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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 "ordered-data.h"
  38 #include "ioctl.h"
  39 #include "print-tree.h"
  40 #include "compat.h"
  41
  42
  43 static int btrfs_copy_from_user(loff_t pos, int num_pages, int write_bytes,
  44                                 struct page **prepared_pages,
  45                                 const char __user * buf)
  46 {
  47         long page_fault = 0;
  48         int i;
  49         int offset = pos & (PAGE_CACHE_SIZE - 1);
  50
  51         for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
  52                 size_t count = min_t(size_t,
  53                                      PAGE_CACHE_SIZE - offset, write_bytes);
  54                 struct page *page = prepared_pages[i];
  55                 fault_in_pages_readable(buf, count);
  56
  57                 /* Copy data from userspace to the current page */
  58                 kmap(page);
  59                 page_fault = __copy_from_user(page_address(page) + offset,
  60                                               buf, count);
  61                 /* Flush processor's dcache for this page */
  62                 flush_dcache_page(page);
  63                 kunmap(page);
  64                 buf += count;
  65                 write_bytes -= count;
  66
  67                 if (page_fault)
  68                         break;
  69         }
  70         return page_fault ? -EFAULT : 0;
  71 }
  72
  73 static void btrfs_drop_pages(struct page **pages, size_t num_pages)
  74 {
  75         size_t i;
  76         for (i = 0; i < num_pages; i++) {
  77                 if (!pages[i])
  78                         break;
  79                 unlock_page(pages[i]);
  80                 mark_page_accessed(pages[i]);
  81                 page_cache_release(pages[i]);
  82         }
  83 }
  84
  85 static int noinline insert_inline_extent(struct btrfs_trans_handle *trans,
  86                                 struct btrfs_root *root, struct inode *inode,
  87                                 u64 offset, size_t size,
  88                                 struct page **pages, size_t page_offset,
  89                                 int num_pages)
  90 {
  91         struct btrfs_key key;
  92         struct btrfs_path *path;
  93         struct extent_buffer *leaf;
  94         char *kaddr;
  95         unsigned long ptr;
  96         struct btrfs_file_extent_item *ei;
  97         struct page *page;
  98         u32 datasize;
  99         int err = 0;
 100         int ret;
 101         int i;
 102         ssize_t cur_size;
 103
 104         path = btrfs_alloc_path();
 105         if (!path)
 106                 return -ENOMEM;
 107
 108         btrfs_set_trans_block_group(trans, inode);
 109
 110         key.objectid = inode->i_ino;
 111         key.offset = offset;
 112         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
 113
 114         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
 115         if (ret < 0) {
 116                 err = ret;
 117                 goto fail;
 118         }
 119         if (ret == 1) {
 120                 struct btrfs_key found_key;
 121
 122                 if (path->slots[0] == 0)
 123                         goto insert;
 124
 125                 path->slots[0]--;
 126                 leaf = path->nodes[0];
 127                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 128
 129                 if (found_key.objectid != inode->i_ino)
 130                         goto insert;
 131
 132                 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
 133                         goto insert;
 134                 ei = btrfs_item_ptr(leaf, path->slots[0],
 135                                     struct btrfs_file_extent_item);
 136
 137                 if (btrfs_file_extent_type(leaf, ei) !=
 138                     BTRFS_FILE_EXTENT_INLINE) {
 139                         goto insert;
 140                 }
 141                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 142                 ret = 0;
 143         }
 144         if (ret == 0) {
 145                 u32 found_size;
 146                 u64 found_end;
 147
 148                 leaf = path->nodes[0];
 149                 ei = btrfs_item_ptr(leaf, path->slots[0],
 150                                     struct btrfs_file_extent_item);
 151
 152                 if (btrfs_file_extent_type(leaf, ei) !=
 153                     BTRFS_FILE_EXTENT_INLINE) {
 154                         err = ret;
 155                         btrfs_print_leaf(root, leaf);
 156                         printk("found wasn't inline offset %Lu inode %lu\n",
 157                                offset, inode->i_ino);
 158                         goto fail;
 159                 }
 160                 found_size = btrfs_file_extent_inline_len(leaf,
 161                                           btrfs_item_nr(leaf, path->slots[0]));
 162                 found_end = key.offset + found_size;
 163
 164                 if (found_end < offset + size) {
 165                         btrfs_release_path(root, path);
 166                         ret = btrfs_search_slot(trans, root, &key, path,
 167                                                 offset + size - found_end, 1);
 168                         BUG_ON(ret != 0);
 169
 170                         ret = btrfs_extend_item(trans, root, path,
 171                                                 offset + size - found_end);
 172                         if (ret) {
 173                                 err = ret;
 174                                 goto fail;
 175                         }
 176                         leaf = path->nodes[0];
 177                         ei = btrfs_item_ptr(leaf, path->slots[0],
