btrfs: hold a ref on the root in __btrfs_run_defrag_inode

We are looking up an arbitrary inode, we need to hold a ref on the root
while we're doing this.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 1bc7665f8ff0c7d4c4762272ad758c57ffb9a606..27237bbaad65451d09fe3473300f8e941e77d6a8 100644 (file)
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -292,11 +292,16 @@ static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
                ret = PTR_ERR(inode_root);
                goto cleanup;
        }
+       if (!btrfs_grab_fs_root(inode_root)) {
+               ret = -ENOENT;
+               goto cleanup;
+       }
 
        key.objectid = defrag->ino;
        key.type = BTRFS_INODE_ITEM_KEY;
        key.offset = 0;
        inode = btrfs_iget(fs_info->sb, &key, inode_root);
+       btrfs_put_fs_root(inode_root);
        if (IS_ERR(inode)) {
                ret = PTR_ERR(inode);
                goto cleanup;