dm snapshot persistent: fix missing cleanup in persistent_ctr error path

If an unsupported option is given then the early return from
persistent_ctr() leaked memory allocated for the 'pstore' and never
destroyed the 'metadata_wq'.

Fixes: b0d3cc011e53 ("dm snapshot: add new persistent store option to support overflow")
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c
index aeacad9be51dcb1c10c78df1398abddb9e8bc4f1..117a05e40090a9b78829ed415446d906c8268701 100644 (file)
--- 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 r;
 
        /* 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;
+               r = -ENOMEM;
+               goto err_workqueue;
        }
 
        if (options) {
@@ -879,13 +880,21 @@ 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;
+                       r = -EINVAL;
+                       goto err_options;
                }
        }
 
        store->context = ps;
 
        return 0;
+
+err_options:
+       destroy_workqueue(ps->metadata_wq);
+err_workqueue:
+       kfree(ps);
+
+       return r;
 }
 
 static unsigned persistent_status(struct dm_exception_store *store,