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,
 138                        struct bio *bio, char **sums_ret)
 139 {
 140         u32 *sums;
 141         char *data;
 142         struct bio_vec *bvec = bio->bi_io_vec;
 143         int bio_index = 0;
 144
 145         sums = kmalloc(bio->bi_vcnt * BTRFS_CRC32_SIZE, GFP_NOFS);
 146         if (!sums)
 147                 return -ENOMEM;
 148         *sums_ret = (char *)sums;
 149
 150         while(bio_index < bio->bi_vcnt) {
 151                 data = kmap_atomic(bvec->bv_page, KM_USER0);
 152                 *sums = ~(u32)0;
 153                 *sums = btrfs_csum_data(root, data + bvec->bv_offset,
 154                                         *sums, bvec->bv_len);
 155                 kunmap_atomic(data, KM_USER0);
 156                 btrfs_csum_final(*sums, (char *)sums);
 157                 sums++;
 158                 bio_index++;
 159                 bvec++;
 160         }
 161         return 0;
 162 }
 163
 164 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 165                            struct btrfs_root *root, struct inode *inode,
 166                            struct bio *bio, char *sums)
 167 {
 168         u64 objectid = inode->i_ino;
 169         u64 offset;
 170         int ret;
 171         struct btrfs_key file_key;
 172         struct btrfs_key found_key;
 173         u64 next_offset;
 174         int found_next;
 175         struct btrfs_path *path;
 176         struct btrfs_csum_item *item;
 177         struct btrfs_csum_item *item_end;
 178         struct extent_buffer *leaf = NULL;
 179         u64 csum_offset;
 180         u32 *sums32 = (u32 *)sums;
 181         u32 nritems;
 182         u32 ins_size;
 183         int bio_index = 0;
 184         struct bio_vec *bvec = bio->bi_io_vec;
 185         char *eb_map;
 186         char *eb_token;
 187         unsigned long map_len;
 188         unsigned long map_start;
 189
 190         path = btrfs_alloc_path();
 191         BUG_ON(!path);
 192 again:
 193         next_offset = (u64)-1;
 194         found_next = 0;
 195         offset = page_offset(bvec->bv_page) + bvec->bv_offset;
 196         file_key.objectid = objectid;
 197         file_key.offset = offset;
 198         btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
 199
 200         item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
 201         if (!IS_ERR(item)) {
 202                 leaf = path->nodes[0];
 203                 goto found;
 204         }
 205         ret = PTR_ERR(item);
 206         if (ret == -EFBIG) {
 207                 u32 item_size;
 208                 /* we found one, but it isn't big enough yet */
 209                 leaf = path->nodes[0];
 210                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 211                 if ((item_size / BTRFS_CRC32_SIZE) >= MAX_CSUM_ITEMS(root)) {
 212                         /* already at max size, make a new one */
 213                         goto insert;
 214                 }
 215         } else {
 216                 int slot = path->slots[0] + 1;
 217                 /* we didn't find a csum item, insert one */
 218                 nritems = btrfs_header_nritems(path->nodes[0]);
 219                 if (path->slots[0] >= nritems - 1) {
 220                         ret = btrfs_next_leaf(root, path);
 221                         if (ret == 1)
 222                                 found_next = 1;
 223                         if (ret != 0)
 224                                 goto insert;
 225                         slot = 0;
 226                 }
 227                 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
 228                 if (found_key.objectid != objectid ||
 229                     found_key.type != BTRFS_CSUM_ITEM_KEY) {
 230                         found_next = 1;
 231                         goto insert;
 232                 }
 233                 next_offset = found_key.offset;
 234                 found_next = 1;
 235                 goto insert;
 236         }
 237
 238         /*
 239          * at this point, we know the tree has an item, but it isn't big
 240          * enough yet to put our csum in.  Grow it
 241          */
 242         btrfs_release_path(root, path);
 243         ret = btrfs_search_slot(trans, root, &file_key, path,
 244                                 BTRFS_CRC32_SIZE, 1);
 245         if (ret < 0)
 246                 goto fail;
 247         if (ret == 0) {
 248                 BUG();
 249         }
 250         if (path->slots[0] == 0) {
 251                 goto insert;
 252         }
 253         path->slots[0]--;
 254         leaf = path->nodes[0];
 255         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 256         csum_offset = (offset - found_key.offset) >>
 257                         root->fs_info->sb->s_blocksize_bits;
 258         if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
 259             found_key.objectid != objectid ||
 260             csum_offset >= MAX_CSUM_ITEMS(root)) {
