Add '-u' - nomount flag for zfs set

This commit adds '-u' flag for zfs set operation. With this flag,
mountpoint, sharenfs and sharesmb properties can be updated
without actually mounting or sharing the dataset.

Previously, if dataset was unmounted, and mountpoint property was
updated, dataset was not mounted after the update. This behavior
is changed in previous commit. We now mount the dataset whenever
mountpoint property is updated, regardless if it's mounted or not.

To provide the user with option to keep the dataset unmounted and
still update the mountpoint without mounting the dataset, '-u'
flag can be used.

While unmounted, if sharenfs or sharesmb is set to on, this leads
to mounting the dataset. If sharenfs and sharesmb properties are
set with '-u' flag while dataset is unmounted, this will not mount
or share the dataset, but it will set the property to desired
value.

When dataset is mounted, and '-u' flag is used to update any of
mountpoint, sharenfs and sharesmb property/properties, the
property itself is updated but no action is performed. For
mountpoint property, the property is updated but dataset is still
mounted at previous mountpoint. For sharenfs and sharesmb, the
property is set but dataset in not shared/unshared.

'-u' flag would only work if any of mountpoint, sharenfs or
sharesmb is found in property list.

Signed-off-by: Umer Saleem <[email protected]>

cmd/zfs/zfs_main.c

@@ -337,7 +337,7 @@ get_usage(zfs_help_t idx)
 		    "\tsend [-nVvPe] -t <receive_resume_token>\n"
 		    "\tsend [-PnVv] --saved filesystem\n"));
 	case HELP_SET:
-		return (gettext("\tset <property=value> ... "
+		return (gettext("\tset [-u] <property=value> ... "
 		    "<filesystem|volume|snapshot> ...\n"));
 	case HELP_SHARE:
 		return (gettext("\tshare [-l] <-a [nfs|smb] | filesystem>\n"));
@@ -4197,9 +4197,9 @@ zfs_do_rollback(int argc, char **argv)
 static int
 set_callback(zfs_handle_t *zhp, void *data)
 {
-	nvlist_t *props = data;
+	zprop_set_cbdata_t *cb = data;
 	int ret = 0;
-	ret = zfs_prop_set_list(zhp, props);
+	ret = zfs_prop_set_list(zhp, cb->cb_proplist, cb->cb_flags);
 
 	if (ret != 0 || libzfs_errno(g_zfs) != EZFS_SUCCESS) {
 		switch (libzfs_errno(g_zfs)) {
@@ -4219,25 +4219,35 @@ set_callback(zfs_handle_t *zhp, void *data)
 static int
 zfs_do_set(int argc, char **argv)
 {
-	nvlist_t *props = NULL;
+	zprop_set_cbdata_t cb = { 0 };
 	int ds_start = -1; /* argv idx of first dataset arg */
 	int ret = 0;
-	int i;
+	int i, c;
 
-	/* check for options */
-	if (argc > 1 && argv[1][0] == '-') {
-		(void) fprintf(stderr, gettext("invalid option '%c'\n"),
-		    argv[1][1]);
-		usage(B_FALSE);
+	/* check options */
+	while ((c = getopt(argc, argv, "u")) != -1) {
+		switch (c) {
+		case 'u':
+			cb.cb_flags |= ZFS_SET_NOMOUNT;
+			break;
+		case '?':
+		default:
+			(void) fprintf(stderr, gettext("invalid option '%c'\n"),
+			    optopt);
+			usage(B_FALSE);
+		}
 	}
 
+	argc -= optind;
+	argv += optind;
+
 	/* check number of arguments */
-	if (argc < 2) {
+	if (argc < 1) {
 		(void) fprintf(stderr, gettext("missing arguments\n"));
 		usage(B_FALSE);
 	}
-	if (argc < 3) {
-		if (strchr(argv[1], '=') == NULL) {
+	if (argc < 2) {
+		if (strchr(argv[0], '=') == NULL) {
 			(void) fprintf(stderr, gettext("missing property=value "
 			    "argument(s)\n"));
 		} else {
@@ -4248,7 +4258,7 @@ zfs_do_set(int argc, char **argv)
 	}
 
 	/* validate argument order:  prop=val args followed by dataset args */
-	for (i = 1; i < argc; i++) {
+	for (i = 0; i < argc; i++) {
 		if (strchr(argv[i], '=') != NULL) {
 			if (ds_start > 0) {
 				/* out-of-order prop=val argument */
@@ -4266,20 +4276,20 @@ zfs_do_set(int argc, char **argv)
 	}
 
