Implemented zpool sync command

This addition will enable us to sync an open TXG to the main pool
on demand. The functionality is similar to 'sync(2)' but 'zpool sync'
will return when data has hit the main storage instead of potentially
just the ZIL as is the case with the 'sync(2)' cmd.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Alek Pinchuk <apinchuk@datto.com>
Closes #6122

cmd/zpool/zpool_main.c

@@ -27,6 +27,7 @@
  * Copyright (c) 2012 by Cyril Plisko. All rights reserved.
  * Copyright (c) 2013 by Prasad Joshi (sTec). All rights reserved.
  * Copyright 2016 Igor Kozhukhov <ikozhukhov@gmail.com>.
+ * Copyright (c) 2017 Datto Inc.
  */
 
 #include <assert.h>
@@ -100,6 +101,8 @@ static int zpool_do_events(int, char **);
 static int zpool_do_get(int, char **);
 static int zpool_do_set(int, char **);
 
+static int zpool_do_sync(int, char **);
+
 /*
  * These libumem hooks provide a reasonable set of defaults for the allocator's
  * debugging facilities.
@@ -143,6 +146,7 @@ typedef enum {
 	HELP_GET,
 	HELP_SET,
 	HELP_SPLIT,
+	HELP_SYNC,
 	HELP_REGUID,
 	HELP_REOPEN
 } zpool_help_t;
@@ -272,6 +276,7 @@ static zpool_command_t command_table[] = {
 	{ NULL },
 	{ "get",	zpool_do_get,		HELP_GET		},
 	{ "set",	zpool_do_set,		HELP_SET		},
+	{ "sync",	zpool_do_sync,		HELP_SYNC		},
 };
 
 #define	NCOMMAND	(ARRAY_SIZE(command_table))
@@ -358,6 +363,8 @@ get_usage(zpool_help_t idx)
 		    "[<device> ...]\n"));
 	case HELP_REGUID:
 		return (gettext("\treguid <pool>\n"));
+	case HELP_SYNC:
+		return (gettext("\tsync [pool] ...\n"));
 	}
 
 	abort();
@@ -2693,6 +2700,45 @@ error:
 	return (err ? 1 : 0);
 }
 
+/*
+ * zpool sync [-f] [pool] ...
+ *
+ * -f (undocumented) force uberblock (and config including zpool cache file)
+ *    update.
+ *
+ * Sync the specified pool(s).
+ * Without arguments "zpool sync" will sync all pools.
+ * This command initiates TXG sync(s) and will return after the TXG(s) commit.
+ *
+ */
+static int
+zpool_do_sync(int argc, char **argv)
+{
+	int ret;
+	boolean_t force = B_FALSE;
+
+	/* check options */
+	while ((ret  = getopt(argc, argv, "f")) != -1) {
+		switch (ret) {
+		case 'f':
+			force = B_TRUE;
+			break;
+		case '?':
+			(void) fprintf(stderr, gettext("invalid option '%c'\n"),
+			    optopt);
+			usage(B_FALSE);
+		}
+	}
+
+	argc -= optind;
+	argv += optind;
+
+	/* if argc == 0 we will execute zpool_sync_one on all pools */
+	ret = for_each_pool(argc, argv, B_FALSE, NULL, zpool_sync_one, &force);
+
+	return (ret);
+}
+
 typedef struct iostat_cbdata {
 	uint64_t cb_flags;
 	int cb_name_flags;

configure.ac

@@ -223,6 +223,7 @@ AC_CONFIG_FILES([
 	tests/zfs-tests/tests/functional/cli_root/zpool_scrub/Makefile
 	tests/zfs-tests/tests/functional/cli_root/zpool_set/Makefile
 	tests/zfs-tests/tests/functional/cli_root/zpool_status/Makefile
+	tests/zfs-tests/tests/functional/cli_root/zpool_sync/Makefile
 	tests/zfs-tests/tests/functional/cli_root/zpool_upgrade/Makefile
 	tests/zfs-tests/tests/functional/cli_user/Makefile
 	tests/zfs-tests/tests/functional/cli_user/misc/Makefile

include/libzfs.h

@@ -26,6 +26,7 @@
  * Copyright (c) 2013 Steven Hartland. All rights reserved.
  * Copyright (c) 2016, Intel Corporation.
  * Copyright 2016 Nexenta Systems, Inc.
+ * Copyright (c) 2017 Datto Inc.
  */
 
