From 125bfc7cd750e68c99f1d446e2c22abea08c237f Mon Sep 17 00:00:00 2001 From: Li Nan Date: Fri, 9 Jun 2023 17:43:20 +0800 Subject: [PATCH] md/raid10: fix the condition to call bio_end_io_acct() /sys/block/[device]/queue/iostats is used to control whether to count io stat. Write 0 to it will clear queue_flags QUEUE_FLAG_IO_STAT which means iostats is disabled. If we disable iostats and later endable it, the io issued during this period will be counted incorrectly, inflight will be decreased to -1. //T1 set iostats echo 0 > /sys/block/md0/queue/iostats clear QUEUE_FLAG_IO_STAT //T2 issue io if (QUEUE_FLAG_IO_STAT) -> false bio_start_io_acct inflight++ echo 1 > /sys/block/md0/queue/iostats set QUEUE_FLAG_IO_STAT //T3 io end if (QUEUE_FLAG_IO_STAT) -> true bio_end_io_acct inflight-- -> -1 Also, if iostats is enabled while issuing io but disabled while io end, inflight will never be decreased. Fix it by checking start_time when io end. If start_time is not 0, call bio_end_io_acct(). Fixes: 528bc2cf2fcc ("md/raid10: enable io accounting") Signed-off-by: Li Nan Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20230609094320.2397604-1-linan666@huaweicloud.com --- drivers/md/raid10.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index d0de8c9..7906776 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -325,7 +325,7 @@ static void raid_end_bio_io(struct r10bio *r10_bio) if (!test_bit(R10BIO_Uptodate, &r10_bio->state)) bio->bi_status = BLK_STS_IOERR; - if (blk_queue_io_stat(bio->bi_bdev->bd_disk->queue)) + if (r10_bio->start_time) bio_end_io_acct(bio, r10_bio->start_time); bio_endio(bio); /* -- 2.7.4