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@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index c293d9c..6056ee7 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1554,7 +1554,8 @@ 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;
 }