Commit c093bf30 authored by David Sterba's avatar David Sterba
Browse files

btrfs: handle invalid range and start in merge_extent_mapping() 



Turn a BUG_ON to a properly handled error and update the error message
in the caller.  It is expected that @em_in and @start passed to
btrfs_add_extent_mapping() overlap. Besides tests, the only caller
btrfs_get_extent() makes sure this is true.

Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Reviewed-by: default avatarAnand Jain <anand.jain@oracle.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 16865702

fs/btrfs/extent_map.c

+5 −4
Original line number Diff line number Diff line
@@ -538,7 +538,8 @@ static noinline int merge_extent_mapping(struct extent_map_tree *em_tree, 
	u64 end;

	u64 start_diff;



	BUG_ON(map_start < em->start || map_start >= extent_map_end(em));

	if (map_start < em->start || map_start >= extent_map_end(em))

		return -EINVAL;



	if (existing->start > map_start) {

		next = existing;
@@ -633,9 +634,9 @@ int btrfs_add_extent_mapping(struct btrfs_fs_info *fs_info, 
				free_extent_map(em);

				*em_in = NULL;

				WARN_ONCE(ret,

"unexpected error %d: merge existing(start %llu len %llu) with em(start %llu len %llu)\n",

					  ret, existing->start, existing->len,

					  orig_start, orig_len);

"extent map merge error existing [%llu, %llu) with em [%llu, %llu) start %llu\n",

					  existing->start, existing->len,

					  orig_start, orig_len, start);

			}

			free_extent_map(existing);

		}