diff options
Diffstat (limited to 'fs/btrfs/dir-item.c')
-rw-r--r-- | fs/btrfs/dir-item.c | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c index aea621c72b..b49aaacbd8 100644 --- a/fs/btrfs/dir-item.c +++ b/fs/btrfs/dir-item.c @@ -8,6 +8,112 @@ #include "btrfs.h" #include "disk-io.h" +static int verify_dir_item(struct btrfs_root *root, + struct extent_buffer *leaf, + struct btrfs_dir_item *dir_item) +{ + u16 namelen = BTRFS_NAME_LEN; + u8 type = btrfs_dir_type(leaf, dir_item); + + if (type == BTRFS_FT_XATTR) + namelen = XATTR_NAME_MAX; + + if (btrfs_dir_name_len(leaf, dir_item) > namelen) { + fprintf(stderr, "invalid dir item name len: %u\n", + (unsigned)btrfs_dir_data_len(leaf, dir_item)); + return 1; + } + + /* BTRFS_MAX_XATTR_SIZE is the same for all dir items */ + if ((btrfs_dir_data_len(leaf, dir_item) + + btrfs_dir_name_len(leaf, dir_item)) > + BTRFS_MAX_XATTR_SIZE(root->fs_info)) { + fprintf(stderr, "invalid dir item name + data len: %u + %u\n", + (unsigned)btrfs_dir_name_len(leaf, dir_item), + (unsigned)btrfs_dir_data_len(leaf, dir_item)); + return 1; + } + + return 0; +} + +struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root, + struct btrfs_path *path, + const char *name, int name_len) +{ + struct btrfs_dir_item *dir_item; + unsigned long name_ptr; + u32 total_len; + u32 cur = 0; + u32 this_len; + struct extent_buffer *leaf; + + leaf = path->nodes[0]; + dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item); + total_len = btrfs_item_size_nr(leaf, path->slots[0]); + if (verify_dir_item(root, leaf, dir_item)) + return NULL; + + while(cur < total_len) { + this_len = sizeof(*dir_item) + + btrfs_dir_name_len(leaf, dir_item) + + btrfs_dir_data_len(leaf, dir_item); + if (this_len > (total_len - cur)) { + fprintf(stderr, "invalid dir item size\n"); + return NULL; + } + + name_ptr = (unsigned long)(dir_item + 1); + + if (btrfs_dir_name_len(leaf, dir_item) == name_len && + memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) + return dir_item; + + cur += this_len; + dir_item = (struct btrfs_dir_item *)((char *)dir_item + + this_len); + } + return NULL; +} + +struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, u64 dir, + const char *name, int name_len, + int mod) +{ + int ret; + struct btrfs_key key; + int ins_len = mod < 0 ? -1 : 0; + int cow = mod != 0; + struct btrfs_key found_key; + struct extent_buffer *leaf; + + key.objectid = dir; + key.type = BTRFS_DIR_ITEM_KEY; + + key.offset = btrfs_name_hash(name, name_len); + + ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow); + if (ret < 0) + return ERR_PTR(ret); + if (ret > 0) { + if (path->slots[0] == 0) + return NULL; + path->slots[0]--; + } + + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); + + if (found_key.objectid != dir || + found_key.type != BTRFS_DIR_ITEM_KEY || + found_key.offset != key.offset) + return NULL; + + return btrfs_match_dir_item_name(root, path, name, name_len); +} + static int __verify_dir_item(struct btrfs_dir_item *item, u32 start, u32 total) { u16 max_len = BTRFS_NAME_LEN; |