[PATCH AUTOSEL 4.19 042/244] btrfs: Don't panic when we can't find a root key

[Sasha Levin]

From: Qu Wenruo <wqu@xxxxxxxx>

[ Upstream commit 7ac1e464c4d473b517bb784f30d40da1f842482e ]

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@xxxxxxxx>
Reviewed-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/btrfs/root-tree.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 65bda0682928b..f51a4a425a457 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -137,11 +137,14 @@ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
 		goto out;
 	}
 
-	if (ret != 0) {
-		btrfs_print_leaf(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];
-- 
2.20.1