Add -t option to zfs destroy

Resolves #9522 by adding an optional [-t type] option gate to the
`zfs destroy` command. Checks the type of the supplied argument,
then checks if the supplied type is the same or one of the aliases
that are also used in `zfs list`. If the type doesn't match, it
prints an error to stderr and exits.

Signed-off-by: Chris Simons <chris@simons.network>

cmd/zfs/zfs_main.c

@@ -287,7 +287,8 @@ get_usage(zfs_help_t idx)
 		    "\tcreate [-Pnpsv] [-b blocksize] [-o property=value] ... "
 		    "-V <size> <volume>\n"));
 	case HELP_DESTROY:
-		return (gettext("\tdestroy [-fnpRrv] <filesystem|volume>\n"
+		return (gettext("\tdestroy [-fnpRrv] [-t type] "
+		    "<filesystem|volume>\n"
 		    "\tdestroy [-dnpRrv] "
 		    "<filesystem|volume>@<snap>[%<snap>][,...]\n"
 		    "\tdestroy <filesystem|volume>#<bookmark>\n"));
@@ -1642,9 +1643,10 @@ zfs_do_destroy(int argc, char **argv)
 	zfs_handle_t *zhp = NULL;
 	char *at, *pound;
 	zfs_type_t type = ZFS_TYPE_DATASET;
+	char *type_filter = NULL;
 
 	/* check options */
-	while ((c = getopt(argc, argv, "vpndfrR")) != -1) {
+	while ((c = getopt(argc, argv, "vpndfrRt:")) != -1) {
 		switch (c) {
 		case 'v':
 			cb.cb_verbose = B_TRUE;
@@ -1670,6 +1672,9 @@ zfs_do_destroy(int argc, char **argv)
 			cb.cb_recurse = B_TRUE;
 			cb.cb_doclones = B_TRUE;
 			break;
+		case 't':
+			type_filter = optarg;
+			break;
 		case '?':
 		default:
 			(void) fprintf(stderr, gettext("invalid option '%c'\n"),
@@ -1691,6 +1696,54 @@ zfs_do_destroy(int argc, char **argv)
 		usage(B_FALSE);
 	}
 
+	/* check type before destroying if specified */
+	if (type_filter != NULL) {
+		zhp = zfs_open(g_zfs, argv[0], ZFS_TYPE_DATASET);
+		if (zhp != NULL) {
+			zfs_type_t type = zfs_get_type(zhp);
+			boolean_t type_matches = B_FALSE;
+
+			switch (type) {
+			case ZFS_TYPE_FILESYSTEM:
+				type_matches = (
+				    (strcmp(type_filter, "fs") == 0) ||
+				    (strcmp(type_filter, "filesystem") == 0));
+				break;
+			case ZFS_TYPE_VOLUME:
+				type_matches = (
+				    (strcmp(type_filter, "vol") == 0) ||
+				    (strcmp(type_filter, "volume") == 0));
+				break;
+			case ZFS_TYPE_SNAPSHOT:
+				type_matches = (
+				    (strcmp(type_filter, "snap") == 0) ||
+				    (strcmp(type_filter, "snapshot") == 0));
+				break;
+			case ZFS_TYPE_BOOKMARK:
+				type_matches =
+				    (strcmp(type_filter, "bookmark") == 0);
+				break;
+			default:
+				type_matches = B_FALSE;
+				break;
+			}
+
+			zfs_close(zhp);
+
+			if (!type_matches) {
+				(void) fprintf(stderr,
+				    gettext("cannot destroy '%s': "
+				    "type does not match '%s'\n"),
+				    argv[0], type_filter);
+				return (1);
+			}
+
+		} else {
+			return (1);
+		}
+	}
+
+
 	at = strchr(argv[0], '@');
 	pound = strchr(argv[0], '#');
 	if (at != NULL) {

man/man8/zfs-destroy.8

@@ -40,10 +40,12 @@
 .Nm zfs
 .Cm destroy
 .Op Fl Rfnprv
+.Oo Fl t Ar type Ns Oc
 .Ar filesystem Ns | Ns Ar volume
 .Nm zfs
 .Cm destroy
 .Op Fl Rdnprv
+.Oo Fl t Ar type Ns Oc
 .Ar filesystem Ns | Ns Ar volume Ns @ Ns Ar snap Ns
 .Oo % Ns Ar snap Ns Oo , Ns Ar snap Ns Oo % Ns Ar snap Oc Oc Oc Ns …
 .Nm zfs
@@ -56,6 +58,7 @@
 .Nm zfs
 .Cm destroy
 .Op Fl Rfnprv
+.Oo Fl t Ar type Ns Oc
 .Ar filesystem Ns | Ns Ar volume
 .Xc
 Destroys the given dataset.
@@ -84,6 +87,28 @@ flags to determine what data would be deleted.
 Print machine-parsable verbose information about the deleted data.
 .It Fl r
 Recursively destroy all children.
+.It Fl t Ar type
+The specified type to destroy, where
+.Ar type
+is one of
+.Sy filesystem ,
+.Sy snapshot ,
+.Sy volume ,
+or
+.Sy bookmark .
+For example, specifying
+.Fl t Sy snapshot
+will not destroy data if the supplied argument is not a
+.Sy snapshot .
+.Sy fs ,
+.Sy snap ,
+or
+.Sy vol
+can be used as aliases for
+.Sy filesystem ,
+.Sy snapshot ,
+or
+.Sy volume .
 .It Fl v
 Print verbose information about the deleted data.
 .El
@@ -98,6 +123,7 @@ behavior for mounted file systems in use.
 .Nm zfs
 .Cm destroy
 .Op Fl Rdnprv
+.Oo Fl t Ar type Ns Oc
 .Ar filesystem Ns | Ns Ar volume Ns @ Ns Ar snap Ns
 .Oo % Ns Ar snap Ns Oo , Ns Ar snap Ns Oo % Ns Ar snap Oc Oc Oc Ns …
 .Xc
@@ -155,6 +181,28 @@ Print machine-parsable verbose information about the deleted data.
 Destroy
 .Pq or mark for deferred deletion
 all snapshots with this name in descendent file systems.
+.It Fl t Ar type
+The specified type to destroy, where
+.Ar type
+is one of
+.Sy filesystem ,
+.Sy snapshot ,
+.Sy volume ,
+or
+.Sy bookmark .
+For example, specifying
+.Fl t Sy snapshot
+will not destroy data if the supplied argument is not a
+.Sy snapshot .
+.Sy fs ,
+.Sy snap ,
+or
+.Sy vol
+can be used as aliases for
+.Sy filesystem ,
+.Sy snapshot ,
+or
+.Sy volume .
 .It Fl v
 Print verbose information about the deleted data.
 .Pp

