From 7ac1e464c4d473b517bb784f30d40da1f842482e Mon Sep 17 00:00:00 2001
From: Qu Wenruo <wqu@suse.com>
Date: Tue, 26 Feb 2019 16:33:56 +0800
Git-commit: 7ac1e464c4d473b517bb784f30d40da1f842482e
References: bsc#1112063
Patch-mainline: v5.2-rc1
Subject: [PATCH] btrfs: Don't panic when we can't find a root key

When we failed to find a root key in btrfs_update_root(), we just panic.

That's definitely not cool, fix it by outputting an unique error
message, aborting current transaction and return -EUCLEAN. This should
not normally happen as the root has been used by the callers in some
way.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/root-tree.c |   13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -150,11 +150,14 @@ int btrfs_update_root(struct btrfs_trans
 		goto out;
 	}
 
-	if (ret != 0) {
-		btrfs_print_leaf(fs_info, path->nodes[0]);
-		btrfs_crit(fs_info, "unable to update root key %llu %u %llu",
-			   key->objectid, key->type, key->offset);
-		BUG_ON(1);
+	if (ret > 0) {
+		btrfs_crit(fs_info,
+			"unable to find root key (%llu %u %llu) in tree %llu",
+			key->objectid, key->type, key->offset,
+			root->root_key.objectid);
+		ret = -EUCLEAN;
+		btrfs_abort_transaction(trans, ret);
+		goto out;
 	}
 
 	l = path->nodes[0];