This is a note to let you know that I've just added the patch titled
btrfs: be a bit more careful when setting mirror_num_ret in btrfs_map_block
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-be-a-bit-more-careful-when-setting-mirror_num_.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit e73188bd438294cee72fe11e00cbce1b297072ac
Author: Christoph Hellwig <hch@xxxxxx>
Date: Tue Jun 27 08:13:23 2023 +0200
btrfs: be a bit more careful when setting mirror_num_ret in btrfs_map_block
[ 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@xxxxxxxxxx>
Reviewed-by: Qu Wenruo <wqu@xxxxxxxx>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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;
