Address review feedback

also allow clear of suspended mmp pool in debug builds if
it passes the spa_activity_check()

Signed-off-by: Don Brady <don.brady@klarasystems.com>

include/sys/spa.h

@@ -1120,6 +1120,8 @@ extern uint32_t spa_get_hostid(spa_t *spa);
 extern void spa_activate_allocation_classes(spa_t *, dmu_tx_t *);
 extern boolean_t spa_livelist_delete_check(spa_t *spa);
 
+extern boolean_t spa_mmp_remote_host_active(spa_t *spa);
+
 extern spa_mode_t spa_mode(spa_t *spa);
 extern uint64_t zfs_strtonum(const char *str, char **nptr);
 

module/zfs/spa.c

@@ -3600,7 +3600,8 @@ spa_activity_check_duration(spa_t *spa, uberblock_t *ub)
  * we detected activity then fail.
  */
 static int
-spa_activity_check(spa_t *spa, uberblock_t *ub, nvlist_t *config)
+spa_activity_check(spa_t *spa, uberblock_t *ub, nvlist_t *config,
+    boolean_t importing)
 {
 	uint64_t txg = ub->ub_txg;
 	uint64_t timestamp = ub->ub_timestamp;
@@ -3645,19 +3646,23 @@ spa_activity_check(spa_t *spa, uberblock_t *ub, nvlist_t *config)
 
 	import_expire = gethrtime() + import_delay;
 
-	spa_import_progress_set_notes(spa, "Checking MMP activity, waiting "
-	    "%llu ms", (u_longlong_t)NSEC2MSEC(import_delay));
+	if (importing) {
+		spa_import_progress_set_notes(spa, "Checking MMP activity, "
+		    "waiting %llu ms", (u_longlong_t)NSEC2MSEC(import_delay));
+	}
 
 	int interations = 0;
 	while ((now = gethrtime()) < import_expire) {
-		if (interations++ % 30 == 0) {
+		if (importing && interations++ % 30 == 0) {
 			spa_import_progress_set_notes(spa, "Checking MMP "
 			    "activity, %llu ms remaining",
 			    (u_longlong_t)NSEC2MSEC(import_expire - now));
 		}
 
-		(void) spa_import_progress_set_mmp_check(spa_guid(spa),
-		    NSEC2SEC(import_expire - gethrtime()));
+		if (importing) {
+			(void) spa_import_progress_set_mmp_check(spa_guid(spa),
+			    NSEC2SEC(import_expire - gethrtime()));
+		}
 
 		vdev_uberblock_load(rvd, ub, &mmp_label);
 
@@ -3739,6 +3744,25 @@ spa_activity_check(spa_t *spa, uberblock_t *ub, nvlist_t *config)
 	return (error);
 }
 
+/*
+ * Called from zfs_ioc_clear for a pool that was suspended after failing
+ * mmp write checks.
+ */
+boolean_t
+spa_mmp_remote_host_active(spa_t *spa)
+{
+#ifdef ZFS_DEBUG
+	ASSERT(spa_multihost(spa) && spa_suspended(spa));
+	cmn_err(CE_WARN, "spa_mmp_remote_host_active: checking '%s'",
+	    spa_name(spa));
+
+	return (spa_activity_check(spa, &spa->spa_uberblock, spa->spa_config,
+	    B_FALSE) != 0);
+#else
+	return (B_TRUE);
+#endif
+}
+
 static int
 spa_verify_host(spa_t *spa, nvlist_t *mos_config)
 {
@@ -4065,7 +4089,8 @@ spa_ld_select_uberblock(spa_t *spa, spa_import_type_t type)
 			return (spa_vdev_err(rvd, VDEV_AUX_ACTIVE, EREMOTEIO));
 		}
 
-		int error = spa_activity_check(spa, ub, spa->spa_config);
+		int error =
+		    spa_activity_check(spa, ub, spa->spa_config, B_TRUE);
 		if (error) {
 			nvlist_free(label);
 			return (error);

module/zfs/zfs_ioctl.c

@@ -5763,24 +5763,6 @@ zfs_ioc_error_log(zfs_cmd_t *zc)
 	return (error);
 }
 
-/*
- * Is this a test pool?
- *
- * Used by ZTS functional/mmp/mmp_write_slow_disk to tear down a
- * suspended mmp pool.
- */
-static boolean_t
-spa_is_test_pool(spa_t *spa)
-{
-	if (strstr(spa_name(spa), "test") == NULL)
-		return (B_FALSE);
-
-	uint64_t size = metaslab_class_get_space(spa_normal_class(spa));
-	size += metaslab_class_get_space(spa_embedded_log_class(spa));
-
-	return (size <= 1024 * 1024 * 1024);
-}
-
 static int
 zfs_ioc_clear(zfs_cmd_t *zc)
 {
@@ -5833,10 +5815,12 @@ zfs_ioc_clear(zfs_cmd_t *zc)
 
