Update cache file when setting compatibility property

module/zfs/spa.c

@@ -8730,12 +8730,16 @@ spa_sync_props(void *arg, dmu_tx_t *tx)
 			spa->spa_comment = spa_strdup(strval);
 			/*
 			 * We need to dirty the configuration on all the vdevs
-			 * so that their labels get updated.  It's unnecessary
-			 * to do this for pool creation since the vdev's
-			 * configuration has already been dirtied.
+			 * so that their labels get updated.  We also need to
+			 * update the cache file to keep it in sync with the
+			 * MOS version. It's unnecessary to do this for pool
+			 * creation since the vdev's configuration has already
+			 * been dirtied.
 			 */
-			if (tx->tx_txg != TXG_INITIAL)
+			if (tx->tx_txg != TXG_INITIAL) {
 				vdev_config_dirty(spa->spa_root_vdev);
+				spa_async_request(spa, SPA_ASYNC_CONFIG_UPDATE);
+			}
 			spa_history_log_internal(spa, "set", tx,
 			    "%s=%s", nvpair_name(elem), strval);
 			break;
@@ -8747,8 +8751,11 @@ spa_sync_props(void *arg, dmu_tx_t *tx)
 			/*
 			 * Dirty the configuration on vdevs as above.
 			 */
-			if (tx->tx_txg != TXG_INITIAL)
+			if (tx->tx_txg != TXG_INITIAL) {
 				vdev_config_dirty(spa->spa_root_vdev);
+				spa_async_request(spa, SPA_ASYNC_CONFIG_UPDATE);
+			}
+
 			spa_history_log_internal(spa, "set", tx,
 			    "%s=%s", nvpair_name(elem), strval);
 			break;

tests/runfiles/common.run

@@ -351,7 +351,8 @@ tests = ['zpool_create_001_pos', 'zpool_create_002_pos',
     'zpool_create_features_003_pos', 'zpool_create_features_004_neg',
     'zpool_create_features_005_pos', 'zpool_create_features_006_pos',
     'zpool_create_features_007_pos', 'zpool_create_features_008_pos',
-    'create-o_ashift', 'zpool_create_tempname', 'zpool_create_dryrun_output']
+    'zpool_create_features_009_pos', 'create-o_ashift',
+    'zpool_create_tempname', 'zpool_create_dryrun_output']
 tags = ['functional', 'cli_root', 'zpool_create']
 
 [tests/functional/cli_root/zpool_destroy]

tests/zfs-tests/tests/functional/cli_root/zpool_create/Makefile.am

@@ -39,6 +39,7 @@ dist_pkgdata_SCRIPTS = \
 	zpool_create_features_006_pos.ksh \
 	zpool_create_features_007_pos.ksh \
 	zpool_create_features_008_pos.ksh \
+	zpool_create_features_009_pos.ksh \
 	create-o_ashift.ksh \
 	zpool_create_tempname.ksh \
 	zpool_create_dryrun_output.ksh

tests/zfs-tests/tests/functional/cli_root/zpool_create/zpool_create_features_009_pos.ksh

@@ -0,0 +1,92 @@
+#!/bin/ksh -p
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright (c) 2021 Lawrence Livermore National Security, LLC.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+#
+# DESCRIPTION:
+#	Verify '-o compatibility' property is updated in both the
+#	pool config MOS object and the cache file.
+#
+# STRATEGY:
+#	1. Create a pool with '-o compatibility=legacy', then verify
+#	   the property exists in the MOS config and cache file.
+#	2. Create a pool, set the 'compatibility=off' property, then
+#	   verify the property exists in the MOS config and cache file.
+#
+
+verify_runnable "global"
+
+function cleanup
+{
+	datasetexists $TESTPOOL && log_must zpool destroy $TESTPOOL
+	rm -f $CACHE_FILE
+}
+
+function check_config
+{
+	typeset propval=$1
+
+	poolval="$(zpool get -H -o value compatibility $TESTPOOL)"
+	if [ "$poolval" != "$propval" ]; then
+		log_fail "compatibility property set incorrectly $curval"
+	fi
+
+	if ! zdb -C -U $CACHE_FILE | grep "compatibility: '$propval'"; then
+		log_fail "compatibility property missing in cache file"
+	fi
+
+	if ! zdb -C -U $CACHE_FILE $TESTPOOL | grep "compatibility: '$propval'"; then
+		log_fail "compatibility property missing from MOS object"
+	fi
+}
+
+log_onexit cleanup
+
+log_assert "verify '-o compatibility' in MOS object and cache file"
+
+CACHE_FILE=$TEST_BASE_DIR/cachefile.$$
+
+# 1. Create a pool with '-o compatibility=legacy', then verify
+#    the property exists in the MOS config and cache file.
+log_must zpool create -f -o cachefile=$CACHE_FILE -o compatibility=legacy $TESTPOOL $DISKS
+log_must check_config legacy
+log_must zpool export -F $TESTPOOL
+log_must zpool import -c $CACHE_FILE $TESTPOOL
+log_must check_config legacy
+log_must zpool destroy -f $TESTPOOL
+
+# 2. Create a pool, set the 'compatibility=off' property, then
+#    verify the property exists in the MOS config and cache file.
+log_must zpool create -f -o cachefile=$CACHE_FILE $TESTPOOL $DISKS
+log_must zpool set compatibility=legacy $TESTPOOL
+log_must check_config legacy
+log_must zpool export -F $TESTPOOL
+log_must zpool import -c $CACHE_FILE $TESTPOOL
+log_must check_config legacy
+log_must zpool destroy -f $TESTPOOL
+
+log_pass "verify '-o compatibility' in MOS object and cache file"