Illumos #3090 and #3102

3090 vdev_reopen() during reguid causes vdev to be treated as corrupt
3102 vdev_uberblock_load() and vdev_validate() may read the wrong label

Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Christopher Siden <chris.siden@delphix.com>
Reviewed by: Garrett D'Amore <garrett@damore.org>
Approved by: Eric Schrock <Eric.Schrock@delphix.com>

References:
  illumos/illumos-gate@dfbb943217bf8ab22a1a9d2e9dca01d4da95ee0b
  illumos changeset: 13777:b1e53580146d
  https://www.illumos.org/issues/3090
  https://www.illumos.org/issues/3102

Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #939

1 files changed, 58 insertions, 18 deletions

diff --git a/module/zfs/spa.c b/module/zfs/spa.c
index 244f10d47e92..59c43f40c171 100644
--- a/module/zfs/spa.c
+++ b/module/zfs/spa.c
@@ -117,6 +117,8 @@ const zio_taskq_info_t zio_taskqs[ZIO_TYPES][ZIO_TASKQ_TYPES] = {
 
 static dsl_syncfunc_t spa_sync_version;
 static dsl_syncfunc_t spa_sync_props;
+static dsl_checkfunc_t spa_change_guid_check;
+static dsl_syncfunc_t spa_change_guid_sync;
 static boolean_t spa_has_active_shared_spare(spa_t *spa);
 static inline int spa_load_impl(spa_t *spa, uint64_t, nvlist_t *config,
     spa_load_state_t state, spa_import_type_t type, boolean_t mosconfig,
@@ -676,6 +678,47 @@ spa_prop_clear_bootfs(spa_t *spa, uint64_t dsobj, dmu_tx_t *tx)
 	}
 }
 
+/*ARGSUSED*/
+static int
+spa_change_guid_check(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	spa_t *spa = arg1;
+	vdev_t *rvd = spa->spa_root_vdev;
+	uint64_t vdev_state;
+	ASSERTV(uint64_t *newguid = arg2);
+
+	spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
+	vdev_state = rvd->vdev_state;
+	spa_config_exit(spa, SCL_STATE, FTAG);
+
+	if (vdev_state != VDEV_STATE_HEALTHY)
+		return (ENXIO);
+
+	ASSERT3U(spa_guid(spa), !=, *newguid);
+
+	return (0);
+}
+
+static void
+spa_change_guid_sync(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	spa_t *spa = arg1;
+	uint64_t *newguid = arg2;
+	uint64_t oldguid;
+	vdev_t *rvd = spa->spa_root_vdev;
+
+	oldguid = spa_guid(spa);
+
+	spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
+	rvd->vdev_guid = *newguid;
+	rvd->vdev_guid_sum += (*newguid - oldguid);
+	vdev_config_dirty(rvd);
+	spa_config_exit(spa, SCL_STATE, FTAG);
+
+	spa_history_log_internal(LOG_POOL_GUID_CHANGE, spa, tx,
+	    "old=%lld new=%lld", oldguid, *newguid);
+}
+
 /*
  * Change the GUID for the pool.  This is done so that we can later
  * re-import a pool built from a clone of our own vdevs.  We will modify
@@ -688,29 +731,23 @@ spa_prop_clear_bootfs(spa_t *spa, uint64_t dsobj, dmu_tx_t *tx)
 int
 spa_change_guid(spa_t *spa)
 {
-	uint64_t	oldguid, newguid;
-	uint64_t	txg;
-
-	if (!(spa_mode_global & FWRITE))
-		return (EROFS);
-
-	txg = spa_vdev_enter(spa);
-
-	if (spa->spa_root_vdev->vdev_state != VDEV_STATE_HEALTHY)
-		return (spa_vdev_exit(spa, NULL, txg, ENXIO));
+	int error;
+	uint64_t guid;
 
-	oldguid = spa_guid(spa);
-	newguid = spa_generate_guid(NULL);
-	ASSERT3U(oldguid, !=, newguid);
+	mutex_enter(&spa_namespace_lock);
+	guid = spa_generate_guid(NULL);
 
-	spa->spa_root_vdev->vdev_guid = newguid;
-	spa->spa_root_vdev->vdev_guid_sum += (newguid - oldguid);
+	error = dsl_sync_task_do(spa_get_dsl(spa), spa_change_guid_check,
+	    spa_change_guid_sync, spa, &guid, 5);
 
-	vdev_config_dirty(spa->spa_root_vdev);
+	if (error == 0) {
+		spa_config_sync(spa, B_FALSE, B_TRUE);
+		spa_event_notify(spa, NULL, FM_EREPORT_ZFS_POOL_REGUID);
+	}
 
-	spa_event_notify(spa, NULL, FM_EREPORT_ZFS_POOL_REGUID);
+	mutex_exit(&spa_namespace_lock);
 
-	return (spa_vdev_exit(spa, NULL, txg, 0));
+	return (error);
 }
 
 /*
@@ -6083,6 +6120,9 @@ spa_sync(spa_t *spa, uint64_t txg)
 				    rvd->vdev_children, txg, B_TRUE);
 		}
 
+		if (error == 0)
+			spa->spa_last_synced_guid = rvd->vdev_guid;
+
 		spa_config_exit(spa, SCL_STATE, FTAG);
 
 		if (error == 0)