fs/btrfs/file.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/fs.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/highmem.h>
  22 #include <linux/time.h>
  23 #include <linux/init.h>
  24 #include <linux/string.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/backing-dev.h>
  27 #include <linux/mpage.h>
  28 #include <linux/swap.h>
  29 #include <linux/writeback.h>
  30 #include <linux/statfs.h>
  31 #include <linux/compat.h>
  32 #include <linux/version.h>
  33 #include "ctree.h"
  34 #include "disk-io.h"
  35 #include "transaction.h"
  36 #include "btrfs_inode.h"
  37 #include "ioctl.h"
  38 #include "print-tree.h"
  39 #include "compat.h"
  40
  41
  42 static int btrfs_copy_from_user(loff_t pos, int num_pages, int write_bytes,
  43                                 struct page **prepared_pages,
  44                                 const char __user * buf)
  45 {
  46         long page_fault = 0;
  47         int i;
  48         int offset = pos & (PAGE_CACHE_SIZE - 1);
  49
  50         for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
  51                 size_t count = min_t(size_t,
  52                                      PAGE_CACHE_SIZE - offset, write_bytes);
  53                 struct page *page = prepared_pages[i];
  54                 fault_in_pages_readable(buf, count);
  55
  56                 /* Copy data from userspace to the current page */
  57                 kmap(page);
  58                 page_fault = __copy_from_user(page_address(page) + offset,
  59                                               buf, count);
  60                 /* Flush processor's dcache for this page */
  61                 flush_dcache_page(page);
  62                 kunmap(page);
  63                 buf += count;
  64                 write_bytes -= count;
  65
  66                 if (page_fault)
  67                         break;
  68         }
  69         return page_fault ? -EFAULT : 0;
  70 }
  71
  72 static void btrfs_drop_pages(struct page **pages, size_t num_pages)
  73 {
  74         size_t i;
  75         for (i = 0; i < num_pages; i++) {
  76                 if (!pages[i])
  77                         break;
  78                 unlock_page(pages[i]);
  79                 mark_page_accessed(pages[i]);
  80                 page_cache_release(pages[i]);
  81         }
  82 }
  83
  84 static int noinline insert_inline_extent(struct btrfs_trans_handle *trans,
  85                                 struct btrfs_root *root, struct inode *inode,
  86                                 u64 offset, size_t size,
  87                                 struct page **pages, size_t page_offset,
  88                                 int num_pages)
  89 {
  90         struct btrfs_key key;
  91         struct btrfs_path *path;
  92         struct extent_buffer *leaf;
  93         char *kaddr;
  94         unsigned long ptr;
  95         struct btrfs_file_extent_item *ei;
  96         struct page *page;
  97         u32 datasize;
  98         int err = 0;
  99         int ret;
 100         int i;
 101         ssize_t cur_size;
 102
 103         path = btrfs_alloc_path();
 104         if (!path)
 105                 return -ENOMEM;
 106
 107         btrfs_set_trans_block_group(trans, inode);
 108
 109         key.objectid = inode->i_ino;
 110         key.offset = offset;
 111         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
 112
 113         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
 114         if (ret < 0) {
 115                 err = ret;
 116                 goto fail;
 117         }
 118         if (ret == 1) {
 119                 struct btrfs_key found_key;
 120
 121                 if (path->slots[0] == 0)
 122                         goto insert;
 123
 124                 path->slots[0]--;
 125                 leaf = path->nodes[0];
 126                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 127
 128                 if (found_key.objectid != inode->i_ino)
 129                         goto insert;
 130
 131                 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
 132                         goto insert;
 133                 ei = btrfs_item_ptr(leaf, path->slots[0],
 134                                     struct btrfs_file_extent_item);
 135
 136                 if (btrfs_file_extent_type(leaf, ei) !=
 137                     BTRFS_FILE_EXTENT_INLINE) {
 138                         goto insert;
 139                 }
 140                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 141                 ret = 0;
 142         }
 143         if (ret == 0) {
 144                 u32 found_size;
 145                 u64 found_end;
 146
 147                 leaf = path->nodes[0];
 148                 ei = btrfs_item_ptr(leaf, path->slots[0],
 149                                     struct btrfs_file_extent_item);
 150
 151                 if (btrfs_file_extent_type(leaf, ei) !=
 152                     BTRFS_FILE_EXTENT_INLINE) {
 153                         err = ret;
 154                         btrfs_print_leaf(root, leaf);
 155                         printk("found wasn't inline offset %Lu inode %lu\n",
 156                                offset, inode->i_ino);
 157                         goto fail;
 158                 }
 159                 found_size = btrfs_file_extent_inline_len(leaf,
 160                                           btrfs_item_nr(leaf, path->slots[0]));
 161                 found_end = key.offset + found_size;
 162
 163                 if (found_end < offset + size) {
 164                         btrfs_release_path(root, path);
 165                         ret = btrfs_search_slot(trans, root, &key, path,
 166                                                 offset + size - found_end, 1);
 167                         BUG_ON(ret != 0);
 168
 169                         ret = btrfs_extend_item(trans, root, path,
 170                                                 offset + size - found_end);
 171                         if (ret) {
 172                                 err = ret;
 173                                 goto fail;
 174                         }
 175                         leaf = path->nodes[0];
 176                         ei = btrfs_item_ptr(leaf, path->slots[0],
 177                                             struct btrfs_file_extent_item);