 178                                             struct btrfs_file_extent_item);
 179                         inode->i_blocks += (offset + size - found_end) >> 9;
 180                 }
 181                 if (found_end < offset) {
 182                         ptr = btrfs_file_extent_inline_start(ei) + found_size;
 183                         memset_extent_buffer(leaf, 0, ptr, offset - found_end);
 184                 }
 185         } else {
 186 insert:
 187                 btrfs_release_path(root, path);
 188                 datasize = offset + size - key.offset;
 189                 inode->i_blocks += datasize >> 9;
 190                 datasize = btrfs_file_extent_calc_inline_size(datasize);
 191                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 192                                               datasize);
 193                 if (ret) {
 194                         err = ret;
 195                         printk("got bad ret %d\n", ret);
 196                         goto fail;
 197                 }
 198                 leaf = path->nodes[0];
 199                 ei = btrfs_item_ptr(leaf, path->slots[0],
 200                                     struct btrfs_file_extent_item);
 201                 btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 202                 btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 203         }
 204         ptr = btrfs_file_extent_inline_start(ei) + offset - key.offset;
 205
 206         cur_size = size;
 207         i = 0;
 208         while (size > 0) {
 209                 page = pages[i];
 210                 kaddr = kmap_atomic(page, KM_USER0);
 211                 cur_size = min_t(size_t, PAGE_CACHE_SIZE - page_offset, size);
 212                 write_extent_buffer(leaf, kaddr + page_offset, ptr, cur_size);
 213                 kunmap_atomic(kaddr, KM_USER0);
 214                 page_offset = 0;
 215                 ptr += cur_size;
 216                 size -= cur_size;
 217                 if (i >= num_pages) {
 218                         printk("i %d num_pages %d\n", i, num_pages);
 219                 }
 220                 i++;
 221         }
 222         btrfs_mark_buffer_dirty(leaf);
 223 fail:
 224         btrfs_free_path(path);
 225         return err;
 226 }
 227
 228 static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
 229                                    struct btrfs_root *root,
 230                                    struct file *file,
 231                                    struct page **pages,
 232                                    size_t num_pages,
 233                                    loff_t pos,
 234                                    size_t write_bytes)
 235 {
 236         int err = 0;
 237         int i;
 238         struct inode *inode = fdentry(file)->d_inode;
 239         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 240         u64 hint_byte;
 241         u64 num_bytes;
 242         u64 start_pos;
 243         u64 end_of_last_block;
 244         u64 end_pos = pos + write_bytes;
 245         u64 inline_size;
 246         loff_t isize = i_size_read(inode);
 247
 248         start_pos = pos & ~((u64)root->sectorsize - 1);
 249         num_bytes = (write_bytes + pos - start_pos +
 250                     root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
 251
 252         end_of_last_block = start_pos + num_bytes - 1;
 253
 254         lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 255         trans = btrfs_start_transaction(root, 1);
 256         if (!trans) {
 257                 err = -ENOMEM;
 258                 goto out_unlock;
 259         }
 260         btrfs_set_trans_block_group(trans, inode);
 261         hint_byte = 0;
 262
 263         if ((end_of_last_block & 4095) == 0) {
 264                 printk("strange end of last %Lu %zu %Lu\n", start_pos, write_bytes, end_of_last_block);
 265         }
 266         set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 267
 268         /* FIXME...EIEIO, ENOSPC and more */
 269         /* insert any holes we need to create */
 270         if (isize < start_pos) {
 271                 u64 last_pos_in_file;
 272                 u64 hole_size;
 273                 u64 mask = root->sectorsize - 1;
 274                 last_pos_in_file = (isize + mask) & ~mask;
 275                 hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
 276                 if (last_pos_in_file < start_pos) {
 277                         err = btrfs_drop_extents(trans, root, inode,
 278                                                  last_pos_in_file,
 279                                                  last_pos_in_file + hole_size,
 280                                                  last_pos_in_file,
 281                                                  &hint_byte);
 282                         if (err)
 283                                 goto failed;
 284
 285                         err = btrfs_insert_file_extent(trans, root,
 286                                                        inode->i_ino,
 287                                                        last_pos_in_file,
 288                                                        0, 0, hole_size, 0);
 289                         btrfs_drop_extent_cache(inode, last_pos_in_file,
 290                                         last_pos_in_file + hole_size -1);
 291                         btrfs_check_file(root, inode);
 292                 }
 293                 if (err)
 294                         goto failed;
 295         }
 296
 297         /*
 298          * either allocate an extent for the new bytes or setup the key
 299          * to show we are doing inline data in the extent
 300          */
 301         inline_size = end_pos;
 302         if (isize >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 303             inline_size > root->fs_info->max_inline ||
