inode)->io_tree,
 993                               start_pos, last_pos - 1, GFP_NOFS);
 994         }
 995         for (i = 0; i < num_pages; i++) {
 996                 clear_page_dirty_for_io(pages[i]);
 997                 set_page_extent_mapped(pages[i]);
 998                 WARN_ON(!PageLocked(pages[i]));
 999         }
1000         return 0;
1001 }
1002
1003 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
1004                                 size_t count, loff_t *ppos)
1005 {
1006         loff_t pos;
1007         loff_t start_pos;
1008         ssize_t num_written = 0;
1009         ssize_t err = 0;
1010         int ret = 0;
1011         struct inode *inode = fdentry(file)->d_inode;
1012         struct btrfs_root *root = BTRFS_I(inode)->root;
1013         struct page **pages = NULL;
1014         int nrptrs;
1015         struct page *pinned[2];
1016         unsigned long first_index;
1017         unsigned long last_index;
1018         int will_write;
1019
1020         will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) ||
1021                       (file->f_flags & O_DIRECT));
1022
1023         nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
1024                      PAGE_CACHE_SIZE / (sizeof(struct page *)));
1025         pinned[0] = NULL;
1026         pinned[1] = NULL;
1027
1028         pos = *ppos;
1029         start_pos = pos;
1030
1031         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
1032         current->backing_dev_info = inode->i_mapping->backing_dev_info;
1033         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1034         if (err)
1035                 goto out_nolock;
1036         if (count == 0)
1037                 goto out_nolock;
1038
1039         err = file_remove_suid(file);
1040         if (err)
1041                 goto out_nolock;
1042         file_update_time(file);
1043
1044         pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1045
1046         mutex_lock(&inode->i_mutex);
1047         first_index = pos >> PAGE_CACHE_SHIFT;
1048         last_index = (pos + count) >> PAGE_CACHE_SHIFT;
1049
1050         /*
1051          * if this is a nodatasum mount, force summing off for the inode
1052          * all the time.  That way a later mount with summing on won't
1053          * get confused
1054          */
1055         if (btrfs_test_opt(root, NODATASUM))
1056                 btrfs_set_flag(inode, NODATASUM);
1057
1058         /*
1059          * there are lots of better ways to do this, but this code
1060          * makes sure the first and last page in the file range are
1061          * up to date and ready for cow
1062          */
1063         if ((pos & (PAGE_CACHE_SIZE - 1))) {
1064                 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
1065                 if (!PageUptodate(pinned[0])) {
1066                         ret = btrfs_readpage(NULL, pinned[0]);
1067                         BUG_ON(ret);
1068                         wait_on_page_locked(pinned[0]);
1069                 } else {
1070                         unlock_page(pinned[0]);
1071                 }
1072         }
1073         if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
1074                 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
1075                 if (!PageUptodate(pinned[1])) {
1076                         ret = btrfs_readpage(NULL, pinned[1]);
1077                         BUG_ON(ret);
1078                         wait_on_page_locked(pinned[1]);
1079                 } else {
1080                         unlock_page(pinned[1]);
1081                 }
1082         }
1083
1084         while(count > 0) {
1085                 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1086                 size_t write_bytes = min(count, nrptrs *
1087                                         (size_t)PAGE_CACHE_SIZE -
1088                                          offset);
1089                 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
1090                                         PAGE_CACHE_SHIFT;
1091
1092                 WARN_ON(num_pages > nrptrs);
1093                 memset(pages, 0, sizeof(pages));
1094
1095                 ret = btrfs_check_free_space(root, write_bytes, 0);
1096                 if (ret)
1097                         goto out;
1098
1099                 ret = prepare_pages(root, file, pages, num_pages,
1100                                     pos, first_index, last_index,
1101                                     write_bytes);
1102                 if (ret)
1103                         goto out;
1104
1105                 ret = btrfs_copy_from_user(pos, num_pages,
1106                                            write_bytes, pages, buf);
1107                 if (ret) {
1108                         btrfs_drop_pages(pages, num_pages);
1109                         goto out;
1110                 }
1111
1112                 ret = dirty_and_release_pages(NULL, root, file, pages,
1113                                               num_pages, pos, write_bytes);
1114                 btrfs_drop_pages(pages, num_pages);
1115                 if (ret)
1116                         goto out;
1117
1118                 if (will_write) {
1119                         btrfs_fdatawrite_range(inode->i_mapping, pos,
1120                                                pos + write_bytes - 1,
1121                                                WB_SYNC_NONE);
1122                 } else {
1123                         balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1124                                                            num_pages);
1125                         if (num_pages <
1126                             (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1127                                 btrfs_btree_balance_dirty(root, 1);
1128                         btrfs_throttle(root);
1129                 }
1130
1131                 buf += write_bytes;
1132                 count -= write_bytes;
1133                 pos += write_bytes;
1134                 num_written += write_bytes;
1135
1136                 cond_resched();
1137         }
1138 out:
1139         mutex_unlock(&inode->i_mutex);
1140
1141 out_nolock:
1142         kfree(pages);
1143         if (pinned[0])
1144                 page_cache_release(pinned[0]);
1145         if (pinned[1])
1146                 page_cache_release(pinned[1]);
1147         *ppos = pos;
1148
1149         if (num_written > 0 && will_write) {
1150                 struct btrfs_trans_handle *trans;
1151
1152                 err = btrfs_wait_ordered_range(inode, start_pos, num_written);
1153                 if (err)
1154                         num_written = err;
1155
1156                 if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
1157                         trans = btrfs_start_transaction(root, 1);
1158                         ret = btrfs_log_dentry_safe(trans, root,
1159                                                     file->f_dentry);
1160                         if (ret == 0) {
1161                                 btrfs_sync_log(trans, root);
1162                                 btrfs_end_transaction(trans, root);
1163                         } else {
1164                                 btrfs_commit_transaction(trans, root);
1165                         }
1166                 }
1167                 if (file->f_flags & O_DIRECT) {
1168                         invalidate_mapping_pages(inode->i_mapping,
1169                               start_pos >> PAGE_CACHE_SHIFT,
1170                              (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1171                 }
1172         }
1173         current->backing_dev_info = NULL;
1174         return num_written ? num_written : err;
1175 }
1176
1177 int btrfs_release_file(struct inode * inode, struct file * filp)
1178 {
1179         if (filp->private_data)
1180                 btrfs_ioctl_trans_end(filp);
1181         return 0;
1182 }
1183
1184 /*
1185  * fsync call for both files and directories.  This logs the inode into
1186  * the tree log instead of forcing full commits whenever possible.
