From 3f232d6a95fc0fe539e0855ee7f3854b03c8104e Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 2 Jun 2016 16:19:52 +1000 Subject: [PATCH] md/raid5: add rcu protection to rdev accesses in want_replace Being in the middle of resync is no longer protection against failed rdevs disappearing. So add rcu protection. Signed-off-by: NeilBrown Signed-off-by: Shaohua Li --- drivers/md/raid5.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index e56c7e0627fa..198b2a9eef98 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -3239,15 +3239,16 @@ static int want_replace(struct stripe_head *sh, int disk_idx) { struct md_rdev *rdev; int rv = 0; - /* Doing recovery so rcu locking not required */ - rdev = sh->raid_conf->disks[disk_idx].replacement; + + rcu_read_lock(); + rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement); if (rdev && !test_bit(Faulty, &rdev->flags) && !test_bit(In_sync, &rdev->flags) && (rdev->recovery_offset <= sh->sector || rdev->mddev->recovery_cp <= sh->sector)) rv = 1; - + rcu_read_unlock(); return rv; } -- 2.25.1