[3.13.y.z extended stable] Patch "md/raid1: clean up request counts properly in close_sync()" has been added to staging queue

Kamal Mostafa kamal at canonical.com
Thu Oct 9 20:51:43 UTC 2014


This is a note to let you know that I have just added a patch titled

    md/raid1: clean up request counts properly in close_sync()

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.9.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 2c700e294392c2fa22b38637d28998fdbbd8596f Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb at suse.de>
Date: Thu, 4 Sep 2014 16:30:38 +1000
Subject: md/raid1: clean up request counts properly in close_sync()

commit 669cc7ba77864e7b1ac39c9f2b2afb8730f341f4 upstream.

If there are outstanding writes when close_sync is called,
the change to ->start_next_window might cause them to
decrement the wrong counter when they complete.  Fix this
by merging the two counters into the one that will be decremented.

Having an incorrect value in a counter can cause raise_barrier()
to hangs, so this is suitable for -stable.

Fixes: 79ef3a8aa1cb1523cc231c9a90a278333c21f761
Signed-off-by: NeilBrown <neilb at suse.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/md/raid1.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index e124f01..2414a79 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1544,8 +1544,13 @@ static void close_sync(struct r1conf *conf)
 	mempool_destroy(conf->r1buf_pool);
 	conf->r1buf_pool = NULL;

+	spin_lock_irq(&conf->resync_lock);
 	conf->next_resync = 0;
 	conf->start_next_window = MaxSector;
+	conf->current_window_requests +=
+		conf->next_window_requests;
+	conf->next_window_requests = 0;
+	spin_unlock_irq(&conf->resync_lock);
 }

 static int raid1_spare_active(struct mddev *mddev)
--
1.9.1





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