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_csum_one_bio(struct btrfs_root *root, struct inode *inode,
 138                        struct bio *bio)
 139 {
 140         struct btrfs_ordered_sum *sums;
 141         struct btrfs_sector_sum *sector_sum;
 142         struct btrfs_ordered_extent *ordered;
 143         char *data;
 144         struct bio_vec *bvec = bio->bi_io_vec;
 145         int bio_index = 0;
 146         unsigned long total_bytes = 0;
 147         unsigned long this_sum_bytes = 0;
 148         u64 offset;
 149
 150         WARN_ON(bio->bi_vcnt <= 0);
 151         sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS);
 152         if (!sums)
 153                 return -ENOMEM;
 154
 155         sector_sum = &sums->sums;
 156         sums->file_offset = page_offset(bvec->bv_page) + bvec->bv_offset;
 157         sums->len = bio->bi_size;
 158         INIT_LIST_HEAD(&sums->list);
 159         ordered = btrfs_lookup_ordered_extent(inode, sums->file_offset);
 160         BUG_ON(!ordered);
 161
 162         while(bio_index < bio->bi_vcnt) {
 163                 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
 164                 if (offset >= ordered->file_offset + ordered->len ||
 165                     offset < ordered->file_offset) {
 166                         unsigned long bytes_left;
 167                         sums->len = this_sum_bytes;
 168                         this_sum_bytes = 0;
 169                         btrfs_add_ordered_sum(inode, ordered, sums);
 170                         btrfs_put_ordered_extent(ordered);
 171
 172                         bytes_left = bio->bi_size - total_bytes;
 173
 174                         sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
 175                                        GFP_NOFS);
 176                         BUG_ON(!sums);
 177                         sector_sum = &sums->sums;
 178                         sums->len = bytes_left;
 179                         sums->file_offset = offset;
 180                         ordered = btrfs_lookup_ordered_extent(inode,
 181                                                       sums->file_offset);
 182                         BUG_ON(!ordered);
 183                 }
 184
 185                 data = kmap_atomic(bvec->bv_page, KM_USER0);
 186                 sector_sum->sum = ~(u32)0;
 187                 sector_sum->sum = btrfs_csum_data(root,
 188                                                   data + bvec->bv_offset,
 189                                                   sector_sum->sum,
 190                                                   bvec->bv_len);
 191                 kunmap_atomic(data, KM_USER0);
 192                 btrfs_csum_final(sector_sum->sum,
 193                                  (char *)&sector_sum->sum);
 194                 sector_sum->offset = page_offset(bvec->bv_page) +
 195                         bvec->bv_offset;
 196                 sector_sum++;
 197                 bio_index++;
 198                 total_bytes += bvec->bv_len;
 199                 this_sum_bytes += bvec->bv_len;
 200                 bvec++;
 201         }
 202         btrfs_add_ordered_sum(inode, ordered, sums);
 203         btrfs_put_ordered_extent(ordered);
 204         return 0;
 205 }
 206
 207 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 208                            struct btrfs_root *root, struct inode *inode,
 209                            struct btrfs_ordered_sum *sums)
 210 {
 211         u64 objectid = inode->i_ino;
 212         u64 offset;
 213         int ret;
 214         struct btrfs_key file_key;
 215         struct btrfs_key found_key;
 216         u64 next_offset;
 217         u64 total_bytes = 0;
 218         int found_next;
 219         struct btrfs_path *path;
 220         struct btrfs_csum_item *item;
 221         struct btrfs_csum_item *item_end;
 222         struct extent_buffer *leaf = NULL;
 223         u64 csum_offset;
 224         struct btrfs_sector_sum *sector_sum;
 225         u32 nritems;
 226         u32 ins_size;
 227         char *eb_map;
 228         char *eb_token;
 229         unsigned long map_len;
 230         unsigned long map_start;
 231
 232         path = btrfs_alloc_path();
 233         BUG_ON(!path);
 234         sector_sum = &sums->sums;
 235 again:
 236         next_offset = (u64)-1;
 237         found_next = 0;
 238         offset = sector_sum->offset;
 239         file_key.objectid = objectid;
 240         file_key.offset = offset;
 241         btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
 242
 243         item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
 244         if (!IS_ERR(item)) {
 245                 leaf = path->nodes[0];
 246                 goto found;
 247         }
 248         ret = PTR_ERR(item);
 249         if (ret == -EFBIG) {
 250                 u32 item_size;
 251                 /* we found one, but it isn't big enough yet */
 252                 leaf = path->nodes[0];
 253                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 254                 if ((item_size / BTRFS_CRC32_SIZE) >= MAX_CSUM_ITEMS(root)) {
 255                         /* already at max size, make a new one */
 256                         goto insert;
 257                 }
 258         } else {
 259                 int slot = path->slots[0] + 1;
 260                 /* we didn't find a csum item, insert one */
 261                 nritems = btrfs_header_nritems(path->nodes[0]);
 262                 if (path->slots[0] >= nritems - 1) {
 263                         ret = btrfs_next_leaf(root, path);
 264                         if (ret == 1)
 265                                 found_next = 1;
 266                         if (ret != 0)
 267                                 goto insert;
 268                         slot = 0;
 269                 }
 270                 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
 271                 if (found_key.objectid != objectid ||
 272                     found_key.type != BTRFS_CSUM_ITEM_KEY) {
 273                         found_next = 1;
 274                         goto insert;
 275                 }
