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         path->reada = 2;
 154
 155         WARN_ON(bio->bi_vcnt <= 0);
 156
 157         while(bio_index < bio->bi_vcnt) {
 158                 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
 159                 ret = btrfs_find_ordered_sum(inode, offset, &sum);
 160                 if (ret == 0)
 161                         goto found;
 162
 163                 if (!item || offset < item_start_offset ||
 164                     offset >= item_last_offset) {
 165                         struct btrfs_key found_key;
 166                         u32 item_size;
 167
 168                         if (item)
 169                                 btrfs_release_path(root, path);
 170                         item = btrfs_lookup_csum(NULL, root, path,
 171                                                  inode->i_ino, offset, 0);
 172                         if (IS_ERR(item)) {
 173                                 ret = PTR_ERR(item);
 174                                 if (ret == -ENOENT || ret == -EFBIG)
 175                                         ret = 0;
 176                                 sum = 0;
 177                                 printk("no csum found for inode %lu start "
 178                                        "%llu\n", inode->i_ino,
 179                                        (unsigned long long)offset);
 180                                 goto found;
 181                         }
 182                         btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 183                                               path->slots[0]);
 184
 185                         item_start_offset = found_key.offset;
 186                         item_size = btrfs_item_size_nr(path->nodes[0],
 187                                                        path->slots[0]);
 188                         item_last_offset = item_start_offset +
 189                                 (item_size / BTRFS_CRC32_SIZE) *
 190                                 root->sectorsize;
 191                         item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 192                                               struct btrfs_csum_item);
 193                 }
 194                 /*
 195                  * this byte range must be able to fit inside
 196                  * a single leaf so it will also fit inside a u32
 197                  */
 198                 diff = offset - item_start_offset;
 199                 diff = diff / root->sectorsize;
 200                 diff = diff * BTRFS_CRC32_SIZE;
 201
 202                 read_extent_buffer(path->nodes[0], &sum,
 203                                    (unsigned long)item + diff,
 204                                    BTRFS_CRC32_SIZE);
 205 found:
 206                 set_state_private(io_tree, offset, sum);
 207                 bio_index++;
 208                 bvec++;
 209         }
 210         btrfs_free_path(path);
 211         return 0;
 212 }
 213
 214 int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
 215                        struct bio *bio)
 216 {
 217         struct btrfs_ordered_sum *sums;
 218         struct btrfs_sector_sum *sector_sum;
 219         struct btrfs_ordered_extent *ordered;
 220         char *data;
 221         struct bio_vec *bvec = bio->bi_io_vec;
 222         int bio_index = 0;
 223         unsigned long total_bytes = 0;
 224         unsigned long this_sum_bytes = 0;
 225         u64 offset;
 226
 227         WARN_ON(bio->bi_vcnt <= 0);
 228         sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS);
 229         if (!sums)
 230                 return -ENOMEM;
 231
 232         sector_sum = sums->sums;
 233         sums->file_offset = page_offset(bvec->bv_page) + bvec->bv_offset;
 234         sums->len = bio->bi_size;
 235         INIT_LIST_HEAD(&sums->list);
 236         ordered = btrfs_lookup_ordered_extent(inode, sums->file_offset);
 237         BUG_ON(!ordered);
 238
 239         while(bio_index < bio->bi_vcnt) {
 240                 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
 241                 if (offset >= ordered->file_offset + ordered->len ||
 242                     offset < ordered->file_offset) {
 243                         unsigned long bytes_left;
 244                         sums->len = this_sum_bytes;
 245                         this_sum_bytes = 0;
 246                         btrfs_add_ordered_sum(inode, ordered, sums);
 247                         btrfs_put_ordered_extent(ordered);
 248
 249                         bytes_left = bio->bi_size - total_bytes;
 250
 251                         sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
 252                                        GFP_NOFS);
 253                         BUG_ON(!sums);
 254                         sector_sum = sums->sums;
 255                         sums->len = bytes_left;
 256                         sums->file_offset = offset;
 257                         ordered = btrfs_lookup_ordered_extent(inode,
 258                                                       sums->file_offset);