 178                         inode->i_blocks += (offset + size - found_end) >> 9;
 179                 }
 180                 if (found_end < offset) {
 181                         ptr = btrfs_file_extent_inline_start(ei) + found_size;
 182                         memset_extent_buffer(leaf, 0, ptr, offset - found_end);
 183                 }
 184         } else {
 185 insert:
 186                 btrfs_release_path(root, path);
 187                 datasize = offset + size - key.offset;
 188                 inode->i_blocks += datasize >> 9;
 189                 datasize = btrfs_file_extent_calc_inline_size(datasize);
 190                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 191                                               datasize);
 192                 if (ret) {
 193                         err = ret;
 194                         printk("got bad ret %d\n", ret);
 195                         goto fail;
 196                 }
 197                 leaf = path->nodes[0];
 198                 ei = btrfs_item_ptr(leaf, path->slots[0],
 199                                     struct btrfs_file_extent_item);
 200                 btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 201                 btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 202         }
 203         ptr = btrfs_file_extent_inline_start(ei) + offset - key.offset;
 204
 205         cur_size = size;
 206         i = 0;
 207         while (size > 0) {
 208                 page = pages[i];
 209                 kaddr = kmap_atomic(page, KM_USER0);
 210                 cur_size = min_t(size_t, PAGE_CACHE_SIZE - page_offset, size);
 211                 write_extent_buffer(leaf, kaddr + page_offset, ptr, cur_size);
 212                 kunmap_atomic(kaddr, KM_USER0);
 213                 page_offset = 0;
 214                 ptr += cur_size;
 215                 size -= cur_size;
 216                 if (i >= num_pages) {
 217                         printk("i %d num_pages %d\n", i, num_pages);
 218                 }
 219                 i++;
 220         }
 221         btrfs_mark_buffer_dirty(leaf);
 222 fail:
 223         btrfs_free_path(path);
 224         return err;
 225 }
 226
 227 static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
 228                                    struct btrfs_root *root,
 229                                    struct file *file,
 230                                    struct page **pages,
 231                                    size_t num_pages,
 232                                    loff_t pos,
 233                                    size_t write_bytes)
 234 {
 235         int err = 0;
 236         int i;
 237         struct inode *inode = fdentry(file)->d_inode;
 238         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 239         u64 hint_byte;
 240         u64 num_bytes;
 241         u64 start_pos;
 242         u64 end_of_last_block;
 243         u64 end_pos = pos + write_bytes;
 244         u64 inline_size;
 245         loff_t isize = i_size_read(inode);
 246
 247         start_pos = pos & ~((u64)root->sectorsize - 1);
 248         num_bytes = (write_bytes + pos - start_pos +
 249                     root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
 250
 251         end_of_last_block = start_pos + num_bytes - 1;
 252
 253         lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 254         trans = btrfs_start_transaction(root, 1);
 255         if (!trans) {
 256                 err = -ENOMEM;
 257                 goto out_unlock;
 258         }
 259         btrfs_set_trans_block_group(trans, inode);
 260         hint_byte = 0;
 261
 262         if ((end_of_last_block & 4095) == 0) {
 263                 printk("strange end of last %Lu %zu %Lu\n", start_pos, write_bytes, end_of_last_block);
 264         }
 265         set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 266
 267         /* FIXME...EIEIO, ENOSPC and more */
 268         /* insert any holes we need to create */
 269         if (isize < start_pos) {
 270                 u64 last_pos_in_file;
 271                 u64 hole_size;
 272                 u64 mask = root->sectorsize - 1;
 273                 last_pos_in_file = (isize + mask) & ~mask;
 274                 hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
 275                 if (hole_size > 0) {
 276                         btrfs_wait_ordered_range(inode, last_pos_in_file,
 277                                                  last_pos_in_file + hole_size);
 278                         err = btrfs_drop_extents(trans, root, inode,
 279                                                  last_pos_in_file,
 280                                                  last_pos_in_file + hole_size,
 281                                                  last_pos_in_file,
 282                                                  &hint_byte);
 283                         if (err)
 284                                 goto failed;
 285
 286                         err = btrfs_insert_file_extent(trans, root,
 287                                                        inode->i_ino,
 288                                                        last_pos_in_file,
 289                                                        0, 0, hole_size, 0);
 290                         btrfs_drop_extent_cache(inode, last_pos_in_file,
 291                                         last_pos_in_file + hole_size -1);
 292                         btrfs_check_file(root, inode);
 293                 }
 294                 if (err)
 295                         goto failed;
 296         }
 297
 298         /*
 299          * either allocate an extent for the new bytes or setup the key
 300          * to show we are doing inline data in the extent
 301          */
 302         inline_size = end_pos;
 303         if (isize >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 304             inline_size > root->fs_info->max_inline ||
 305             (inline_size & (root->sectorsize -1)) == 0 ||
 306             inline_size >= BTRFS_MAX_INLINE_DATA_SIZE(root)) {
 307                 /* check for reserved extents on each page, we don't want
 308                  * to reset the delalloc bit on things that already have
 309                  * extents reserved.
