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-rw-r--r--fs/btrfs/dir-item.c59
1 files changed, 59 insertions, 0 deletions
diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
index c1a074d0696..502c2158167 100644
--- a/fs/btrfs/dir-item.c
+++ b/fs/btrfs/dir-item.c
@@ -213,6 +213,65 @@ struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
return btrfs_match_dir_item_name(root, path, name, name_len);
}
+int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
+ const char *name, int name_len)
+{
+ int ret;
+ struct btrfs_key key;
+ struct btrfs_dir_item *di;
+ int data_size;
+ struct extent_buffer *leaf;
+ int slot;
+ struct btrfs_path *path;
+
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = dir;
+ btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
+ key.offset = btrfs_name_hash(name, name_len);
+
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+
+ /* return back any errors */
+ if (ret < 0)
+ goto out;
+
+ /* nothing found, we're safe */
+ if (ret > 0) {
+ ret = 0;
+ goto out;
+ }
+
+ /* we found an item, look for our name in the item */
+ di = btrfs_match_dir_item_name(root, path, name, name_len);
+ if (di) {
+ /* our exact name was found */
+ ret = -EEXIST;
+ goto out;
+ }
+
+ /*
+ * see if there is room in the item to insert this
+ * name
+ */
+ data_size = sizeof(*di) + name_len + sizeof(struct btrfs_item);
+ leaf = path->nodes[0];
+ slot = path->slots[0];
+ if (data_size + btrfs_item_size_nr(leaf, slot) +
+ sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root)) {
+ ret = -EOVERFLOW;
+ } else {
+ /* plenty of insertion room */
+ ret = 0;
+ }
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
/*
* lookup a directory item based on index. 'dir' is the objectid
* we're searching in, and 'mod' tells us if you plan on deleting the