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 "ctree.h"
  20 #include "disk-io.h"
  21 #include "transaction.h"
  22 #include "print-tree.h"
  23
  24 #define MAX_CSUM_ITEMS(r) ((((BTRFS_LEAF_DATA_SIZE(r) - \
  25                                sizeof(struct btrfs_item) * 2) / \
  26                                BTRFS_CRC32_SIZE) - 1))
  27 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
  28                                struct btrfs_root *root,
  29                                u64 objectid, u64 pos,
  30                                u64 offset, u64 disk_num_blocks,
  31                                u64 num_blocks)
  32 {
  33         int ret = 0;
  34         struct btrfs_file_extent_item *item;
  35         struct btrfs_key file_key;
  36         struct btrfs_path *path;
  37         struct extent_buffer *leaf;
  38
  39         path = btrfs_alloc_path();
  40         BUG_ON(!path);
  41         file_key.objectid = objectid;
  42         file_key.offset = pos;
  43         btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
  44
  45         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
  46                                       sizeof(*item));
  47         if (ret < 0)
  48                 goto out;
  49         BUG_ON(ret);
  50         leaf = path->nodes[0];
  51         item = btrfs_item_ptr(leaf, path->slots[0],
  52                               struct btrfs_file_extent_item);
  53         btrfs_set_file_extent_disk_blocknr(leaf, item, offset);
  54         btrfs_set_file_extent_disk_num_blocks(leaf, item, disk_num_blocks);
  55         btrfs_set_file_extent_offset(leaf, item, 0);
  56         btrfs_set_file_extent_num_blocks(leaf, item, num_blocks);
  57         btrfs_set_file_extent_generation(leaf, item, trans->transid);
  58         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
  59         btrfs_mark_buffer_dirty(leaf);
  60 out:
  61         btrfs_free_path(path);
  62         return ret;
  63 }
  64
  65 struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
  66                                           struct btrfs_root *root,
  67                                           struct btrfs_path *path,
  68                                           u64 objectid, u64 offset,
  69                                           int cow)
  70 {
  71         int ret;
  72         struct btrfs_key file_key;
  73         struct btrfs_key found_key;
  74         struct btrfs_csum_item *item;
  75         struct extent_buffer *leaf;
  76         u64 csum_offset = 0;
  77         int csums_in_item;
  78
  79         file_key.objectid = objectid;
  80         file_key.offset = offset;
  81         btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
  82         ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
  83         if (ret < 0)
  84                 goto fail;
  85         leaf = path->nodes[0];
  86         if (ret > 0) {
  87                 ret = 1;
  88                 if (path->slots[0] == 0)
  89                         goto fail;
  90                 path->slots[0]--;
  91                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
  92                 if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
  93                     found_key.objectid != objectid) {
  94                         goto fail;
  95                 }
  96                 csum_offset = (offset - found_key.offset) >>
  97                                 root->fs_info->sb->s_blocksize_bits;
  98                 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
  99                 csums_in_item /= BTRFS_CRC32_SIZE;
 100
 101                 if (csum_offset >= csums_in_item) {
 102                         ret = -EFBIG;
 103                         goto fail;
 104                 }
 105         }
 106         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 107         item = (struct btrfs_csum_item *)((unsigned char *)item +
 108                                           csum_offset * BTRFS_CRC32_SIZE);
 109         return item;
 110 fail:
 111         if (ret > 0)
 112                 ret = -ENOENT;
 113         return ERR_PTR(ret);
 114 }
 115
 116
 117 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
 118                              struct btrfs_root *root,
 119                              struct btrfs_path *path, u64 objectid,
 120                              u64 offset, int mod)
 121 {
 122         int ret;
 123         struct btrfs_key file_key;
 124         int ins_len = mod < 0 ? -1 : 0;
 125         int cow = mod != 0;
 126
 127         file_key.objectid = objectid;
 128         file_key.offset = offset;
 129         btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
 130         ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
 131         return ret;
 132 }
 133
 134 int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
 135                           struct btrfs_root *root,
