Hi Neil,
I have tested with this patch, and it fixes the problem.
I have also tried various combinations of failing and replacing disks,
with echo idle to /sys/block/md1/md/sync_action, they all work fine.
Regards,
Qin Dehua
At 2013-07-22 11:04:15,NeilBrown <neilb@xxxxxxx> wrote:
>Hi Qin,
> thanks for the report. I can easily reproduce the bug.
>
>I think this will fix it. Could you please test and confirm that it fixes
>the problem for you too.
>
>Thanks,
>NeilBrown
>
>
>From: NeilBrown <neilb@xxxxxxx>
>Date: Mon, 22 Jul 2013 12:57:21 +1000
>Subject: [PATCH] md/raid5: fix interaction of 'replace' and 'recovery'.
>
>If a device in a RAID4/5/6 is being replaced while another is being
>recovered, then the writes to the replacement device currently don't
>happen, resulting in corruption when the replacement completes and the
>new drive takes over.
>
>This is because the replacement writes are only triggered when
>'s.replacing' is set and not when the similar 's.sync' is set (which
>is the case during resync and recovery - it means all devices need to
>be read).
>
>So schedule those writes when s.replacing is set as well.
>
>In this case we cannot use "STRIPE_INSYNC" to record that the
>replacement has happened as that is needed for recording that any
>parity calculation is complete. So introduce STRIPE_REPLACED to
>record if the replacement has happened.
>
>This bug was introduced in commit 9a3e1101b827a59ac9036a672f5fa8d5279d0fe2
>(md/raid5: detect and handle replacements during recovery.)
>which introduced replacement for raid5.
>That was in 3.3-rc3, so any stable kernel since then would benefit
>from this fix.
>
>Cc: stable@xxxxxxxxxxxxxxx (3.3+)
>Reported-by: qindehua <13691222965@xxxxxxx>
>Signed-off-by: NeilBrown <neilb@xxxxxxx>
>
>diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
>index 2bf094a..f0aa7abd 100644
>--- a/drivers/md/raid5.c
>+++ b/drivers/md/raid5.c
>@@ -3607,8 +3607,8 @@ static void handle_stripe(struct stripe_head *sh)
> handle_parity_checks5(conf, sh, &s, disks);
> }
>
>- if (s.replacing && s.locked == 0
>- && !test_bit(STRIPE_INSYNC, &sh->state)) {
>+ if ((s.replacing || s.syncing) && s.locked == 0
>+ && !test_bit(STRIPE_REPLACED, &sh->state)) {
> /* Write out to replacement devices where possible */
> for (i = 0; i < conf->raid_disks; i++)
> if (test_bit(R5_UPTODATE, &sh->dev[i].flags) &&
>@@ -3617,7 +3617,9 @@ static void handle_stripe(struct stripe_head *sh)
> set_bit(R5_LOCKED, &sh->dev[i].flags);
> s.locked++;
> }
>- set_bit(STRIPE_INSYNC, &sh->state);
>+ if (s.replacing)
>+ set_bit(STRIPE_INSYNC, &sh->state);
>+ set_bit(STRIPE_REPLACED, &sh->state);
> }
> if ((s.syncing || s.replacing) && s.locked == 0 &&
> test_bit(STRIPE_INSYNC, &sh->state)) {
>diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
>index b0b663b..70c4932 100644
>--- a/drivers/md/raid5.h
>+++ b/drivers/md/raid5.h
>@@ -306,6 +306,7 @@ enum {
> STRIPE_SYNC_REQUESTED,
> STRIPE_SYNCING,
> STRIPE_INSYNC,
>+ STRIPE_REPLACED,
> STRIPE_PREREAD_ACTIVE,
> STRIPE_DELAYED,
> STRIPE_DEGRADED,
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