git.oblomov.eu Git - linux-2.6/blob - fs/btrfs/file.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/fs.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/highmem.h>
  22 #include <linux/time.h>
  23 #include <linux/init.h>
  24 #include <linux/string.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/backing-dev.h>
  27 #include <linux/mpage.h>
  28 #include <linux/swap.h>
  29 #include <linux/writeback.h>
  30 #include <linux/statfs.h>
  31 #include <linux/compat.h>
  32 #include <linux/version.h>
  33 #include "ctree.h"
  34 #include "disk-io.h"
  35 #include "transaction.h"
  36 #include "btrfs_inode.h"
  37 #include "ioctl.h"
  38 #include "print-tree.h"
  39 #include "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                 ClearPageChecked(pages[i]);
  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         int did_inline = 0;
 247         loff_t isize = i_size_read(inode);
 248
 249         start_pos = pos & ~((u64)root->sectorsize - 1);
 250         num_bytes = (write_bytes + pos - start_pos +
 251                     root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
 252
 253         end_of_last_block = start_pos + num_bytes - 1;
 254
 255         lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 256         trans = btrfs_start_transaction(root, 1);
 257         if (!trans) {
 258                 err = -ENOMEM;
 259                 goto out_unlock;
 260         }
 261         btrfs_set_trans_block_group(trans, inode);
 262         hint_byte = 0;
 263
 264         if ((end_of_last_block & 4095) == 0) {
 265                 printk("strange end of last %Lu %zu %Lu\n", start_pos, write_bytes, end_of_last_block);
 266         }
 267         set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 268
 269         /* FIXME...EIEIO, ENOSPC and more */
 270         /* insert any holes we need to create */
 271         if (isize < start_pos) {
 272                 u64 last_pos_in_file;
 273                 u64 hole_size;
 274                 u64 mask = root->sectorsize - 1;
 275                 last_pos_in_file = (isize + mask) & ~mask;
 276                 hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
 277                 if (hole_size > 0) {
 278                         btrfs_wait_ordered_range(inode, last_pos_in_file,
 279                                                  last_pos_in_file + hole_size);
 280                         mutex_lock(&BTRFS_I(inode)->extent_mutex);
 281                         err = btrfs_drop_extents(trans, root, inode,
 282                                                  last_pos_in_file,
 283                                                  last_pos_in_file + hole_size,
 284                                                  last_pos_in_file,
 285                                                  &hint_byte);
 286                         if (err)
 287                                 goto failed;
 288
 289                         err = btrfs_insert_file_extent(trans, root,
 290                                                        inode->i_ino,
 291                                                        last_pos_in_file,
 292                                                        0, 0, hole_size, 0);
 293                         btrfs_drop_extent_cache(inode, last_pos_in_file,
 294                                         last_pos_in_file + hole_size -1);
 295                         mutex_unlock(&BTRFS_I(inode)->extent_mutex);
 296                         btrfs_check_file(root, inode);
 297                 }
 298                 if (err)
 299                         goto failed;
 300         }
 301
 302         /*
 303          * either allocate an extent for the new bytes or setup the key
 304          * to show we are doing inline data in the extent
 305          */
 306         inline_size = end_pos;
 307         if (isize >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 308             inline_size > root->fs_info->max_inline ||
 309             (inline_size & (root->sectorsize -1)) == 0 ||
 310             inline_size >= BTRFS_MAX_INLINE_DATA_SIZE(root)) {
 311                 /* check for reserved extents on each page, we don't want
 312                  * to reset the delalloc bit on things that already have
 313                  * extents reserved.