 304             (inline_size & (root->sectorsize -1)) == 0 ||
 305             inline_size >= BTRFS_MAX_INLINE_DATA_SIZE(root)) {
 306                 u64 last_end;
 307
 308                 for (i = 0; i < num_pages; i++) {
 309                         struct page *p = pages[i];
 310                         SetPageUptodate(p);
 311                         set_page_dirty(p);
 312                 }
 313                 last_end = (u64)(pages[num_pages -1]->index) <<
 314                                 PAGE_CACHE_SHIFT;
 315                 last_end += PAGE_CACHE_SIZE - 1;
 316                 set_extent_delalloc(io_tree, start_pos, end_of_last_block,
 317                                  GFP_NOFS);
 318                 btrfs_add_ordered_inode(inode);
 319         } else {
 320                 u64 aligned_end;
 321                 /* step one, delete the existing extents in this range */
 322                 aligned_end = (pos + write_bytes + root->sectorsize - 1) &
 323                         ~((u64)root->sectorsize - 1);
 324                 err = btrfs_drop_extents(trans, root, inode, start_pos,
 325                                          aligned_end, aligned_end, &hint_byte);
 326                 if (err)
 327                         goto failed;
 328                 if (isize > inline_size)
 329                         inline_size = min_t(u64, isize, aligned_end);
 330                 inline_size -= start_pos;
 331                 err = insert_inline_extent(trans, root, inode, start_pos,
 332                                            inline_size, pages, 0, num_pages);
 333                 btrfs_drop_extent_cache(inode, start_pos, aligned_end - 1);
 334                 BUG_ON(err);
 335         }
 336         if (end_pos > isize) {
 337                 i_size_write(inode, end_pos);
 338                 btrfs_update_inode(trans, root, inode);
 339         }
 340 failed:
 341         err = btrfs_end_transaction(trans, root);
 342 out_unlock:
 343         unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 344         return err;
 345 }
 346
 347 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
 348 {
 349         struct extent_map *em;
 350         struct extent_map *split = NULL;
 351         struct extent_map *split2 = NULL;
 352         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 353         u64 len = end - start + 1;
 354         int ret;
 355         int testend = 1;
 356
 357         if (end == (u64)-1) {
 358                 len = (u64)-1;
 359                 testend = 0;
 360         }
 361         while(1) {
 362                 if (!split)
 363                         split = alloc_extent_map(GFP_NOFS);
 364                 if (!split2)
 365                         split2 = alloc_extent_map(GFP_NOFS);
 366
 367                 spin_lock(&em_tree->lock);
 368                 em = lookup_extent_mapping(em_tree, start, len);
 369                 if (!em) {
 370                         spin_unlock(&em_tree->lock);
 371                         break;
 372                 }
 373                 remove_extent_mapping(em_tree, em);
 374
 375                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
 376                     em->start < start) {
 377                         split->start = em->start;
 378                         split->len = start - em->start;
 379                         split->block_start = em->block_start;
 380                         split->bdev = em->bdev;
 381                         split->flags = em->flags;
 382                         ret = add_extent_mapping(em_tree, split);
 383                         BUG_ON(ret);
 384                         free_extent_map(split);
 385                         split = split2;
 386                         split2 = NULL;
 387                 }
 388                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
 389                     testend && em->start + em->len > start + len) {
 390                         u64 diff = start + len - em->start;
 391
 392                         split->start = start + len;
 393                         split->len = em->start + em->len - (start + len);
 394                         split->bdev = em->bdev;
 395                         split->flags = em->flags;
 396
 397                         split->block_start = em->block_start + diff;
 398
 399                         ret = add_extent_mapping(em_tree, split);
 400                         BUG_ON(ret);
 401                         free_extent_map(split);
 402                         split = NULL;
 403                 }
 404                 spin_unlock(&em_tree->lock);
 405
 406                 /* once for us */
 407                 free_extent_map(em);
 408                 /* once for the tree*/
 409                 free_extent_map(em);
 410         }
 411         if (split)
 412                 free_extent_map(split);
 413         if (split2)
 414                 free_extent_map(split2);
 415         return 0;
 416 }
 417
 418 int btrfs_check_file(struct btrfs_root *root, struct inode *inode)
 419 {
 420         return 0;
 421 #if 0
 422         struct btrfs_path *path;
 423         struct btrfs_key found_key;
 424         struct extent_buffer *leaf;
 425         struct btrfs_file_extent_item *extent;
 426         u64 last_offset = 0;
 427         int nritems;
 428         int slot;
 429         int found_type;
 430         int ret;
 431         int err = 0;
 432         u64 extent_end = 0;
 433
 434         path = btrfs_alloc_path();
 435         ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,
 436                                        last_offset, 0);
 437         while(1) {
 438                 nritems = btrfs_header_nritems(path->nodes[0]);
 439                 if (path->slots[0] >= nritems) {