 259                         BUG_ON(!ordered);
 260                 }
 261
 262                 data = kmap_atomic(bvec->bv_page, KM_USER0);
 263                 sector_sum->sum = ~(u32)0;
 264                 sector_sum->sum = btrfs_csum_data(root,
 265                                                   data + bvec->bv_offset,
 266                                                   sector_sum->sum,
 267                                                   bvec->bv_len);
 268                 kunmap_atomic(data, KM_USER0);
 269                 btrfs_csum_final(sector_sum->sum,
 270                                  (char *)&sector_sum->sum);
 271                 sector_sum->offset = page_offset(bvec->bv_page) +
 272                         bvec->bv_offset;
 273
 274                 sector_sum++;
 275                 bio_index++;
 276                 total_bytes += bvec->bv_len;
 277                 this_sum_bytes += bvec->bv_len;
 278                 bvec++;
 279         }
 280         this_sum_bytes = 0;
 281         btrfs_add_ordered_sum(inode, ordered, sums);
 282         btrfs_put_ordered_extent(ordered);
 283         return 0;
 284 }
 285
 286 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 287                            struct btrfs_root *root, struct inode *inode,
 288                            struct btrfs_ordered_sum *sums)
 289 {
 290         u64 objectid = inode->i_ino;
 291         u64 offset;
 292         int ret;
 293         struct btrfs_key file_key;
 294         struct btrfs_key found_key;
 295         u64 next_offset;
 296         u64 total_bytes = 0;
 297         int found_next;
 298         struct btrfs_path *path;
 299         struct btrfs_csum_item *item;
 300         struct btrfs_csum_item *item_end;
 301         struct extent_buffer *leaf = NULL;
 302         u64 csum_offset;
 303         struct btrfs_sector_sum *sector_sum;
 304         u32 nritems;
 305         u32 ins_size;
 306         char *eb_map;
 307         char *eb_token;
 308         unsigned long map_len;
 309         unsigned long map_start;
 310
 311         path = btrfs_alloc_path();
 312         BUG_ON(!path);
 313         sector_sum = sums->sums;
 314 again:
 315         next_offset = (u64)-1;
 316         found_next = 0;
 317         offset = sector_sum->offset;
 318         file_key.objectid = objectid;
 319         file_key.offset = offset;
 320         btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
 321
 322         item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
 323         if (!IS_ERR(item)) {
 324                 leaf = path->nodes[0];
 325                 goto found;
 326         }
 327         ret = PTR_ERR(item);
 328         if (ret == -EFBIG) {
 329                 u32 item_size;
 330                 /* we found one, but it isn't big enough yet */
 331                 leaf = path->nodes[0];
 332                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 333                 if ((item_size / BTRFS_CRC32_SIZE) >= MAX_CSUM_ITEMS(root)) {
 334                         /* already at max size, make a new one */
 335                         goto insert;
 336                 }
 337         } else {
 338                 int slot = path->slots[0] + 1;
 339                 /* we didn't find a csum item, insert one */
 340                 nritems = btrfs_header_nritems(path->nodes[0]);
 341                 if (path->slots[0] >= nritems - 1) {
 342                         ret = btrfs_next_leaf(root, path);
 343                         if (ret == 1)
 344                                 found_next = 1;
 345                         if (ret != 0)
 346                                 goto insert;
 347                         slot = 0;
 348                 }
 349                 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
 350                 if (found_key.objectid != objectid ||
 351                     found_key.type != BTRFS_CSUM_ITEM_KEY) {
 352                         found_next = 1;
 353                         goto insert;
 354                 }
 355                 next_offset = found_key.offset;
 356                 found_next = 1;
 357                 goto insert;
 358         }
 359
 360         /*
 361          * at this point, we know the tree has an item, but it isn't big
 362          * enough yet to put our csum in.  Grow it
 363          */
 364         btrfs_release_path(root, path);
 365         ret = btrfs_search_slot(trans, root, &file_key, path,
 366                                 BTRFS_CRC32_SIZE, 1);
 367         if (ret < 0)
 368                 goto fail;
 369         if (ret == 0) {
 370                 BUG();
 371         }
 372         if (path->slots[0] == 0) {
 373                 goto insert;
 374         }
 375         path->slots[0]--;
 376         leaf = path->nodes[0];
 377         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 378         csum_offset = (offset - found_key.offset) >>
 379                         root->fs_info->sb->s_blocksize_bits;
 380         if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
 381             found_key.objectid != objectid ||
