OS-7867 zfs create needs dry-run

Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Approved by: Jerry Jelinek <jerry.jelinek@joyent.com>

3 files changed, 264 insertions, 21 deletions

diff --git a/usr/src/cmd/zfs/zfs_main.c b/usr/src/cmd/zfs/zfs_main.c
index 51b4260c71..525ba2022f 100644
--- a/usr/src/cmd/zfs/zfs_main.c
+++ b/usr/src/cmd/zfs/zfs_main.c
@@ -777,8 +777,8 @@ usage:
 }
 
 /*
- * zfs create [-p] [-o prop=value] ... fs
- * zfs create [-ps] [-b blocksize] [-o prop=value] ... -V vol size
+ * zfs create [-Pnpv] [-o prop=value] ... fs
+ * zfs create [-Pnpsv] [-b blocksize] [-o prop=value] ... -V vol size
  *
  * Create a new dataset.  This command can be used to create filesystems
  * and volumes.  Snapshot creation is handled by 'zfs snapshot'.
@@ -790,17 +790,33 @@ usage:
  * SPA_VERSION_REFRESERVATION, we set a refreservation instead.
  *
  * The '-p' flag creates all the non-existing ancestors of the target first.
+ *
+ * The '-n' flag is no-op (dry run) mode.  This will perform a user-space sanity
+ * check of arguments and properties, but does not check for permissions,
+ * available space, etc.
+ *
+ * The following flags are private in SmartOS pending acceptance of interface
+ * changes by the external ZFS community.
+ *
+ * The '-v' flag is for verbose output.
+ *
+ * The '-P' flag is used for parseable output.  It implies '-v'.
  */
 static int
 zfs_do_create(int argc, char **argv)
 {
 	zfs_type_t type = ZFS_TYPE_FILESYSTEM;
 	zfs_handle_t *zhp = NULL;
+	zpool_handle_t *zpool_handle = NULL;
+	nvlist_t *real_props = NULL;
 	uint64_t volsize = 0;
 	int c;
 	boolean_t noreserve = B_FALSE;
 	boolean_t bflag = B_FALSE;
 	boolean_t parents = B_FALSE;
+	boolean_t dryrun = B_FALSE;
+	boolean_t verbose = B_FALSE;
+	boolean_t parseable = B_FALSE;
 	int ret = 1;
 	nvlist_t *props;
 	uint64_t intval;
@@ -809,7 +825,7 @@ zfs_do_create(int argc, char **argv)
 		nomem();
 
 	/* check options */
-	while ((c = getopt(argc, argv, ":V:b:so:p")) != -1) {
+	while ((c = getopt(argc, argv, ":PV:b:nso:pv")) != -1) {
 		switch (c) {
 		case 'V':
 			type = ZFS_TYPE_VOLUME;
@@ -825,6 +841,10 @@ zfs_do_create(int argc, char **argv)
 				nomem();
 			volsize = intval;
 			break;
+		case 'P':	/* Private to SmartOS */
+			verbose = B_TRUE;
+			parseable = B_TRUE;
+			break;
 		case 'p':
 			parents = B_TRUE;
 			break;
@@ -842,6 +862,9 @@ zfs_do_create(int argc, char **argv)
 			    intval) != 0)
 				nomem();
 			break;
+		case 'n':	/* Private to SmartOS */
+			dryrun = B_TRUE;
+			break;
 		case 'o':
 			if (parseprop(props, optarg) != 0)
 				goto error;
@@ -849,6 +872,9 @@ zfs_do_create(int argc, char **argv)
 		case 's':
 			noreserve = B_TRUE;
 			break;
+		case 'v':	/* Private to SmartOS */
+			verbose = B_TRUE;
+			break;
 		case ':':
 			(void) fprintf(stderr, gettext("missing size "
 			    "argument\n"));
@@ -880,14 +906,9 @@ zfs_do_create(int argc, char **argv)
 		goto badusage;
 	}
 