 #ifndef	_LIBZFS_H
@@ -264,6 +265,8 @@ extern int zpool_clear(zpool_handle_t *, const char *, nvlist_t *);
 extern int zpool_reguid(zpool_handle_t *);
 extern int zpool_reopen(zpool_handle_t *);
 
+extern int zpool_sync_one(zpool_handle_t *, void *);
+
 extern int zpool_vdev_online(zpool_handle_t *, const char *, int,
     vdev_state_t *);
 extern int zpool_vdev_offline(zpool_handle_t *, const char *, boolean_t);

include/libzfs_core.h

@@ -21,6 +21,7 @@
 
 /*
  * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
+ * Copyright (c) 2017 Datto Inc.
  */
 
 #ifndef	_LIBZFS_CORE_H
@@ -89,6 +90,8 @@ boolean_t lzc_exists(const char *);
 
 int lzc_rollback(const char *, char *, int);
 
+int lzc_sync(const char *, nvlist_t *, nvlist_t **);
+
 #ifdef	__cplusplus
 }
 #endif

include/sys/fs/zfs.h

@@ -24,6 +24,7 @@
  * Copyright (c) 2011, 2014 by Delphix. All rights reserved.
  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2013, Joyent, Inc. All rights reserved.
+ * Copyright (c) 2017 Datto Inc.
  */
 
 /* Portions Copyright 2010 Robert Milkowski */
@@ -1020,6 +1021,7 @@ typedef enum zfs_ioc {
 	ZFS_IOC_GET_BOOKMARKS,
 	ZFS_IOC_DESTROY_BOOKMARKS,
 	ZFS_IOC_RECV_NEW,
+	ZFS_IOC_POOL_SYNC,
 
 	/*
 	 * Linux - 3/64 numbers reserved.

lib/libzfs/libzfs_pool.c

@@ -24,6 +24,7 @@
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2011, 2014 by Delphix. All rights reserved.
  * Copyright 2016 Igor Kozhukhov <ikozhukhov@gmail.com>
+ * Copyright (c) 2017 Datto Inc.
  */
 
 #include <ctype.h>
@@ -3288,6 +3289,27 @@ zpool_reopen(zpool_handle_t *zhp)
 	return (zpool_standard_error(hdl, errno, msg));
 }
 
+/* call into libzfs_core to execute the sync IOCTL per pool */
+int
+zpool_sync_one(zpool_handle_t *zhp, void *data)
+{
+	int ret;
+	libzfs_handle_t *hdl = zpool_get_handle(zhp);
+	const char *pool_name = zpool_get_name(zhp);
+	boolean_t *force = data;
+	nvlist_t *innvl = fnvlist_alloc();
+
+	fnvlist_add_boolean_value(innvl, "force", *force);
+	if ((ret = lzc_sync(pool_name, innvl, NULL)) != 0) {
+		nvlist_free(innvl);
+		return (zpool_standard_error_fmt(hdl, ret,
+		    dgettext(TEXT_DOMAIN, "sync '%s' failed"), pool_name));
+	}
+	nvlist_free(innvl);
+
+	return (0);
+}
+
 #if defined(__sun__) || defined(__sun)
 /*
  * Convert from a devid string to a path.

lib/libzfs_core/libzfs_core.c

@@ -22,6 +22,7 @@
 /*
  * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
  * Copyright (c) 2013 Steven Hartland. All rights reserved.
+ * Copyright (c) 2017 Datto Inc.
  */
 
