btrfs: add a return value for readahead_tree_block()

From: Liu Bo <[email protected]>

Fix return value to get from read_extent_buffer_pages().

Signed-off-by Liu Bo <[email protected]>

Signed-off-by Miao Xie <[email protected]>

---
 fs/btrfs/disk-io.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

fs/btrfs/disk-io.c +1 -1

index 6632e5c..35916d5 100644
@@ -794,7 +794,7 @@ int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
 	buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 	if (!buf)
 		return 0;
-	read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
+	ret = read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
 				 buf, 0, 0, btree_get_extent, 0);
 	free_extent_buffer(buf);
 	return ret;