fs/btrfs/file-item.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/bio.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/highmem.h>
  22 #include "ctree.h"
  23 #include "disk-io.h"
  24 #include "transaction.h"
  25 #include "print-tree.h"
  26
  27 #define MAX_CSUM_ITEMS(r) ((((BTRFS_LEAF_DATA_SIZE(r) - \
  28                                sizeof(struct btrfs_item) * 2) / \
  29                                BTRFS_CRC32_SIZE) - 1))
  30 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
  31                              struct btrfs_root *root,
  32                              u64 objectid, u64 pos,
  33                              u64 disk_offset, u64 disk_num_bytes,
  34                              u64 num_bytes, u64 offset)
  35 {
  36         int ret = 0;
  37         struct btrfs_file_extent_item *item;
  38         struct btrfs_key file_key;
  39         struct btrfs_path *path;
  40         struct extent_buffer *leaf;
  41
  42         path = btrfs_alloc_path();
  43         BUG_ON(!path);
  44         file_key.objectid = objectid;
  45         file_key.offset = pos;
  46         btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
  47
  48         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
  49                                       sizeof(*item));
  50         if (ret < 0)
  51                 goto out;
  52         BUG_ON(ret);
  53         leaf = path->nodes[0];
  54         item = btrfs_item_ptr(leaf, path->slots[0],
  55                               struct btrfs_file_extent_item);
  56         btrfs_set_file_extent_disk_bytenr(leaf, item, disk_offset);
  57         btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
  58         btrfs_set_file_extent_offset(leaf, item, offset);
  59         btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
  60         btrfs_set_file_extent_generation(leaf, item, trans->transid);
  61         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
  62         btrfs_mark_buffer_dirty(leaf);
  63 out:
  64         btrfs_free_path(path);
  65         return ret;
  66 }
  67
  68 struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
  69                                           struct btrfs_root *root,
  70                                           struct btrfs_path *path,
  71                                           u64 objectid, u64 offset,
  72                                           int cow)
  73 {
  74         int ret;
  75         struct btrfs_key file_key;
  76         struct btrfs_key found_key;
  77         struct btrfs_csum_item *item;
  78         struct extent_buffer *leaf;
  79         u64 csum_offset = 0;
  80         int csums_in_item;
  81
  82         file_key.objectid = objectid;
  83         file_key.offset = offset;
  84         btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
  85         ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
  86         if (ret < 0)
  87                 goto fail;
  88         leaf = path->nodes[0];
  89         if (ret > 0) {
  90                 ret = 1;
  91                 if (path->slots[0] == 0)
  92                         goto fail;
  93                 path->slots[0]--;
  94                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
  95                 if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
  96                     found_key.objectid != objectid) {
  97                         goto fail;
  98                 }
  99                 csum_offset = (offset - found_key.offset) >>
 100                                 root->fs_info->sb->s_blocksize_bits;
 101                 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
 102                 csums_in_item /= BTRFS_CRC32_SIZE;
 103
 104                 if (csum_offset >= csums_in_item) {
 105                         ret = -EFBIG;
 106                         goto fail;
 107                 }
 108         }
 109         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 110         item = (struct btrfs_csum_item *)((unsigned char *)item +
 111                                           csum_offset * BTRFS_CRC32_SIZE);
 112         return item;
 113 fail:
 114         if (ret > 0)
 115                 ret = -ENOENT;
 116         return ERR_PTR(ret);
 117 }
 118
 119
 120 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
 121                              struct btrfs_root *root,
 122                              struct btrfs_path *path, u64 objectid,
 123                              u64 offset, int mod)
 124 {
 125         int ret;
 126         struct btrfs_key file_key;
 127         int ins_len = mod < 0 ? -1 : 0;
 128         int cow = mod != 0;
 129
 130         file_key.objectid = objectid;
 131         file_key.offset = offset;
 132         btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
 133         ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
 134         return ret;
 135 }
 136
 137 int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode,
 138                           struct bio *bio)
 139 {
 140         u32 sum;
 141         struct bio_vec *bvec = bio->bi_io_vec;
 142         int bio_index = 0;
 143         u64 offset;
 144         u64 item_start_offset = 0;
 145         u64 item_last_offset = 0;
 146         u32 diff;
 147         int ret;