 310                  */
 311                 set_extent_delalloc(io_tree, start_pos,
 312                                     end_of_last_block, GFP_NOFS);
 313                 for (i = 0; i < num_pages; i++) {
 314                         struct page *p = pages[i];
 315                         SetPageUptodate(p);
 316                         ClearPageChecked(p);
 317                         set_page_dirty(p);
 318                 }
 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_throttle(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         struct extent_map *tmp;
 354         u64 len = end - start + 1;
 355         u64 next_start;
 356         int ret;
 357         int testend = 1;
 358
 359         WARN_ON(end < start);
 360         if (end == (u64)-1) {
 361                 len = (u64)-1;
 362                 testend = 0;
 363         }
 364         while(1) {
 365                 if (!split)
 366                         split = alloc_extent_map(GFP_NOFS);
 367                 if (!split2)
 368                         split2 = alloc_extent_map(GFP_NOFS);
 369
 370                 spin_lock(&em_tree->lock);
 371                 em = lookup_extent_mapping(em_tree, start, len);
 372                 if (!em) {
 373                         spin_unlock(&em_tree->lock);
 374                         break;
 375                 }
 376                 tmp = rb_entry(&em->rb_node, struct extent_map, rb_node);
 377                 next_start = tmp->start;
 378                 remove_extent_mapping(em_tree, em);
 379
 380                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
 381                     em->start < start) {
 382                         split->start = em->start;
 383                         split->len = start - em->start;
 384                         split->block_start = em->block_start;
 385                         split->bdev = em->bdev;
 386                         split->flags = em->flags;
 387                         ret = add_extent_mapping(em_tree, split);
 388                         BUG_ON(ret);
 389                         free_extent_map(split);
 390                         split = split2;
 391                         split2 = NULL;
 392                 }
 393                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
 394                     testend && em->start + em->len > start + len) {
 395                         u64 diff = start + len - em->start;
 396
 397                         split->start = start + len;
 398                         split->len = em->start + em->len - (start + len);
 399                         split->bdev = em->bdev;
 400                         split->flags = em->flags;
 401
 402                         split->block_start = em->block_start + diff;
 403
 404                         ret = add_extent_mapping(em_tree, split);
 405                         BUG_ON(ret);
 406                         free_extent_map(split);
 407                         split = NULL;
 408                 }
 409                 spin_unlock(&em_tree->lock);
 410
 411                 /* once for us */
 412                 free_extent_map(em);
 413                 /* once for the tree*/
 414                 free_extent_map(em);
 415         }
 416         if (split)
 417                 free_extent_map(split);
 418         if (split2)
 419                 free_extent_map(split2);
 420         return 0;
 421 }
 422
 423 int btrfs_check_file(struct btrfs_root *root, struct inode *inode)
 424 {
 425         return 0;
 426 #if 0
 427         struct btrfs_path *path;
 428         struct btrfs_key found_key;
 429         struct extent_buffer *leaf;
 430         struct btrfs_file_extent_item *extent;
 431         u64 last_offset = 0;
 432         int nritems;
 433         int slot;
 434         int found_type;
 435         int ret;
 436         int err = 0;
 437         u64 extent_end = 0;
 438
 439         path = btrfs_alloc_path();
 440         ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,
 441                                        last_offset, 0);
 442         while(1) {
 443                 nritems = btrfs_header_nritems(path->nodes[0]);
 444                 if (path->slots[0] >= nritems) {
 445                         ret = btrfs_next_leaf(root, path);
 446                         if (ret)
 447                                 goto out;
 448                         nritems = btrfs_header_nritems(path->nodes[0]);
 449                 }
 450                 slot = path->slots[0];
 451                 leaf = path->nodes[0];
 452                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
 453                 if (found_key.objectid != inode->i_ino)
 454                         break;
 455                 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
 456                         goto out;
 457
 458                 if (found_key.offset < last_offset) {
 459                         WARN_ON(1);
 460                         btrfs_print_leaf(root, leaf);
 461                         printk("inode %lu found offset %Lu expected %Lu\n",
 462                                inode->i_ino, found_key.offset, last_offset);
 463                         err = 1;
 464                         goto out;
 465                 }
 466                 extent = btrfs_item_ptr(leaf, slot,
 467                                         struct btrfs_file_extent_item);
 468                 found_type = btrfs_file_extent_type(leaf, extent);
 469                 if (found_type == BTRFS_FILE_EXTENT_REG) {
 470                         extent_end = found_key.offset +
 471                              btrfs_file_extent_num_bytes(leaf, extent);
