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, 55 insertions, 10 deletions

diff --git a/drivers/md/dm-snap-transient.c b/drivers/md/dm-snap-transient.c
index b558176ff020..51bc4a78ce9a 100644
--- a/drivers/md/dm-snap-transient.c
+++ b/drivers/md/dm-snap-transient.c
@@ -23,7 +23,7 @@ struct transient_c {
         sector_t next_free;
 };
 
-static void transient_destroy(struct dm_exception_store *store)
+static void transient_dtr(struct dm_exception_store *store)
 {
         kfree(store->context);
 }
@@ -67,17 +67,11 @@ static void transient_fraction_full(struct dm_exception_store *store,
         *denominator = get_dev_size(store->snap->cow->bdev);
 }
 
-int dm_create_transient(struct dm_exception_store *store)
+static int transient_ctr(struct dm_exception_store *store,
+                         unsigned argc, char **argv)
 {
         struct transient_c *tc;
 
-        store->type.dtr = transient_destroy;
-        store->type.read_metadata = transient_read_metadata;
-        store->type.prepare_exception = transient_prepare_exception;
-        store->type.commit_exception = transient_commit_exception;
-        store->type.drop_snapshot = NULL;
-        store->type.fraction_full = transient_fraction_full;
-
         tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL);
         if (!tc)
                 return -ENOMEM;
@@ -88,11 +82,62 @@ int dm_create_transient(struct dm_exception_store *store)
         return 0;
 }
 
+static int transient_status(struct dm_exception_store *store,
+                            status_type_t status, char *result,
+                            unsigned maxlen)
+{
+        int sz = 0;
+
+        return sz;
+}
+
+static struct dm_exception_store_type _transient_type = {
+        .name = "transient",
+        .module = THIS_MODULE,
+        .ctr = transient_ctr,
+        .dtr = transient_dtr,
+        .read_metadata = transient_read_metadata,
+        .prepare_exception = transient_prepare_exception,
+        .commit_exception = transient_commit_exception,
+        .fraction_full = transient_fraction_full,
+        .status = transient_status,
+};
+
+static struct dm_exception_store_type _transient_compat_type = {
+        .name = "N",
+        .module = THIS_MODULE,
+        .ctr = transient_ctr,
+        .dtr = transient_dtr,
+        .read_metadata = transient_read_metadata,
+        .prepare_exception = transient_prepare_exception,
+        .commit_exception = transient_commit_exception,
+        .fraction_full = transient_fraction_full,
+        .status = transient_status,
+};
+
 int dm_transient_snapshot_init(void)
 {
-        return 0;
+        int r;
+
+        r = dm_exception_store_type_register(&_transient_type);
+        if (r) {
+                DMWARN("Unable to register transient exception store type");
+                return r;
+        }
+
+        r = dm_exception_store_type_register(&_transient_compat_type);
+        if (r) {
+                DMWARN("Unable to register old-style transient "
+                       "exception store type");
+                dm_exception_store_type_unregister(&_transient_type);
+                return r;
+        }
+
+        return r;
 }
 
 void dm_transient_snapshot_exit(void)
 {
+        dm_exception_store_type_unregister(&_transient_type);
+        dm_exception_store_type_unregister(&_transient_compat_type);
 }