 440                         ret = btrfs_next_leaf(root, path);
 441                         if (ret)
 442                                 goto out;
 443                         nritems = btrfs_header_nritems(path->nodes[0]);
 444                 }
 445                 slot = path->slots[0];
 446                 leaf = path->nodes[0];
 447                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
 448                 if (found_key.objectid != inode->i_ino)
 449                         break;
 450                 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
 451                         goto out;
 452
 453                 if (found_key.offset < last_offset) {
 454                         WARN_ON(1);
 455                         btrfs_print_leaf(root, leaf);
 456                         printk("inode %lu found offset %Lu expected %Lu\n",
 457                                inode->i_ino, found_key.offset, last_offset);
 458                         err = 1;
 459                         goto out;
 460                 }
 461                 extent = btrfs_item_ptr(leaf, slot,
 462                                         struct btrfs_file_extent_item);
 463                 found_type = btrfs_file_extent_type(leaf, extent);
 464                 if (found_type == BTRFS_FILE_EXTENT_REG) {
 465                         extent_end = found_key.offset +
 466                              btrfs_file_extent_num_bytes(leaf, extent);
 467                 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 468                         struct btrfs_item *item;
 469                         item = btrfs_item_nr(leaf, slot);
 470                         extent_end = found_key.offset +
 471                              btrfs_file_extent_inline_len(leaf, item);
 472                         extent_end = (extent_end + root->sectorsize - 1) &
 473                                 ~((u64)root->sectorsize -1 );
 474                 }
 475                 last_offset = extent_end;
 476                 path->slots[0]++;
 477         }
 478         if (0 && last_offset < inode->i_size) {
 479                 WARN_ON(1);
 480                 btrfs_print_leaf(root, leaf);
 481                 printk("inode %lu found offset %Lu size %Lu\n", inode->i_ino,
 482                        last_offset, inode->i_size);
 483                 err = 1;
 484
 485         }
 486 out:
 487         btrfs_free_path(path);
 488         return err;
 489 #endif
 490 }
 491
 492 /*
 493  * this is very complex, but the basic idea is to drop all extents
 494  * in the range start - end.  hint_block is filled in with a block number
 495  * that would be a good hint to the block allocator for this file.
 496  *
 497  * If an extent intersects the range but is not entirely inside the range
 498  * it is either truncated or split.  Anything entirely inside the range
 499  * is deleted from the tree.
 500  */
 501 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 502                        struct btrfs_root *root, struct inode *inode,
 503                        u64 start, u64 end, u64 inline_limit, u64 *hint_byte)
 504 {
 505         u64 extent_end = 0;
 506         u64 search_start = start;
 507         struct extent_buffer *leaf;
 508         struct btrfs_file_extent_item *extent;
 509         struct btrfs_path *path;
 510         struct btrfs_key key;
 511         struct btrfs_file_extent_item old;
 512         int keep;
 513         int slot;
 514         int bookend;
 515         int found_type;
 516         int found_extent;
 517         int found_inline;
 518         int recow;
 519         int ret;
 520
 521         btrfs_drop_extent_cache(inode, start, end - 1);
 522
 523         path = btrfs_alloc_path();
 524         if (!path)
 525                 return -ENOMEM;
 526         while(1) {
 527                 recow = 0;
 528                 btrfs_release_path(root, path);
 529                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
 530                                                search_start, -1);
 531                 if (ret < 0)
 532                         goto out;
 533                 if (ret > 0) {
 534                         if (path->slots[0] == 0) {
 535                                 ret = 0;
 536                                 goto out;
 537                         }
 538                         path->slots[0]--;
 539                 }
 540 next_slot:
 541                 keep = 0;
 542                 bookend = 0;
 543                 found_extent = 0;
 544                 found_inline = 0;
 545                 extent = NULL;
 546                 leaf = path->nodes[0];
 547                 slot = path->slots[0];
 548                 ret = 0;
 549                 btrfs_item_key_to_cpu(leaf, &key, slot);
 550                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
 551                     key.offset >= end) {
 552                         goto out;
 553                 }
 554                 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
 555                     key.objectid != inode->i_ino) {
 556                         goto out;
 557                 }
 558                 if (recow) {
 559                         search_start = key.offset;
 560                         continue;
 561                 }
 562                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
 563                         extent = btrfs_item_ptr(leaf, slot,
 564                                                 struct btrfs_file_extent_item);
 565                         found_type = btrfs_file_extent_type(leaf, extent);
 566                         if (found_type == BTRFS_FILE_EXTENT_REG) {
 567                                 extent_end =
 568                                      btrfs_file_extent_disk_bytenr(leaf,