 472                 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 473                         struct btrfs_item *item;
 474                         item = btrfs_item_nr(leaf, slot);
 475                         extent_end = found_key.offset +
 476                              btrfs_file_extent_inline_len(leaf, item);
 477                         extent_end = (extent_end + root->sectorsize - 1) &
 478                                 ~((u64)root->sectorsize -1 );
 479                 }
 480                 last_offset = extent_end;
 481                 path->slots[0]++;
 482         }
 483         if (0 && last_offset < inode->i_size) {
 484                 WARN_ON(1);
 485                 btrfs_print_leaf(root, leaf);
 486                 printk("inode %lu found offset %Lu size %Lu\n", inode->i_ino,
 487                        last_offset, inode->i_size);
 488                 err = 1;
 489
 490         }
 491 out:
 492         btrfs_free_path(path);
 493         return err;
 494 #endif
 495 }
 496
 497 /*
 498  * this is very complex, but the basic idea is to drop all extents
 499  * in the range start - end.  hint_block is filled in with a block number
 500  * that would be a good hint to the block allocator for this file.
 501  *
 502  * If an extent intersects the range but is not entirely inside the range
 503  * it is either truncated or split.  Anything entirely inside the range
 504  * is deleted from the tree.
 505  */
 506 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 507                        struct btrfs_root *root, struct inode *inode,
 508                        u64 start, u64 end, u64 inline_limit, u64 *hint_byte)
 509 {
 510         u64 extent_end = 0;
 511         u64 search_start = start;
 512         struct extent_buffer *leaf;
 513         struct btrfs_file_extent_item *extent;
 514         struct btrfs_path *path;
 515         struct btrfs_key key;
 516         struct btrfs_file_extent_item old;
 517         int keep;
 518         int slot;
 519         int bookend;
 520         int found_type;
 521         int found_extent;
 522         int found_inline;
 523         int recow;
 524         int ret;
 525
 526         btrfs_drop_extent_cache(inode, start, end - 1);
 527
 528         path = btrfs_alloc_path();
 529         if (!path)
 530                 return -ENOMEM;
 531         while(1) {
 532                 recow = 0;
 533                 btrfs_release_path(root, path);
 534                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
 535                                                search_start, -1);
 536                 if (ret < 0)
 537                         goto out;
 538                 if (ret > 0) {
 539                         if (path->slots[0] == 0) {
 540                                 ret = 0;
 541                                 goto out;
 542                         }
 543                         path->slots[0]--;
 544                 }
 545 next_slot:
 546                 keep = 0;
 547                 bookend = 0;
 548                 found_extent = 0;
 549                 found_inline = 0;
 550                 extent = NULL;
 551                 leaf = path->nodes[0];
 552                 slot = path->slots[0];
 553                 ret = 0;
 554                 btrfs_item_key_to_cpu(leaf, &key, slot);
 555                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
 556                     key.offset >= end) {
 557                         goto out;
 558                 }
 559                 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
 560                     key.objectid != inode->i_ino) {
 561                         goto out;
 562                 }
 563                 if (recow) {
 564                         search_start = key.offset;
 565                         continue;
 566                 }
 567                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
 568                         extent = btrfs_item_ptr(leaf, slot,
 569                                                 struct btrfs_file_extent_item);
 570                         found_type = btrfs_file_extent_type(leaf, extent);
 571                         if (found_type == BTRFS_FILE_EXTENT_REG) {
 572                                 extent_end =
 573                                      btrfs_file_extent_disk_bytenr(leaf,
 574                                                                    extent);
 575                                 if (extent_end)
 576                                         *hint_byte = extent_end;
 577
 578                                 extent_end = key.offset +
 579                                      btrfs_file_extent_num_bytes(leaf, extent);
 580                                 found_extent = 1;
 581                         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 582                                 struct btrfs_item *item;
 583                                 item = btrfs_item_nr(leaf, slot);
 584                                 found_inline = 1;
 585                                 extent_end = key.offset +
 586                                      btrfs_file_extent_inline_len(leaf, item);
 587                         }
 588                 } else {
 589                         extent_end = search_start;
 590                 }
 591
 592                 /* we found nothing we can drop */
 593                 if ((!found_extent && !found_inline) ||
 594                     search_start >= extent_end) {
 595                         int nextret;
 596                         u32 nritems;
 597                         nritems = btrfs_header_nritems(leaf);
 598                         if (slot >= nritems - 1) {
 599                                 nextret = btrfs_next_leaf(root, path);
