fs: btrfs: Use btrfs_iter_dir() to replace btrfs_readdir()
Use extent buffer based infrastructure to re-implement btrfs_readdir().
Along this rework, some small corner cases fixed:
- Subvolume tree mtime
Mtime of a subvolume tree is recorded in its root item, since there is
no INODE_ITEM for it.
This needs extra search from tree root.
- Output the unknown type
If the DIR_ITEM is corrupted, at least don't try to access the memory
out of boundary.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
index b49aaac..1a3929a 100644
--- a/fs/btrfs/dir-item.c
+++ b/fs/btrfs/dir-item.c
@@ -193,39 +193,55 @@
return res ? 0 : -1;
}
-int btrfs_readdir(const struct __btrfs_root *root, u64 dir,
- btrfs_readdir_callback_t callback)
+int btrfs_iter_dir(struct btrfs_root *root, u64 ino,
+ btrfs_iter_dir_callback_t callback)
{
- struct __btrfs_path path;
- struct btrfs_key key, *found_key;
- struct btrfs_dir_item *item;
- int res = 0;
+ struct btrfs_path path;
+ struct btrfs_key key;
+ int ret;
- key.objectid = dir;
+ btrfs_init_path(&path);
+ key.objectid = ino;
key.type = BTRFS_DIR_INDEX_KEY;
key.offset = 0;
- if (btrfs_search_tree(root, &key, &path))
- return -1;
-
+ ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
+ if (ret < 0)
+ return ret;
+ /* Should not happen */
+ if (ret == 0) {
+ ret = -EUCLEAN;
+ goto out;
+ }
+ if (path.slots[0] >= btrfs_header_nritems(path.nodes[0])) {
+ ret = btrfs_next_leaf(root, &path);
+ if (ret < 0)
+ goto out;
+ if (ret > 0) {
+ ret = 0;
+ goto out;
+ }
+ }
do {
- found_key = btrfs_path_leaf_key(&path);
- if (btrfs_comp_keys_type(&key, found_key))
+ struct btrfs_dir_item *di;
+
+ btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
+ if (key.objectid != ino || key.type != BTRFS_DIR_INDEX_KEY)
break;
+ di = btrfs_item_ptr(path.nodes[0], path.slots[0],
+ struct btrfs_dir_item);
+ if (verify_dir_item(root, path.nodes[0], di)) {
+ ret = -EUCLEAN;
+ goto out;
+ }
+ ret = callback(root, path.nodes[0], di);
+ if (ret < 0)
+ goto out;
+ } while (!(ret = btrfs_next_item(root, &path)));
- item = btrfs_path_item_ptr(&path, struct btrfs_dir_item);
- btrfs_dir_item_to_cpu(item);
-
- if (__verify_dir_item(item, 0, sizeof(*item) + item->name_len))
- continue;
- if (item->type == BTRFS_FT_XATTR)
- continue;
-
- if (callback(root, item))
- break;
- } while (!(res = btrfs_next_slot(&path)));
-
- __btrfs_free_path(&path);
-
- return res < 0 ? -1 : 0;
+ if (ret > 0)
+ ret = 0;
+out:
+ btrfs_release_path(&path);
+ return ret;
}