dm space map metadata: fix extending the space map

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@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c
index e93084419068b6039c69204074876a5e81f2587d..bfbfe03228c11bc6019f06cb63ac890c56d64216 100644 (file)
--- 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;
 }