[PATCH 3.10 017/268] dm space map metadata: fix 'struct sm_metadata' leak on failed create

Willy Tarreau
2017-06-19T18:37:55Z

From: Benjamin Marzinski <bmarzins@redhat.com>

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: Willy Tarreau <w@1wt.eu>
---
drivers/md/persistent-data/dm-space-map-metadata.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c
index 056d09c..c79d648 100644
--- a/drivers/md/persistent-data/dm-space-map-metadata.c
+++ b/drivers/md/persistent-data/dm-space-map-metadata.c
@@ -679,15 +679,13 @@ 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.
--
2.8.0.rc2.1.gbe9624a