 148         struct btrfs_path *path;
 149         struct btrfs_csum_item *item = NULL;
 150         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 151
 152         path = btrfs_alloc_path();
 153         if (bio->bi_size > PAGE_CACHE_SIZE * 8)
 154                 path->reada = 2;
 155
 156         WARN_ON(bio->bi_vcnt <= 0);
 157
 158         while(bio_index < bio->bi_vcnt) {
 159                 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
 160                 ret = btrfs_find_ordered_sum(inode, offset, &sum);
 161                 if (ret == 0)
 162                         goto found;
 163
 164                 if (!item || offset < item_start_offset ||
 165                     offset >= item_last_offset) {
 166                         struct btrfs_key found_key;
 167                         u32 item_size;
 168
 169                         if (item)
 170                                 btrfs_release_path(root, path);
 171                         item = btrfs_lookup_csum(NULL, root, path,
 172                                                  inode->i_ino, offset, 0);
 173                         if (IS_ERR(item)) {
 174                                 ret = PTR_ERR(item);
 175                                 if (ret == -ENOENT || ret == -EFBIG)
 176                                         ret = 0;
 177                                 sum = 0;
 178                                 printk("no csum found for inode %lu start "
 179                                        "%llu\n", inode->i_ino,
 180                                        (unsigned long long)offset);
 181                                 item = NULL;
 182                                 goto found;
 183                         }
 184                         btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 185                                               path->slots[0]);
 186
 187                         item_start_offset = found_key.offset;
 188                         item_size = btrfs_item_size_nr(path->nodes[0],
 189                                                        path->slots[0]);
 190                         item_last_offset = item_start_offset +
 191                                 (item_size / BTRFS_CRC32_SIZE) *
 192                                 root->sectorsize;
 193                         item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 194                                               struct btrfs_csum_item);
 195                 }
 196                 /*
 197                  * this byte range must be able to fit inside
 198                  * a single leaf so it will also fit inside a u32
 199                  */
 200                 diff = offset - item_start_offset;
 201                 diff = diff / root->sectorsize;
 202                 diff = diff * BTRFS_CRC32_SIZE;
 203
 204                 read_extent_buffer(path->nodes[0], &sum,
 205                                    ((unsigned long)item) + diff,
 206                                    BTRFS_CRC32_SIZE);
 207 found:
 208                 set_state_private(io_tree, offset, sum);
 209                 bio_index++;
 210                 bvec++;
 211         }
 212         btrfs_free_path(path);
 213         return 0;
 214 }
 215
 216 int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
 217                        struct bio *bio)
 218 {
 219         struct btrfs_ordered_sum *sums;
 220         struct btrfs_sector_sum *sector_sum;
 221         struct btrfs_ordered_extent *ordered;
 222         char *data;
 223         struct bio_vec *bvec = bio->bi_io_vec;
 224         int bio_index = 0;
 225         unsigned long total_bytes = 0;
 226         unsigned long this_sum_bytes = 0;
 227         u64 offset;
 228
 229         WARN_ON(bio->bi_vcnt <= 0);
 230         sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS);
 231         if (!sums)
 232                 return -ENOMEM;
 233
 234         sector_sum = sums->sums;
 235         sums->file_offset = page_offset(bvec->bv_page) + bvec->bv_offset;
 236         sums->len = bio->bi_size;
 237         INIT_LIST_HEAD(&sums->list);
 238         ordered = btrfs_lookup_ordered_extent(inode, sums->file_offset);
 239         BUG_ON(!ordered);
 240
 241         while(bio_index < bio->bi_vcnt) {
 242                 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
 243                 if (offset >= ordered->file_offset + ordered->len ||
 244                     offset < ordered->file_offset) {
 245                         unsigned long bytes_left;
 246                         sums->len = this_sum_bytes;
 247                         this_sum_bytes = 0;
 248                         btrfs_add_ordered_sum(inode, ordered, sums);
 249                         btrfs_put_ordered_extent(ordered);
 250
 251                         bytes_left = bio->bi_size - total_bytes;
 252
 253                         sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
 254                                        GFP_NOFS);
 255                         BUG_ON(!sums);
 256                         sector_sum = sums->sums;
 257                         sums->len = bytes_left;
 258                         sums->file_offset = offset;
 259                         ordered = btrfs_lookup_ordered_extent(inode,
