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