 569                                                                    extent);
 570                                 if (extent_end)
 571                                         *hint_byte = extent_end;
 572
 573                                 extent_end = key.offset +
 574                                      btrfs_file_extent_num_bytes(leaf, extent);
 575                                 found_extent = 1;
 576                         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 577                                 struct btrfs_item *item;
 578                                 item = btrfs_item_nr(leaf, slot);
 579                                 found_inline = 1;
 580                                 extent_end = key.offset +
 581                                      btrfs_file_extent_inline_len(leaf, item);
 582                         }
 583                 } else {
 584                         extent_end = search_start;
 585                 }
 586
 587                 /* we found nothing we can drop */
 588                 if ((!found_extent && !found_inline) ||
 589                     search_start >= extent_end) {
 590                         int nextret;
 591                         u32 nritems;
 592                         nritems = btrfs_header_nritems(leaf);
 593                         if (slot >= nritems - 1) {
 594                                 nextret = btrfs_next_leaf(root, path);
 595                                 if (nextret)
 596                                         goto out;
 597                                 recow = 1;
 598                         } else {
 599                                 path->slots[0]++;
 600                         }
 601                         goto next_slot;
 602                 }
 603
 604                 if (found_inline) {
 605                         u64 mask = root->sectorsize - 1;
 606                         search_start = (extent_end + mask) & ~mask;
 607                 } else
 608                         search_start = extent_end;
 609                 if (end <= extent_end && start >= key.offset && found_inline) {
 610                         *hint_byte = EXTENT_MAP_INLINE;
 611                         continue;
 612                 }
 613                 if (end < extent_end && end >= key.offset) {
 614                         if (found_extent) {
 615                                 u64 disk_bytenr =
 616                                     btrfs_file_extent_disk_bytenr(leaf, extent);
 617                                 u64 disk_num_bytes =
 618                                     btrfs_file_extent_disk_num_bytes(leaf,
 619                                                                       extent);
 620                                 read_extent_buffer(leaf, &old,
 621                                                    (unsigned long)extent,
 622                                                    sizeof(old));
 623                                 if (disk_bytenr != 0) {
 624                                         ret = btrfs_inc_extent_ref(trans, root,
 625                                                  disk_bytenr, disk_num_bytes,
 626                                                  root->root_key.objectid,
 627                                                  trans->transid,
 628                                                  key.objectid, end);
 629                                         BUG_ON(ret);
 630                                 }
 631                         }
 632                         bookend = 1;
 633                         if (found_inline && start <= key.offset)
 634                                 keep = 1;
 635                 }
 636                 /* truncate existing extent */
 637                 if (start > key.offset) {
 638                         u64 new_num;
 639                         u64 old_num;
 640                         keep = 1;
 641                         WARN_ON(start & (root->sectorsize - 1));
 642                         if (found_extent) {
 643                                 new_num = start - key.offset;
 644                                 old_num = btrfs_file_extent_num_bytes(leaf,
 645                                                                       extent);
 646                                 *hint_byte =
 647                                         btrfs_file_extent_disk_bytenr(leaf,
 648                                                                       extent);
 649                                 if (btrfs_file_extent_disk_bytenr(leaf,
 650                                                                   extent)) {
 651                                         dec_i_blocks(inode, old_num - new_num);
 652                                 }
 653                                 btrfs_set_file_extent_num_bytes(leaf, extent,
 654                                                                 new_num);
 655                                 btrfs_mark_buffer_dirty(leaf);
 656                         } else if (key.offset < inline_limit &&
 657                                    (end > extent_end) &&
 658                                    (inline_limit < extent_end)) {
 659                                 u32 new_size;
 660                                 new_size = btrfs_file_extent_calc_inline_size(
 661                                                    inline_limit - key.offset);
 662                                 dec_i_blocks(inode, (extent_end - key.offset) -
 663                                         (inline_limit - key.offset));
 664                                 btrfs_truncate_item(trans, root, path,
 665                                                     new_size, 1);
 666                         }
 667                 }
 668                 /* delete the entire extent */
 669                 if (!keep) {
