From edfa1f651e93261eecb034d02284ece103dd691a Mon Sep 17 00:00:00 2001 From: Bian Yu Date: Thu, 14 Nov 2013 15:16:17 +1100 Subject: [PATCH] raid5: Retry R5_ReadNoMerge flag when hit a read error. Because of block layer merge, one bio fails will cause other bios which belongs to the same request fails, so raid5_end_read_request will record all these bios as badblocks. If retry request with R5_ReadNoMerge flag to avoid bios merge, badblocks can only record sector which is bad exactly. test: hdparm --yes-i-know-what-i-am-doing --make-bad-sector 300000 /dev/sdb mdadm -C /dev/md0 -l5 -n3 /dev/sd[bcd] --assume-clean mdadm /dev/md0 -f /dev/sdd mdadm /dev/md0 -r /dev/sdd mdadm --zero-superblock /dev/sdd mdadm /dev/md0 -a /dev/sdd 1. Without this patch: cat /sys/block/md0/md/rd*/bad_blocks 299776 256 299776 256 2. With this patch: cat /sys/block/md0/md/rd*/bad_blocks 300000 8 300000 8 Signed-off-by: Bian Yu Signed-off-by: NeilBrown --- drivers/md/raid5.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 1fb28c56457a..2c8907706109 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -2056,6 +2056,9 @@ static void raid5_end_read_request(struct bio * bi, int error) mdname(conf->mddev), bdn); else retry = 1; + if (set_bad && test_bit(In_sync, &rdev->flags) + && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) + retry = 1; if (retry) if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) { set_bit(R5_ReadError, &sh->dev[i].flags);