On Fri, Jan 24, 2020 at 09:32:49AM -0500, Josef Bacik wrote:
> We lookup the name of a subvol which means we'll cross into different
> roots. Hold a ref while we're doing the look ups in the fs_root we're
> searching.
>
> Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
> ---
> fs/btrfs/super.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
> index 3118bc01321e..5c3a1b7de6ee 100644
> --- a/fs/btrfs/super.c
> +++ b/fs/btrfs/super.c
> @@ -1101,6 +1101,10 @@ static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
> ret = PTR_ERR(fs_root);
> goto err;
> }
> + if (!btrfs_grab_fs_root(fs_root)) {
> + ret = -ENOENT;
> + goto err;
> + }
>
> /*
> * Walk up the filesystem tree by inode refs until we hit the
> @@ -1113,13 +1117,16 @@ static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
>
> ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
> if (ret < 0) {
> + btrfs_put_fs_root(fs_root);
> goto err;
> } else if (ret > 0) {
> ret = btrfs_previous_item(fs_root, path, dirid,
> BTRFS_INODE_REF_KEY);
> if (ret < 0) {
> + btrfs_put_fs_root(fs_root);
> goto err;
> } else if (ret > 0) {
> + btrfs_put_fs_root(fs_root);
> ret = -ENOENT;
> goto err;
> }
> @@ -1136,6 +1143,7 @@ static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
> ptr -= len + 1;
> if (ptr < name) {
> ret = -ENAMETOOLONG;
> + btrfs_put_fs_root(fs_root);
> goto err;
> }
> read_extent_buffer(path->nodes[0], ptr + 1,
> @@ -1143,6 +1151,7 @@ static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
> ptr[0] = '/';
> btrfs_release_path(path);
> }
> + btrfs_put_fs_root(fs_root);
> }
>
> btrfs_free_path(path);
All the put_fs_root before goto err can and should be merged into the
exit block that's already there.
> --
> 2.24.1