1187  *
1188  * It needs to call filemap_fdatawait so that all ordered extent updates are
1189  * in the metadata btree are up to date for copying to the log.
1190  *
1191  * It drops the inode mutex before doing the tree log commit.  This is an
1192  * important optimization for directories because holding the mutex prevents
1193  * new operations on the dir while we write to disk.
1194  */
1195 int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
1196 {
1197         struct inode *inode = dentry->d_inode;
1198         struct btrfs_root *root = BTRFS_I(inode)->root;
1199         int ret = 0;
1200         struct btrfs_trans_handle *trans;
1201
1202         /*
1203          * check the transaction that last modified this inode
1204          * and see if its already been committed
1205          */
1206         if (!BTRFS_I(inode)->last_trans)
1207                 goto out;
1208
1209         mutex_lock(&root->fs_info->trans_mutex);
1210         if (BTRFS_I(inode)->last_trans <=
1211             root->fs_info->last_trans_committed) {
1212                 BTRFS_I(inode)->last_trans = 0;
1213                 mutex_unlock(&root->fs_info->trans_mutex);
1214                 goto out;
1215         }
1216         mutex_unlock(&root->fs_info->trans_mutex);
1217
1218         root->fs_info->tree_log_batch++;
1219         filemap_fdatawait(inode->i_mapping);
1220         root->fs_info->tree_log_batch++;
1221
1222         /*
1223          * ok we haven't committed the transaction yet, lets do a commit
1224          */
1225         if (file->private_data)
1226                 btrfs_ioctl_trans_end(file);
1227
1228         trans = btrfs_start_transaction(root, 1);
1229         if (!trans) {
1230                 ret = -ENOMEM;
1231                 goto out;
1232         }
1233
1234         ret = btrfs_log_dentry_safe(trans, root, file->f_dentry);
1235         if (ret < 0) {
1236                 goto out;
1237         }
1238
1239         /* we've logged all the items and now have a consistent
1240          * version of the file in the log.  It is possible that
1241          * someone will come in and modify the file, but that's
1242          * fine because the log is consistent on disk, and we
1243          * have references to all of the file's extents
1244          *
1245          * It is possible that someone will come in and log the
1246          * file again, but that will end up using the synchronization
1247          * inside btrfs_sync_log to keep things safe.
1248          */
1249         mutex_unlock(&file->f_dentry->d_inode->i_mutex);
1250
1251         if (ret > 0) {
1252                 ret = btrfs_commit_transaction(trans, root);
1253         } else {
1254                 btrfs_sync_log(trans, root);
1255                 ret = btrfs_end_transaction(trans, root);
1256         }
1257         mutex_lock(&file->f_dentry->d_inode->i_mutex);
1258 out:
1259         return ret > 0 ? EIO : ret;
1260 }
1261
1262 static struct vm_operations_struct btrfs_file_vm_ops = {
1263         .fault          = filemap_fault,
1264         .page_mkwrite   = btrfs_page_mkwrite,
1265 };
1266
1267 static int btrfs_file_mmap(struct file  *filp, struct vm_area_struct *vma)
1268 {
1269         vma->vm_ops = &btrfs_file_vm_ops;
1270         file_accessed(filp);
1271         return 0;
1272 }
1273
1274 struct file_operations btrfs_file_operations = {
1275         .llseek         = generic_file_llseek,
1276         .read           = do_sync_read,
1277         .aio_read       = generic_file_aio_read,
1278         .splice_read    = generic_file_splice_read,
1279         .write          = btrfs_file_write,
1280         .mmap           = btrfs_file_mmap,
1281         .open           = generic_file_open,
1282         .release        = btrfs_release_file,
1283         .fsync          = btrfs_sync_file,
1284         .unlocked_ioctl = btrfs_ioctl,
1285 #ifdef CONFIG_COMPAT
1286         .compat_ioctl   = btrfs_ioctl,
1287 #endif
1288 };