 260                                                       sums->file_offset);
 261                         BUG_ON(!ordered);
 262                 }
 263
 264                 data = kmap_atomic(bvec->bv_page, KM_USER0);
 265                 sector_sum->sum = ~(u32)0;
 266                 sector_sum->sum = btrfs_csum_data(root,
 267                                                   data + bvec->bv_offset,
 268                                                   sector_sum->sum,
 269                                                   bvec->bv_len);
 270                 kunmap_atomic(data, KM_USER0);
 271                 btrfs_csum_final(sector_sum->sum,
 272                                  (char *)&sector_sum->sum);
 273                 sector_sum->offset = page_offset(bvec->bv_page) +
 274                         bvec->bv_offset;
 275
 276                 sector_sum++;
 277                 bio_index++;
 278                 total_bytes += bvec->bv_len;
 279                 this_sum_bytes += bvec->bv_len;
 280                 bvec++;
 281         }
 282         this_sum_bytes = 0;
 283         btrfs_add_ordered_sum(inode, ordered, sums);
 284         btrfs_put_ordered_extent(ordered);
 285         return 0;
 286 }
 287
 288 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 289                            struct btrfs_root *root, struct inode *inode,
 290                            struct btrfs_ordered_sum *sums)
 291 {
 292         u64 objectid = inode->i_ino;
 293         u64 offset;
 294         int ret;
 295         struct btrfs_key file_key;
 296         struct btrfs_key found_key;
 297         u64 next_offset;
 298         u64 total_bytes = 0;
 299         int found_next;
 300         struct btrfs_path *path;
 301         struct btrfs_csum_item *item;
 302         struct btrfs_csum_item *item_end;
 303         struct extent_buffer *leaf = NULL;
 304         u64 csum_offset;
 305         struct btrfs_sector_sum *sector_sum;
 306         u32 nritems;
 307         u32 ins_size;
 308         char *eb_map;
 309         char *eb_token;
 310         unsigned long map_len;
 311         unsigned long map_start;
 312
 313         path = btrfs_alloc_path();
 314         BUG_ON(!path);
 315         sector_sum = sums->sums;
 316 again:
 317         next_offset = (u64)-1;
 318         found_next = 0;
 319         offset = sector_sum->offset;
 320         file_key.objectid = objectid;
 321         file_key.offset = offset;
 322         btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
 323
 324         mutex_lock(&BTRFS_I(inode)->csum_mutex);
 325         item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
 326         if (!IS_ERR(item)) {
 327                 leaf = path->nodes[0];
 328                 ret = 0;
 329                 goto found;
 330         }
 331         ret = PTR_ERR(item);
 332         if (ret == -EFBIG) {
 333                 u32 item_size;
 334                 /* we found one, but it isn't big enough yet */
 335                 leaf = path->nodes[0];
 336                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 337                 if ((item_size / BTRFS_CRC32_SIZE) >= MAX_CSUM_ITEMS(root)) {
 338                         /* already at max size, make a new one */
 339                         goto insert;
 340                 }
 341         } else {
 342                 int slot = path->slots[0] + 1;
 343                 /* we didn't find a csum item, insert one */
 344                 nritems = btrfs_header_nritems(path->nodes[0]);
 345                 if (path->slots[0] >= nritems - 1) {
 346                         ret = btrfs_next_leaf(root, path);
 347                         if (ret == 1)
 348                                 found_next = 1;
 349                         if (ret != 0)
 350                                 goto insert;
 351                         slot = 0;
 352                 }
 353                 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
 354                 if (found_key.objectid != objectid ||
 355                     found_key.type != BTRFS_CSUM_ITEM_KEY) {
 356                         found_next = 1;
 357                         goto insert;
 358                 }
 359                 next_offset = found_key.offset;
 360                 found_next = 1;
 361                 goto insert;
 362         }
 363
 364         /*
 365          * at this point, we know the tree has an item, but it isn't big
 366          * enough yet to put our csum in.  Grow it
 367          */
 368         btrfs_release_path(root, path);
 369         ret = btrfs_search_slot(trans, root, &file_key, path,
 370                                 BTRFS_CRC32_SIZE, 1);
 371         if (ret < 0)
 372                 goto fail_unlock;
 373         if (ret == 0) {
 374                 BUG();
 375         }
 376         if (path->slots[0] == 0) {
 377                 goto insert;
 378         }
 379         path->slots[0]--;
 380         leaf = path->nodes[0];
 381         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 382         csum_offset = (offset - found_key.offset) >>
 383                         root->fs_info->sb->s_blocksize_bits;
 384         if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
 385             found_key.objectid != objectid ||