 	/* Populate a list of property settings */
-	if (nvlist_alloc(&props, NV_UNIQUE_NAME, 0) != 0)
+	if (nvlist_alloc(&cb.cb_proplist, NV_UNIQUE_NAME, 0) != 0)
 		nomem();
-	for (i = 1; i < ds_start; i++) {
-		if (!parseprop(props, argv[i])) {
+	for (i = 0; i < ds_start; i++) {
+		if (!parseprop(cb.cb_proplist, argv[i])) {
 			ret = -1;
 			goto error;
 		}
 	}
 
 	ret = zfs_for_each(argc - ds_start, argv + ds_start, 0,
-	    ZFS_TYPE_DATASET, NULL, NULL, 0, set_callback, props);
+	    ZFS_TYPE_DATASET, NULL, NULL, 0, set_callback, &cb);
 
 error:
-	nvlist_free(props);
+	nvlist_free(cb.cb_proplist);
 	return (ret);
 }
 

include/libzfs.h

@@ -522,7 +522,7 @@ _LIBZFS_H nvlist_t *zfs_valid_proplist(libzfs_handle_t *, zfs_type_t,
 
 _LIBZFS_H const char *zfs_prop_to_name(zfs_prop_t);
 _LIBZFS_H int zfs_prop_set(zfs_handle_t *, const char *, const char *);
-_LIBZFS_H int zfs_prop_set_list(zfs_handle_t *, nvlist_t *);
+_LIBZFS_H int zfs_prop_set_list(zfs_handle_t *, nvlist_t *, int);
 _LIBZFS_H int zfs_prop_get(zfs_handle_t *, zfs_prop_t, char *, size_t,
     zprop_source_t *, char *, size_t, boolean_t);
 _LIBZFS_H int zfs_prop_get_recvd(zfs_handle_t *, const char *, char *, size_t,
@@ -645,6 +645,13 @@ typedef struct zprop_get_cbdata {
 	vdev_cbdata_t cb_vdevs;
 } zprop_get_cbdata_t;
 
+#define	ZFS_SET_NOMOUNT		1
+
+typedef struct zprop_set_cbdata {
+	int cb_flags;
+	nvlist_t *cb_proplist;
+} zprop_set_cbdata_t;
+
 _LIBZFS_H void zprop_print_one_property(const char *, zprop_get_cbdata_t *,
     const char *, const char *, zprop_source_t, const char *,
     const char *);

lib/libzfs/libzfs.abi

@@ -4422,6 +4422,7 @@
     <function-decl name='zfs_prop_set_list' mangled-name='zfs_prop_set_list' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zfs_prop_set_list'>
       <parameter type-id='9200a744' name='zhp'/>
       <parameter type-id='5ce45b60' name='props'/>
+      <parameter type-id='95e97e5e' name='flags'/>
       <return type-id='95e97e5e'/>
     </function-decl>
     <function-decl name='zfs_prop_inherit' mangled-name='zfs_prop_inherit' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zfs_prop_inherit'>

lib/libzfs/libzfs_changelist.c

@@ -129,7 +129,8 @@ changelist_prefix(prop_changelist_t *clp)
 			 */
 			switch (clp->cl_prop) {
 			case ZFS_PROP_MOUNTPOINT:
-				if (clp->cl_gflags & CL_GATHER_DONT_UNMOUNT)
+				if ((clp->cl_gflags & CL_GATHER_DONT_UNMOUNT) ||
+				    (clp->cl_gflags & CL_GATHER_DONT_MOUNT))
 					break;
 				if (zfs_unmount(cn->cn_handle, NULL,
 				    clp->cl_mflags) != 0) {
@@ -138,6 +139,8 @@ changelist_prefix(prop_changelist_t *clp)
 				}
 				break;
 			case ZFS_PROP_SHARESMB:
+				if (clp->cl_gflags & CL_GATHER_DONT_MOUNT)
+					break;
 				(void) zfs_unshare(cn->cn_handle, NULL,
 				    smb);
 				commit_smb_shares = B_TRUE;
@@ -188,7 +191,8 @@ changelist_postfix(prop_changelist_t *clp)
 		return (0);
 
 	if (clp->cl_prop == ZFS_PROP_MOUNTPOINT &&
-	    !(clp->cl_gflags & CL_GATHER_DONT_UNMOUNT))
+	    !(clp->cl_gflags & CL_GATHER_DONT_UNMOUNT) &&
+	    !(clp->cl_gflags & CL_GATHER_DONT_MOUNT))
 		remove_mountpoint(cn->cn_handle);
 
