[PATCH] dm snapshot: fix memory leak

[Sudip Mukherjee <sudipm.mukherjee@gmail.com>]

If wrong option is given then we are returning but we missed releasing
the workqueue and pstore.
Add an error path and use it to correctly release resources on failure.

Fixes: b0d3cc011e53 ("dm snapshot: add new persistent store option to support overflow")
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
---
 drivers/md/dm-snap-persistent.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c
index 229be55..5ff7c23 100644
--- a/drivers/md/dm-snap-persistent.c
+++ b/drivers/md/dm-snap-persistent.c
@@ -847,6 +847,7 @@ static void persistent_drop_snapshot(struct dm_exception_store *store)
 static int persistent_ctr(struct dm_exception_store *store, char *options)
 {
 	struct pstore *ps;
+	int ret;
 
 	/* allocate the pstore */
 	ps = kzalloc(sizeof(*ps), GFP_KERNEL);
@@ -868,9 +869,9 @@ static int persistent_ctr(struct dm_exception_store *store, char *options)
 
 	ps->metadata_wq = alloc_workqueue("ksnaphd", WQ_MEM_RECLAIM, 0);
 	if (!ps->metadata_wq) {
-		kfree(ps);
 		DMERR("couldn't start header metadata update thread");
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto err_free_ps;
 	}
 
 	if (options) {
@@ -879,13 +880,20 @@ static int persistent_ctr(struct dm_exception_store *store, char *options)
 			store->userspace_supports_overflow = true;
 		else {
 			DMERR("Unsupported persistent store option: %s", options);
-			return -EINVAL;
+			ret = -EINVAL;
+			goto err_option;
 		}
 	}
 
 	store->context = ps;
 
 	return 0;
+
+err_option:
+	destroy_workqueue(ps->metadata_wq);
+err_free_ps:
+	kfree(ps);
+	return ret;
 }
 
 static unsigned persistent_status(struct dm_exception_store *store,
-- 
1.9.1