-	if (type == ZFS_TYPE_VOLUME && !noreserve) {
-		zpool_handle_t *zpool_handle;
-		nvlist_t *real_props = NULL;
-		uint64_t spa_version;
+	if (dryrun || (type == ZFS_TYPE_VOLUME && !noreserve)) {
+		char msg[ZFS_MAX_DATASET_NAME_LEN * 2];
 		char *p;
-		zfs_prop_t resv_prop;
-		char *strval;
-		char msg[1024];
 
 		if ((p = strchr(argv[0], '/')) != NULL)
 			*p = '\0';
@@ -896,25 +917,31 @@ zfs_do_create(int argc, char **argv)
 			*p = '/';
 		if (zpool_handle == NULL)
 			goto error;
-		spa_version = zpool_get_prop_int(zpool_handle,
-		    ZPOOL_PROP_VERSION, NULL);
-		if (spa_version >= SPA_VERSION_REFRESERVATION)
-			resv_prop = ZFS_PROP_REFRESERVATION;
-		else
-			resv_prop = ZFS_PROP_RESERVATION;
 
 		(void) snprintf(msg, sizeof (msg),
+		    dryrun ? gettext("cannot verify '%s'") :
 		    gettext("cannot create '%s'"), argv[0]);
 		if (props && (real_props = zfs_valid_proplist(g_zfs, type,
 		    props, 0, NULL, zpool_handle, B_TRUE, msg)) == NULL) {
 			zpool_close(zpool_handle);
 			goto error;
 		}
+	}
+
+	if (type == ZFS_TYPE_VOLUME && !noreserve) {
+		uint64_t spa_version;
+		zfs_prop_t resv_prop;
+		char *strval;
+
+		spa_version = zpool_get_prop_int(zpool_handle,
+		    ZPOOL_PROP_VERSION, NULL);
+		if (spa_version >= SPA_VERSION_REFRESERVATION)
+			resv_prop = ZFS_PROP_REFRESERVATION;
+		else
+			resv_prop = ZFS_PROP_RESERVATION;
 
 		volsize = zvol_volsize_to_reservation(zpool_handle, volsize,
 		    real_props);
-		nvlist_free(real_props);
-		zpool_close(zpool_handle);
 
 		if (nvlist_lookup_string(props, zfs_prop_to_name(resv_prop),
 		    &strval) != 0) {
@@ -925,6 +952,10 @@ zfs_do_create(int argc, char **argv)
 			}
 		}
 	}
+	if (zpool_handle != NULL) {
+		zpool_close(zpool_handle);
+		nvlist_free(real_props);
+	}
 
 	if (parents && zfs_name_valid(argv[0], type)) {
 		/*
@@ -936,8 +967,50 @@ zfs_do_create(int argc, char **argv)
 			ret = 0;
 			goto error;
 		}
-		if (zfs_create_ancestors(g_zfs, argv[0]) != 0)
-			goto error;
+		if (verbose) {
+			(void) printf(parseable ? "create_ancestors\t%s\n" :
+			    dryrun ? "would create ancestors of %s\n" :
+			    "create ancestors of %s\n", argv[0]);
+		}
+		if (!dryrun) {
+			if (zfs_create_ancestors(g_zfs, argv[0]) != 0) {
+				goto error;
+			}
+		}
+	}
+
+	if (verbose) {
+		nvpair_t *nvp = NULL;
+		(void) printf(parseable ? "create\t%s\n" :
+		    dryrun ? "would create %s\n" : "create %s\n", argv[0]);
+		while ((nvp = nvlist_next_nvpair(props, nvp)) != NULL) {
+			uint64_t uval;
+			char *sval;
+
+			switch (nvpair_type(nvp)) {
+			case DATA_TYPE_UINT64:
+				VERIFY0(nvpair_value_uint64(nvp, &uval));
+				(void) printf(parseable ?
+				    "property\t%s\t%llu\n" : "\t%s=%llu\n",
+				    nvpair_name(nvp), uval);
+				break;
+			case DATA_TYPE_STRING:
+				VERIFY0(nvpair_value_string(nvp, &sval));
+				(void) printf(parseable ?
+				    "property\t%s\t%s\n" : "\t%s=%s\n",
+				    nvpair_name(nvp), sval);
+				break;
+			default:
+				(void) fprintf(stderr, "property '%s' "
+				    "has illegal type %d\n",
+				    nvpair_name(nvp), nvpair_type(nvp));
+				abort();
+			}
+		}
+	}
+	if (dryrun) {
+		ret = 0;
+		goto error;
 	}
 
