md/raid1{,0}: fix deadlock in bitmap_unplug. (874807a8) · Commits · 戴 / test

If the raid1 or raid10 unplug function gets called from a make_request function (which is very possible) when there are bios on the current->bio_list list, then it will not be able to successfully call bitmap_unplug() and it could need to submit more bios and wait for them to complete. But they won't complete while current->bio_list is non-empty. So detect that case and handle the unplugging off to another thread just like we already do when called from within the scheduler. RAID1 version of bug was introduced in 3.6, so that part of fix is suitable for 3.6.y. RAID10 part won't apply. Cc: stable@vger.kernel.org Reported-by:

Torsten Kaiser <just.for.lkml@googlemail.com> Reported-by:

Peter Maloney <peter.maloney@brockmann-consult.de> Signed-off-by:

NeilBrown <neilb@suse.de>

drivers/md/raid1.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -963,7 +963,7 @@ static void raid1_unplug(struct blk_plug_cb *cb, bool from_schedule)
	struct r1conf *conf = mddev->private;		struct r1conf *conf = mddev->private;
	struct bio *bio;		struct bio *bio;

	if (from_schedule) {		if (from_schedule \|\| current->bio_list) {
	spin_lock_irq(&conf->device_lock);		spin_lock_irq(&conf->device_lock);
	bio_list_merge(&conf->pending_bio_list, &plug->pending);		bio_list_merge(&conf->pending_bio_list, &plug->pending);
	conf->pending_count += plug->pending_cnt;		conf->pending_count += plug->pending_cnt;

drivers/md/raid10.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -1069,7 +1069,7 @@ static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule)
	struct r10conf *conf = mddev->private;		struct r10conf *conf = mddev->private;
	struct bio *bio;		struct bio *bio;

	if (from_schedule) {		if (from_schedule \|\| current->bio_list) {
	spin_lock_irq(&conf->device_lock);		spin_lock_irq(&conf->device_lock);
	bio_list_merge(&conf->pending_bio_list, &plug->pending);		bio_list_merge(&conf->pending_bio_list, &plug->pending);
	conf->pending_count += plug->pending_cnt;		conf->pending_count += plug->pending_cnt;

Admin message