 314                  */
 315                 set_extent_delalloc(io_tree, start_pos,
 316                                     end_of_last_block, GFP_NOFS);
 317                 for (i = 0; i < num_pages; i++) {
 318                         struct page *p = pages[i];
 319                         SetPageUptodate(p);
 320                         ClearPageChecked(p);
 321                         set_page_dirty(p);
 322                 }
 323         } else {
 324                 u64 aligned_end;
 325                 /* step one, delete the existing extents in this range */
 326                 aligned_end = (pos + write_bytes + root->sectorsize - 1) &
 327                         ~((u64)root->sectorsize - 1);
 328                 mutex_lock(&BTRFS_I(inode)->extent_mutex);
 329                 err = btrfs_drop_extents(trans, root, inode, start_pos,
 330                                          aligned_end, aligned_end, &hint_byte);
 331                 if (err)
 332                         goto failed;
 333                 if (isize > inline_size)
 334                         inline_size = min_t(u64, isize, aligned_end);
 335                 inline_size -= start_pos;
 336                 err = insert_inline_extent(trans, root, inode, start_pos,
 337                                            inline_size, pages, 0, num_pages);
 338                 btrfs_drop_extent_cache(inode, start_pos, aligned_end - 1);
 339                 BUG_ON(err);
 340                 mutex_unlock(&BTRFS_I(inode)->extent_mutex);
 341                 did_inline = 1;
 342         }
 343         if (end_pos > isize) {
 344                 i_size_write(inode, end_pos);
 345                 if (did_inline)
 346                         BTRFS_I(inode)->disk_i_size = end_pos;
 347                 btrfs_update_inode(trans, root, inode);
 348         }
 349 failed:
 350         err = btrfs_end_transaction(trans, root);
 351 out_unlock:
 352         unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 353         return err;
 354 }
 355
 356 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
 357 {
 358         struct extent_map *em;
 359         struct extent_map *split = NULL;
 360         struct extent_map *split2 = NULL;
 361         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 362         u64 len = end - start + 1;
 363         int ret;
 364         int testend = 1;
 365
 366         WARN_ON(end < start);
 367         if (end == (u64)-1) {
 368                 len = (u64)-1;
 369                 testend = 0;
 370         }
 371         while(1) {
 372                 if (!split)
 373                         split = alloc_extent_map(GFP_NOFS);
 374                 if (!split2)
 375                         split2 = alloc_extent_map(GFP_NOFS);
 376
 377                 spin_lock(&em_tree->lock);
 378                 em = lookup_extent_mapping(em_tree, start, len);
 379                 if (!em) {
 380                         spin_unlock(&em_tree->lock);
 381                         break;
 382                 }
 383                 if (test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
 384                         printk(KERN_CRIT "inode %lu trying to drop pinned "
 385                                "extent start %llu end %llu, em [%llu %llu]\n",
 386                                inode->i_ino,
 387                                (unsigned long long)start,
 388                                (unsigned long long)end,
 389                                (unsigned long long)em->start,
 390                                (unsigned long long)em->len);
 391                 }
 392                 remove_extent_mapping(em_tree, em);
 393
 394                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
 395                     em->start < start) {
 396                         split->start = em->start;
 397                         split->len = start - em->start;
 398                         split->block_start = em->block_start;
 399                         split->bdev = em->bdev;
 400                         split->flags = em->flags;
 401                         ret = add_extent_mapping(em_tree, split);
 402                         BUG_ON(ret);
 403                         free_extent_map(split);
 404                         split = split2;
 405                         split2 = NULL;
 406                 }
 407                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
 408                     testend && em->start + em->len > start + len) {
 409                         u64 diff = start + len - em->start;
 410
 411                         split->start = start + len;
 412                         split->len = em->start + em->len - (start + len);
 413                         split->bdev = em->bdev;
 414                         split->flags = em->flags;
 415
 416                         split->block_start = em->block_start + diff;
 417
 418                         ret = add_extent_mapping(em_tree, split);
 419                         BUG_ON(ret);
 420                         free_extent_map(split);
 421                         split = NULL;
 422                 }
 423                 spin_unlock(&em_tree->lock);
 424
