FAILED: patch "[PATCH] btrfs: fix missing error return in btrfs_drop_snapshot" failed to apply to 4.4-stable tree

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From: Jeff Mahoney <[email protected]>
Date: Mon, 4 Dec 2017 13:11:45 -0500
Subject: [PATCH] btrfs: fix missing error return in btrfs_drop_snapshot

If btrfs_del_root fails in btrfs_drop_snapshot, we'll pick up the error but then return 0 anyway due to mixing err and ret.

index 784d41e95ed9..16e46ee3cd16 100644
@@ -9220,6 +9220,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root,
 	ret = btrfs_del_root(trans, fs_info, &root->root_key);
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
+		err = ret;
 		goto out_end_trans;
 	}