 276                 next_offset = found_key.offset;
 277                 found_next = 1;
 278                 goto insert;
 279         }
 280
 281         /*
 282          * at this point, we know the tree has an item, but it isn't big
 283          * enough yet to put our csum in.  Grow it
 284          */
 285         btrfs_release_path(root, path);
 286         ret = btrfs_search_slot(trans, root, &file_key, path,
 287                                 BTRFS_CRC32_SIZE, 1);
 288         if (ret < 0)
 289                 goto fail;
 290         if (ret == 0) {
 291                 BUG();
 292         }
 293         if (path->slots[0] == 0) {
 294                 goto insert;
 295         }
 296         path->slots[0]--;
 297         leaf = path->nodes[0];
 298         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 299         csum_offset = (offset - found_key.offset) >>
 300                         root->fs_info->sb->s_blocksize_bits;
 301         if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
 302             found_key.objectid != objectid ||
 303             csum_offset >= MAX_CSUM_ITEMS(root)) {
 304                 goto insert;
 305         }
 306         if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
 307             BTRFS_CRC32_SIZE) {
 308                 u32 diff = (csum_offset + 1) * BTRFS_CRC32_SIZE;
 309                 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
 310                 if (diff != BTRFS_CRC32_SIZE)
 311                         goto insert;
 312                 ret = btrfs_extend_item(trans, root, path, diff);
 313                 BUG_ON(ret);
 314                 goto csum;
 315         }
 316
 317 insert:
 318         btrfs_release_path(root, path);
 319         csum_offset = 0;
 320         if (found_next) {
 321                 u64 tmp = min((u64)i_size_read(inode), next_offset);
 322                 tmp -= offset & ~((u64)root->sectorsize -1);
 323                 tmp >>= root->fs_info->sb->s_blocksize_bits;
 324                 tmp = max((u64)1, tmp);
 325                 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root));
 326                 ins_size = BTRFS_CRC32_SIZE * tmp;
 327         } else {
 328                 ins_size = BTRFS_CRC32_SIZE;
 329         }
 330         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 331                                       ins_size);
 332         if (ret < 0)
 333                 goto fail;
 334         if (ret != 0) {
 335                 WARN_ON(1);
 336                 goto fail;
 337         }
 338 csum:
 339         leaf = path->nodes[0];
 340         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 341         ret = 0;
 342         item = (struct btrfs_csum_item *)((unsigned char *)item +
 343                                           csum_offset * BTRFS_CRC32_SIZE);
 344 found:
 345         item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 346         item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
 347                                       btrfs_item_size_nr(leaf, path->slots[0]));
 348         eb_token = NULL;
 349 next_sector:
 350
 351         if (!eb_token ||
 352            (unsigned long)item  + BTRFS_CRC32_SIZE >= map_start + map_len) {
 353                 int err;
 354
 355                 if (eb_token)
 356                         unmap_extent_buffer(leaf, eb_token, KM_USER1);
 357                 eb_token = NULL;
 358                 err = map_private_extent_buffer(leaf, (unsigned long)item,
 359                                                 BTRFS_CRC32_SIZE,
 360                                                 &eb_token, &eb_map,
 361                                                 &map_start, &map_len, KM_USER1);
 362                 if (err)
 363                         eb_token = NULL;
 364         }
 365         if (eb_token) {
 366                 memcpy(eb_token + ((unsigned long)item & (PAGE_CACHE_SIZE - 1)),
 367                        &sector_sum->sum, BTRFS_CRC32_SIZE);
 368         } else {
 369                 write_extent_buffer(leaf, &sector_sum->sum,
 370                                     (unsigned long)item, BTRFS_CRC32_SIZE);
 371         }
 372
 373         total_bytes += root->sectorsize;
 374         sector_sum++;
 375         if (total_bytes < sums->len) {
 376                 item = (struct btrfs_csum_item *)((char *)item +
 377                                                   BTRFS_CRC32_SIZE);
 378                 if (item < item_end && offset + PAGE_CACHE_SIZE ==
 379                     sector_sum->offset) {
 380                             offset = sector_sum->offset;
 381                         goto next_sector;
 382                 }
 383         }
 384         if (eb_token) {
 385                 unmap_extent_buffer(leaf, eb_token, KM_USER1);
 386                 eb_token = NULL;
 387         }
 388         btrfs_mark_buffer_dirty(path->nodes[0]);
 389         if (total_bytes < sums->len) {
 390                 btrfs_release_path(root, path);
 391                 goto again;
 392         }
 393 fail:
 394         btrfs_free_path(path);
 395         return ret;
 396 }
 397
 398 int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
 399                         struct btrfs_root *root, struct btrfs_path *path,
 400                         u64 isize)
 401 {
 402         struct btrfs_key key;
 403         struct extent_buffer *leaf = path->nodes[0];
 404         int slot = path->slots[0];
 405         int ret;
 406         u32 new_item_size;
 407         u64 new_item_span;
 408         u64 blocks;
 409
 410         btrfs_item_key_to_cpu(leaf, &key, slot);
 411         if (isize <= key.offset)
 412                 return 0;
 413         new_item_span = isize - key.offset;
 414         blocks = (new_item_span + root->sectorsize - 1) >>
 415                 root->fs_info->sb->s_blocksize_bits;
 416         new_item_size = blocks * BTRFS_CRC32_SIZE;
 417         if (new_item_size >= btrfs_item_size_nr(leaf, slot))
 418                 return 0;
 419         ret = btrfs_truncate_item(trans, root, path, new_item_size, 1);
 420         BUG_ON(ret);
 421         return ret;
 422 }
 423