 600                                 if (nextret)
 601                                         goto out;
 602                                 recow = 1;
 603                         } else {
 604                                 path->slots[0]++;
 605                         }
 606                         goto next_slot;
 607                 }
 608
 609                 if (found_inline) {
 610                         u64 mask = root->sectorsize - 1;
 611                         search_start = (extent_end + mask) & ~mask;
 612                 } else
 613                         search_start = extent_end;
 614                 if (end <= extent_end && start >= key.offset && found_inline) {
 615                         *hint_byte = EXTENT_MAP_INLINE;
 616                         continue;
 617                 }
 618                 if (end < extent_end && end >= key.offset) {
 619                         if (found_extent) {
 620                                 u64 disk_bytenr =
 621                                     btrfs_file_extent_disk_bytenr(leaf, extent);
 622                                 u64 disk_num_bytes =
 623                                     btrfs_file_extent_disk_num_bytes(leaf,
 624                                                                       extent);
 625                                 read_extent_buffer(leaf, &old,
 626                                                    (unsigned long)extent,
 627                                                    sizeof(old));
 628                                 if (disk_bytenr != 0) {
 629                                         ret = btrfs_inc_extent_ref(trans, root,
 630                                                  disk_bytenr, disk_num_bytes,
 631                                                  root->root_key.objectid,
 632                                                  trans->transid,
 633                                                  key.objectid, end);
 634                                         BUG_ON(ret);
 635                                 }
 636                         }
 637                         bookend = 1;
 638                         if (found_inline && start <= key.offset)
 639                                 keep = 1;
 640                 }
 641                 /* truncate existing extent */
 642                 if (start > key.offset) {
 643                         u64 new_num;
 644                         u64 old_num;
 645                         keep = 1;
 646                         WARN_ON(start & (root->sectorsize - 1));
 647                         if (found_extent) {
 648                                 new_num = start - key.offset;
 649                                 old_num = btrfs_file_extent_num_bytes(leaf,
 650                                                                       extent);
 651                                 *hint_byte =
 652                                         btrfs_file_extent_disk_bytenr(leaf,
 653                                                                       extent);
 654                                 if (btrfs_file_extent_disk_bytenr(leaf,
 655                                                                   extent)) {
 656                                         dec_i_blocks(inode, old_num - new_num);
 657                                 }
 658                                 btrfs_set_file_extent_num_bytes(leaf, extent,
 659                                                                 new_num);
 660                                 btrfs_mark_buffer_dirty(leaf);
 661                         } else if (key.offset < inline_limit &&
 662                                    (end > extent_end) &&
 663                                    (inline_limit < extent_end)) {
 664                                 u32 new_size;
 665                                 new_size = btrfs_file_extent_calc_inline_size(
 666                                                    inline_limit - key.offset);
 667                                 dec_i_blocks(inode, (extent_end - key.offset) -
 668                                         (inline_limit - key.offset));
 669                                 btrfs_truncate_item(trans, root, path,
 670                                                     new_size, 1);
 671                         }
 672                 }
 673                 /* delete the entire extent */
 674                 if (!keep) {
 675                         u64 disk_bytenr = 0;
 676                         u64 disk_num_bytes = 0;
 677                         u64 extent_num_bytes = 0;
 678                         u64 root_gen;
 679                         u64 root_owner;
 680
 681                         root_gen = btrfs_header_generation(leaf);
 682                         root_owner = btrfs_header_owner(leaf);
 683                         if (found_extent) {
 684                                 disk_bytenr =
 685                                       btrfs_file_extent_disk_bytenr(leaf,
 686                                                                      extent);
 687                                 disk_num_bytes =
 688                                       btrfs_file_extent_disk_num_bytes(leaf,
 689                                                                        extent);
 690                                 extent_num_bytes =
 691                                       btrfs_file_extent_num_bytes(leaf, extent);
 692                                 *hint_byte =
 693                                         btrfs_file_extent_disk_bytenr(leaf,
 694                                                                       extent);
 695                         }