 261                 goto insert;
 262         }
 263         if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
 264             BTRFS_CRC32_SIZE) {
 265                 u32 diff = (csum_offset + 1) * BTRFS_CRC32_SIZE;
 266                 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
 267                 if (diff != BTRFS_CRC32_SIZE)
 268                         goto insert;
 269                 ret = btrfs_extend_item(trans, root, path, diff);
 270                 BUG_ON(ret);
 271                 goto csum;
 272         }
 273
 274 insert:
 275         btrfs_release_path(root, path);
 276         csum_offset = 0;
 277         if (found_next) {
 278                 u64 tmp = min((u64)i_size_read(inode), next_offset);
 279                 tmp -= offset & ~((u64)root->sectorsize -1);
 280                 tmp >>= root->fs_info->sb->s_blocksize_bits;
 281                 tmp = max((u64)1, tmp);
 282                 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root));
 283                 ins_size = BTRFS_CRC32_SIZE * tmp;
 284         } else {
 285                 ins_size = BTRFS_CRC32_SIZE;
 286         }
 287         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 288                                       ins_size);
 289         if (ret < 0)
 290                 goto fail;
 291         if (ret != 0) {
 292                 WARN_ON(1);
 293                 goto fail;
 294         }
 295 csum:
 296         leaf = path->nodes[0];
 297         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 298         ret = 0;
 299         item = (struct btrfs_csum_item *)((unsigned char *)item +
 300                                           csum_offset * BTRFS_CRC32_SIZE);
 301 found:
 302         item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 303         item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
 304                                       btrfs_item_size_nr(leaf, path->slots[0]));
 305         eb_token = NULL;
 306 next_bvec:
 307
 308         if (!eb_token ||
 309            (unsigned long)item  + BTRFS_CRC32_SIZE >= map_start + map_len) {
 310                 int err;
 311
 312                 if (eb_token)
 313                         unmap_extent_buffer(leaf, eb_token, KM_USER1);
 314                 eb_token = NULL;
 315                 err = map_private_extent_buffer(leaf, (unsigned long)item,
 316                                                 BTRFS_CRC32_SIZE,
 317                                                 &eb_token, &eb_map,
 318                                                 &map_start, &map_len, KM_USER1);
 319                 if (err)
 320                         eb_token = NULL;
 321         }
 322         if (eb_token) {
 323                 memcpy(eb_token + ((unsigned long)item & (PAGE_CACHE_SIZE - 1)),
 324                        sums32, BTRFS_CRC32_SIZE);
 325         } else {
 326                 write_extent_buffer(leaf, sums32, (unsigned long)item,
 327                                     BTRFS_CRC32_SIZE);
 328         }
 329         bio_index++;
 330         bvec++;
 331         sums32++;
 332         if (bio_index < bio->bi_vcnt) {
 333                 item = (struct btrfs_csum_item *)((char *)item +
 334                                                   BTRFS_CRC32_SIZE);
 335                 if (item < item_end && offset + PAGE_CACHE_SIZE ==
 336                     page_offset(bvec->bv_page)) {
 337                         offset = page_offset(bvec->bv_page);
 338                         goto next_bvec;
 339                 }
 340         }
 341         if (eb_token) {
 342                 unmap_extent_buffer(leaf, eb_token, KM_USER1);
 343                 eb_token = NULL;
 344         }
 345         btrfs_mark_buffer_dirty(path->nodes[0]);
 346         if (bio_index < bio->bi_vcnt) {
 347                 btrfs_release_path(root, path);
 348                 goto again;
 349         }
 350 fail:
 351         btrfs_free_path(path);
 352         return ret;
 353 }
 354
 355 int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
 356                         struct btrfs_root *root, struct btrfs_path *path,
 357                         u64 isize)
 358 {
 359         struct btrfs_key key;
 360         struct extent_buffer *leaf = path->nodes[0];
 361         int slot = path->slots[0];
 362         int ret;
 363         u32 new_item_size;
 364         u64 new_item_span;
 365         u64 blocks;
 366
 367         btrfs_item_key_to_cpu(leaf, &key, slot);
 368         if (isize <= key.offset)
 369                 return 0;
 370         new_item_span = isize - key.offset;
 371         blocks = (new_item_span + root->sectorsize - 1) >>
 372                 root->fs_info->sb->s_blocksize_bits;
 373         new_item_size = blocks * BTRFS_CRC32_SIZE;
 374         if (new_item_size >= btrfs_item_size_nr(leaf, slot))
 375                 return 0;
 376         ret = btrfs_truncate_item(trans, root, path, new_item_size, 1);
 377         BUG_ON(ret);
 378         return ret;
 379 }
 380