 670                         u64 disk_bytenr = 0;
 671                         u64 disk_num_bytes = 0;
 672                         u64 extent_num_bytes = 0;
 673                         u64 root_gen;
 674                         u64 root_owner;
 675
 676                         root_gen = btrfs_header_generation(leaf);
 677                         root_owner = btrfs_header_owner(leaf);
 678                         if (found_extent) {
 679                                 disk_bytenr =
 680                                       btrfs_file_extent_disk_bytenr(leaf,
 681                                                                      extent);
 682                                 disk_num_bytes =
 683                                       btrfs_file_extent_disk_num_bytes(leaf,
 684                                                                        extent);
 685                                 extent_num_bytes =
 686                                       btrfs_file_extent_num_bytes(leaf, extent);
 687                                 *hint_byte =
 688                                         btrfs_file_extent_disk_bytenr(leaf,
 689                                                                       extent);
 690                         }
 691                         ret = btrfs_del_item(trans, root, path);
 692                         /* TODO update progress marker and return */
 693                         BUG_ON(ret);
 694                         btrfs_release_path(root, path);
 695                         extent = NULL;
 696                         if (found_extent && disk_bytenr != 0) {
 697                                 dec_i_blocks(inode, extent_num_bytes);
 698                                 ret = btrfs_free_extent(trans, root,
 699                                                 disk_bytenr,
 700                                                 disk_num_bytes,
 701                                                 root_owner,
 702                                                 root_gen, inode->i_ino,
 703                                                 key.offset, 0);
 704                         }
 705
 706                         BUG_ON(ret);
 707                         if (!bookend && search_start >= end) {
 708                                 ret = 0;
 709                                 goto out;
 710                         }
 711                         if (!bookend)
 712                                 continue;
 713                 }
 714                 if (bookend && found_inline && start <= key.offset) {
 715                         u32 new_size;
 716                         new_size = btrfs_file_extent_calc_inline_size(
 717                                                    extent_end - end);
 718                         dec_i_blocks(inode, (extent_end - key.offset) -
 719                                         (extent_end - end));
 720                         btrfs_truncate_item(trans, root, path, new_size, 0);
 721                 }
 722                 /* create bookend, splitting the extent in two */
 723                 if (bookend && found_extent) {
 724                         struct btrfs_key ins;
 725                         ins.objectid = inode->i_ino;
 726                         ins.offset = end;
 727                         btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
 728                         btrfs_release_path(root, path);
 729                         ret = btrfs_insert_empty_item(trans, root, path, &ins,
 730                                                       sizeof(*extent));
 731
 732                         leaf = path->nodes[0];
 733                         if (ret) {
 734                                 btrfs_print_leaf(root, leaf);
 735                                 printk("got %d on inserting %Lu %u %Lu start %Lu end %Lu found %Lu %Lu keep was %d\n", ret , ins.objectid, ins.type, ins.offset, start, end, key.offset, extent_end, keep);
 736                         }
 737                         BUG_ON(ret);
 738                         extent = btrfs_item_ptr(leaf, path->slots[0],
 739                                                 struct btrfs_file_extent_item);
 740                         write_extent_buffer(leaf, &old,
 741                                             (unsigned long)extent, sizeof(old));
 742
 743                         btrfs_set_file_extent_offset(leaf, extent,
 744                                     le64_to_cpu(old.offset) + end - key.offset);
 745                         WARN_ON(le64_to_cpu(old.num_bytes) <
 746                                 (extent_end - end));
 747                         btrfs_set_file_extent_num_bytes(leaf, extent,
 748                                                         extent_end - end);
 749                         btrfs_set_file_extent_type(leaf, extent,
 750                                                    BTRFS_FILE_EXTENT_REG);
 751
 752                         btrfs_mark_buffer_dirty(path->nodes[0]);
 753                         if (le64_to_cpu(old.disk_bytenr) != 0) {
 754                                 inode->i_blocks +=
 755                                       btrfs_file_extent_num_bytes(leaf,
 756                                                                   extent) >> 9;
 757                         }
 758                         ret = 0;
 759                         goto out;
 760                 }
 761         }
 762 out:
 763         btrfs_free_path(path);
 764         btrfs_check_file(root, inode);
 765         return ret;
 766 }
 767
 768 /*
 769  * this gets pages into the page cache and locks them down
 770  */
 771 static int prepare_pages(struct btrfs_root *root, struct file *file,
 772                          struct page **pages, size_t num_pages,
