From: Christoph Hellwig hch@lst.de
[ Upstream commit 4e7de35eb7d1a1d4f2dda15f39fbedd4798a0b8d ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/volumes.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 7433ae929fdcb..2e0832d70406c 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -6595,11 +6595,13 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, if (patch_the_first_stripe_for_dev_replace) { smap->dev = dev_replace->tgtdev; smap->physical = physical_to_patch_in_first_stripe; - *mirror_num_ret = map->num_stripes + 1; + if (mirror_num_ret) + *mirror_num_ret = map->num_stripes + 1; } else { 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;