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
 197                 sector_sum++;
 198                 bio_index++;
 199                 total_bytes += bvec->bv_len;
 200                 this_sum_bytes += bvec->bv_len;
 201                 bvec++;
 202         }
 203         this_sum_bytes = 0;
 204         btrfs_add_ordered_sum(inode, ordered, sums);
 205         btrfs_put_ordered_extent(ordered);
 206         return 0;
 207 }
 208
 209 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 210                            struct btrfs_root *root, struct inode *inode,
 211                            struct btrfs_ordered_sum *sums)
 212 {
 213         u64 objectid = inode->i_ino;
 214         u64 offset;
 215         int ret;
 216         struct btrfs_key file_key;
 217         struct btrfs_key found_key;
 218         u64 next_offset;
 219         u64 total_bytes = 0;
 220         int found_next;
 221         struct btrfs_path *path;
 222         struct btrfs_csum_item *item;
 223         struct btrfs_csum_item *item_end;
 224         struct extent_buffer *leaf = NULL;
 225         u64 csum_offset;
 226         struct btrfs_sector_sum *sector_sum;
 227         u32 nritems;
 228         u32 ins_size;
 229         char *eb_map;
 230         char *eb_token;
 231         unsigned long map_len;
 232         unsigned long map_start;
 233
 234         path = btrfs_alloc_path();
 235         BUG_ON(!path);
 236         sector_sum = sums->sums;
 237 again:
 238         next_offset = (u64)-1;
 239         found_next = 0;
 240         offset = sector_sum->offset;
 241         file_key.objectid = objectid;
 242         file_key.offset = offset;
 243         btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
 244
 245         item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
 246         if (!IS_ERR(item)) {
 247                 leaf = path->nodes[0];
 248                 goto found;
 249         }
 250         ret = PTR_ERR(item);
 251         if (ret == -EFBIG) {
 252                 u32 item_size;
 253                 /* we found one, but it isn't big enough yet */
 254                 leaf = path->nodes[0];
 255                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 256                 if ((item_size / BTRFS_CRC32_SIZE) >= MAX_CSUM_ITEMS(root)) {
 257                         /* already at max size, make a new one */
 258                         goto insert;
 259                 }
 260         } else {
 261                 int slot = path->slots[0] + 1;
 262                 /* we didn't find a csum item, insert one */
 263                 nritems = btrfs_header_nritems(path->nodes[0]);
 264                 if (path->slots[0] >= nritems - 1) {
 265                         ret = btrfs_next_leaf(root, path);
 266                         if (ret == 1)
 267                                 found_next = 1;
 268                         if (ret != 0)
 269                                 goto insert;
 270                         slot = 0;
 271                 }
 272                 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
 273                 if (found_key.objectid != objectid ||
 274                     found_key.type != BTRFS_CSUM_ITEM_KEY) {
 275                         found_next = 1;
 276                         goto insert;
 277                 }
 278                 next_offset = found_key.offset;
 279                 found_next = 1;
 280                 goto insert;
 281         }
 282
 283         /*
 284          * at this point, we know the tree has an item, but it isn't big
 285          * enough yet to put our csum in.  Grow it
 286          */
 287         btrfs_release_path(root, path);
 288         ret = btrfs_search_slot(trans, root, &file_key, path,
 289                                 BTRFS_CRC32_SIZE, 1);
 290         if (ret < 0)
 291                 goto fail;
 292         if (ret == 0) {
 293                 BUG();
 294         }
 295         if (path->slots[0] == 0) {
 296                 goto insert;
 297         }
 298         path->slots[0]--;
 299         leaf = path->nodes[0];
 300         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 301         csum_offset = (offset - found_key.offset) >>
 302                         root->fs_info->sb->s_blocksize_bits;
 303         if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
 304             found_key.objectid != objectid ||
 305             csum_offset >= MAX_CSUM_ITEMS(root)) {
 306                 goto insert;
 307         }
 308         if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
 309             BTRFS_CRC32_SIZE) {
 310                 u32 diff = (csum_offset + 1) * BTRFS_CRC32_SIZE;
 311                 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
