Add -u option to 'zfs create'

Add -u option to 'zfs create' that prevents file system from being
automatically mounted. This is similar to the 'zfs receive -u'.

Authored by: pjd <pjd@FreeBSD.org>
FreeBSD-commit: freebsd/freebsd-src@35c5823

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Ported-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes openzfs#11254

cmd/zfs/zfs_main.c

@@ -270,7 +270,7 @@ get_usage(zfs_help_t idx)
 		return (gettext("\tclone [-p] [-o property=value] ... "
 		    "<snapshot> <filesystem|volume>\n"));
 	case HELP_CREATE:
-		return (gettext("\tcreate [-Pnpv] [-o property=value] ... "
+		return (gettext("\tcreate [-Pnpuv] [-o property=value] ... "
 		    "<filesystem>\n"
 		    "\tcreate [-Pnpsv] [-b blocksize] [-o property=value] ... "
 		    "-V <size> <volume>\n"));
@@ -1012,6 +1012,8 @@ default_volblocksize(zpool_handle_t *zhp, nvlist_t *props)
  * check of arguments and properties, but does not check for permissions,
  * available space, etc.
  *
+ * The '-u' flag prevents the newly created file system from being mounted.
+ *
  * The '-v' flag is for verbose output.
  *
  * The '-P' flag is used for parseable output.  It implies '-v'.
@@ -1028,6 +1030,7 @@ zfs_do_create(int argc, char **argv)
 	boolean_t bflag = B_FALSE;
 	boolean_t parents = B_FALSE;
 	boolean_t dryrun = B_FALSE;
+	boolean_t nomount = B_FALSE;
 	boolean_t verbose = B_FALSE;
 	boolean_t parseable = B_FALSE;
 	int ret = 1;
@@ -1039,7 +1042,7 @@ zfs_do_create(int argc, char **argv)
 		nomem();
 
 	/* check options */
-	while ((c = getopt(argc, argv, ":PV:b:nso:pv")) != -1) {
+	while ((c = getopt(argc, argv, ":PV:b:nso:puv")) != -1) {
 		switch (c) {
 		case 'V':
 			type = ZFS_TYPE_VOLUME;
@@ -1086,6 +1089,9 @@ zfs_do_create(int argc, char **argv)
 		case 's':
 			noreserve = B_TRUE;
 			break;
+		case 'u':
+			nomount = B_TRUE;
+			break;
 		case 'v':
 			verbose = B_TRUE;
 			break;
@@ -1105,6 +1111,11 @@ zfs_do_create(int argc, char **argv)
 		    "used when creating a volume\n"));
 		goto badusage;
 	}
+	if (nomount && type != ZFS_TYPE_FILESYSTEM) {
+		(void) fprintf(stderr, gettext("'-u' can only be "
+		    "used when creating a filesystem\n"));
+		goto badusage;
+	}
 
 	argc -= optind;
 	argv += optind;
@@ -1265,6 +1276,11 @@ zfs_do_create(int argc, char **argv)
 		log_history = B_FALSE;
 	}
 
+	if (nomount) {
+		ret = 0;
+		goto error;
+	}
+
 	ret = zfs_mount_and_share(g_zfs, argv[0], ZFS_TYPE_DATASET);
 error:
 	nvlist_free(props);

man/man8/zfs-create.8

@@ -30,7 +30,7 @@
 .\" Copyright 2018 Nexenta Systems, Inc.
 .\" Copyright 2019 Joyent, Inc.
 .\"
-.Dd June 30, 2019
+.Dd December 1, 2020
 .Dt ZFS-CREATE 8
 .Os
 .Sh NAME
@@ -39,7 +39,7 @@
 .Sh SYNOPSIS
 .Nm zfs
 .Cm create
-.Op Fl Pnpv
+.Op Fl Pnpuv
 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
 .Ar filesystem
 .Nm zfs
@@ -53,14 +53,16 @@
 .It Xo
 .Nm zfs
 .Cm create
-.Op Fl Pnpv
+.Op Fl Pnpuv
 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
 .Ar filesystem
 .Xc
 Creates a new ZFS file system.
 The file system is automatically mounted according to the
 .Sy mountpoint
-property inherited from the parent.
+property inherited from the parent, unless the
+.Fl u
+option is used.
 .Bl -tag -width "-o"
 .It Fl o Ar property Ns = Ns Ar value
 Sets the specified property as if the command
@@ -122,6 +124,8 @@ to
 due to the use of the
 .Fl o
 option.
+.It Fl u
+Do not mount the newly created file system.
 .It Fl v
 Print verbose information about the created dataset.
 .El

tests/runfiles/common.run

@@ -156,7 +156,8 @@ tests = ['zfs_create_001_pos', 'zfs_create_002_pos', 'zfs_create_003_pos',
     'zfs_create_007_pos', 'zfs_create_008_neg', 'zfs_create_009_neg',
     'zfs_create_010_neg', 'zfs_create_011_pos', 'zfs_create_012_pos',
     'zfs_create_013_pos', 'zfs_create_014_pos', 'zfs_create_encrypted',
-    'zfs_create_crypt_combos', 'zfs_create_dryrun', 'zfs_create_verbose']
+    'zfs_create_crypt_combos', 'zfs_create_dryrun', 'zfs_create_nomount',
+    'zfs_create_verbose']
 tags = ['functional', 'cli_root', 'zfs_create']
 
 [tests/functional/cli_root/zfs_destroy]

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

@@ -19,6 +19,7 @@ dist_pkgdata_SCRIPTS = \
 	zfs_create_encrypted.ksh \
 	zfs_create_crypt_combos.ksh \
 	zfs_create_dryrun.ksh \
+	zfs_create_nomount.ksh \
 	zfs_create_verbose.ksh
 
 dist_pkgdata_DATA = \

tests/zfs-tests/tests/functional/cli_root/zfs_create/zfs_create_nomount.ksh

@@ -0,0 +1,51 @@
+#!/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.
+#
+
+#
+# Copyright 2020 iXsystems, Inc.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+#
+# DESCRIPTION:
+# zfs create -u should leave the new file system unmounted.
+# It should not work for a volume.
+#
+# STRATEGY:
+# 1. Create a file system using -u and make sure the file system is not mounted.
+# 3. Do it for a volume to verify it fails.
+#
+
+verify_runnable "both"
+
+function cleanup
+{
+	local ds
+
+	for ds in "$fs" "$vol"; do
+		datasetexists "$ds" && destroy_dataset "$ds"
+	done
+}
+log_onexit cleanup
+
+log_assert "zfs create -u leaves the new file system unmounted"
+
+typeset fs="$TESTPOOL/$TESTFS1"
+typeset vol="$TESTPOOL/$TESTVOL1"
+
+log_must create_dataset "$fs" "-u"
+log_mustnot ismounted "$fs"
+
+log_mustnot zfs create -V $VOLSIZE -u "$vol"
+
+log_pass "zfs create -u leaves the new file system unmounted"