From e5c86471f933608db5d43679f84cb4346c32033e Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 19 Sep 2012 12:52:30 +1000 Subject: md/raid5: fix calculate of 'degraded' when a replacement becomes active. When a replacement device becomes active, we mark the device that it replaces as 'faulty' so that it can subsequently get removed. However 'calc_degraded' only pays attention to the primary device, not the replacement, so the array appears to become degraded, which is wrong. So teach 'calc_degraded' to consider any replacement if a primary device is faulty. This is suitable for -stable as an incorrect 'degraded' value can confuse md and could lead to data corruption. This is only relevant for 3.3 and later. Cc: stable@vger.kernel.org Reported-by: Robin Hill Reported-by: John Drescher Signed-off-by: NeilBrown diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 380cb68..7031b86 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -393,6 +393,8 @@ static int calc_degraded(struct r5conf *conf) degraded = 0; for (i = 0; i < conf->previous_raid_disks; i++) { struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev); + if (rdev && test_bit(Faulty, &rdev->flags)) + rdev = rcu_dereference(conf->disks[i].replacement); if (!rdev || test_bit(Faulty, &rdev->flags)) degraded++; else if (test_bit(In_sync, &rdev->flags)) @@ -417,6 +419,8 @@ static int calc_degraded(struct r5conf *conf) degraded2 = 0; for (i = 0; i < conf->raid_disks; i++) { struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev); + if (rdev && test_bit(Faulty, &rdev->flags)) + rdev = rcu_dereference(conf->disks[i].replacement); if (!rdev || test_bit(Faulty, &rdev->flags)) degraded2++; else if (test_bit(In_sync, &rdev->flags)) -- cgit v0.10.2