 /*
@@ -126,17 +127,20 @@ lzc_ioctl(zfs_ioc_t ioc, const char *name,
 {
 	zfs_cmd_t zc = {"\0"};
 	int error = 0;
-	char *packed;
-	size_t size;
+	char *packed = NULL;
+	size_t size = 0;
 
 	ASSERT3S(g_refcount, >, 0);
 	VERIFY3S(g_fd, !=, -1);
 
-	(void) strlcpy(zc.zc_name, name, sizeof (zc.zc_name));
+	if (name != NULL)
+		(void) strlcpy(zc.zc_name, name, sizeof (zc.zc_name));
 
-	packed = fnvlist_pack(source, &size);
-	zc.zc_nvlist_src = (uint64_t)(uintptr_t)packed;
-	zc.zc_nvlist_src_size = size;
+	if (source != NULL) {
+		packed = fnvlist_pack(source, &size);
+		zc.zc_nvlist_src = (uint64_t)(uintptr_t)packed;
+		zc.zc_nvlist_src_size = size;
+	}
 
 	if (resultp != NULL) {
 		*resultp = NULL;
@@ -340,6 +344,18 @@ lzc_exists(const char *dataset)
 	return (ioctl(g_fd, ZFS_IOC_OBJSET_STATS, &zc) == 0);
 }
 
+/*
+ * outnvl is unused.
+ * It was added to preserve the function signature in case it is
+ * needed in the future.
+ */
+/*ARGSUSED*/
+int
+lzc_sync(const char *pool_name, nvlist_t *innvl, nvlist_t **outnvl)
+{
+	return (lzc_ioctl(ZFS_IOC_POOL_SYNC, pool_name, innvl, NULL));
+}
+
 /*
  * Create "user holds" on snapshots.  If there is a hold on a snapshot,
  * the snapshot can not be destroyed.  (However, it can be marked for deletion
@@ -440,11 +456,7 @@ lzc_release(nvlist_t *holds, nvlist_t **errlist)
 int
 lzc_get_holds(const char *snapname, nvlist_t **holdsp)
 {
-	int error;
-	nvlist_t *innvl = fnvlist_alloc();
-	error = lzc_ioctl(ZFS_IOC_GET_HOLDS, snapname, innvl, holdsp);
-	fnvlist_free(innvl);
-	return (error);
+	return (lzc_ioctl(ZFS_IOC_GET_HOLDS, snapname, NULL, holdsp));
 }
 
 /*

man/man8/zpool.8

@@ -3,6 +3,7 @@
 .\" Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
 .\" Copyright (c) 2013 by Delphix. All rights reserved.
 .\" Copyright (c) 2012 Cyril Plisko. All Rights Reserved.
+.\" Copyright (c) 2017 Datto Inc.
 .\" 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
@@ -15,7 +16,7 @@
 .\" CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your
 .\" own identifying information:
 .\" Portions Copyright [yyyy] [name of copyright owner]
-.TH zpool 8 "May 11, 2016" "ZFS pool 28, filesystem 5" "System Administration Commands"
+.TH zpool 8 "April 12, 2017" "ZFS pool 28, filesystem 5" "System Administration Commands"
 .SH NAME
 zpool \- configures ZFS storage pools
 .SH SYNOPSIS
@@ -162,6 +163,11 @@ zpool \- configures ZFS storage pools
 \fBzpool status\fR [\fB-c\fR \fBSCRIPT\fR] [\fB-gLPvxD\fR] [\fB-T\fR d | u] [\fIpool\fR] ... [\fIinterval\fR [\fIcount\fR]]
 .fi
 
+.LP
+.nf
+\fBzpool sync\fR [\fBpool\fR] ...
+.fi
+
 .LP
 .nf
 \fBzpool upgrade\fR
@@ -2240,6 +2246,20 @@ Specify \fBu\fR for a printed representation of the internal representation of t
 
