Commit 84dd97a6 authored Mar 15, 2017 by NeilBrown Committed by Shaohua Li Mar 22, 2017

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 <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>

parent 37011e3a

drivers/md/raid5.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -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;
		}