 696                         ret = btrfs_del_item(trans, root, path);
 697                         /* TODO update progress marker and return */
 698                         BUG_ON(ret);
 699                         btrfs_release_path(root, path);
 700                         extent = NULL;
 701                         if (found_extent && disk_bytenr != 0) {
 702                                 dec_i_blocks(inode, extent_num_bytes);
 703                                 ret = btrfs_free_extent(trans, root,
 704                                                 disk_bytenr,
 705                                                 disk_num_bytes,
 706                                                 root_owner,
 707                                                 root_gen, inode->i_ino,
 708                                                 key.offset, 0);
 709                         }
 710
 711                         BUG_ON(ret);
 712                         if (!bookend && search_start >= end) {
 713                                 ret = 0;
 714                                 goto out;
 715                         }
 716                         if (!bookend)
 717                                 continue;
 718                 }
 719                 if (bookend && found_inline && start <= key.offset) {
 720                         u32 new_size;
 721                         new_size = btrfs_file_extent_calc_inline_size(
 722                                                    extent_end - end);
 723                         dec_i_blocks(inode, (extent_end - key.offset) -
 724                                         (extent_end - end));
 725                         btrfs_truncate_item(trans, root, path, new_size, 0);
 726                 }
 727                 /* create bookend, splitting the extent in two */
 728                 if (bookend && found_extent) {
 729                         struct btrfs_key ins;
 730                         ins.objectid = inode->i_ino;
 731                         ins.offset = end;
 732                         btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
 733                         btrfs_release_path(root, path);
 734                         ret = btrfs_insert_empty_item(trans, root, path, &ins,
 735                                                       sizeof(*extent));
 736
 737                         leaf = path->nodes[0];
 738                         if (ret) {
 739                                 btrfs_print_leaf(root, leaf);
 740                                 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);
 741                         }
 742                         BUG_ON(ret);
 743                         extent = btrfs_item_ptr(leaf, path->slots[0],
 744                                                 struct btrfs_file_extent_item);
 745                         write_extent_buffer(leaf, &old,
 746                                             (unsigned long)extent, sizeof(old));
 747
 748                         btrfs_set_file_extent_offset(leaf, extent,
 749                                     le64_to_cpu(old.offset) + end - key.offset);
 750                         WARN_ON(le64_to_cpu(old.num_bytes) <
 751                                 (extent_end - end));
 752                         btrfs_set_file_extent_num_bytes(leaf, extent,
 753                                                         extent_end - end);
 754                         btrfs_set_file_extent_type(leaf, extent,
 755                                                    BTRFS_FILE_EXTENT_REG);
 756
 757                         btrfs_mark_buffer_dirty(path->nodes[0]);
 758                         if (le64_to_cpu(old.disk_bytenr) != 0) {
 759                                 inode->i_blocks +=
 760                                       btrfs_file_extent_num_bytes(leaf,
 761                                                                   extent) >> 9;
 762                         }
 763                         ret = 0;
 764                         goto out;
 765                 }
 766         }
 767 out:
 768         btrfs_free_path(path);
 769         btrfs_check_file(root, inode);
 770         return ret;
 771 }
 772
 773 /*
 774  * this gets pages into the page cache and locks them down
 775  */
 776 static int prepare_pages(struct btrfs_root *root, struct file *file,
 777                          struct page **pages, size_t num_pages,
 778                          loff_t pos, unsigned long first_index,
 779                          unsigned long last_index, size_t write_bytes)
 780 {
 781         int i;
 782         unsigned long index = pos >> PAGE_CACHE_SHIFT;
 783         struct inode *inode = fdentry(file)->d_inode;
 784         int err = 0;
 785         u64 start_pos;
 786         u64 last_pos;
 787
 788         start_pos = pos & ~((u64)root->sectorsize - 1);
 789         last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
 790
 791         memset(pages, 0, num_pages * sizeof(struct page *));
 792 again:
 793         for (i = 0; i < num_pages; i++) {
 794                 pages[i] = grab_cache_page(inode->i_mapping, index + i);
 795                 if (!pages[i]) {
 796                         err = -ENOMEM;
 797                         BUG_ON(1);
 798                 }
 799                 wait_on_page_writeback(pages[i]);
 800         }
 801         if (start_pos < inode->i_size) {
 802                 struct btrfs_ordered_extent *ordered;
 803                 lock_extent(&BTRFS_I(inode)->io_tree,
 804                             start_pos, last_pos - 1, GFP_NOFS);
 805                 ordered = btrfs_lookup_first_ordered_extent(inode, last_pos -1);
 806                 if (ordered &&
