[PATCH] fs/btrfs: On error always free subvol_name in btrfs_mount

[ebiederm@xmission.com (Eric W. Biederman)]

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
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: David Sterba <dsterba@suse.com>
Cc: linux-btrfs@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 fs/btrfs/super.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index c5586ffd1426..0a3f122dd61f 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1621,6 +1621,7 @@ 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;
 			}
 
@@ -1630,12 +1631,14 @@ 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;
 	}
 
-- 
2.17.1