 .RE
 
+.sp
+.ne 2
+.na
+\fB\fBzpool sync\fR\fR [\fBpool\fR] ...
+.ad
+.sp .6
+.RS 4n
+This command forces all in-core dirty data to be written to the primary pool
+storage and not the ZIL. It will also update administrative information
+including quota reporting.
+Without arguments, \fBzpool sync\fR will sync all pools on the system.
+Otherwise, it will sync only the specified pool(s).
+.RE
+
 .sp
 .ne 2
 .na

module/zfs/zfs_ioctl.c

@@ -34,6 +34,7 @@
  * Copyright 2016 Toomas Soome <tsoome@me.com>
  * Copyright (c) 2016 Actifio, Inc. All rights reserved.
  * Copyright (c) 2017, loli10K <ezomori.nozomu@gmail.com>. All rights reserved.
+ * Copyright (c) 2017 Datto Inc.
  */
 
 /*
@@ -5466,6 +5467,7 @@ zfs_ioc_hold(const char *pool, nvlist_t *args, nvlist_t *errlist)
 static int
 zfs_ioc_get_holds(const char *snapname, nvlist_t *args, nvlist_t *outnvl)
 {
+	ASSERT3P(args, ==, NULL);
 	return (dsl_dataset_get_holds(snapname, outnvl));
 }
 
@@ -5823,6 +5825,44 @@ out:
 	return (error);
 }
 
+/*
+ * Sync the currently open TXG to disk for the specified pool.
+ * This is somewhat similar to 'zfs_sync()'.
+ * For cases that do not result in error this ioctl will wait for
+ * the currently open TXG to commit before returning back to the caller.
+ *
+ * innvl: {
+ *  "force" -> when true, force uberblock update even if there is no dirty data.
+ *             In addition this will cause the vdev configuration to be written
+ *             out including updating the zpool cache file. (boolean_t)
+ * }
+ *
+ * onvl is unused
+ */
+/* ARGSUSED */
+static int
+zfs_ioc_pool_sync(const char *pool, nvlist_t *innvl, nvlist_t *onvl)
+{
+	int err;
+	boolean_t force;
+	spa_t *spa;
+
+	if ((err = spa_open(pool, &spa, FTAG)) != 0)
+		return (err);
+
+	force = fnvlist_lookup_boolean_value(innvl, "force");
+	if (force) {
+		spa_config_enter(spa, SCL_CONFIG, FTAG, RW_WRITER);
+		vdev_config_dirty(spa->spa_root_vdev);
+		spa_config_exit(spa, SCL_CONFIG, FTAG);
+	}
+	txg_wait_synced(spa_get_dsl(spa), 0);
+
+	spa_close(spa, FTAG);
+
+	return (err);
+}
+
 static zfs_ioc_vec_t zfs_ioc_vec[ZFS_IOC_LAST - ZFS_IOC_FIRST];
 
 static void
@@ -5995,6 +6035,10 @@ zfs_ioctl_init(void)
 	    zfs_ioc_recv_new, zfs_secpolicy_recv_new, DATASET_NAME,
 	    POOL_CHECK_SUSPENDED | POOL_CHECK_READONLY, B_TRUE, B_TRUE);
 
+	zfs_ioctl_register("sync", ZFS_IOC_POOL_SYNC,
+	    zfs_ioc_pool_sync, zfs_secpolicy_none, POOL_NAME,
+	    POOL_CHECK_SUSPENDED | POOL_CHECK_READONLY, B_FALSE, B_FALSE);
+
 	/* IOCTLS that use the legacy function signature */
 
 	zfs_ioctl_register_legacy(ZFS_IOC_POOL_FREEZE, zfs_ioc_pool_freeze,

tests/runfiles/linux.run

@@ -319,6 +319,9 @@ tests = ['zpool_upgrade_001_pos', 'zpool_upgrade_002_pos',
     'zpool_upgrade_007_pos', 'zpool_upgrade_008_pos',
     'zpool_upgrade_009_neg']
 