 807                     ordered->file_offset + ordered->len > start_pos &&
 808                     ordered->file_offset < last_pos) {
 809                         btrfs_put_ordered_extent(ordered);
 810                         unlock_extent(&BTRFS_I(inode)->io_tree,
 811                                       start_pos, last_pos - 1, GFP_NOFS);
 812                         for (i = 0; i < num_pages; i++) {
 813                                 unlock_page(pages[i]);
 814                                 page_cache_release(pages[i]);
 815                         }
 816                         btrfs_wait_ordered_range(inode, start_pos,
 817                                                  last_pos - start_pos);
 818                         goto again;
 819                 }
 820                 if (ordered)
 821                         btrfs_put_ordered_extent(ordered);
 822
 823                 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
 824                                   last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
 825                                   GFP_NOFS);
 826                 unlock_extent(&BTRFS_I(inode)->io_tree,
 827                               start_pos, last_pos - 1, GFP_NOFS);
 828         }
 829         for (i = 0; i < num_pages; i++) {
 830 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
 831                 ClearPageDirty(pages[i]);
 832 #else
 833                 cancel_dirty_page(pages[i], PAGE_CACHE_SIZE);
 834 #endif
 835                 set_page_extent_mapped(pages[i]);
 836                 WARN_ON(!PageLocked(pages[i]));
 837         }
 838         return 0;
 839 }
 840
 841 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
 842                                 size_t count, loff_t *ppos)
 843 {
 844         loff_t pos;
 845         loff_t start_pos;
 846         ssize_t num_written = 0;
 847         ssize_t err = 0;
 848         int ret = 0;
 849         struct inode *inode = fdentry(file)->d_inode;
 850         struct btrfs_root *root = BTRFS_I(inode)->root;
 851         struct page **pages = NULL;
 852         int nrptrs;
 853         struct page *pinned[2];
 854         unsigned long first_index;
 855         unsigned long last_index;
 856
 857         nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
 858                      PAGE_CACHE_SIZE / (sizeof(struct page *)));
 859         pinned[0] = NULL;
 860         pinned[1] = NULL;
 861
 862         pos = *ppos;
 863         start_pos = pos;
 864
 865         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
 866         current->backing_dev_info = inode->i_mapping->backing_dev_info;
 867         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
 868         if (err)
 869                 goto out_nolock;
 870         if (count == 0)
 871                 goto out_nolock;
 872 #ifdef REMOVE_SUID_PATH
 873         err = remove_suid(&file->f_path);
 874 #else
 875         err = remove_suid(fdentry(file));
 876 #endif
 877         if (err)
 878                 goto out_nolock;
 879         file_update_time(file);
 880
 881         pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
 882
 883         mutex_lock(&inode->i_mutex);
 884         first_index = pos >> PAGE_CACHE_SHIFT;
 885         last_index = (pos + count) >> PAGE_CACHE_SHIFT;
 886
 887         /*
 888          * if this is a nodatasum mount, force summing off for the inode
 889          * all the time.  That way a later mount with summing on won't
 890          * get confused
 891          */
 892         if (btrfs_test_opt(root, NODATASUM))
 893                 btrfs_set_flag(inode, NODATASUM);
 894
 895         /*
 896          * there are lots of better ways to do this, but this code
 897          * makes sure the first and last page in the file range are
 898          * up to date and ready for cow
 899          */
 900         if ((pos & (PAGE_CACHE_SIZE - 1))) {
 901                 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
 902                 if (!PageUptodate(pinned[0])) {
 903                         ret = btrfs_readpage(NULL, pinned[0]);
 904                         BUG_ON(ret);
 905                         wait_on_page_locked(pinned[0]);
 906                 } else {
 907                         unlock_page(pinned[0]);
 908                 }
 909         }
 910         if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
 911                 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
 912                 if (!PageUptodate(pinned[1])) {
 913                         ret = btrfs_readpage(NULL, pinned[1]);
 914                         BUG_ON(ret);
 915                         wait_on_page_locked(pinned[1]);
 916                 } else {
 917                         unlock_page(pinned[1]);
 918                 }
 919         }
 920
 921         while(count > 0) {
 922                 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
 923                 size_t write_bytes = min(count, nrptrs *
 924                                         (size_t)PAGE_CACHE_SIZE -
 925                                          offset);
 926                 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
 927                                         PAGE_CACHE_SHIFT;
 928
 929                 WARN_ON(num_pages > nrptrs);
 930                 memset(pages, 0, sizeof(pages));
 931
 932                 ret = btrfs_check_free_space(root, write_bytes, 0);
 933                 if (ret)
 934                         goto out;
 935
 936                 ret = prepare_pages(root, file, pages, num_pages,
 937                                     pos, first_index, last_index,
 938                                     write_bytes);
