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md: avoid stale clone I/O accounting timestamps

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md_clone_bio() always allocates the clone from mddev->io_clone_set, even
when queue I/O stats are disabled. In that case it does not call
bio_start_io_acct(), but it also left md_io_clone->start_time untouched.

The clone private data comes from a mempool and can contain data from a
previous user. md_end_clone_io() checks start_time to decide whether it
needs to call bio_end_io_acct(), so a stale non-zero value can make the
completion path end accounting that was never started for this bio.

Set start_time to 0 in the no-stats branch. This keeps the end path tied
to whether bio_start_io_acct() actually ran.

Fixes: c687297b88 ("md: also clone new io if io accounting is disabled")
Tested-by: Mykola Marzhan <mykola@meshstor.io>
Link: https://patch.msgid.link/20260802195038.164272-8-yukuai@kernel.org
Signed-off-by: Yu Kuai <yukuai@fygo.io>
This commit is contained in:
Yu Kuai
2026-08-03 03:50:16 +08:00
parent 2a79365b22
commit 45102fc833
1 changed files with 2 additions and 0 deletions
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2
drivers/md/md.c
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@@ -9448,6 +9448,8 @@ static void md_clone_bio(struct mddev *mddev, struct bio **bio)
md_io_clone->mddev = mddev;
if (blk_queue_io_stat(bdev->bd_disk->queue))
md_io_clone->start_time = bio_start_io_acct(*bio);
else
md_io_clone->start_time = 0;
if (bio_data_dir(*bio) == WRITE && md_bitmap_enabled(mddev, false)) {
md_io_clone->offset = (*bio)->bi_iter.bi_sector;