 773                          loff_t pos, unsigned long first_index,
 774                          unsigned long last_index, size_t write_bytes)
 775 {
 776         int i;
 777         unsigned long index = pos >> PAGE_CACHE_SHIFT;
 778         struct inode *inode = fdentry(file)->d_inode;
 779         int err = 0;
 780         u64 start_pos;
 781
 782         start_pos = pos & ~((u64)root->sectorsize - 1);
 783
 784         memset(pages, 0, num_pages * sizeof(struct page *));
 785
 786         for (i = 0; i < num_pages; i++) {
 787                 pages[i] = grab_cache_page(inode->i_mapping, index + i);
 788                 if (!pages[i]) {
 789                         err = -ENOMEM;
 790                         BUG_ON(1);
 791                 }
 792 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
 793                 ClearPageDirty(pages[i]);
 794 #else
 795                 cancel_dirty_page(pages[i], PAGE_CACHE_SIZE);
 796 #endif
 797                 wait_on_page_writeback(pages[i]);
 798                 set_page_extent_mapped(pages[i]);
 799                 WARN_ON(!PageLocked(pages[i]));
 800         }
 801         if (start_pos < inode->i_size) {
 802                 u64 last_pos;
 803                 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
 804                 lock_extent(&BTRFS_I(inode)->io_tree,
 805                             start_pos, last_pos - 1, GFP_NOFS);
 806                 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
 807                                   last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
 808                                   GFP_NOFS);
 809                 unlock_extent(&BTRFS_I(inode)->io_tree,
 810                               start_pos, last_pos - 1, GFP_NOFS);
 811         }
 812         return 0;
 813 }
 814
 815 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
 816                                 size_t count, loff_t *ppos)
 817 {
 818         loff_t pos;
 819         loff_t start_pos;
 820         ssize_t num_written = 0;
 821         ssize_t err = 0;
 822         int ret = 0;
 823         struct inode *inode = fdentry(file)->d_inode;
 824         struct btrfs_root *root = BTRFS_I(inode)->root;
 825         struct page **pages = NULL;
 826         int nrptrs;
 827         struct page *pinned[2];
 828         unsigned long first_index;
 829         unsigned long last_index;
 830
 831         nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
 832                      PAGE_CACHE_SIZE / (sizeof(struct page *)));
 833         pinned[0] = NULL;
 834         pinned[1] = NULL;
 835
 836         pos = *ppos;
 837         start_pos = pos;
 838
 839         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
 840         current->backing_dev_info = inode->i_mapping->backing_dev_info;
 841         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
 842         if (err)
 843                 goto out_nolock;
 844         if (count == 0)
 845                 goto out_nolock;
 846 #ifdef REMOVE_SUID_PATH
 847         err = remove_suid(&file->f_path);
 848 #else
 849         err = remove_suid(fdentry(file));
 850 #endif
 851         if (err)
 852                 goto out_nolock;
 853         file_update_time(file);
 854
 855         pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
 856
 857         mutex_lock(&inode->i_mutex);
 858         first_index = pos >> PAGE_CACHE_SHIFT;
 859         last_index = (pos + count) >> PAGE_CACHE_SHIFT;
 860
 861         /*
 862          * if this is a nodatasum mount, force summing off for the inode
 863          * all the time.  That way a later mount with summing on won't
 864          * get confused
 865          */
 866         if (btrfs_test_opt(root, NODATASUM))
 867                 btrfs_set_flag(inode, NODATASUM);
 868
 869         /*
 870          * there are lots of better ways to do this, but this code
 871          * makes sure the first and last page in the file range are
 872          * up to date and ready for cow
 873          */
 874         if ((pos & (PAGE_CACHE_SIZE - 1))) {
 875                 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
 876                 if (!PageUptodate(pinned[0])) {
 877                         ret = btrfs_readpage(NULL, pinned[0]);
 878                         BUG_ON(ret);
 879                         wait_on_page_locked(pinned[0]);
 880                 } else {
 881                         unlock_page(pinned[0]);
 882                 }
 883         }
 884         if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
 885                 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
 886                 if (!PageUptodate(pinned[1])) {
 887                         ret = btrfs_readpage(NULL, pinned[1]);
 888                         BUG_ON(ret);
 889                         wait_on_page_locked(pinned[1]);
 890                 } else {
 891                         unlock_page(pinned[1]);
 892                 }
 893         }
 894
 895         while(count > 0) {
 896                 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
 897                 size_t write_bytes = min(count, nrptrs *
 898                                         (size_t)PAGE_CACHE_SIZE -
 899                                          offset);
 900                 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
 901                                         PAGE_CACHE_SHIFT;
 902
 903                 WARN_ON(num_pages > nrptrs);
 904                 memset(pages, 0, sizeof(pages));
 905
 906                 ret = btrfs_check_free_space(root, write_bytes, 0);
 907                 if (ret)
 908                         goto out;
 909
 910                 ret = prepare_pages(root, file, pages, num_pages,
 911                                     pos, first_index, last_index,
