dm exception store: introduce registry

Move exception stores into a registry.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 57 insertions, 10 deletions

diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c
index 0bbbe3b7431e..e85b7a186a13 100644
--- a/drivers/md/dm-snap-persistent.c
+++ b/drivers/md/dm-snap-persistent.c
@@ -478,7 +478,7 @@ static void persistent_fraction_full(struct dm_exception_store *store,
         *denominator = get_dev_size(store->snap->cow->bdev);
 }
 
-static void persistent_destroy(struct dm_exception_store *store)
+static void persistent_dtr(struct dm_exception_store *store)
 {
         struct pstore *ps = get_info(store);
 
@@ -656,7 +656,8 @@ static void persistent_drop_snapshot(struct dm_exception_store *store)
                 DMWARN("write header failed");
 }
 
-int dm_create_persistent(struct dm_exception_store *store)
+static int persistent_ctr(struct dm_exception_store *store,
+                          unsigned argc, char **argv)
 {
         struct pstore *ps;
 
@@ -683,23 +684,69 @@ int dm_create_persistent(struct dm_exception_store *store)
                 return -ENOMEM;
         }
 
-        store->type.dtr = persistent_destroy;
-        store->type.read_metadata = persistent_read_metadata;
-        store->type.prepare_exception = persistent_prepare_exception;
-        store->type.commit_exception = persistent_commit_exception;
-        store->type.drop_snapshot = persistent_drop_snapshot;
-        store->type.fraction_full = persistent_fraction_full;
-
         store->context = ps;
 
         return 0;
 }
 
+static int persistent_status(struct dm_exception_store *store,
+                             status_type_t status, char *result,
+                             unsigned int maxlen)
+{
+        int sz = 0;
+
+        return sz;
+}
+
+static struct dm_exception_store_type _persistent_type = {
+        .name = "persistent",
+        .module = THIS_MODULE,
+        .ctr = persistent_ctr,
+        .dtr = persistent_dtr,
+        .read_metadata = persistent_read_metadata,
+        .prepare_exception = persistent_prepare_exception,
+        .commit_exception = persistent_commit_exception,
+        .drop_snapshot = persistent_drop_snapshot,
+        .fraction_full = persistent_fraction_full,
+        .status = persistent_status,
+};
+
+static struct dm_exception_store_type _persistent_compat_type = {
+        .name = "P",
+        .module = THIS_MODULE,
+        .ctr = persistent_ctr,
+        .dtr = persistent_dtr,
+        .read_metadata = persistent_read_metadata,
+        .prepare_exception = persistent_prepare_exception,
+        .commit_exception = persistent_commit_exception,
+        .drop_snapshot = persistent_drop_snapshot,
+        .fraction_full = persistent_fraction_full,
+        .status = persistent_status,
+};
+
 int dm_persistent_snapshot_init(void)
 {
-        return 0;
+        int r;
+
+        r = dm_exception_store_type_register(&_persistent_type);
+        if (r) {
+                DMERR("Unable to register persistent exception store type");
+                return r;
+        }
+
+        r = dm_exception_store_type_register(&_persistent_compat_type);
+        if (r) {
+                DMERR("Unable to register old-style persistent exception "
+                      "store type");
+                dm_exception_store_type_unregister(&_persistent_type);
+                return r;
+        }
+
+        return r;
 }
 
 void dm_persistent_snapshot_exit(void)
 {
+        dm_exception_store_type_unregister(&_persistent_type);
+        dm_exception_store_type_unregister(&_persistent_compat_type);
 }