[3.11.y.z extended stable] Patch "md: avoid possible spinning md thread at shutdown." has been added to staging queue

Luis Henriques luis.henriques at canonical.com
Fri May 30 09:28:30 UTC 2014


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

    md: avoid possible spinning md thread at shutdown.

to the linux-3.11.y-queue branch of the 3.11.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-3.11.y-queue

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

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 6a10ebddd95b37a457283eb72247ec6ea444df1d Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb at suse.de>
Date: Tue, 6 May 2014 09:36:08 +1000
Subject: md: avoid possible spinning md thread at shutdown.

commit 0f62fb220aa4ebabe8547d3a9ce4a16d3c045f21 upstream.

If an md array with externally managed metadata (e.g. DDF or IMSM)
is in use, then we should not set safemode==2 at shutdown because:

1/ this is ineffective: user-space need to be involved in any 'safemode' handling,
2/ The safemode management code doesn't cope with safemode==2 on external metadata
   and md_check_recover enters an infinite loop.

Even at shutdown, an infinite-looping process can be problematic, so this
could cause shutdown to hang.

Signed-off-by: NeilBrown <neilb at suse.de>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/md/md.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index c4b33642d125..78a848cc106e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8502,7 +8502,8 @@ static int md_notify_reboot(struct notifier_block *this,
 		if (mddev_trylock(mddev)) {
 			if (mddev->pers)
 				__md_stop_writes(mddev);
-			mddev->safemode = 2;
+			if (mddev->persistent)
+				mddev->safemode = 2;
 			mddev_unlock(mddev);
 		}
 		need_delay = 1;
--
1.9.1





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