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 | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 5ec000813f047..436e15e3759da 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -6399,7 +6399,8 @@ int __btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, (!need_full_stripe(op) || !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;