+[tests/functional/cli_root/zpool_sync]
+tests = ['zpool_sync_001_pos', 'zpool_sync_002_neg']
+
 # DISABLED:
 # zfs_share_001_neg - requires additional dependencies
 # zfs_unshare_001_neg - requires additional dependencies

tests/zfs-tests/include/libtest.shlib

@@ -26,6 +26,7 @@
 # Copyright (c) 2012, 2016 by Delphix. All rights reserved.
 # Copyright 2016 Nexenta Systems, Inc.
 # Copyright (c) 2017 Lawrence Livermore National Security, LLC.
+# Copyright (c) 2017 Datto Inc.
 #
 
 . ${STF_TOOLS}/include/logapi.shlib
@@ -3203,29 +3204,23 @@ function get_objnum
 }
 
 #
-# Synchronize all the data in pool
+# Sync data to the pool
 #
 # $1 pool name
+# $2 boolean to force uberblock (and config including zpool cache file) update
 #
-function sync_pool #pool
+function sync_pool #pool <force>
 {
 	typeset pool=${1:-$TESTPOOL}
+	typeset force=${2:-false}
 
-	log_must $SYNC
-	log_must sleep 2
-	# Flush all the pool data.
-	typeset -i ret
-	zpool scrub $pool >/dev/null 2>&1
-	ret=$?
-	(( $ret != 0 )) && \
-	log_fail "zpool scrub $pool failed."
+	if [[ $force == true ]]; then
+		log_must zpool sync -f $pool
+	else
+		log_must zpool sync $pool
+	fi
 
-	while ! is_pool_scrubbed $pool; do
-		if is_pool_resilvered $pool ; then
-			log_fail "$pool should not be resilver completed."
-		fi
-		log_must sleep 2
-	done
+	return 0
 }
 
 #

tests/zfs-tests/tests/functional/clean_mirror/clean_mirror_common.kshlib

@@ -26,8 +26,10 @@
 
 #
 # Copyright (c) 2013, 2016 by Delphix. All rights reserved.
+# Copyright (c) 2017 Datto Inc.
 #
 
+. $STF_SUITE/include/libtest.shlib
 . $STF_SUITE/tests/functional/clean_mirror/default.cfg
 
 # Most of the code related to the clearing of mirrors is duplicated in all
@@ -36,32 +38,6 @@
 # the contents of the mirror.
 # This code is sourced into each of these test cases.
 
-#
-# Synchronize all the data in pool
-#
-# $1 pool name
-#
-function sync_pool #pool
-{
-	typeset pool=$1
-
-	log_must sync
-	log_must sleep 2
-	# Flush all the pool data.
-	typeset -i ret
-	zpool scrub $pool >/dev/null 2>&1
-	ret=$?
-	(( $ret != 0 )) && \
-		log_fail "zpool scrub $pool failed."
-
-	while ! is_pool_scrubbed $pool; do
-		if is_pool_resilvered $pool ; then
-			log_fail "$pool should not be resilver completed."
-		fi
-		log_must sleep 2
-	done
-}
-
 function overwrite_verify_mirror
 {
 	typeset AFFECTED_DEVICE=$1

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

@@ -45,4 +45,5 @@ SUBDIRS = \
 	zpool_scrub \
 	zpool_set \
 	zpool_status \
+	zpool_sync \
 	zpool_upgrade

tests/zfs-tests/tests/functional/cli_root/zpool_create/create-o_ashift.ksh

@@ -22,6 +22,7 @@
 
 #
 # Copyright 2016, loli10K. All rights reserved.
+# Copyright (c) 2017 Datto Inc.
 #
 
 . $STF_SUITE/include/libtest.shlib
@@ -48,30 +49,22 @@ function cleanup
 }
 
 #
-# FIXME: Ugly hack to force a $1 number of txg syncs.
-# This is used on Linux because we can't force it via sync(1) like on Illumos.
-# This could eventually (an hopefully) be replaced by a 'zpool sync' command.
+# Commit the specified number of TXGs to the provided pool
+# We use 'zpool sync' here because we can't force it via sync(1) like on illumos
 # $1 pool name
 # $2 number of txg syncs
 #
 function txg_sync
 {
 	typeset pool=$1
-	typeset count=$2
+	typeset -i count=$2
 	typeset -i i=0;
 
 	while [ $i -lt $count ]
 	do
-		zfs snapshot $pool@sync$$$i
-		if [[ $? -ne 0 ]]
-		then
-			log_fail "Failed to sync pool $pool (snapshot $i)"
-			return 1
-		fi
+		log_must sync_pool $pool true
 		((i = i + 1))
 	done
-
-	return 0
 }
 