 425                 /* once for us */
 426                 free_extent_map(em);
 427                 /* once for the tree*/
 428                 free_extent_map(em);
 429         }
 430         if (split)
 431                 free_extent_map(split);
 432         if (split2)
 433                 free_extent_map(split2);
 434         return 0;
 435 }
 436
 437 int btrfs_check_file(struct btrfs_root *root, struct inode *inode)
 438 {
 439         return 0;
 440 #if 0
 441         struct btrfs_path *path;
 442         struct btrfs_key found_key;
 443         struct extent_buffer *leaf;
 444         struct btrfs_file_extent_item *extent;
 445         u64 last_offset = 0;
 446         int nritems;
 447         int slot;
 448         int found_type;
 449         int ret;
 450         int err = 0;
 451         u64 extent_end = 0;
 452
 453         path = btrfs_alloc_path();
 454         ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,
 455                                        last_offset, 0);
 456         while(1) {
 457                 nritems = btrfs_header_nritems(path->nodes[0]);
 458                 if (path->slots[0] >= nritems) {
 459                         ret = btrfs_next_leaf(root, path);
 460                         if (ret)
 461                                 goto out;
 462                         nritems = btrfs_header_nritems(path->nodes[0]);
 463                 }
 464                 slot = path->slots[0];
 465                 leaf = path->nodes[0];
 466                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
 467                 if (found_key.objectid != inode->i_ino)
 468                         break;
 469                 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
 470                         goto out;
 471
 472                 if (found_key.offset < last_offset) {
 473                         WARN_ON(1);
 474                         btrfs_print_leaf(root, leaf);
 475                         printk("inode %lu found offset %Lu expected %Lu\n",
 476                                inode->i_ino, found_key.offset, last_offset);
 477                         err = 1;
 478                         goto out;
 479                 }
 480                 extent = btrfs_item_ptr(leaf, slot,
 481                                         struct btrfs_file_extent_item);
 482                 found_type = btrfs_file_extent_type(leaf, extent);
 483                 if (found_type == BTRFS_FILE_EXTENT_REG) {
 484                         extent_end = found_key.offset +
 485                              btrfs_file_extent_num_bytes(leaf, extent);
 486                 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 487                         struct btrfs_item *item;
 488                         item = btrfs_item_nr(leaf, slot);
 489                         extent_end = found_key.offset +
 490                              btrfs_file_extent_inline_len(leaf, item);
 491                         extent_end = (extent_end + root->sectorsize - 1) &
 492                                 ~((u64)root->sectorsize -1 );
 493                 }
 494                 last_offset = extent_end;
 495                 path->slots[0]++;
 496         }
 497         if (0 && last_offset < inode->i_size) {
 498                 WARN_ON(1);
 499                 btrfs_print_leaf(root, leaf);
 500                 printk("inode %lu found offset %Lu size %Lu\n", inode->i_ino,
 501                        last_offset, inode->i_size);
 502                 err = 1;
 503
 504         }
 505 out:
 506         btrfs_free_path(path);
 507         return err;
 508 #endif
 509 }
 510
 511 /*
 512  * this is very complex, but the basic idea is to drop all extents
 513  * in the range start - end.  hint_block is filled in with a block number
 514  * that would be a good hint to the block allocator for this file.
 515  *
 516  * If an extent intersects the range but is not entirely inside the range
 517  * it is either truncated or split.  Anything entirely inside the range
 518  * is deleted from the tree.
 519  */
 520 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 521                        struct btrfs_root *root, struct inode *inode,
 522                        u64 start, u64 end, u64 inline_limit, u64 *hint_byte)
 523 {
 524         u64 extent_end = 0;
 525         u64 search_start = start;
 526         struct extent_buffer *leaf;
 527         struct btrfs_file_extent_item *extent;
 528         struct btrfs_path *path;
 529         struct btrfs_key key;
 530         struct btrfs_file_extent_item old;
 531         int keep;
 532         int slot;
 533         int bookend;
 534         int found_type;
 535         int found_extent;
 536         int found_inline;
 537         int recow;
 538         int ret;
 539
 540         btrfs_drop_extent_cache(inode, start, end - 1);
 541
 542         path = btrfs_alloc_path();
 543         if (!path)
 544                 return -ENOMEM;
 545         while(1) {
 546                 recow = 0;
 547                 btrfs_release_path(root, path);
 548                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
 549                                                search_start, -1);
