[3.19.y-ckt stable] Patch "md/raid5: don't record new size if resize_stripes fails." has been added to staging queue

[Kamal Mostafa]

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

    md/raid5: don't record new size if resize_stripes fails.

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt2.

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

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From e42028a606c0f8e5baa7fc4f0a118bffdad024fa Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb at suse.de>
Date: Fri, 8 May 2015 18:19:34 +1000
Subject: md/raid5: don't record new size if resize_stripes fails.

commit 6e9eac2dcee5e19f125967dd2be3e36558c42fff upstream.

If any memory allocation in resize_stripes fails we will return
-ENOMEM, but in some cases we update conf->pool_size anyway.

This means that if we try again, the allocations will be assumed
to be larger than they are, and badness results.

So only update pool_size if there is no error.

This bug was introduced in 2.6.17 and the patch is suitable for
-stable.

Fixes: ad01c9e3752f ("[PATCH] md: Allow stripes to be expanded in preparation for expanding an array")
Signed-off-by: NeilBrown <neilb at suse.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/md/raid5.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 8577cc7..e421016 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1936,7 +1936,8 @@ static int resize_stripes(struct r5conf *conf, int newsize)

 	conf->slab_cache = sc;
 	conf->active_name = 1-conf->active_name;
-	conf->pool_size = newsize;
+	if (!err)
+		conf->pool_size = newsize;
 	return err;
 }

--
1.9.1