 	/*
 	 * If multihost is enabled, resuming I/O is unsafe as another
-	 * host may have imported the pool. (allowed for mini test pool)
+	 * host may have imported the pool.
 	 */
-	if (spa_multihost(spa) && spa_suspended(spa) && !spa_is_test_pool(spa))
+	if (spa_multihost(spa) && spa_suspended(spa) &&
+	    spa_mmp_remote_host_active(spa)) {
 		return (SET_ERROR(EINVAL));
+	}
 
 	spa_vdev_state_enter(spa, SCL_NONE);
 

tests/zfs-tests/tests/functional/mmp/mmp_write_slow_disk.ksh

@@ -22,10 +22,10 @@
 #	Verify that long VDEV probes do not cause MMP checks to suspend pool
 #	Note: without PR-15839 fix, this test will suspend the pool.
 #
-#	A device that is returning unexpeced errors will trigger a vdev_probe.
+#	A device that is returning unexpected errors will trigger a vdev_probe.
 #	When the device additionally has slow response times, the probe can hold
-#	the spa config loack as a writer for a long period of time such that the
-#	mmp uberblock updates stall when trying to aquire the spa config lock.
+#	the spa config lock as a writer for a long period of time such that the
+#	mmp uberblock updates stall when trying to acquire the spa config lock.
 #
 # STRATEGY:
 #	1. Create a pool with multiple leaf vdevs
@@ -40,29 +40,25 @@
 
 verify_runnable "both"
 
-# Note pool name must contain 'test' to allow pool clear to resume pool io
-MMP_POOL="test-mmp-pool"
-
 function cleanup
 {
 	log_must zinject -c all
 
 	if [[ $(zpool list -H -o health $MMP_POOL) == "SUSPENDED" ]]; then
-		# Note this clear works for suspended small test pools
 		log_must zpool clear $MMP_POOL
 		zpool get state $MMP_POOL $MMP_DIR/file.3
 		zpool events | grep ".fs.zfs." | grep -v "history_event"
 	fi
 
-	log_must zpool destroy $MMP_POOL
+	poolexists $MMP_POOL && destroy_pool $MMP_POOL
 	log_must rm -r $MMP_DIR
 	log_must mmp_clear_hostid
 }
 
 log_assert "A long VDEV probe doesn't cause a MMP check suspend"
 log_onexit cleanup
 
-MMP_HISTORY=/proc/spl/kstat/zfs/$MMP_POOL/multihost
+MMP_HISTORY_URL=/proc/spl/kstat/zfs/$MMP_POOL/multihost
 
 # Create a multiple drive pool
 log_must zpool events -c
@@ -75,8 +71,7 @@ log_must zpool create -f $MMP_POOL \
 # Enable MMP
 log_must mmp_set_hostid $HOSTID1
 log_must zpool set multihost=on $MMP_POOL
-set_tunable64 MULTIHOST_HISTORY 0
-set_tunable64 MULTIHOST_HISTORY 40
+clear_mmp_history
 
 # Inject vdev write error along with a delay
 log_must zinject -f 33 -e io -L pad2 -T write -d $MMP_DIR/file.3 $MMP_POOL
@@ -85,11 +80,11 @@ log_must zinject -D 2000:4 -T write -d $MMP_DIR/file.3 $MMP_POOL
 
 log_must dd if=/dev/urandom of=/$MMP_POOL/data bs=1M count=5
 sleep 10
-log_must zpool sync
+sync_pool $MMP_POOL
 
 # Confirm mmp writes to the non-slow disks have taken place
 for x in {0,1,2,4}; do
-	write_count=$(grep -c file.${x} $MMP_HISTORY)
+	write_count=$(grep -c file.${x} $MMP_HISTORY_URL)
 	[[ $write_count -gt 0 ]] || log_fail "expecting mmp writes"
 done