 	/* pass to libzfs */
diff --git a/usr/src/test/zfs-tests/runfiles/smartos.run b/usr/src/test/zfs-tests/runfiles/smartos.run
index 6486a104db..f452ef7a84 100644
--- a/usr/src/test/zfs-tests/runfiles/smartos.run
+++ b/usr/src/test/zfs-tests/runfiles/smartos.run
@@ -96,7 +96,8 @@ tests = ['zfs_create_001_pos', 'zfs_create_002_pos', 'zfs_create_003_pos',
     'zfs_create_004_pos', 'zfs_create_005_pos', 'zfs_create_006_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_encrypted', 'zfs_create_crypt_combos']
+    'zfs_create_013_pos', 'zfs_create_encrypted', 'zfs_create_crypt_combos',
+    'zfs_create_dryrun']
 
 [/opt/zfs-tests/tests/functional/cli_root/zfs_destroy]
 tests = ['zfs_destroy_001_pos', 'zfs_destroy_002_pos', 'zfs_destroy_003_pos',
diff --git a/usr/src/test/zfs-tests/tests/functional/cli_root/zfs_create/zfs_create_dryrun.ksh b/usr/src/test/zfs-tests/tests/functional/cli_root/zfs_create/zfs_create_dryrun.ksh
new file mode 100644
index 0000000000..64b8296f46
--- /dev/null
+++ b/usr/src/test/zfs-tests/tests/functional/cli_root/zfs_create/zfs_create_dryrun.ksh
@@ -0,0 +1,169 @@
+#!/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 2019 Joyent, Inc.
+#
+
+. $STF_SUITE/include/libtest.shlib
+. $STF_SUITE/tests/functional/cli_root/zfs_create/zfs_create_common.kshlib
+
+#
+# DESCRIPTION:
+# zfs create -n should perform basic sanity checking but should never create a
+# dataset.  If -v and/or -P are used, it should verbose about what would be
+# created if sanity checks pass.
+#
+# STRATEGY:
+# 1. Attempt to create a file system and a volume using various combinations of
+#    -n with -v and -P.
+#
+
+verify_runnable "both"
+
+#
+# Verifies that valid commands with -n and without -[vP]:
+# - succeed
+# - do not create a dataset
+# - do not generate output
+#
+function dry_create_no_output
+{
+	typeset -a cmd=(zfs create -n "$@")
+
+	log_note "$0: ${cmd[@]}"
+	log_must "${cmd[@]}"
+	datasetexists "$TESTPOOL/$TESTFS1" &&
+	    log_fail "$TESTPOOL/$TESTFS1 unexpectedly created by '${cmd[@]}'"
+	typeset out=$("${cmd[@]}" 2>&1)
+	[[ -z "$out" ]] ||
+	    log_fail "unexpected output '$out' from '${cmd[@]}'"
+}
+
+#
+# Verifies that commands with invalid properties or invalid property values
+# - fail
+# - do not create a dataset
+# - generate a message on stderr
+#
+function dry_create_error
+{
+	typeset -a cmd=(zfs create -n "$@")
+
+	log_note "$0: ${cmd[@]}"
+	log_mustnot "${cmd[@]}"
+	datasetexists "$TESTPOOL/$TESTFS1" &&
+	    log_fail "$TESTPOOL/$TESTFS1 unexpectedly created by '${cmd[@]}'"
+	typeset out=$("${cmd[@]}" 2>&1 >/dev/null)
+	[[ -z "$out" ]] &&
+	    log_fail "expected an error message but got none from '${cmd[@]}'"
+}
+
+#
+# Verifies that dry-run commands with parseable output
+# - succeed
+# - do not create datasets
+# - generate parseable output on stdout