 386             csum_offset >= MAX_CSUM_ITEMS(root)) {
 387                 goto insert;
 388         }
 389         if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
 390             BTRFS_CRC32_SIZE) {
 391                 u32 diff = (csum_offset + 1) * BTRFS_CRC32_SIZE;
 392                 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
 393                 if (diff != BTRFS_CRC32_SIZE)
 394                         goto insert;
 395                 ret = btrfs_extend_item(trans, root, path, diff);
 396                 BUG_ON(ret);
 397                 goto csum;
 398         }
 399
 400 insert:
 401         btrfs_release_path(root, path);
 402         csum_offset = 0;
 403         if (found_next) {
 404                 u64 tmp = min((u64)i_size_read(inode), next_offset);
 405                 tmp -= offset & ~((u64)root->sectorsize -1);
 406                 tmp >>= root->fs_info->sb->s_blocksize_bits;
 407                 tmp = max((u64)1, tmp);
 408                 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root));
 409                 ins_size = BTRFS_CRC32_SIZE * tmp;
 410         } else {
 411                 ins_size = BTRFS_CRC32_SIZE;
 412         }
 413         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 414                                       ins_size);
 415         if (ret < 0)
 416                 goto fail_unlock;
 417         if (ret != 0) {
 418                 WARN_ON(1);
 419                 goto fail_unlock;
 420         }
 421 csum:
 422         leaf = path->nodes[0];
 423         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 424         ret = 0;
 425         item = (struct btrfs_csum_item *)((unsigned char *)item +
 426                                           csum_offset * BTRFS_CRC32_SIZE);
 427 found:
 428         item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 429         item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
 430                                       btrfs_item_size_nr(leaf, path->slots[0]));
 431         eb_token = NULL;
 432         mutex_unlock(&BTRFS_I(inode)->csum_mutex);
 433         cond_resched();
 434 next_sector:
 435
 436         if (!eb_token ||
 437            (unsigned long)item  + BTRFS_CRC32_SIZE >= map_start + map_len) {
 438                 int err;
 439
 440                 if (eb_token)
 441                         unmap_extent_buffer(leaf, eb_token, KM_USER1);
 442                 eb_token = NULL;
 443                 err = map_private_extent_buffer(leaf, (unsigned long)item,
 444                                                 BTRFS_CRC32_SIZE,
 445                                                 &eb_token, &eb_map,
 446                                                 &map_start, &map_len, KM_USER1);
 447                 if (err)
 448                         eb_token = NULL;
 449         }
 450         if (eb_token) {
 451                 memcpy(eb_token + ((unsigned long)item & (PAGE_CACHE_SIZE - 1)),
 452                        &sector_sum->sum, BTRFS_CRC32_SIZE);
 453         } else {
 454                 write_extent_buffer(leaf, &sector_sum->sum,
 455                                     (unsigned long)item, BTRFS_CRC32_SIZE);
 456         }
 457
 458         total_bytes += root->sectorsize;
 459         sector_sum++;
 460         if (total_bytes < sums->len) {
 461                 item = (struct btrfs_csum_item *)((char *)item +
 462                                                   BTRFS_CRC32_SIZE);
 463                 if (item < item_end && offset + PAGE_CACHE_SIZE ==
 464                     sector_sum->offset) {
 465                             offset = sector_sum->offset;
 466                         goto next_sector;
 467                 }
 468         }
 469         if (eb_token) {
 470                 unmap_extent_buffer(leaf, eb_token, KM_USER1);
 471                 eb_token = NULL;
 472         }
 473         btrfs_mark_buffer_dirty(path->nodes[0]);
 474         cond_resched();
 475         if (total_bytes < sums->len) {
 476                 btrfs_release_path(root, path);
 477                 goto again;
 478         }
 479 out:
 480         btrfs_free_path(path);
 481         return ret;
 482
 483 fail_unlock:
 484         mutex_unlock(&BTRFS_I(inode)->csum_mutex);
 485         goto out;
 486 }
 487
 488 int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
 489                         struct btrfs_root *root, struct btrfs_path *path,
 490                         u64 isize)
 491 {
 492         struct btrfs_key key;
 493         struct extent_buffer *leaf = path->nodes[0];
 494         int slot = path->slots[0];
 495         int ret;
 496         u32 new_item_size;
 497         u64 new_item_span;
 498         u64 blocks;
 499
 500         btrfs_item_key_to_cpu(leaf, &key, slot);
 501         if (isize <= key.offset)
 502                 return 0;
 503         new_item_span = isize - key.offset;
 504         blocks = (new_item_span + root->sectorsize - 1) >>
 505                 root->fs_info->sb->s_blocksize_bits;
 506         new_item_size = blocks * BTRFS_CRC32_SIZE;
 507         if (new_item_size >= btrfs_item_size_nr(leaf, slot))
 508                 return 0;
 509         ret = btrfs_truncate_item(trans, root, path, new_item_size, 1);
 510         BUG_ON(ret);
 511         return ret;
 512 }