 550                 if (ret < 0)
 551                         goto out;
 552                 if (ret > 0) {
 553                         if (path->slots[0] == 0) {
 554                                 ret = 0;
 555                                 goto out;
 556                         }
 557                         path->slots[0]--;
 558                 }
 559 next_slot:
 560                 keep = 0;
 561                 bookend = 0;
 562                 found_extent = 0;
 563                 found_inline = 0;
 564                 extent = NULL;
 565                 leaf = path->nodes[0];
 566                 slot = path->slots[0];
 567                 ret = 0;
 568                 btrfs_item_key_to_cpu(leaf, &key, slot);
 569                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
 570                     key.offset >= end) {
 571                         goto out;
 572                 }
 573                 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
 574                     key.objectid != inode->i_ino) {
 575                         goto out;
 576                 }
 577                 if (recow) {
 578                         search_start = key.offset;
 579                         continue;
 580                 }
 581                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
 582                         extent = btrfs_item_ptr(leaf, slot,
 583                                                 struct btrfs_file_extent_item);
 584                         found_type = btrfs_file_extent_type(leaf, extent);
 585                         if (found_type == BTRFS_FILE_EXTENT_REG) {
 586                                 extent_end =
 587                                      btrfs_file_extent_disk_bytenr(leaf,
 588                                                                    extent);
 589                                 if (extent_end)
 590                                         *hint_byte = extent_end;
 591
 592                                 extent_end = key.offset +
 593                                      btrfs_file_extent_num_bytes(leaf, extent);
 594                                 found_extent = 1;
 595                         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 596                                 struct btrfs_item *item;
 597                                 item = btrfs_item_nr(leaf, slot);
 598                                 found_inline = 1;
 599                                 extent_end = key.offset +
 600                                      btrfs_file_extent_inline_len(leaf, item);
 601                         }
 602                 } else {
 603                         extent_end = search_start;
 604                 }
 605
 606                 /* we found nothing we can drop */
 607                 if ((!found_extent && !found_inline) ||
 608                     search_start >= extent_end) {
 609                         int nextret;
 610                         u32 nritems;
 611                         nritems = btrfs_header_nritems(leaf);
 612                         if (slot >= nritems - 1) {
 613                                 nextret = btrfs_next_leaf(root, path);
 614                                 if (nextret)
 615                                         goto out;
 616                                 recow = 1;
 617                         } else {
 618                                 path->slots[0]++;
 619                         }
 620                         goto next_slot;
 621                 }
 622
 623                 if (found_inline) {
 624                         u64 mask = root->sectorsize - 1;
 625                         search_start = (extent_end + mask) & ~mask;
 626                 } else
 627                         search_start = extent_end;
 628                 if (end <= extent_end && start >= key.offset && found_inline) {
 629                         *hint_byte = EXTENT_MAP_INLINE;
 630                         continue;
 631                 }
 632                 if (end < extent_end && end >= key.offset) {
 633                         if (found_extent) {
 634                                 u64 disk_bytenr =
 635                                     btrfs_file_extent_disk_bytenr(leaf, extent);
 636                                 u64 disk_num_bytes =
 637                                     btrfs_file_extent_disk_num_bytes(leaf,
 638                                                                       extent);
 639                                 read_extent_buffer(leaf, &old,
 640                                                    (unsigned long)extent,
 641                                                    sizeof(old));
 642                                 if (disk_bytenr != 0) {
 643                                         ret = btrfs_inc_extent_ref(trans, root,
 644                                                  disk_bytenr, disk_num_bytes,
 645                                                  root->root_key.objectid,
 646                                                  trans->transid,
 647                                                  key.objectid, end);
 648                                         BUG_ON(ret);