 	/*
@@ -205,6 +209,7 @@ changelist_postfix(prop_changelist_t *clp)
 		boolean_t sharenfs;
 		boolean_t sharesmb;
 		boolean_t mounted;
+		boolean_t nomount;
 		boolean_t needs_key;
 
 		/*
@@ -242,7 +247,9 @@ changelist_postfix(prop_changelist_t *clp)
 		mounted = (clp->cl_gflags & CL_GATHER_DONT_UNMOUNT) ||
 		    zfs_is_mounted(cn->cn_handle, NULL);
 
-		if (!mounted && !needs_key && (cn->cn_mounted ||
+		nomount = (clp->cl_gflags & CL_GATHER_DONT_MOUNT) != 0;
+
+		if (!mounted && !nomount && !needs_key && (cn->cn_mounted ||
 		    (((clp->cl_prop == ZFS_PROP_MOUNTPOINT &&
 		    clp->cl_prop == clp->cl_realprop) ||
 		    sharenfs || sharesmb || clp->cl_waslegacy) &&
@@ -260,19 +267,19 @@ changelist_postfix(prop_changelist_t *clp)
 		 */
 		const enum sa_protocol nfs[] =
 		    {SA_PROTOCOL_NFS, SA_NO_PROTOCOL};
-		if (sharenfs && mounted) {
+		if (sharenfs && mounted && !nomount) {
 			zfs_share(cn->cn_handle, nfs);
 			commit_nfs_shares = B_TRUE;
-		} else if (cn->cn_shared || clp->cl_waslegacy) {
+		} else if ((cn->cn_shared || clp->cl_waslegacy) && !nomount) {
 			zfs_unshare(cn->cn_handle, NULL, nfs);
 			commit_nfs_shares = B_TRUE;
 		}
 		const enum sa_protocol smb[] =
 		    {SA_PROTOCOL_SMB, SA_NO_PROTOCOL};
-		if (sharesmb && mounted) {
+		if (sharesmb && mounted && !nomount) {
 			zfs_share(cn->cn_handle, smb);
 			commit_smb_shares = B_TRUE;
-		} else if (cn->cn_shared || clp->cl_waslegacy) {
+		} else if ((cn->cn_shared || clp->cl_waslegacy) && !nomount) {
 			zfs_unshare(cn->cn_handle, NULL, smb);
 			commit_smb_shares = B_TRUE;
 		}

lib/libzfs/libzfs_dataset.c

@@ -1764,7 +1764,7 @@ zfs_prop_set(zfs_handle_t *zhp, const char *propname, const char *propval)
 		goto error;
 	}
 
-	ret = zfs_prop_set_list(zhp, nvl);
+	ret = zfs_prop_set_list(zhp, nvl, 0);
 
 error:
 	nvlist_free(nvl);
@@ -1778,7 +1778,7 @@ zfs_prop_set(zfs_handle_t *zhp, const char *propname, const char *propval)
  * given dataset.
  */
 int
-zfs_prop_set_list(zfs_handle_t *zhp, nvlist_t *props)
+zfs_prop_set_list(zfs_handle_t *zhp, nvlist_t *props, int flags)
 {
 	zfs_cmd_t zc = {"\0"};
 	int ret = -1;
@@ -1848,7 +1848,9 @@ zfs_prop_set_list(zfs_handle_t *zhp, nvlist_t *props)
 		if (prop != ZFS_PROP_CANMOUNT ||
 		    (fnvpair_value_uint64(elem) == ZFS_CANMOUNT_OFF &&
 		    zfs_is_mounted(zhp, NULL))) {
-			cls[cl_idx] = changelist_gather(zhp, prop, 0, 0);
+			cls[cl_idx] = changelist_gather(zhp, prop,
+			    ((flags & ZFS_SET_NOMOUNT) ?
+			    CL_GATHER_DONT_MOUNT : 0), 0);
 			if (cls[cl_idx] == NULL)
 				goto error;
 		}

lib/libzfs/libzfs_impl.h

@@ -158,6 +158,10 @@ extern int zprop_expand_list(libzfs_handle_t *hdl, zprop_list_t **plp,
  * Use this changelist_gather() flag to prevent unmounting of file systems.
  */
 #define	CL_GATHER_DONT_UNMOUNT	4
+/*
+ * Use this changelist_gather() flag to prevent mounting of file systems.
+ */
+#define	CL_GATHER_DONT_MOUNT	8
 
 typedef struct prop_changelist prop_changelist_t;
 

