Hi,
在 2025/08/21 17:33, Hannes Reinecke 写道:
On 8/21/25 11:02, Christoph Hellwig wrote:
On Thu, Aug 21, 2025 at 04:56:33PM +0800, Yu Kuai wrote:
Can you give some examples as how to chain the right way?
fs/xfs/xfs_bio_io.c: xfs_rw_bdev
fs/xfs/xfs_buf.c: xfs_buf_submit_bio
fs/xfs/xfs_log.c: xlog_write_iclog
BTW, for all
the io split case, should this order be fixed? I feel we should, this
disorder can happen on any stack case, where top max_sector is greater
than stacked disk.
Yes, I've been trying get Bart to fix this for a while instead of
putting in a workaround very similar to the one proposed here,
but so far nothing happened.
This feels like a really stupid fix, but wouldn't that help?
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 023649fe2476..2b342bb59612 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5478,7 +5478,6 @@ static struct bio *chunk_aligned_read(struct mddev
*mddev, struct bio *raid_bio)
split = bio_split(raid_bio, sectors, GFP_NOIO,
&conf->bio_split);
bio_chain(split, raid_bio);
submit_bio_noacct(raid_bio);
- raid_bio = split;
}
I do not understand how can this help, do you miss that submit split
instead?
And with this change, this can help, however, I think we'll still submit
the last lba bio first, like bio_last -> bio0 -> bio1 ... where the
following is sequential.
BTW, this is not just a raid5 problem, this is also possible for
raid0/10 and all other recursive split case.
Thanks,
Kuai
Cheers,
Hannes