 382             csum_offset >= MAX_CSUM_ITEMS(root)) {
 383                 goto insert;
 384         }
 385         if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
 386             BTRFS_CRC32_SIZE) {
 387                 u32 diff = (csum_offset + 1) * BTRFS_CRC32_SIZE;
 388                 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
 389                 if (diff != BTRFS_CRC32_SIZE)
 390                         goto insert;
 391                 ret = btrfs_extend_item(trans, root, path, diff);
 392                 BUG_ON(ret);
 393                 goto csum;
 394         }
 395
 396 insert:
 397         btrfs_release_path(root, path);
 398         csum_offset = 0;
 399         if (found_next) {
 400                 u64 tmp = min((u64)i_size_read(inode), next_offset);
 401                 tmp -= offset & ~((u64)root->sectorsize -1);
 402                 tmp >>= root->fs_info->sb->s_blocksize_bits;
 403                 tmp = max((u64)1, tmp);
 404                 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root));
 405                 ins_size = BTRFS_CRC32_SIZE * tmp;
 406         } else {
 407                 ins_size = BTRFS_CRC32_SIZE;
 408         }
 409         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 410                                       ins_size);
 411         if (ret < 0)
 412                 goto fail;
 413         if (ret != 0) {
 414                 WARN_ON(1);
 415                 goto fail;
 416         }
 417 csum:
 418         leaf = path->nodes[0];
 419         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 420         ret = 0;
 421         item = (struct btrfs_csum_item *)((unsigned char *)item +
 422                                           csum_offset * BTRFS_CRC32_SIZE);
 423 found:
 424         item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 425         item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
 426                                       btrfs_item_size_nr(leaf, path->slots[0]));
 427         eb_token = NULL;
 428 next_sector:
 429
 430         if (!eb_token ||
 431            (unsigned long)item  + BTRFS_CRC32_SIZE >= map_start + map_len) {
 432                 int err;
 433
 434                 if (eb_token)
 435                         unmap_extent_buffer(leaf, eb_token, KM_USER1);
 436                 eb_token = NULL;
 437                 err = map_private_extent_buffer(leaf, (unsigned long)item,
 438                                                 BTRFS_CRC32_SIZE,
 439                                                 &eb_token, &eb_map,
 440                                                 &map_start, &map_len, KM_USER1);
 441                 if (err)
 442                         eb_token = NULL;
 443         }
 444         if (eb_token) {
 445                 memcpy(eb_token + ((unsigned long)item & (PAGE_CACHE_SIZE - 1)),
 446                        &sector_sum->sum, BTRFS_CRC32_SIZE);
 447         } else {
 448                 write_extent_buffer(leaf, &sector_sum->sum,
 449                                     (unsigned long)item, BTRFS_CRC32_SIZE);
 450         }
 451
 452         total_bytes += root->sectorsize;
 453         sector_sum++;
 454         if (total_bytes < sums->len) {
 455                 item = (struct btrfs_csum_item *)((char *)item +
 456                                                   BTRFS_CRC32_SIZE);
 457                 if (item < item_end && offset + PAGE_CACHE_SIZE ==
 458                     sector_sum->offset) {
 459                             offset = sector_sum->offset;
 460                         goto next_sector;
 461                 }
 462         }
 463         if (eb_token) {
 464                 unmap_extent_buffer(leaf, eb_token, KM_USER1);
 465                 eb_token = NULL;
 466         }
 467         btrfs_mark_buffer_dirty(path->nodes[0]);
 468         if (total_bytes < sums->len) {
 469                 btrfs_release_path(root, path);
 470                 goto again;
 471         }
 472 fail:
 473         btrfs_free_path(path);
 474         return ret;
 475 }
 476
 477 int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
 478                         struct btrfs_root *root, struct btrfs_path *path,
 479                         u64 isize)
 480 {
 481         struct btrfs_key key;
 482         struct extent_buffer *leaf = path->nodes[0];
 483         int slot = path->slots[0];
 484         int ret;
 485         u32 new_item_size;
 486         u64 new_item_span;
 487         u64 blocks;
 488
 489         btrfs_item_key_to_cpu(leaf, &key, slot);
 490         if (isize <= key.offset)
 491                 return 0;
 492         new_item_span = isize - key.offset;
 493         blocks = (new_item_span + root->sectorsize - 1) >>
 494                 root->fs_info->sb->s_blocksize_bits;
 495         new_item_size = blocks * BTRFS_CRC32_SIZE;
 496         if (new_item_size >= btrfs_item_size_nr(leaf, slot))
 497                 return 0;
 498         ret = btrfs_truncate_item(trans, root, path, new_item_size, 1);
 499         BUG_ON(ret);
 500         return ret;
 501 }