 649                                 }
 650                         }
 651                         bookend = 1;
 652                         if (found_inline && start <= key.offset)
 653                                 keep = 1;
 654                 }
 655                 /* truncate existing extent */
 656                 if (start > key.offset) {
 657                         u64 new_num;
 658                         u64 old_num;
 659                         keep = 1;
 660                         WARN_ON(start & (root->sectorsize - 1));
 661                         if (found_extent) {
 662                                 new_num = start - key.offset;
 663                                 old_num = btrfs_file_extent_num_bytes(leaf,
 664                                                                       extent);
 665                                 *hint_byte =
 666                                         btrfs_file_extent_disk_bytenr(leaf,
 667                                                                       extent);
 668                                 if (btrfs_file_extent_disk_bytenr(leaf,
 669                                                                   extent)) {
 670                                         dec_i_blocks(inode, old_num - new_num);
 671                                 }
 672                                 btrfs_set_file_extent_num_bytes(leaf, extent,
 673                                                                 new_num);
 674                                 btrfs_mark_buffer_dirty(leaf);
 675                         } else if (key.offset < inline_limit &&
 676                                    (end > extent_end) &&
 677                                    (inline_limit < extent_end)) {
 678                                 u32 new_size;
 679                                 new_size = btrfs_file_extent_calc_inline_size(
 680                                                    inline_limit - key.offset);
 681                                 dec_i_blocks(inode, (extent_end - key.offset) -
 682                                         (inline_limit - key.offset));
 683                                 btrfs_truncate_item(trans, root, path,
 684                                                     new_size, 1);
 685                         }
 686                 }
 687                 /* delete the entire extent */
 688                 if (!keep) {
 689                         u64 disk_bytenr = 0;
 690                         u64 disk_num_bytes = 0;
 691                         u64 extent_num_bytes = 0;
 692                         u64 root_gen;
 693                         u64 root_owner;
 694
 695                         root_gen = btrfs_header_generation(leaf);
 696                         root_owner = btrfs_header_owner(leaf);
 697                         if (found_extent) {
 698                                 disk_bytenr =
 699                                       btrfs_file_extent_disk_bytenr(leaf,
 700                                                                      extent);
 701                                 disk_num_bytes =
 702                                       btrfs_file_extent_disk_num_bytes(leaf,
 703                                                                        extent);
 704                                 extent_num_bytes =
 705                                       btrfs_file_extent_num_bytes(leaf, extent);
 706                                 *hint_byte =
 707                                         btrfs_file_extent_disk_bytenr(leaf,
 708                                                                       extent);
 709                         }
 710                         ret = btrfs_del_item(trans, root, path);
 711                         /* TODO update progress marker and return */
 712                         BUG_ON(ret);
 713                         btrfs_release_path(root, path);
 714                         extent = NULL;
 715                         if (found_extent && disk_bytenr != 0) {
 716                                 dec_i_blocks(inode, extent_num_bytes);
 717                                 ret = btrfs_free_extent(trans, root,
 718                                                 disk_bytenr,
 719                                                 disk_num_bytes,
 720                                                 root_owner,
 721                                                 root_gen, inode->i_ino,
 722                                                 key.offset, 0);
 723                         }
 724
 725                         BUG_ON(ret);
 726                         if (!bookend && search_start >= end) {
 727                                 ret = 0;
 728                                 goto out;
 729                         }
 730                         if (!bookend)
 731                                 continue;
 732                 }
 733                 if (bookend && found_inline && start <= key.offset) {
 734                         u32 new_size;
 735                         new_size = btrfs_file_extent_calc_inline_size(
 736                                                    extent_end - end);
 737                         dec_i_blocks(inode, (extent_end - key.offset) -
