btrfs: On error always free subvol_name in btrfs_mount

The subvol_name is allocated in btrfs_parse_subvol_options and is
consumed and freed in mount_subvol.  Add a free to the error paths that
don't call mount_subvol so that it is guaranteed that subvol_name is
freed when an error happens.

Fixes: 312c89fbca06 ("btrfs: cleanup btrfs_mount() using btrfs_mount_root()")
Cc: stable@vger.kernel.org # v4.19+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 368a5b9e6c13..74023786a735 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1677,6 +1677,7 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
                                 flags | SB_RDONLY, device_name, data);
                         if (IS_ERR(mnt_root)) {
                                 root = ERR_CAST(mnt_root);
+                                kfree(subvol_name);
                                 goto out;
                         }
 
@@ -1686,12 +1687,14 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
                         if (error < 0) {
                                 root = ERR_PTR(error);
                                 mntput(mnt_root);
+                                kfree(subvol_name);
                                 goto out;
                         }
                 }
         }
         if (IS_ERR(mnt_root)) {
                 root = ERR_CAST(mnt_root);
+                kfree(subvol_name);
                 goto out;
         }