man/man7/zfsprops.7

@@ -1243,10 +1243,18 @@ Otherwise, they are automatically remounted in the new location if the property
 was previously
 .Sy legacy
 or
-.Sy none ,
-or if they were mounted before the property was changed.
+.Sy none .
 In addition, any shared file systems are unshared and shared in the new
 location.
+.Pp
+When the
+.Sy mountpoint
+property is set with
+.Nm zfs Cm set Fl u
+, the
+.Sy mountpoint
+property is updated but dataset is not mounted or unmounted and remains
+as it was before.
 .It Sy nbmand Ns = Ns Sy on Ns | Ns Sy off
 Controls whether the file system should be mounted with
 .Sy nbmand
@@ -1651,6 +1659,13 @@ by default.
 This means that any additional access control
 (disallow specific user specific access etc) must be done on the underlying file
 system.
+.Pp
+When the
+.Sy sharesmb
+property is updated with
+.Nm zfs Cm set Fl u
+, the property is set to desired value, but the operation to share, reshare
+or unshare the the dataset is not performed.
 .It Sy sharenfs Ns = Ns Sy on Ns | Ns Sy off Ns | Ns Ar opts
 Controls whether the file system is shared via NFS, and what options are to be
 used.
@@ -1694,6 +1709,13 @@ or if they were shared before the property was changed.
 If the new property is
 .Sy off ,
 the file systems are unshared.
+.Pp
+When the
+.Sy sharenfs
+property is updated with
+.Nm zfs Cm set Fl u
+, the property is set to desired value, but the operation to share, reshare
+or unshare the the dataset is not performed.
 .It Sy logbias Ns = Ns Sy latency Ns | Ns Sy throughput
 Provide a hint to ZFS about handling of synchronous requests in this dataset.
 If

man/man8/zfs-set.8

@@ -39,6 +39,7 @@
 .Sh SYNOPSIS
 .Nm zfs
 .Cm set
+.Op Fl u
 .Ar property Ns = Ns Ar value Oo Ar property Ns = Ns Ar value Oc Ns …
 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns …
 .Nm zfs
@@ -60,6 +61,7 @@
 .It Xo
 .Nm zfs
 .Cm set
+.Op Fl u
 .Ar property Ns = Ns Ar value Oo Ar property Ns = Ns Ar value Oc Ns …
 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns …
 .Xc
@@ -79,6 +81,11 @@ For more information, see the
 .Em User Properties
 section of
 .Xr zfsprops 7 .
+.Bl -tag -width "-u"
+.It Fl u
+Update mountpoint, sharenfs, sharesmb property but do not mount or share the
+dataset.
+.El
 .It Xo
 .Nm zfs
 .Cm get

tests/runfiles/common.run

@@ -281,7 +281,7 @@ tests = ['cache_001_pos', 'cache_002_neg', 'canmount_001_pos',
     'user_property_004_pos', 'version_001_neg', 'zfs_set_001_neg',
     'zfs_set_002_neg', 'zfs_set_003_neg', 'property_alias_001_pos',
     'mountpoint_003_pos', 'ro_props_001_pos', 'zfs_set_keylocation',
-    'zfs_set_feature_activation']
+    'zfs_set_feature_activation', 'zfs_set_nomount']
 tags = ['functional', 'cli_root', 'zfs_set']
 
 [tests/functional/cli_root/zfs_share]

tests/runfiles/sanity.run

@@ -212,7 +212,7 @@ tests = ['cache_001_pos', 'cache_002_neg', 'canmount_001_pos',
     'user_property_001_pos', 'user_property_003_neg', 'readonly_001_pos',
     'user_property_004_pos', 'version_001_neg',
     'zfs_set_003_neg', 'property_alias_001_pos',
-    'zfs_set_keylocation', 'zfs_set_feature_activation']
+    'zfs_set_keylocation', 'zfs_set_feature_activation', 'zfs_set_nomount']
 tags = ['functional', 'cli_root', 'zfs_set']
 
 [tests/functional/cli_root/zfs_snapshot]

tests/zfs-tests/tests/Makefile.am

@@ -868,6 +868,7 @@ nobase_dist_datadir_zfs_tests_tests_SCRIPTS += \
 	functional/cli_root/zfs_set/zfs_set_003_neg.ksh \
 	functional/cli_root/zfs_set/zfs_set_feature_activation.ksh \
 	functional/cli_root/zfs_set/zfs_set_keylocation.ksh \
+	functional/cli_root/zfs_set/zfs_set_nomount.ksh \
 	functional/cli_root/zfs_share/cleanup.ksh \
 	functional/cli_root/zfs_share/setup.ksh \
 	functional/cli_root/zfs_share/zfs_share_001_pos.ksh \