 738                                         (extent_end - end));
 739                         btrfs_truncate_item(trans, root, path, new_size, 0);
 740                 }
 741                 /* create bookend, splitting the extent in two */
 742                 if (bookend && found_extent) {
 743                         struct btrfs_key ins;
 744                         ins.objectid = inode->i_ino;
 745                         ins.offset = end;
 746                         btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
 747                         btrfs_release_path(root, path);
 748                         ret = btrfs_insert_empty_item(trans, root, path, &ins,
 749                                                       sizeof(*extent));
 750
 751                         leaf = path->nodes[0];
 752                         if (ret) {
 753                                 btrfs_print_leaf(root, leaf);
 754                                 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);
 755                         }
 756                         BUG_ON(ret);
 757                         extent = btrfs_item_ptr(leaf, path->slots[0],
 758                                                 struct btrfs_file_extent_item);
 759                         write_extent_buffer(leaf, &old,
 760                                             (unsigned long)extent, sizeof(old));
 761
 762                         btrfs_set_file_extent_offset(leaf, extent,
 763                                     le64_to_cpu(old.offset) + end - key.offset);
 764                         WARN_ON(le64_to_cpu(old.num_bytes) <
 765                                 (extent_end - end));
 766                         btrfs_set_file_extent_num_bytes(leaf, extent,
 767                                                         extent_end - end);
 768                         btrfs_set_file_extent_type(leaf, extent,
 769                                                    BTRFS_FILE_EXTENT_REG);
 770
 771                         btrfs_mark_buffer_dirty(path->nodes[0]);
 772                         if (le64_to_cpu(old.disk_bytenr) != 0) {
 773                                 inode->i_blocks +=
 774                                       btrfs_file_extent_num_bytes(leaf,
 775                                                                   extent) >> 9;
 776                         }
 777                         ret = 0;
 778                         goto out;
 779                 }
 780         }
 781 out:
 782         btrfs_free_path(path);
 783         btrfs_check_file(root, inode);
 784         return ret;
 785 }
 786
 787 /*
 788  * this gets pages into the page cache and locks them down
 789  */
 790 static int prepare_pages(struct btrfs_root *root, struct file *file,
 791                          struct page **pages, size_t num_pages,
 792                          loff_t pos, unsigned long first_index,
 793                          unsigned long last_index, size_t write_bytes)
 794 {
 795         int i;
 796         unsigned long index = pos >> PAGE_CACHE_SHIFT;
 797         struct inode *inode = fdentry(file)->d_inode;
 798         int err = 0;
 799         u64 start_pos;
 800         u64 last_pos;
 801
 802         start_pos = pos & ~((u64)root->sectorsize - 1);
 803         last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
 804
 805         memset(pages, 0, num_pages * sizeof(struct page *));
 806 again:
 807         for (i = 0; i < num_pages; i++) {
 808                 pages[i] = grab_cache_page(inode->i_mapping, index + i);
 809                 if (!pages[i]) {
 810                         err = -ENOMEM;
 811                         BUG_ON(1);
 812                 }
 813                 wait_on_page_writeback(pages[i]);
 814         }
 815         if (start_pos < inode->i_size) {
 816                 struct btrfs_ordered_extent *ordered;
 817                 lock_extent(&BTRFS_I(inode)->io_tree,
 818                             start_pos, last_pos - 1, GFP_NOFS);
 819                 ordered = btrfs_lookup_first_ordered_extent(inode, last_pos -1);
 820                 if (ordered &&
 821                     ordered->file_offset + ordered->len > start_pos &&
 822                     ordered->file_offset < last_pos) {
 823                         btrfs_put_ordered_extent(ordered);
 824                         unlock_extent(&BTRFS_I(inode)->io_tree,
 825                                       start_pos, last_pos - 1, GFP_NOFS);
 826                         for (i = 0; i < num_pages; i++) {
 827                                 unlock_page(pages[i]);
 828                                 page_cache_release(pages[i]);
 829                         }
 830                         btrfs_wait_ordered_range(inode, start_pos,
 831                                                  last_pos - start_pos);
 832                         goto again;
 833                 }
 834                 if (ordered)
 835                         btrfs_put_ordered_extent(ordered);
 836
 837                 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
 838                                   last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
