mirror of
https://git.yoctoproject.org/meta-ti
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Koen Kooi
bb34e69f3d
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net> Signed-off-by: Denys Dmytriyenko <denys@ti.com>
98 lines
3.2 KiB
Diff
98 lines
3.2 KiB
Diff
From 250082bf56c6157c888f21df27d73475cb6f0065 Mon Sep 17 00:00:00 2001
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From: NeilBrown <neilb@suse.de>
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Date: Mon, 19 Mar 2012 12:46:38 +1100
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Subject: [PATCH 068/147] md/raid1,raid10: avoid deadlock during
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resync/recovery.
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commit d6b42dcb995e6acd7cc276774e751ffc9f0ef4bf upstream.
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If RAID1 or RAID10 is used under LVM or some other stacking
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block device, it is possible to enter a deadlock during
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resync or recovery.
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This can happen if the upper level block device creates
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two requests to the RAID1 or RAID10. The first request gets
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processed, blocks recovery and queue requests for underlying
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requests in current->bio_list. A resync request then starts
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which will wait for those requests and block new IO.
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But then the second request to the RAID1/10 will be attempted
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and it cannot progress until the resync request completes,
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which cannot progress until the underlying device requests complete,
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which are on a queue behind that second request.
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So allow that second request to proceed even though there is
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a resync request about to start.
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This is suitable for any -stable kernel.
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Reported-by: Ray Morris <support@bettercgi.com>
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Tested-by: Ray Morris <support@bettercgi.com>
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Signed-off-by: NeilBrown <neilb@suse.de>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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---
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drivers/md/raid1.c | 17 +++++++++++++++--
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drivers/md/raid10.c | 17 +++++++++++++++--
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2 files changed, 30 insertions(+), 4 deletions(-)
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diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
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index 7d9e071..7af60ec 100644
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--- a/drivers/md/raid1.c
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+++ b/drivers/md/raid1.c
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@@ -731,9 +731,22 @@ static void wait_barrier(struct r1conf *conf)
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spin_lock_irq(&conf->resync_lock);
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if (conf->barrier) {
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conf->nr_waiting++;
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- wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
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+ /* Wait for the barrier to drop.
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+ * However if there are already pending
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+ * requests (preventing the barrier from
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+ * rising completely), and the
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+ * pre-process bio queue isn't empty,
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+ * then don't wait, as we need to empty
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+ * that queue to get the nr_pending
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+ * count down.
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+ */
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+ wait_event_lock_irq(conf->wait_barrier,
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+ !conf->barrier ||
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+ (conf->nr_pending &&
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+ current->bio_list &&
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+ !bio_list_empty(current->bio_list)),
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conf->resync_lock,
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- );
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+ );
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conf->nr_waiting--;
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}
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conf->nr_pending++;
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diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
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index 685ddf3..b219449 100644
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--- a/drivers/md/raid10.c
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+++ b/drivers/md/raid10.c
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@@ -790,9 +790,22 @@ static void wait_barrier(struct r10conf *conf)
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spin_lock_irq(&conf->resync_lock);
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if (conf->barrier) {
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conf->nr_waiting++;
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- wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
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+ /* Wait for the barrier to drop.
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+ * However if there are already pending
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+ * requests (preventing the barrier from
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+ * rising completely), and the
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+ * pre-process bio queue isn't empty,
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+ * then don't wait, as we need to empty
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+ * that queue to get the nr_pending
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+ * count down.
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+ */
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+ wait_event_lock_irq(conf->wait_barrier,
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+ !conf->barrier ||
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+ (conf->nr_pending &&
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+ current->bio_list &&
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+ !bio_list_empty(current->bio_list)),
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conf->resync_lock,
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- );
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+ );
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conf->nr_waiting--;
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}
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conf->nr_pending++;
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--
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1.7.9.4
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