From 4e7de35eb7d1a1d4f2dda15f39fbedd4798a0b8d Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 27 Jun 2023 08:13:23 +0200 Subject: [PATCH] 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 Reviewed-by: Qu Wenruo Reviewed-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba --- 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 30b8744..efa19a5 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -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; -- 2.7.4