 939                 if (ret)
 940                         goto out;
 941
 942                 ret = btrfs_copy_from_user(pos, num_pages,
 943                                            write_bytes, pages, buf);
 944                 if (ret) {
 945                         btrfs_drop_pages(pages, num_pages);
 946                         goto out;
 947                 }
 948
 949                 ret = dirty_and_release_pages(NULL, root, file, pages,
 950                                               num_pages, pos, write_bytes);
 951                 btrfs_drop_pages(pages, num_pages);
 952                 if (ret)
 953                         goto out;
 954
 955                 buf += write_bytes;
 956                 count -= write_bytes;
 957                 pos += write_bytes;
 958                 num_written += write_bytes;
 959
 960                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, num_pages);
 961                 if (num_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
 962                         btrfs_btree_balance_dirty(root, 1);
 963                 cond_resched();
 964         }
 965 out:
 966         mutex_unlock(&inode->i_mutex);
 967
 968 out_nolock:
 969         kfree(pages);
 970         if (pinned[0])
 971                 page_cache_release(pinned[0]);
 972         if (pinned[1])
 973                 page_cache_release(pinned[1]);
 974         *ppos = pos;
 975
 976         if (num_written > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
 977                 err = sync_page_range(inode, inode->i_mapping,
 978                                       start_pos, num_written);
 979                 if (err < 0)
 980                         num_written = err;
 981         } else if (num_written > 0 && (file->f_flags & O_DIRECT)) {
 982 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
 983                 do_sync_file_range(file, start_pos,
 984                                       start_pos + num_written - 1,
 985                                       SYNC_FILE_RANGE_WRITE |
 986                                       SYNC_FILE_RANGE_WAIT_AFTER);
 987 #else
 988                 do_sync_mapping_range(inode->i_mapping, start_pos,
 989                                       start_pos + num_written - 1,
 990                                       SYNC_FILE_RANGE_WRITE |
 991                                       SYNC_FILE_RANGE_WAIT_AFTER);
 992 #endif
 993                 invalidate_mapping_pages(inode->i_mapping,
 994                       start_pos >> PAGE_CACHE_SHIFT,
 995                      (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
 996         }
 997         current->backing_dev_info = NULL;
 998         return num_written ? num_written : err;
 999 }
1000
1001 int btrfs_release_file(struct inode * inode, struct file * filp)
1002 {
1003         if (filp->private_data)
1004                 btrfs_ioctl_trans_end(filp);
1005         return 0;
1006 }
1007
1008 static int btrfs_sync_file(struct file *file,
1009                            struct dentry *dentry, int datasync)
1010 {
1011         struct inode *inode = dentry->d_inode;
1012         struct btrfs_root *root = BTRFS_I(inode)->root;
1013         int ret = 0;
1014         struct btrfs_trans_handle *trans;
1015
1016         /*
1017          * check the transaction that last modified this inode
1018          * and see if its already been committed
1019          */
1020         if (!BTRFS_I(inode)->last_trans)
1021                 goto out;
1022
1023         mutex_lock(&root->fs_info->trans_mutex);
1024         if (BTRFS_I(inode)->last_trans <=
1025             root->fs_info->last_trans_committed) {
1026                 BTRFS_I(inode)->last_trans = 0;
1027                 mutex_unlock(&root->fs_info->trans_mutex);
1028                 goto out;
1029         }
1030         mutex_unlock(&root->fs_info->trans_mutex);
1031
1032         /*
1033          * ok we haven't committed the transaction yet, lets do a commit
1034          */
1035         if (file->private_data)
1036                 btrfs_ioctl_trans_end(file);
1037
1038         trans = btrfs_start_transaction(root, 1);
1039         if (!trans) {
1040                 ret = -ENOMEM;
1041                 goto out;
1042         }
1043         ret = btrfs_commit_transaction(trans, root);
1044 out:
1045         return ret > 0 ? EIO : ret;
1046 }
1047
1048 static struct vm_operations_struct btrfs_file_vm_ops = {
1049 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
1050         .nopage         = filemap_nopage,
1051         .populate       = filemap_populate,
1052 #else
1053         .fault          = filemap_fault,
1054 #endif
1055         .page_mkwrite   = btrfs_page_mkwrite,
1056 };
1057
1058 static int btrfs_file_mmap(struct file  *filp, struct vm_area_struct *vma)
1059 {
1060         vma->vm_ops = &btrfs_file_vm_ops;
1061         file_accessed(filp);
1062         return 0;
1063 }
1064
1065 struct file_operations btrfs_file_operations = {
1066         .llseek         = generic_file_llseek,
1067         .read           = do_sync_read,
1068         .aio_read       = generic_file_aio_read,
1069         .splice_read    = generic_file_splice_read,
1070 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
1071         .sendfile       = generic_file_sendfile,
1072 #endif
1073         .write          = btrfs_file_write,
1074         .mmap           = btrfs_file_mmap,
1075         .open           = generic_file_open,
1076         .release        = btrfs_release_file,
1077         .fsync          = btrfs_sync_file,
1078         .unlocked_ioctl = btrfs_ioctl,
1079 #ifdef CONFIG_COMPAT
1080         .compat_ioctl   = btrfs_ioctl,
1081 #endif
1082 };
1083