[TA3151]feat(snap_rebuild)Flush outstanding IOs before taking snapsho…

…t on rebuild clone. (#123)

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

cmd/uzfs_test/zrepl_utest.c

@@ -295,6 +295,7 @@ zrepl_utest_replica_rebuild_start(int fd, mgmt_ack_t *mgmt_ack,
 	return (0);
 }
 
+
 static void
 reader_thread(void *arg)
 {
@@ -1026,7 +1027,7 @@ zrepl_rebuild_test(void *arg)
 		goto exit;
 	}
 	/*
-	 * Check rebuild status of of downgrade replica ds1.
+	 * Check rebuild status of downgrade replica ds1.
 	 */
 status_check:
 	count = zrepl_utest_get_replica_status(ds1, ds1_mgmt_fd, &status_ack);
@@ -1195,7 +1196,7 @@ zrepl_rebuild_test(void *arg)
 
 	/*
 	 * Start rebuild process on downgraded replica ds3
-	 * by sharing IP and rebuild_Port info with ds3.
+	 * by sharing IP and rebuild_port info with ds3.
 	 */
 	rc = zrepl_utest_replica_rebuild_start(ds3_mgmt_fd, mgmt_ack_ds3,
 	    sizeof (mgmt_ack_t) * 3);

include/sys/uzfs_zvol.h

@@ -97,11 +97,14 @@ typedef struct zvol_state zvol_state_t;
 #define	UZFS_IO_MREAD_FAIL	3
 
 #define	ZINFO_IS_DEGRADED(zinfo)	(ZVOL_IS_DEGRADED(zinfo->main_zv))
-#define	ZVOL_IS_DEGRADED(zv)	(zv->zv_status == ZVOL_STATUS_DEGRADED)
+#define	ZVOL_IS_DEGRADED(zv)		(zv->zv_status == ZVOL_STATUS_DEGRADED)
+#define	ZVOL_IS_HEALTHY(zv)		(zv->zv_status == ZVOL_STATUS_HEALTHY)
 
 #define	ZVOL_IS_REBUILDING(zv)		\
 	((zv->rebuild_info.zv_rebuild_status == ZVOL_REBUILDING_SNAP) || \
 	(zv->rebuild_info.zv_rebuild_status == ZVOL_REBUILDING_AFS))
+#define	ZVOL_IS_REBUILDING_AFS(zv)		\
+	(zv->rebuild_info.zv_rebuild_status == ZVOL_REBUILDING_AFS)
 #define	ZVOL_IS_REBUILDED(zv)		\
 	(zv->rebuild_info.zv_rebuild_status == ZVOL_REBUILDING_DONE)
 #define	ZVOL_IS_REBUILDING_ERRORED(zv)	\

include/sys/zfs_context.h

@@ -515,6 +515,7 @@ extern int	taskq_member(taskq_t *, kthread_t *);
 extern int	taskq_cancel_id(taskq_t *, taskqid_t);
 extern void	system_taskq_init(void);
 extern void	system_taskq_fini(void);
+extern int taskq_check_active_ios(taskq_t *tq);
 
 #define	XVA_MAPSIZE	3
 #define	XVA_MAGIC	0x78766174

include/zrepl_mgmt.h

@@ -158,6 +158,11 @@ typedef struct zvol_info_s {
 
 	/* Will be used to singal ack-sender to exit */
 	uint8_t		conn_closed;
+
+	/* Rebuild flags to quiesce IOs */
+	uint8_t		quiesce_requested;
+	uint8_t		quiesce_done;
+
 	/* Pointer to mgmt connection for this zinfo */
 	void		*mgmt_conn;
 

lib/libzpool/taskq.c

@@ -213,6 +213,19 @@ taskq_wait_outstanding(taskq_t *tq, taskqid_t id)
 	taskq_wait(tq);
 }
 
+int
+taskq_check_active_ios(taskq_t *tq)
+{
+	int ret = 0;
+	taskq_ent_t *t;
+	mutex_enter(&tq->tq_lock);
+	if (((t = tq->tq_task.tqent_next) != &tq->tq_task) ||
+	    (tq->tq_active != 0))
+		ret = 1;
+	mutex_exit(&tq->tq_lock);
+	return (ret);
+}
+
 static void
 taskq_thread(void *arg)
 {

lib/libzrepl/data_conn.c

@@ -228,14 +228,20 @@ uzfs_submit_writes(zvol_info_t *zinfo, zvol_io_cmd_t *zio_cmd)
 		remain -= sizeof (*write_hdr);
 		if (remain < write_hdr->len)
 			return (-1);
-
-		rc = uzfs_write_data(zinfo->main_zv, datap, data_offset,
-		    write_hdr->len, &metadata, is_rebuild);
-		if (rc != 0)
-			break;
+		/*
+		 * Write to main_zv when volume is either
+		 * healthy or in REBUILD_AFS state of rebuild
+		 */
+		if (ZVOL_IS_REBUILDING_AFS(zinfo->main_zv) ||
+		    ZVOL_IS_HEALTHY(zinfo->main_zv)) {
+			rc = uzfs_write_data(zinfo->main_zv, datap, data_offset,
+			    write_hdr->len, &metadata, is_rebuild);
+			if (rc != 0)
+				break;
+		}
 