tests/runfiles/common.run

@@ -210,8 +210,9 @@ tests = ['zfs_clone_livelist_condense_and_disable',
     'zfs_destroy_007_neg', 'zfs_destroy_008_pos', 'zfs_destroy_009_pos',
     'zfs_destroy_010_pos', 'zfs_destroy_011_pos', 'zfs_destroy_012_pos',
     'zfs_destroy_013_neg', 'zfs_destroy_014_pos', 'zfs_destroy_015_pos',
-    'zfs_destroy_016_pos', 'zfs_destroy_clone_livelist',
+    'zfs_destroy_016_pos', 'zfs_destroy_017_pos',
-    'zfs_destroy_dev_removal', 'zfs_destroy_dev_removal_condense']
+    'zfs_destroy_clone_livelist', 'zfs_destroy_dev_removal',
+    'zfs_destroy_dev_removal_condense']
 tags = ['functional', 'cli_root', 'zfs_destroy']
 
 [tests/functional/cli_root/zfs_diff]

tests/zfs-tests/tests/functional/cli_root/zfs_destroy/zfs_destroy_017_pos.ksh

@@ -0,0 +1,77 @@
+#!/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) 2024 by Chris Simons <chris@simons.network>
+#
+
+. $STF_SUITE/include/libtest.shlib
+. $STF_SUITE/tests/functional/cli_root/zfs_destroy/zfs_destroy.cfg
+
+#
+# DESCRIPTION:
+# Verify that 'zfs destroy' with a type filter only destroys the datasets
+# of the specified type.
+#
+# STRATEGY:
+# 1. Create various types
+# 2. Attempt to destroy with correct and incorrect types
+# 3. Verify only expected items are destroyed
+# 4. Ensure recursive destruction still occurs
+#
+
+function cleanup
+{
+    for ds in $TESTPOOL/$TESTFS1 $TESTPOOL/$TESTVOL; do
+        datasetexists $ds && log_must zfs destroy -r $ds
+    done
+}
+
+log_assert "Verify 'zfs destroy' with a type filter only affects specified type"
+log_onexit cleanup
+
+# Create a filesystem, dataset and a volume
+log_must zfs create $TESTPOOL/$TESTFS1
+log_must zfs create $TESTPOOL/$TESTFS1/testdataset
+log_must zfs create -V $VOLSIZE $TESTPOOL/$TESTVOL
+
+# Take a snapshots
+log_must zfs snapshot $TESTPOOL/$TESTFS1@snap
+log_must zfs snapshot $TESTPOOL/$TESTVOL@snap
+log_must zfs snapshot $TESTPOOL/$TESTFS1@snap_del
+log_must zfs snapshot $TESTPOOL/$TESTVOL@snap_del
+log_must zfs snapshot -r $TESTPOOL/$TESTFS1@snap_recursive
+
+# Destroy only snapshots with the type filter
+log_mustnot zfs destroy -t snapshot $TESTPOOL/$TESTFS1
+log_mustnot zfs destroy -t snapshot -r $TESTPOOL/$TESTFS1
+log_mustnot zfs destroy -t snapshot $TESTPOOL/$TESTVOL
+log_mustnot zfs destroy -t snapshot -r $TESTPOOL/$TESTVOL
+log_must zfs destroy -t snapshot $TESTPOOL/$TESTFS1@snap_del
+log_must zfs destroy -t snapshot $TESTPOOL/$TESTVOL@snap_del
+log_must zfs destroy -t snapshot -r $TESTPOOL/$TESTFS1@snap_recursive
+
+# Verify the filesystem snapshot is destroyed and the volume snapshot remains
+log_must datasetexists $TESTPOOL/$TESTFS1
+log_must datasetexists $TESTPOOL/$TESTVOL
+log_mustnot datasetexists $TESTPOOL/$TESTFS1@snap_del
+log_mustnot datasetexists $TESTPOOL/$TESTVOL@snap_del
+log_mustnot datasetexists $TESTPOOL/$TESTVOL@snap_recursive
+log_mustnot datasetexists $TESTPOOL/$TESTVOL/testdataset@snap_recursive
+
+log_pass "zfs destroy with a snapshot filter only affects specified type"
+