 312                 if (diff != BTRFS_CRC32_SIZE)
 313                         goto insert;
 314                 ret = btrfs_extend_item(trans, root, path, diff);
 315                 BUG_ON(ret);
 316                 goto csum;
 317         }
 318
 319 insert:
 320         btrfs_release_path(root, path);
 321         csum_offset = 0;
 322         if (found_next) {
 323                 u64 tmp = min((u64)i_size_read(inode), next_offset);
 324                 tmp -= offset & ~((u64)root->sectorsize -1);
 325                 tmp >>= root->fs_info->sb->s_blocksize_bits;
 326                 tmp = max((u64)1, tmp);
 327                 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root));
 328                 ins_size = BTRFS_CRC32_SIZE * tmp;
 329         } else {
 330                 ins_size = BTRFS_CRC32_SIZE;
 331         }
 332         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 333                                       ins_size);
 334         if (ret < 0)
 335                 goto fail;
 336         if (ret != 0) {
 337                 WARN_ON(1);
 338                 goto fail;
 339         }
 340 csum:
 341         leaf = path->nodes[0];
 342         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 343         ret = 0;
 344         item = (struct btrfs_csum_item *)((unsigned char *)item +
 345                                           csum_offset * BTRFS_CRC32_SIZE);
 346 found:
 347         item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 348         item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
 349                                       btrfs_item_size_nr(leaf, path->slots[0]));
 350         eb_token = NULL;
 351 next_sector:
 352
 353         if (!eb_token ||
 354            (unsigned long)item  + BTRFS_CRC32_SIZE >= map_start + map_len) {
 355                 int err;
 356
 357                 if (eb_token)
 358                         unmap_extent_buffer(leaf, eb_token, KM_USER1);
 359                 eb_token = NULL;
 360                 err = map_private_extent_buffer(leaf, (unsigned long)item,
 361                                                 BTRFS_CRC32_SIZE,
 362                                                 &eb_token, &eb_map,
 363                                                 &map_start, &map_len, KM_USER1);
 364                 if (err)
 365                         eb_token = NULL;
 366         }
 367         if (eb_token) {
 368                 memcpy(eb_token + ((unsigned long)item & (PAGE_CACHE_SIZE - 1)),
 369                        &sector_sum->sum, BTRFS_CRC32_SIZE);
 370         } else {
 371                 write_extent_buffer(leaf, &sector_sum->sum,
 372                                     (unsigned long)item, BTRFS_CRC32_SIZE);
 373         }
 374
 375         total_bytes += root->sectorsize;
 376         sector_sum++;
 377         if (total_bytes < sums->len) {
 378                 item = (struct btrfs_csum_item *)((char *)item +
 379                                                   BTRFS_CRC32_SIZE);
 380                 if (item < item_end && offset + PAGE_CACHE_SIZE ==
 381                     sector_sum->offset) {
 382                             offset = sector_sum->offset;
 383                         goto next_sector;
 384                 }
 385         }
 386         if (eb_token) {
 387                 unmap_extent_buffer(leaf, eb_token, KM_USER1);
 388                 eb_token = NULL;
 389         }
 390         btrfs_mark_buffer_dirty(path->nodes[0]);
 391         if (total_bytes < sums->len) {
 392                 btrfs_release_path(root, path);
 393                 goto again;
 394         }
 395 fail:
 396         btrfs_free_path(path);
 397         return ret;
 398 }
 399
 400 int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
 401                         struct btrfs_root *root, struct btrfs_path *path,
 402                         u64 isize)
 403 {
 404         struct btrfs_key key;
 405         struct extent_buffer *leaf = path->nodes[0];
 406         int slot = path->slots[0];
 407         int ret;
 408         u32 new_item_size;
 409         u64 new_item_span;
 410         u64 blocks;
 411
 412         btrfs_item_key_to_cpu(leaf, &key, slot);
 413         if (isize <= key.offset)
 414                 return 0;
 415         new_item_span = isize - key.offset;
 416         blocks = (new_item_span + root->sectorsize - 1) >>
 417                 root->fs_info->sb->s_blocksize_bits;
 418         new_item_size = blocks * BTRFS_CRC32_SIZE;
 419         if (new_item_size >= btrfs_item_size_nr(leaf, slot))
 420                 return 0;
 421         ret = btrfs_truncate_item(trans, root, path, new_item_size, 1);
 422         BUG_ON(ret);
 423         return ret;
 424 }
 425