dm space map metadata: fix 'struct sm_metadata' leak on failed create

commit 314c25c56c1ee5026cf99c570bdfe01847927acb upstream.

In dm_sm_metadata_create() we temporarily change the dm_space_map
operations from 'ops' (whose .destroy function deallocates the
sm_metadata) to 'bootstrap_ops' (whose .destroy function doesn't).

If dm_sm_metadata_create() fails in sm_ll_new_metadata() or
sm_ll_extend(), it exits back to dm_tm_create_internal(), which calls
dm_sm_destroy() with the intention of freeing the sm_metadata, but it
doesn't (because the dm_space_map operations is still set to
'bootstrap_ops').

Fix this by setting the dm_space_map operations back to 'ops' if
dm_sm_metadata_create() fails when it is set to 'bootstrap_ops'.

[js] no nr_blocks test in 3.12 yet

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c
index 8a8f06bcde6014e93bf63d02df3485cf1484bec7..1543f37c272a86e68d4e685447e39a8e430d0709 100644 (file)
--- a/drivers/md/persistent-data/dm-space-map-metadata.c
+++ b/drivers/md/persistent-data/dm-space-map-metadata.c
@@ -773,15 +773,13 @@ int dm_sm_metadata_create(struct dm_space_map *sm,
        memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
 
        r = sm_ll_new_metadata(&smm->ll, tm);
+       if (!r) {
+               r = sm_ll_extend(&smm->ll, nr_blocks);
+       }
+       memcpy(&smm->sm, &ops, sizeof(smm->sm));
        if (r)
                return r;
 
-       r = sm_ll_extend(&smm->ll, nr_blocks);
-       if (r)
-               return r;
-
-       memcpy(&smm->sm, &ops, sizeof(smm->sm));
-
        /*
         * Now we need to update the newly created data structures with the
         * allocated blocks that they were built from.