From 84dd97a69092cef858483b775f1900d743d796a4 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 15 Mar 2017 14:05:14 +1100 Subject: [PATCH] md/raid5: don't test ->writes_pending in raid5_remove_disk This test on ->writes_pending cannot be safe as the counter can be incremented at any moment and cannot be locked against. Change it to test conf->active_stripes, which at least can be locked against. More changes are still needed. A future patch will change ->writes_pending, and testing it here will be very inconvenient. Signed-off-by: NeilBrown Signed-off-by: Shaohua Li --- drivers/md/raid5.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 00a34faabcdf..0b1a4339a437 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -7532,9 +7532,12 @@ static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev) /* * we can't wait pending write here, as this is called in * raid5d, wait will deadlock. + * neilb: there is no locking about new writes here, + * so this cannot be safe. */ - if (atomic_read(&mddev->writes_pending)) + if (atomic_read(&conf->active_stripes)) { return -EBUSY; + } log_exit(conf); return 0; } -- 2.30.2