Extend import_progress kstat with a notes field

Detail the import progress of log spacemaps as they can take a very
long time.  Also grab the spa_note() messages to, as they provide
insight into what is happening

Sponsored-By: OpenDrives Inc.
Sponsored-By: Klara Inc.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Don Brady <don.brady@klarasystems.com>
Co-authored-by: Allan Jude <allan@klarasystems.com>
Closes #15539

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

@@ -0,0 +1,132 @@
+#!/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 https://opensource.org/licenses/CDDL-1.0.
+# 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 2007 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+
+#
+# Copyright (c) 2023 Klara, Inc.
+#
+
+. $STF_SUITE/include/libtest.shlib
+. $STF_SUITE/tests/functional/cli_root/zpool_import/zpool_import.cfg
+
+#
+# DESCRIPTION:
+# 	During a pool import, the 'import_progress' kstat contains details
+# 	on the import progress.
+#
+# STRATEGY:
+#	1. Create test pool with several devices
+#	2. Generate some ZIL records and spacemap logs
+#	3. Export the pool
+#	4. Import the pool in the background and monitor the kstat content
+#	5. Check the zfs debug messages for import progress
+#
+
+verify_runnable "global"
+
+function cleanup
+{
+	log_must set_tunable64 KEEP_LOG_SPACEMAPS_AT_EXPORT 0
+	log_must set_tunable64 METASLAB_DEBUG_LOAD 0
+
+	destroy_pool $TESTPOOL1
+}
+
+log_assert "During a pool import, the 'import_progress' kstat contains " \
+	"notes on the progress"
+
+log_onexit cleanup
+
+log_must zpool create $TESTPOOL1 $VDEV0 $VDEV1 $VDEV2
+typeset guid=$(zpool get -H -o value guid $TESTPOOL1)
+
+log_must zfs create -o recordsize=8k $TESTPOOL1/fs
+#
+# This dd command works around an issue where ZIL records aren't created
+# after freezing the pool unless a ZIL header already exists. Create a file
+# synchronously to force ZFS to write one out.
+#
+log_must dd if=/dev/zero of=/$TESTPOOL1/fs/sync conv=fsync bs=1 count=1
+
+#
+# Overwrite some blocks to populate spacemap logs
+#
+log_must dd if=/dev/urandom of=/$TESTPOOL1/fs/00 bs=1M count=200
+sync_all_pools
+log_must dd if=/dev/urandom of=/$TESTPOOL1/fs/00 bs=1M count=200
+sync_all_pools
+
+#
+# Freeze the pool to retain intent log records
+#
+log_must zpool freeze $TESTPOOL1
+
+# fill_fs [destdir] [dirnum] [filenum] [bytes] [num_writes] [data]
+log_must fill_fs /$TESTPOOL1/fs 1 2000 100 1024 R
+
+log_must zpool list -v $TESTPOOL1
+
+#
+# Unmount filesystem and export the pool
+#
+# At this stage the zfs intent log contains
+# a set of records to replay.
+#
+log_must zfs unmount /$TESTPOOL1/fs
+
+log_must set_tunable64 KEEP_LOG_SPACEMAPS_AT_EXPORT 1
+log_must zpool export $TESTPOOL1
+
+log_must set_tunable64 METASLAB_DEBUG_LOAD 1
+log_note "Starting zpool import in background at" $(date +'%H:%M:%S')
+zpool import -d $DEVICE_DIR -f $guid &
+pid=$!
+
+#
+# capture progress until import is finished
+#
+log_note waiting for pid $pid to exit
+kstat import_progress
+while [[ -d /proc/"$pid" ]]; do
+	line=$(kstat import_progress | grep -v pool_guid)
+	if [[ -n $line ]]; then
+		echo $line
+	fi
+	if [[ -f /$TESTPOOL1/fs/00 ]]; then
+		break;
+	fi
+	sleep 0.0001
+done
+log_note "zpool import completed at" $(date +'%H:%M:%S')
+
+entries=$(kstat dbgmsg | grep "spa_import_progress_set_notes_impl(): 'testpool1'" | wc -l)
+log_note "found $entries progress notes in dbgmsg"
+log_must test $entries -gt 20
+
+log_must zpool status $TESTPOOL1
+
+log_pass "During a pool import, the 'import_progress' kstat contains " \
+	"notes on the progress"