Illumos 6414 - vdev_config_sync could be simpler

6414 vdev_config_sync could be simpler
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>

References:
  https://www.illumos.org/issues/6414
  illumos/illumos-gate@eb5bb58

Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <tuxoko@gmail.com>

Author: behlendorf

include/sys/vdev.h

@@ -121,8 +121,7 @@ extern void vdev_queue_io_done(zio_t *zio);
 
 extern void vdev_config_dirty(vdev_t *vd);
 extern void vdev_config_clean(vdev_t *vd);
-extern int vdev_config_sync(vdev_t **svd, int svdcount, uint64_t txg,
-    boolean_t);
+extern int vdev_config_sync(vdev_t **svd, int svdcount, uint64_t txg);
 
 extern void vdev_state_dirty(vdev_t *vd);
 extern void vdev_state_clean(vdev_t *vd);

module/zfs/spa.c

@@ -6518,16 +6518,10 @@ spa_sync(spa_t *spa, uint64_t txg)
 				if (svdcount == SPA_DVAS_PER_BP)
 					break;
 			}
-			error = vdev_config_sync(svd, svdcount, txg, B_FALSE);
-			if (error != 0)
-				error = vdev_config_sync(svd, svdcount, txg,
-				    B_TRUE);
+			error = vdev_config_sync(svd, svdcount, txg);
 		} else {
 			error = vdev_config_sync(rvd->vdev_child,
-			    rvd->vdev_children, txg, B_FALSE);
-			if (error != 0)
-				error = vdev_config_sync(rvd->vdev_child,
-				    rvd->vdev_children, txg, B_TRUE);
+			    rvd->vdev_children, txg);
 		}
 
 		if (error == 0)

module/zfs/vdev_label.c

@@ -1187,24 +1187,28 @@ vdev_label_sync_list(spa_t *spa, int l, uint64_t txg, int flags)
  * at any time, you can just call it again, and it will resume its work.
  */
 int
-vdev_config_sync(vdev_t **svd, int svdcount, uint64_t txg, boolean_t tryhard)
+vdev_config_sync(vdev_t **svd, int svdcount, uint64_t txg)
 {
 	spa_t *spa = svd[0]->vdev_spa;
 	uberblock_t *ub = &spa->spa_uberblock;
 	vdev_t *vd;
 	zio_t *zio;
-	int error;
+	int error = 0;
 	int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL;
 
+retry:
 	/*
 	 * Normally, we don't want to try too hard to write every label and
 	 * uberblock.  If there is a flaky disk, we don't want the rest of the
 	 * sync process to block while we retry.  But if we can't write a
 	 * single label out, we should retry with ZIO_FLAG_TRYHARD before
 	 * bailing out and declaring the pool faulted.
 	 */
-	if (tryhard)
+	if (error != 0) {
+		if ((flags & ZIO_FLAG_TRYHARD) != 0)
+			return (error);
 		flags |= ZIO_FLAG_TRYHARD;
+	}
 
 	ASSERT(ub->ub_txg <= txg);
 
@@ -1248,7 +1252,7 @@ vdev_config_sync(vdev_t **svd, int svdcount, uint64_t txg, boolean_t tryhard)
 	 * are committed to stable storage before the uberblock update.
 	 */
 	if ((error = vdev_label_sync_list(spa, 0, txg, flags)) != 0)
-		return (error);
+		goto retry;
 
 	/*
 	 * Sync the uberblocks to all vdevs in svd[].
@@ -1266,7 +1270,7 @@ vdev_config_sync(vdev_t **svd, int svdcount, uint64_t txg, boolean_t tryhard)
 	 *	to the new uberblocks.
 	 */
 	if ((error = vdev_uberblock_sync_list(svd, svdcount, ub, flags)) != 0)
-		return (error);
+		goto retry;
 
 	/*
 	 * Sync out odd labels for every dirty vdev.  If the system dies
@@ -1278,5 +1282,8 @@ vdev_config_sync(vdev_t **svd, int svdcount, uint64_t txg, boolean_t tryhard)
 	 * to disk to ensure that all odd-label updates are committed to
 	 * stable storage before the next transaction group begins.
 	 */
-	return (vdev_label_sync_list(spa, 1, txg, flags));
+	if ((error = vdev_label_sync_list(spa, 1, txg, flags)) != 0)
+		goto retry;
+
+	return (0);
 }