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>

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 368a5b9..7402378 100644 (file)
--- 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;
        }