9690 metaslab of vdev with no space maps was flushed during removal

illumos/illumos-gate@4e75ba682600b2bf19d158577d528c3db65050e8

Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Author:     Serapheim Dimitropoulos <serapheim@delphix.com>

1 files changed, 10 insertions, 12 deletions

diff --git a/uts/common/fs/zfs/vdev.c b/uts/common/fs/zfs/vdev.c
index f6845f3dcbbd..27d1dcf97f5b 100644
--- a/uts/common/fs/zfs/vdev.c
+++ b/uts/common/fs/zfs/vdev.c
@@ -2823,11 +2823,11 @@ vdev_destroy_spacemaps(vdev_t *vd, dmu_tx_t *tx)
 }
 
 static void
-vdev_remove_empty(vdev_t *vd, uint64_t txg)
+vdev_remove_empty_log(vdev_t *vd, uint64_t txg)
 {
 	spa_t *spa = vd->vdev_spa;
-	dmu_tx_t *tx;
 
+	ASSERT(vd->vdev_islog);
 	ASSERT(vd == vd->vdev_top);
 	ASSERT3U(txg, ==, spa_syncing_txg(spa));
 
@@ -2871,13 +2871,14 @@ vdev_remove_empty(vdev_t *vd, uint64_t txg)
 			ASSERT0(mg->mg_histogram[i]);
 	}
 
-	tx = dmu_tx_create_assigned(spa_get_dsl(spa), txg);
-	vdev_destroy_spacemaps(vd, tx);
+	dmu_tx_t *tx = dmu_tx_create_assigned(spa_get_dsl(spa), txg);
 
-	if (vd->vdev_islog && vd->vdev_top_zap != 0) {
+	vdev_destroy_spacemaps(vd, tx);
+	if (vd->vdev_top_zap != 0) {
 		vdev_destroy_unlink_zap(vd, vd->vdev_top_zap, tx);
 		vd->vdev_top_zap = 0;
 	}
+
 	dmu_tx_commit(tx);
 }
 
@@ -2949,14 +2950,11 @@ vdev_sync(vdev_t *vd, uint64_t txg)
 		vdev_dtl_sync(lvd, txg);
 
 	/*
-	 * Remove the metadata associated with this vdev once it's empty.
-	 * Note that this is typically used for log/cache device removal;
-	 * we don't empty toplevel vdevs when removing them.  But if
-	 * a toplevel happens to be emptied, this is not harmful.
+	 * If this is an empty log device being removed, destroy the
+	 * metadata associated with it.
 	 */
-	if (vd->vdev_stat.vs_alloc == 0 && vd->vdev_removing) {
-		vdev_remove_empty(vd, txg);
-	}
+	if (vd->vdev_islog && vd->vdev_stat.vs_alloc == 0 && vd->vdev_removing)
+		vdev_remove_empty_log(vd, txg);
 
 	(void) txg_list_add(&spa->spa_vdev_txg_list, vd, TXG_CLEAN(txg));
 }