 136                           u64 objectid, u64 offset,
 137                           char *data, size_t len)
 138 {
 139         return 0;
 140 #if 0
 141         int ret;
 142         struct btrfs_key file_key;
 143         struct btrfs_key found_key;
 144         struct btrfs_path *path;
 145         struct btrfs_csum_item *item;
 146         struct extent_buffer *leaf;
 147         u64 csum_offset;
 148
 149         path = btrfs_alloc_path();
 150         BUG_ON(!path);
 151
 152         file_key.objectid = objectid;
 153         file_key.offset = offset;
 154         file_key.flags = 0;
 155         btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
 156
 157         item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
 158         if (!IS_ERR(item))
 159                 goto found;
 160         ret = PTR_ERR(item);
 161         if (ret == -EFBIG) {
 162                 u32 item_size;
 163                 /* we found one, but it isn't big enough yet */
 164                 leaf = path->nodes[0];
 165                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 166                 if ((item_size / BTRFS_CRC32_SIZE) >= MAX_CSUM_ITEMS(root)) {
 167                         /* already at max size, make a new one */
 168                         goto insert;
 169                 }
 170         } else {
 171                 /* we didn't find a csum item, insert one */
 172                 goto insert;
 173         }
 174
 175         /*
 176          * at this point, we know the tree has an item, but it isn't big
 177          * enough yet to put our csum in.  Grow it
 178          */
 179         btrfs_release_path(root, path);
 180         ret = btrfs_search_slot(trans, root, &file_key, path,
 181                                 BTRFS_CRC32_SIZE, 1);
 182         if (ret < 0)
 183                 goto fail;
 184         if (ret == 0) {
 185                 BUG();
 186         }
 187         if (path->slots[0] == 0) {
 188                 goto insert;
 189         }
 190         path->slots[0]--;
 191         leaf = path->nodes[0];
 192         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 193         csum_offset = (offset - found_key.offset) >>
 194                         root->fs_info->sb->s_blocksize_bits;
 195         if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
 196             found_key.objectid != objectid ||
 197             csum_offset >= MAX_CSUM_ITEMS(root)) {
 198                 goto insert;
 199         }
 200         if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
 201             BTRFS_CRC32_SIZE) {
 202                 u32 diff = (csum_offset + 1) * BTRFS_CRC32_SIZE;
 203                 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
 204                 if (diff != BTRFS_CRC32_SIZE)
 205                         goto insert;
 206                 ret = btrfs_extend_item(trans, root, path, diff);
 207                 BUG_ON(ret);
 208                 goto csum;
 209         }
 210
 211 insert:
 212         btrfs_release_path(root, path);
 213         csum_offset = 0;
 214         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 215                                       BTRFS_CRC32_SIZE);
 216         if (ret < 0)
 217                 goto fail;
 218         if (ret != 0) {
 219                 WARN_ON(1);
 220                 goto fail;
 221         }
 222 csum:
 223         leaf = path->nodes[0];
 224         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 225         ret = 0;
 226         item = (struct btrfs_csum_item *)((unsigned char *)item +
 227                                           csum_offset * BTRFS_CRC32_SIZE);
 228 found:
 229         /* FIXME!!!!!!!!!!!! */
 230         ret = btrfs_csum_data(root, data, len, &item->csum);
 231         btrfs_mark_buffer_dirty(path->nodes[0]);
 232 fail:
 233         btrfs_release_path(root, path);
 234         btrfs_free_path(path);
 235         return ret;
 236 #endif
 237 }
 238
 239 int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
 240                         struct btrfs_root *root, struct btrfs_path *path,
 241                         u64 isize)
 242 {
 243         struct btrfs_key key;
 244         struct extent_buffer *leaf = path->nodes[0];
 245         int slot = path->slots[0];
 246         int ret;
 247         u32 new_item_size;
 248         u64 new_item_span;
 249         u64 blocks;
 250
 251         btrfs_item_key_to_cpu(leaf, &key, slot);
 252         if (isize <= key.offset)
 253                 return 0;
 254         new_item_span = isize - key.offset;
 255         blocks = (new_item_span + root->sectorsize - 1) >>
 256                 root->fs_info->sb->s_blocksize_bits;
 257         new_item_size = blocks * BTRFS_CRC32_SIZE;
 258         if (new_item_size >= btrfs_item_size_nr(leaf, slot))
 259                 return 0;
 260         ret = btrfs_truncate_item(trans, root, path, new_item_size);
 261         BUG_ON(ret);
 262         return ret;
 263 }
 264