 #
@@ -118,7 +111,7 @@ do
 		    "$ashift (current = $pprop)"
 	fi
 	# force 128 txg sync to fill the uberblock ring
-	log_must eval "txg_sync $TESTPOOL 128"
+	txg_sync $TESTPOOL 128
 	verify_device_uberblocks $disk ${ubcount[$i]}
 	if [[ $? -ne 0 ]]
 	then

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

@@ -0,0 +1,6 @@
+pkgdatadir = $(datadir)/@PACKAGE@/zfs-tests/tests/functional/cli_root/zpool_sync
+dist_pkgdata_SCRIPTS = \
+	cleanup.ksh \
+	setup.ksh \
+	zpool_sync_001_pos.ksh \
+	zpool_sync_002_neg.ksh

tests/zfs-tests/tests/functional/cli_root/zpool_sync/cleanup.ksh

@@ -0,0 +1,32 @@
+#!/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 2007 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+verify_runnable "global"
+
+default_cleanup

tests/zfs-tests/tests/functional/cli_root/zpool_sync/setup.ksh

@@ -0,0 +1,34 @@
+#!/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 2007 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+verify_runnable "global"
+
+DISK=${DISKS%% *}
+
+default_setup $DISK

tests/zfs-tests/tests/functional/cli_root/zpool_sync/zpool_sync_001_pos.ksh

@@ -0,0 +1,88 @@
+#!/bin/ksh -p
+#
+# CDDL HEADER START
+#
+# 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.
+#
+# CDDL HEADER END
+#
+# Copyright (c) 2017 Datto Inc.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+#
+# DESCRIPTION:
+# Verify 'zpool sync' can sync txgs to the pool(s) main vdevs.
+#
+# STRATEGY:
+# 1. Create a pool
+# 2. Use zdb to obtain current txg
+# 3. Create a file in the pool if we're not using force sync
+# 4. Use zpool sync to sync pool
+# 5. Verify the new txg is now bigger than the saved one
+#
+
+verify_runnable "global"
+
+function get_txg {
+	typeset -i txg=$(zdb -u $1 | sed -n 's/^.*txg = \(.*\)$/\1/p')
+	echo $txg
+}
+
+set -A args "sync $TESTPOOL" "sync -f $TESTPOOL" "sync" "sync -f"
+
+log_assert "Verify 'zpool sync' can sync a pool"
+
+typeset -i i=0
+typeset -i orig_txg=0
+typeset -i new_txg=0
+while [[ $i -lt ${#args[*]} ]]; do
+	orig_txg=$(get_txg $TESTPOOL)
+	if ! [[ "${args[i]}" =~ "-f" ]]; then
+		log_must touch /$TESTPOOL/$i
+	fi
+	log_must zpool ${args[i]}
+	new_txg=$(get_txg $TESTPOOL)
+	if [[ $orig_txg -ge $new_txg ]]; then
+		log_fail "'zpool ${args[i]}' failed: txg $orig_txg >= $new_txg"
+	fi
+	((i = i + 1))
+done
+
+# sync_pool is implemented using 'zpool sync' so let's test it as well
+
+# make sure we can use sync_pool with force sync explicitly not used
+orig_txg=$(get_txg $TESTPOOL)
+log_must touch /$TESTPOOL/$i
+log_must sync_pool $TESTPOOL false
+new_txg=$(get_txg $TESTPOOL)
+if [[ $orig_txg -ge $new_txg ]]; then
+	log_fail "'sync_pool $TESTPOOL false' failed: txg $orig_txg >= $new_txg"
+fi
+
+# make sure we can use sync_pool with force sync explicitly enabled
+orig_txg=$(get_txg $TESTPOOL)
+log_must sync_pool $TESTPOOL true
+new_txg=$(get_txg $TESTPOOL)
+if [[ $orig_txg -ge $new_txg ]]; then
+	log_fail "'sync_pool $TESTPOOL true' failed: txg $orig_txg >= $new_txg"
+fi
+
+# make sure we can use sync_pool with force sync implicitly not used
+orig_txg=$(get_txg $TESTPOOL)
+log_must touch /$TESTPOOL/$i
+log_must sync_pool $TESTPOOL
+new_txg=$(get_txg $TESTPOOL)
+if [[ $orig_txg -ge $new_txg ]]; then
+	log_fail "'sync_pool $TESTPOOL' failed: txg $orig_txg >= $new_txg"
+fi
+
+log_pass "'zpool sync' syncs pool as expected."