+# - output matches expectations
+#
+function dry_create_parseable
+{
+	typeset -n exp=$1
+	shift
+	typeset -a cmd=(zfs create -Pn "$@")
+	typeset ds=${cmd[${#cmd[@]} - 1]}
+	typeset out
+	typeset -a toks
+	typeset -a props
+	typeset found_create=false
+
+	log_note "$0: ${cmd[@]}"
+	out=$("${cmd[@]}")
+	(( $? == 0 )) ||
+	    log_fail "unexpected failure getting stdout from '${cmd[@]}'"
+	datasetexists "$TESTPOOL/$TESTFS1" &&
+	    log_fail "$TESTPOOL/$TESTFS1 unexpectedly created by '${cmd[@]}'"
+	echo "$out" | while IFS=$'\t' read -A toks; do
+		log_note "verifying ${toks[@]}"
+		case ${toks[0]} in
+		create)
+			log_must test "${#toks[@]}" -eq 2
+			log_must test "${toks[1]}" == "$ds"
+			found_create="yes, I found create"
+			;;
+		property)
+			log_must test "${#toks[@]}" -eq 3
+			typeset prop=${toks[1]}
+			typeset val=${toks[2]}
+			if [[ -z "${exp[$prop]}" ]]; then
+				log_fail "unexpectedly got property '$prop'"
+			fi
+			# We may not know the exact value a property will take
+			# on.  This is the case for at least refreservation.
+			if [[ ${exp[$prop]} != "*" ]]; then
+				log_must test "${exp[$prop]}" == "$val"
+			fi
+			unset exp[$prop]
+			;;
+		*)
+			log_fail "Unexpected line ${toks[@]}"
+			;;
+		esac
+	done
+
+	log_must test "$found_create" == "yes, I found create"
+	log_must test "extra props: ${!exp[@]}" == "extra props: "
+}
+
+function cleanup
+{
+	if datasetexists "$TESTPOOL/$TESTFS1"; then
+		log_must zfs destroy -r "$TESTPOOL/$TESTFS1"
+	fi
+}
+log_onexit cleanup
+
+log_assert "zfs create -n creates nothing but can describe what would be" \
+	"created"
+
+# Typical creations should succeed
+dry_create_no_output "$TESTPOOL/$TESTFS1"
+dry_create_no_output -V 10m "$TESTPOOL/$TESTFS1"
+# It shouldn't do a space check right now
+dry_create_no_output -V 100t "$TESTPOOL/$TESTFS1"
+# It shouldn't create parent datasets either
+dry_create_no_output -p "$TESTPOOL/$TESTFS1/$TESTFS2"
+dry_create_no_output -pV 10m "$TESTPOOL/$TESTFS1/$TESTFS2"
+
+# Various invalid properties should be recognized and result in an error
+dry_create_error -o nosuchprop=42 "$TESTPOOL/$TESTFS1"
+dry_create_error -b 1234 -V 10m  "$TESTPOOL/$TESTFS1"
+
+# Parseable output should be parseable.
+typeset -A expect
+expect=([compression]=on)
+dry_create_parseable expect -o compression=on "$TESTPOOL/$TESTFS1"
+
+# Sparse volumes should not get a gratuitous refreservation
+expect=([volblocksize]=4096 [volsize]=$((1024 * 1024 * 10)))
+dry_create_parseable expect -b 4k -V 10m -s "$TESTPOOL/$TESTFS1"
+
+# Non-sparse volumes should have refreservation
+expect=(
+    [volblocksize]=4096
+    [volsize]=$((1024 * 1024 * 10))
+    [refreservation]="*"
+)
+dry_create_parseable expect -b 4k -V 10m "$TESTPOOL/$TESTFS1"
+
+log_pass "zfs create -n creates nothing but can describe what would be" \
+	"created"