zpool import -m also removing spare and cache when log device is missing

spa_import() relies on a pool config fetched by spa_try_import() for
spare/cache devices. Import flags are not passed to spa_tryimport(),
which makes it return early due to a missing log device and missing
retrieving the cache device and spare eventually. Passing
ZFS_IMPORT_MISSING_LOG to spa_tryimport() makes it fetch the correct
configuration regardless of the missing log device.

Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ameer Hamza <ahamza@ixsystems.com>
Closes #14794

module/zfs/spa.c

@@ -6261,6 +6261,16 @@ spa_tryimport(nvlist_t *tryconfig)
 		spa->spa_config_source = SPA_CONFIG_SRC_SCAN;
 	}
 
+	/*
+	 * spa_import() relies on a pool config fetched by spa_try_import()
+	 * for spare/cache devices. Import flags are not passed to
+	 * spa_tryimport(), which makes it return early due to a missing log
+	 * device and missing retrieving the cache device and spare eventually.
+	 * Passing ZFS_IMPORT_MISSING_LOG to spa_tryimport() makes it fetch
+	 * the correct configuration regardless of the missing log device.
+	 */
+	spa->spa_import_flags |= ZFS_IMPORT_MISSING_LOG;
+
 	error = spa_load(spa, SPA_LOAD_TRYIMPORT, SPA_IMPORT_EXISTING);
 
 	/*

tests/runfiles/common.run

@@ -407,7 +407,7 @@ tests = ['zpool_import_001_pos', 'zpool_import_002_pos',
     'import_cachefile_mirror_detached',
     'import_cachefile_paths_changed',
     'import_cachefile_shared_device',
-    'import_devices_missing',
+    'import_devices_missing', 'import_log_missing',
     'import_paths_changed',
     'import_rewind_config_changed',
     'import_rewind_device_replaced']

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

@@ -12,6 +12,7 @@ dist_pkgdata_SCRIPTS = \
 	import_cachefile_paths_changed.ksh \
 	import_cachefile_shared_device.ksh \
 	import_devices_missing.ksh \
+	import_log_missing.ksh \
 	import_paths_changed.ksh \
 	import_rewind_config_changed.ksh \
 	import_rewind_device_replaced.ksh \

tests/zfs-tests/tests/functional/cli_root/zpool_import/import_log_missing.ksh

@@ -0,0 +1,75 @@
+#!/bin/ksh -p
+
+#
+# This file and its contents are supplied under the terms of the
+# Common Development and Distribution License ("CDDL"), version 1.0.
+# You may only use this file in accordance with the terms of version
+# 1.0 of the CDDL.
+#
+# A full copy of the text of the CDDL should have accompanied this
+# source.  A copy of the CDDL is also available via the Internet at
+# http://www.illumos.org/license/CDDL.
+#
+
+. $STF_SUITE/tests/functional/cli_root/zpool_import/zpool_import.kshlib
+
+#
+# DESCRIPTION:
+#	Import with missing log device should not remove spare/cache.
+#
+# STRATEGY:
+#	1. Create a pool.
+#	2. Add spare, cache and log devices to the pool.
+#	3. Export the pool.
+#	4. Remove the log device.
+#	5. Import the pool with -m flag.
+#	6. Verify that spare and cache are still present in the pool.
+#
+
+verify_runnable "global"
+
+log_onexit cleanup
+
+function test_missing_log
+{
+	typeset poolcreate="$1"
+	typeset cachevdev="$2"
+	typeset sparevdev="$3"
+	typeset logvdev="$4"
+	typeset missingvdev="$4"
+
+	log_note "$0: pool '$poolcreate', adding $cachevdev, $sparevdev," \
+		"$logvdev then moving away $missingvdev."
+
+	log_must zpool create $TESTPOOL1 $poolcreate
+
+	log_must zpool add $TESTPOOL1 cache $cachevdev spare $sparevdev \
+		log $logvdev
+
+	log_must_busy zpool export $TESTPOOL1
+
+	log_must mv $missingvdev $BACKUP_DEVICE_DIR
+
+	log_must zpool import -m -d $DEVICE_DIR $TESTPOOL1
+
+	CACHE_PRESENT=$(zpool status -v $TESTPOOL1 | grep $cachevdev)
+
+	SPARE_PRESENT=$(zpool status -v $TESTPOOL1 | grep $sparevdev)
+
+	if [ -z "$CACHE_PRESENT"] || [ -z "SPARE_PRESENT"]
+	then
+		log_fail "cache/spare vdev missing after importing with missing" \
+			"log device"
+	fi
+
+	# Cleanup
+	log_must zpool destroy $TESTPOOL1
+
+	log_note ""
+}
+
+log_must mkdir -p $BACKUP_DEVICE_DIR
+
+test_missing_log "$VDEV0" "$VDEV1" "$VDEV2" "$VDEV3"
+
+log_pass "zpool import succeeded with missing log device"