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authorNeilBrown <neilb@suse.de>2013-07-22 12:57:21 +1000
committerNeilBrown <neilb@suse.de>2013-07-25 16:46:57 +1000
commitf94c0b6658c7edea8bc19d13be321e3860a3fa54 (patch)
treedf40497f1dce20f78fd1c3b794ea1c1c9021d222
parent0eb25bb027a100f5a9df8991f2f628e7d851bc1e (diff)
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. For safety we should also check that STRIPE_COMPUTE_RUN is not set. This has a similar effect to the "s.locked == 0" test. The latter ensure that now IO has been flagged but not started. The former checks if any parity calculation has been flagged by not started. We must wait for both of these to complete before triggering the 'replace'. Add a similar test to the subsequent check for "are we finished yet". This possibly isn't needed (is subsumed in the STRIPE_INSYNC test), but it makes it more obvious that the REPLACE will happen before we think we are finished. Finally if a NeedReplace device is not UPTODATE then that is an error. We really must trigger a warning. 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@vger.kernel.org (3.3+) Reported-by: qindehua <13691222965@163.com> Tested-by: qindehua <qindehua@163.com> Signed-off-by: NeilBrown <neilb@suse.de>
-rw-r--r--drivers/md/raid5.c15
-rw-r--r--drivers/md/raid5.h1
2 files changed, 11 insertions, 5 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 2bf094a587cb..78ea44336e75 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3462,6 +3462,7 @@ static void handle_stripe(struct stripe_head *sh)
test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
set_bit(STRIPE_SYNCING, &sh->state);
clear_bit(STRIPE_INSYNC, &sh->state);
+ clear_bit(STRIPE_REPLACED, &sh->state);
}
spin_unlock(&sh->stripe_lock);
}
@@ -3607,19 +3608,23 @@ 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_COMPUTE_RUN, &sh->state)
+ && !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) &&
- test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
+ if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
+ WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
set_bit(R5_WantReplace, &sh->dev[i].flags);
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_COMPUTE_RUN, &sh->state) &&
test_bit(STRIPE_INSYNC, &sh->state)) {
md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
clear_bit(STRIPE_SYNCING, &sh->state);
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index b0b663b119a8..70c49329ca9a 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,