[3.11.y.z extended stable] Patch "dm space map metadata: fix extending the space map" has been added to staging queue

[Luis Henriques]

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

    dm space map metadata: fix extending the space map

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 37e195a536dbab06dba4d267563246c6f0467c85 Mon Sep 17 00:00:00 2001
From: Joe Thornber <ejt at redhat.com>
Date: Tue, 7 Jan 2014 15:49:02 +0000
Subject: dm space map metadata: fix extending the space map

commit 7e664b3dec431eebf0c5df5ff704d6197634cf35 upstream.

When extending a metadata space map we should do the first commit whilst
still in bootstrap mode -- a mode where all blocks get allocated in the
new area.

That way the commit overhead is allocated from the newly added space.
Otherwise we risk running out of space.

With this fix, and the previous commit "dm space map common: make sure
new space is used during extend", the following device mapper testsuite
test passes:
 dmtest run --suite thin-provisioning -n /resize_metadata_no_io/

Signed-off-by: Joe Thornber <ejt at redhat.com>
Signed-off-by: Mike Snitzer <snitzer at redhat.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/md/persistent-data/dm-space-map-metadata.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c
index 58fc1ee..f04d92f 100644
--- a/drivers/md/persistent-data/dm-space-map-metadata.c
+++ b/drivers/md/persistent-data/dm-space-map-metadata.c
@@ -608,20 +608,28 @@ static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
 	 * Flick into a mode where all blocks get allocated in the new area.
 	 */
 	smm->begin = old_len;
-	memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
+	memcpy(sm, &bootstrap_ops, sizeof(*sm));

 	/*
 	 * Extend.
 	 */
 	r = sm_ll_extend(&smm->ll, extra_blocks);
+	if (r)
+		goto out;
+
+	for (i = old_len; !r && i < smm->begin; i++) {
+		r = sm_ll_inc(&smm->ll, i, &ev);
+		if (r)
+			goto out;
+	}

+	r = sm_metadata_commit(sm);
+
+out:
 	/*
 	 * Switch back to normal behaviour.
 	 */
-	memcpy(&smm->sm, &ops, sizeof(smm->sm));
-	for (i = old_len; !r && i < smm->begin; i++)
-		r = sm_ll_inc(&smm->ll, i, &ev);
-
+	memcpy(sm, &ops, sizeof(*sm));
 	return r;
 }

--
1.8.3.2