tests/zfs-tests/tests/functional/cli_root/zpool_sync/zpool_sync_002_neg.ksh

@@ -0,0 +1,44 @@
+#!/bin/ksh -p
+#
+# CDDL HEADER START
+#
+# 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.
+#
+# CDDL HEADER END
+#
+# Copyright (c) 2017 Datto Inc.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+#
+# DESCRIPTION:
+# A badly formed parameter passed to 'zpool sync' should
+# return an error.
+#
+# STRATEGY:
+# 1. Create an array containing bad 'zpool sync' parameters.
+# 2. For each element, execute the sub-command.
+# 3. Verify it returns an error.
+#
+
+verify_runnable "global"
+
+set -A args "1" "-a" "-?" "--%" "-123456" "0.5" "-o" "-b" "-b no" "-z 2"
+
+log_assert "Execute 'zpool sync' using invalid parameters."
+
+typeset -i i=0
+while [[ $i -lt ${#args[*]} ]]; do
+	log_mustnot zpool sync ${args[i]}
+	((i = i + 1))
+done
+
+log_pass "Invalid parameters to 'zpool sync' fail as expected."

tests/zfs-tests/tests/functional/upgrade/upgrade_userobj_001_pos.ksh

@@ -22,6 +22,7 @@
 
 #
 # Copyright (c) 2013 by Jinshan Xiong. No rights reserved.
+# Copyright (c) 2017 Datto Inc.
 #
 
 . $STF_SUITE/include/libtest.shlib
@@ -71,7 +72,7 @@ zfs userspace -o objused -H $TESTPOOL | head -n 1 | grep -q "-" ||
 
 # Create a file in fs1 should trigger dataset upgrade
 log_must mkfile 1m $TESTDIR/fs1/tf
-sync_pool
+log_must sleep 1 # upgrade done in the background so let's give it a sec
 
 # Make sure userobj accounting is working for fs1
 zfs userspace -o objused -H $TESTPOOL/fs1 | head -n 1 | grep -q "-" &&
@@ -79,7 +80,7 @@ zfs userspace -o objused -H $TESTPOOL/fs1 | head -n 1 | grep -q "-" &&
 
 # Mount a dataset should trigger upgrade
 log_must zfs mount $TESTPOOL/fs2
-sync_pool
+log_must sleep 1 # upgrade done in the background so let's give it a sec
 
 # Make sure userobj accounting is working for fs2
 zfs userspace -o objused -H $TESTPOOL/fs2 | head -n 1 | grep -q "-" &&
@@ -91,6 +92,7 @@ zfs userspace -o objused -H $TESTPOOL | head -n 1 | grep -q "-" ||
 	log_fail "userobj accounting should be disabled for $TESTPOOL"
 
 # Manual upgrade root dataset
+# uses an ioctl which will wait for the upgrade to be done before returning
 log_must zfs set version=current $TESTPOOL
 zfs userspace -o objused -H $TESTPOOL | head -n 1 | grep -q "-" &&
 	log_fail "userobj accounting should be enabled for $TESTPOOL"