[TA2330] API to store snapshot IO num when taking snapshot, to retrie…

…ve snapshot dataset and IO number from given snapname (#98)

Signed-off-by: satbir <[email protected]>

include/mgmt_conn.h

@@ -105,6 +105,12 @@ void zinfo_destroy_cb(zvol_info_t *zinfo);
 void uzfs_zvol_mgmt_thread(void *arg);
 int finish_async_tasks(void);
 
+int uzfs_zvol_create_snapshot_update_zap(zvol_info_t *zinfo,
+    char *snapname, uint64_t snapshot_io_num);
+
+int uzfs_zvol_get_snap_dataset_with_io(zvol_info_t *zinfo,
+    char *snapname, uint64_t *snapshot_io_num, zvol_state_t **snap_zv);
+
 #ifdef __cplusplus
 }
 #endif

lib/libzpool/uzfs_rebuilding.c

@@ -356,7 +356,6 @@ uzfs_zvol_create_snaprebuild_clone(zvol_state_t *zv,
 	if (ret != 0) {
 		LOG_ERR("Failed to get info about %s@%s",
 		    zv->zv_name, REBUILD_SNAPSHOT_SNAPNAME);
-		strfree(snapname);
 		return (ret);
 	}
 

lib/libzrepl/mgmt_conn.c

@@ -598,6 +598,67 @@ finish_async_tasks(void)
 	return (rc);
 }
 
+/*
+ * Take a snapshot and update snapshot IO to ZAP.
+ */
+int
+uzfs_zvol_create_snapshot_update_zap(zvol_info_t *zinfo,
+    char *snapname, uint64_t snapshot_io_num)
+{
+	int ret = 0;
+
+	if (uzfs_zvol_get_status(zinfo->zv) != ZVOL_STATUS_HEALTHY) {
+		return (ret = -1);
+	}
+
+	if (zinfo->running_ionum > snapshot_io_num -1)
+		return (ret = -1);
+
+	mutex_enter(&zvol_list_mutex);
+
+	uzfs_zvol_store_last_committed_io_no(zinfo->zv,
+	    snapshot_io_num -1);
+	zinfo->checkpointed_ionum = snapshot_io_num -1;
+	zinfo->checkpointed_time = time(NULL);
+
+	mutex_exit(&zvol_list_mutex);
+	ret = dmu_objset_snapshot_one(zinfo->name, snapname);
+	return (ret);
+}
+
+/*
+ * For a given snap name, get snap dataset and IO number stored in ZAP
+ * Input: zinfo, snap
+ * Output: snapshot_io_num, snap_zv
+ */
+int
+uzfs_zvol_get_snap_dataset_with_io(zvol_info_t *zinfo,
+    char *snapname, uint64_t *snapshot_io_num, zvol_state_t **snap_zv)
+{
+	int ret = 0;
+
+	char *longsnap = kmem_asprintf("%s@%s",
+	    strchr(zinfo->name, '/') + 1, snapname);
+	ret = uzfs_open_dataset(zinfo->zv->zv_spa, longsnap, snap_zv);
+	if (ret != 0) {
+		LOG_ERR("Failed to get info about %s", longsnap);
+		strfree(longsnap);
+		return (ret);
+	}
+
+	strfree(longsnap);
+	ret = uzfs_hold_dataset(*snap_zv);
+	if (ret != 0) {
+		LOG_ERR("Failed to hold snapshot: %d", ret);
+		uzfs_close_dataset(*snap_zv);
+		*snap_zv = NULL;
+		return (ret);
+	}
+
+	(*snapshot_io_num) = uzfs_zvol_get_last_committed_io_no(*snap_zv);
+	return (ret);
+}
+
 /*
  * Perform the command (in async context).
  *

tests/cbtest/gtest/test_uzfs.cc

@@ -1317,3 +1317,67 @@ TEST(SnapRebuild, CloneReCreateFailure) {
 	EXPECT_EQ(0, uzfs_zvol_destroy_snaprebuild_clone(zinfo->zv,
 	    snap_zv));
 }
+
+uint64_t snapshot_io_num = 1000;
+char *snapname = (char *)"hello_snap";
+
+/* Snap create failure */
+TEST(SnapCreate, SnapCreateFailureHigherIO) {
+
+	/*
+	 * By default volume state is marked downgraded
+	 * so updation of ZAP attribute would fail
+	 */
+	uzfs_zvol_set_rebuild_status(zinfo->zv, ZVOL_REBUILDING_INIT);
+	uzfs_zvol_set_status(zinfo->zv, ZVOL_STATUS_DEGRADED);
+
+	zinfo->running_ionum = snapshot_io_num + 1;
+	/* Create snapshot */
+	EXPECT_EQ(-1, uzfs_zvol_create_snapshot_update_zap(zinfo,
+	    snapname, snapshot_io_num));
+}
+
+/* Snap create failure */
+TEST(SnapCreate, SnapCreateFailure) {
+
+	/*
+	 * By default volume state is marked downgraded
+	 * so updation of ZAP attribute would fail
+	 */
+	uzfs_zvol_set_rebuild_status(zinfo->zv, ZVOL_REBUILDING_INIT);
+	uzfs_zvol_set_status(zinfo->zv, ZVOL_STATUS_DEGRADED);
+
+	zinfo->running_ionum = snapshot_io_num -1;
+	/* Create snapshot */
+	EXPECT_EQ(-1, uzfs_zvol_create_snapshot_update_zap(zinfo,
+	    snapname, snapshot_io_num));
+}
+
+/* Snap create success */
+TEST(SnapCreate, SnapCreateSuccess) {
+
+	/*
+	 * Set volume state to healthy so that we can
+	 * upsate ZAP attribute and take snapshot
+	 */
+	uzfs_zvol_set_rebuild_status(zinfo->zv, ZVOL_REBUILDING_DONE);
+	uzfs_zvol_set_status(zinfo->zv, ZVOL_STATUS_HEALTHY);
+
+	zinfo->running_ionum = snapshot_io_num -1;
+	/* Create snapshot */
+	EXPECT_EQ(0, uzfs_zvol_create_snapshot_update_zap(zinfo,
+	    snapname, snapshot_io_num));
+}
+
+/* Retrieve Snap dataset and IO number */
+TEST(SnapCreate, SnapRetrieve) {
+
+	uint64_t io = 0;
+	zvol_state_t *snap_zv = NULL;
+
+	/* Create snapshot */
+	EXPECT_EQ(0, uzfs_zvol_get_snap_dataset_with_io(zinfo,
+	    snapname, &io, &snap_zv));
+
+	EXPECT_EQ(snapshot_io_num -1, io);
+}