 839                                   GFP_NOFS);
 840                 unlock_extent(&BTRFS_I(inode)->io_tree,
 841                               start_pos, last_pos - 1, GFP_NOFS);
 842         }
 843         for (i = 0; i < num_pages; i++) {
 844 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
 845                 ClearPageDirty(pages[i]);
 846 #else
 847                 cancel_dirty_page(pages[i], PAGE_CACHE_SIZE);
 848 #endif
 849                 set_page_extent_mapped(pages[i]);
 850                 WARN_ON(!PageLocked(pages[i]));
 851         }
 852         return 0;
 853 }
 854
 855 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
 856                                 size_t count, loff_t *ppos)
 857 {
 858         loff_t pos;
 859         loff_t start_pos;
 860         ssize_t num_written = 0;
 861         ssize_t err = 0;
 862         int ret = 0;
 863         struct inode *inode = fdentry(file)->d_inode;
 864         struct btrfs_root *root = BTRFS_I(inode)->root;
 865         struct page **pages = NULL;
 866         int nrptrs;
 867         struct page *pinned[2];
 868         unsigned long first_index;
 869         unsigned long last_index;
 870
 871         nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
 872                      PAGE_CACHE_SIZE / (sizeof(struct page *)));
 873         pinned[0] = NULL;
 874         pinned[1] = NULL;
 875
 876         pos = *ppos;
 877         start_pos = pos;
 878
 879         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
 880         current->backing_dev_info = inode->i_mapping->backing_dev_info;
 881         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
 882         if (err)
 883                 goto out_nolock;
 884         if (count == 0)
 885                 goto out_nolock;
 886 #ifdef REMOVE_SUID_PATH
 887         err = remove_suid(&file->f_path);
 888 #else
 889         err = remove_suid(fdentry(file));
 890 #endif
 891         if (err)
 892                 goto out_nolock;
 893         file_update_time(file);
 894
 895         pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
 896
 897         mutex_lock(&inode->i_mutex);
 898         first_index = pos >> PAGE_CACHE_SHIFT;
 899         last_index = (pos + count) >> PAGE_CACHE_SHIFT;
 900
 901         /*
 902          * if this is a nodatasum mount, force summing off for the inode
 903          * all the time.  That way a later mount with summing on won't
 904          * get confused
 905          */
 906         if (btrfs_test_opt(root, NODATASUM))
 907                 btrfs_set_flag(inode, NODATASUM);
 908
 909         /*
 910          * there are lots of better ways to do this, but this code
 911          * makes sure the first and last page in the file range are
 912          * up to date and ready for cow
 913          */
 914         if ((pos & (PAGE_CACHE_SIZE - 1))) {
 915                 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
 916                 if (!PageUptodate(pinned[0])) {
 917                         ret = btrfs_readpage(NULL, pinned[0]);
 918                         BUG_ON(ret);
 919                         wait_on_page_locked(pinned[0]);
 920                 } else {
 921                         unlock_page(pinned[0]);
 922                 }
 923         }
 924         if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
 925                 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
 926                 if (!PageUptodate(pinned[1])) {
 927                         ret = btrfs_readpage(NULL, pinned[1]);
 928                         BUG_ON(ret);
 929                         wait_on_page_locked(pinned[1]);
 930                 } else {
 931                         unlock_page(pinned[1]);
 932                 }
 933         }
 934
 935         while(count > 0) {
 936                 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
 937                 size_t write_bytes = min(count, nrptrs *
 938                                         (size_t)PAGE_CACHE_SIZE -
 939                                          offset);
 940                 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
 941                                         PAGE_CACHE_SHIFT;
 942
 943                 WARN_ON(num_pages > nrptrs);
 944                 memset(pages, 0, sizeof(pages));
 945
 946                 ret = btrfs_check_free_space(root, write_bytes, 0);
 947                 if (ret)
 948                         goto out;
 949
 950                 ret = prepare_pages(root, file, pages, num_pages,
 951                                     pos, first_index, last_index,
 952                                     write_bytes);
 953                 if (ret)
 954                         goto out;
 955
 956                 ret = btrfs_copy_from_user(pos, num_pages,
 957                                            write_bytes, pages, buf);
 958                 if (ret) {
 959                         btrfs_drop_pages(pages, num_pages);
 960                         goto out;
 961                 }
 962
 963                 ret = dirty_and_release_pages(NULL, root, file, pages,
 964                                               num_pages, pos, write_bytes);