 912                                     write_bytes);
 913                 if (ret)
 914                         goto out;
 915
 916                 ret = btrfs_copy_from_user(pos, num_pages,
 917                                            write_bytes, pages, buf);
 918                 if (ret) {
 919                         btrfs_drop_pages(pages, num_pages);
 920                         goto out;
 921                 }
 922
 923                 ret = dirty_and_release_pages(NULL, root, file, pages,
 924                                               num_pages, pos, write_bytes);
 925                 btrfs_drop_pages(pages, num_pages);
 926                 if (ret)
 927                         goto out;
 928
 929                 buf += write_bytes;
 930                 count -= write_bytes;
 931                 pos += write_bytes;
 932                 num_written += write_bytes;
 933
 934                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, num_pages);
 935                 if (num_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
 936                         btrfs_btree_balance_dirty(root, 1);
 937                 cond_resched();
 938         }
 939 out:
 940         mutex_unlock(&inode->i_mutex);
 941
 942 out_nolock:
 943         kfree(pages);
 944         if (pinned[0])
 945                 page_cache_release(pinned[0]);
 946         if (pinned[1])
 947                 page_cache_release(pinned[1]);
 948         *ppos = pos;
 949
 950         if (num_written > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
 951                 err = sync_page_range(inode, inode->i_mapping,
 952                                       start_pos, num_written);
 953                 if (err < 0)
 954                         num_written = err;
 955         } else if (num_written > 0 && (file->f_flags & O_DIRECT)) {
 956 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
 957                 do_sync_file_range(file, start_pos,
 958                                       start_pos + num_written - 1,
 959                                       SYNC_FILE_RANGE_WRITE |
 960                                       SYNC_FILE_RANGE_WAIT_AFTER);
 961 #else
 962                 do_sync_mapping_range(inode->i_mapping, start_pos,
 963                                       start_pos + num_written - 1,
 964                                       SYNC_FILE_RANGE_WRITE |
 965                                       SYNC_FILE_RANGE_WAIT_AFTER);
 966 #endif
 967                 invalidate_mapping_pages(inode->i_mapping,
 968                       start_pos >> PAGE_CACHE_SHIFT,
 969                      (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
 970         }
 971         current->backing_dev_info = NULL;
 972         btrfs_ordered_throttle(root, inode);
 973         return num_written ? num_written : err;
 974 }
 975
 976 int btrfs_release_file(struct inode * inode, struct file * filp)
 977 {
 978         btrfs_del_ordered_inode(inode, 0);
 979         if (filp->private_data)
 980                 btrfs_ioctl_trans_end(filp);
 981         return 0;
 982 }
 983
 984 static int btrfs_sync_file(struct file *file,
 985                            struct dentry *dentry, int datasync)
 986 {
 987         struct inode *inode = dentry->d_inode;
 988         struct btrfs_root *root = BTRFS_I(inode)->root;
 989         int ret = 0;
 990         struct btrfs_trans_handle *trans;
 991
 992         /*
 993          * check the transaction that last modified this inode
 994          * and see if its already been committed
 995          */
 996         if (!BTRFS_I(inode)->last_trans)
 997                 goto out;
 998
 999         mutex_lock(&root->fs_info->trans_mutex);
1000         if (BTRFS_I(inode)->last_trans <=
1001             root->fs_info->last_trans_committed) {
1002                 BTRFS_I(inode)->last_trans = 0;
1003                 mutex_unlock(&root->fs_info->trans_mutex);
1004                 goto out;
1005         }
1006         mutex_unlock(&root->fs_info->trans_mutex);
1007
1008         /*
1009          * ok we haven't committed the transaction yet, lets do a commit
1010          */
1011         if (file->private_data)
1012                 btrfs_ioctl_trans_end(file);
1013
1014         trans = btrfs_start_transaction(root, 1);
1015         if (!trans) {
1016                 ret = -ENOMEM;
1017                 goto out;
1018         }
1019         ret = btrfs_commit_transaction(trans, root);
1020 out:
1021         return ret > 0 ? EIO : ret;
1022 }
1023
1024 static struct vm_operations_struct btrfs_file_vm_ops = {
1025 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
1026         .nopage         = filemap_nopage,
1027         .populate       = filemap_populate,
1028 #else
1029         .fault          = filemap_fault,
1030 #endif
1031         .page_mkwrite   = btrfs_page_mkwrite,
1032 };
1033
1034 static int btrfs_file_mmap(struct file  *filp, struct vm_area_struct *vma)
1035 {
1036         vma->vm_ops = &btrfs_file_vm_ops;
1037         file_accessed(filp);
1038         return 0;
1039 }
1040
1041 struct file_operations btrfs_file_operations = {
1042         .llseek         = generic_file_llseek,
1043         .read           = do_sync_read,
1044         .aio_read       = generic_file_aio_read,
1045         .splice_read    = generic_file_splice_read,
1046 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
1047         .sendfile       = generic_file_sendfile,
1048 #endif
1049         .write          = btrfs_file_write,
1050         .mmap           = btrfs_file_mmap,
1051         .open           = generic_file_open,
1052         .release        = btrfs_release_file,
1053         .fsync          = btrfs_sync_file,
1054         .unlocked_ioctl = btrfs_ioctl,
1055 #ifdef CONFIG_COMPAT
1056         .compat_ioctl   = btrfs_ioctl,
1057 #endif
1058 };
1059