btrfs: be a bit more careful when setting mirror_num_ret in btrfs_map_block

The mirror_num_ret is allowed to be NULL, although it has to be set when
smap is set.  Unfortunately that is not a well enough specifiable
invariant for static type checkers, so add a NULL check to make sure they
are fine.

Fixes: 03793cbbc80f ("btrfs: add fast path for single device io in __btrfs_map_block")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Christoph Hellwig 2023-06-27 08:13:23 +02:00 committed by David Sterba
parent b19c98f237
commit 4e7de35eb7

View File

@ -6398,7 +6398,8 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
(op == BTRFS_MAP_READ || !dev_replace_is_ongoing ||
!dev_replace->tgtdev)) {
set_io_stripe(smap, map, stripe_index, stripe_offset, stripe_nr);
*mirror_num_ret = mirror_num;
if (mirror_num_ret)
*mirror_num_ret = mirror_num;
*bioc_ret = NULL;
ret = 0;
goto out;