 		/* IO to clone should be sent only when it is from app */
-		if (!is_rebuild && (zinfo->clone_zv != NULL)) {
+		if (!is_rebuild && !ZVOL_IS_HEALTHY(zinfo->main_zv)) {
 			rc = uzfs_write_data(zinfo->clone_zv, datap,
 			    data_offset, write_hdr->len, &metadata,
 			    is_rebuild);
@@ -332,7 +338,9 @@ uzfs_zvol_worker(void *arg)
 					rc = -1;
 					break;
 				}
-			}
+			} else if (!ZVOL_IS_HEALTHY(zinfo->main_zv))
+				/* App IOs should go to clone_zv */
+				read_zv = zinfo->clone_zv;
 
 			rc = uzfs_read_data(read_zv,
 			    (char *)zio_cmd->buf,
@@ -348,6 +356,8 @@ uzfs_zvol_worker(void *arg)
 
 		case ZVOL_OPCODE_SYNC:
 			uzfs_flush_data(zinfo->main_zv);
+			if (!ZVOL_IS_HEALTHY(zinfo->main_zv))
+				uzfs_flush_data(zinfo->clone_zv);
 			atomic_inc_64(&zinfo->sync_req_received_cnt);
 			break;
 
@@ -680,8 +690,29 @@ uzfs_zvol_rebuild_dw_replica(void *arg)
 				    ZVOL_REBUILDING_AFS);
 				if (start_rebuild_from_clone == 0)
 					start_rebuild_from_clone = 1;
+				/*
+				 * Lets ask io_receiver thread to flush
+				 * all outstanding IOs in taskq
+				 */
+				zinfo->quiesce_done = 0;
+				zinfo->quiesce_requested = 1;
 			}
 			mutex_exit(&zinfo->main_zv->rebuild_mtx);
+			/*
+			 * Wait for all outstanding IOs to be flushed
+			 * to disk before making further progress
+			 */
+			while (1) {
+				if (zinfo->quiesce_done ||
+				    !taskq_check_active_ios(
+				    zinfo->uzfs_zvol_taskq)) {
+					zinfo->quiesce_done = 1;
+					zinfo->quiesce_requested = 0;
+					break;
+				}
+				else
+					sleep(1);
+			}
 
 			if (start_rebuild_from_clone == 1) {
 				start_rebuild_from_clone = 2;
@@ -1859,6 +1890,19 @@ uzfs_zvol_io_receiver(void *arg)
 		/* Take refcount for uzfs_zvol_worker to work on it */
 		uzfs_zinfo_take_refcnt(zinfo);
 		zio_cmd->zinfo = zinfo;
+
+		/*
+		 * Rebuild want to take consistent snapshot
+		 * so it asked to flush all outstanding IOs
+		 * before taking snapshot on rebuild_clone
+		 */
+		if (zinfo->quiesce_requested) {
+			ASSERT(ZVOL_IS_REBUILDING_AFS(zinfo->main_zv));
+			taskq_wait_outstanding(zinfo->uzfs_zvol_taskq, 0);
+			zinfo->quiesce_requested = 0;
+			zinfo->quiesce_done = 1;
+		}
+
 		taskq_dispatch(zinfo->uzfs_zvol_taskq, uzfs_zvol_worker,
 		    zio_cmd, TQ_SLEEP);
 	}
@@ -1892,6 +1936,8 @@ uzfs_zvol_io_receiver(void *arg)
 	zinfo->is_io_receiver_created = B_FALSE;
 	(void) uzfs_zvol_release_internal_clone(zinfo->main_zv,
 	    &zinfo->snap_zv, &zinfo->clone_zv);
+	zinfo->quiesce_requested = 0;
+	zinfo->quiesce_done = 1;
 	uzfs_zinfo_drop_refcnt(zinfo);
 thread_exit:
 	close(fd);

lib/libzrepl/mgmt_conn.c

@@ -1261,6 +1261,7 @@ handle_start_rebuild_req(uzfs_mgmt_conn_t *conn, zvol_io_hdr_t *hdrp,
 
 	memset(&zinfo->main_zv->rebuild_info, 0,
 	    sizeof (zvol_rebuild_info_t));
+	zinfo->quiesce_requested = zinfo->quiesce_done = 0;
 	uzfs_zvol_set_rebuild_status(zinfo->main_zv,
 	    ZVOL_REBUILDING_SNAP);