btrfs: abort transaction on unexpected eb generation at btrfs_copy_root()

[ Upstream commit 33e8f24 ]

If we find an unexpected generation for the extent buffer we are cloning
at btrfs_copy_root(), we just WARN_ON() and don't error out and abort the
transaction, meaning we allow to persist metadata with an unexpected
generation. Instead of warning only, abort the transaction and return
-EUCLEAN.

CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Daniel Vacek <neelx@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: fdmanana

fs/btrfs/ctree.c

@@ -283,7 +283,14 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
 
 	write_extent_buffer_fsid(cow, fs_info->fs_devices->metadata_uuid);
 
-	WARN_ON(btrfs_header_generation(buf) > trans->transid);
+	if (unlikely(btrfs_header_generation(buf) > trans->transid)) {
+		btrfs_tree_unlock(cow);
+		free_extent_buffer(cow);
+		ret = -EUCLEAN;
+		btrfs_abort_transaction(trans, ret);
+		return ret;
+	}
+
 	if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
 		ret = btrfs_inc_ref(trans, root, cow, 1);
 	else