 965                 btrfs_drop_pages(pages, num_pages);
 966                 if (ret)
 967                         goto out;
 968
 969                 buf += write_bytes;
 970                 count -= write_bytes;
 971                 pos += write_bytes;
 972                 num_written += write_bytes;
 973
 974                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, num_pages);
 975                 if (num_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
 976                         btrfs_btree_balance_dirty(root, 1);
 977                 btrfs_throttle(root);
 978                 cond_resched();
 979         }
 980 out:
 981         mutex_unlock(&inode->i_mutex);
 982
 983 out_nolock:
 984         kfree(pages);
 985         if (pinned[0])
 986                 page_cache_release(pinned[0]);
 987         if (pinned[1])
 988                 page_cache_release(pinned[1]);
 989         *ppos = pos;
 990
 991         if (num_written > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
 992                 err = sync_page_range(inode, inode->i_mapping,
 993                                       start_pos, num_written);
 994                 if (err < 0)
 995                         num_written = err;
 996         } else if (num_written > 0 && (file->f_flags & O_DIRECT)) {
 997 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
 998                 do_sync_file_range(file, start_pos,
 999                                       start_pos + num_written - 1,
1000                                       SYNC_FILE_RANGE_WRITE |
1001                                       SYNC_FILE_RANGE_WAIT_AFTER);
1002 #else
1003                 do_sync_mapping_range(inode->i_mapping, start_pos,
1004                                       start_pos + num_written - 1,
1005                                       SYNC_FILE_RANGE_WRITE |
1006                                       SYNC_FILE_RANGE_WAIT_AFTER);
1007 #endif
1008                 invalidate_mapping_pages(inode->i_mapping,
1009                       start_pos >> PAGE_CACHE_SHIFT,
1010                      (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1011         }
1012         current->backing_dev_info = NULL;
1013         return num_written ? num_written : err;
1014 }
1015
1016 int btrfs_release_file(struct inode * inode, struct file * filp)
1017 {
1018         if (filp->private_data)
1019                 btrfs_ioctl_trans_end(filp);
1020         return 0;
1021 }
1022
1023 static int btrfs_sync_file(struct file *file,
1024                            struct dentry *dentry, int datasync)
1025 {
1026         struct inode *inode = dentry->d_inode;
1027         struct btrfs_root *root = BTRFS_I(inode)->root;
1028         int ret = 0;
1029         struct btrfs_trans_handle *trans;
1030
1031         /*
1032          * check the transaction that last modified this inode
1033          * and see if its already been committed
1034          */
1035         if (!BTRFS_I(inode)->last_trans)
1036                 goto out;
1037
1038         mutex_lock(&root->fs_info->trans_mutex);
1039         if (BTRFS_I(inode)->last_trans <=
1040             root->fs_info->last_trans_committed) {
1041                 BTRFS_I(inode)->last_trans = 0;
1042                 mutex_unlock(&root->fs_info->trans_mutex);
1043                 goto out;
1044         }
1045         mutex_unlock(&root->fs_info->trans_mutex);
1046
1047         /*
1048          * ok we haven't committed the transaction yet, lets do a commit
1049          */
1050         if (file->private_data)
1051                 btrfs_ioctl_trans_end(file);
1052
1053         trans = btrfs_start_transaction(root, 1);
1054         if (!trans) {
1055                 ret = -ENOMEM;
1056                 goto out;
1057         }
1058         ret = btrfs_commit_transaction(trans, root);
1059 out:
1060         return ret > 0 ? EIO : ret;
1061 }
1062
1063 static struct vm_operations_struct btrfs_file_vm_ops = {
1064 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
1065         .nopage         = filemap_nopage,
1066         .populate       = filemap_populate,
1067 #else
1068         .fault          = filemap_fault,
1069 #endif
1070         .page_mkwrite   = btrfs_page_mkwrite,
1071 };
1072
1073 static int btrfs_file_mmap(struct file  *filp, struct vm_area_struct *vma)
1074 {
1075         vma->vm_ops = &btrfs_file_vm_ops;
1076         file_accessed(filp);
1077         return 0;
1078 }
1079
1080 struct file_operations btrfs_file_operations = {
1081         .llseek         = generic_file_llseek,
1082         .read           = do_sync_read,
1083         .aio_read       = generic_file_aio_read,
1084         .splice_read    = generic_file_splice_read,
1085 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
1086         .sendfile       = generic_file_sendfile,
1087 #endif
1088         .write          = btrfs_file_write,
1089         .mmap           = btrfs_file_mmap,
1090         .open           = generic_file_open,
1091         .release        = btrfs_release_file,
1092         .fsync          = btrfs_sync_file,
1093         .unlocked_ioctl = btrfs_ioctl,
1094 #ifdef CONFIG_COMPAT
1095         .compat_ioctl   = btrfs_ioctl,
1096 #endif
1097 };
1098