receive: don't fail inheriting (-x) properties on wrong dataset type

Receiving datasets while blanket inheriting properties like zfs 
receive -x mountpoint can generally be desirable, e.g. to avoid 
unexpected mounts on backup hosts.

Currently this will fail to receive zvols due to the mountpoint 
property being applicable to filesystems only.  This limitation 
currently requires operators to special-case their minds and tools 
for zvols.

This change gets rid of this limitation for inherit (-x) by
Spiting up the dataset type handling: Warnings for inheriting (-x), 
errors for overriding (-o).

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: InsanePrawn <insane.prawny@gmail.com>
Closes #11416
Closes #11840
Closes #11864

lib/libzfs/libzfs_sendrecv.c

@@ -3951,24 +3951,6 @@ zfs_setup_cmdline_props(libzfs_handle_t *hdl, zfs_type_t type,
 		if (prop == ZFS_PROP_ORIGIN)
 			continue;
 
-		/*
-		 * we're trying to override or exclude a property that does not
-		 * make sense for this type of dataset, but we don't want to
-		 * fail if the receive is recursive: this comes in handy when
-		 * the send stream contains, for instance, a child ZVOL and
-		 * we're trying to receive it with "-o atime=on"
-		 */
-		if (!zfs_prop_valid_for_type(prop, type, B_FALSE) &&
-		    !zfs_prop_user(name)) {
-			if (recursive)
-				continue;
-			zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
-			    "property '%s' does not apply to datasets of this "
-			    "type"), name);
-			ret = zfs_error(hdl, EZFS_BADPROP, errbuf);
-			goto error;
-		}
-
 		/* raw streams can't override encryption properties */
 		if ((zfs_prop_encryption_key_param(prop) ||
 		    prop == ZFS_PROP_ENCRYPTION) && raw) {
@@ -3997,6 +3979,16 @@ zfs_setup_cmdline_props(libzfs_handle_t *hdl, zfs_type_t type,
 			 * a property: this is done by forcing an explicit
 			 * inherit on the destination so the effective value is
 			 * not the one we received from the send stream.
+			 */
+			if (!zfs_prop_valid_for_type(prop, type, B_FALSE) &&
+			    !zfs_prop_user(name)) {
+				(void) fprintf(stderr, dgettext(TEXT_DOMAIN,
+				    "Warning: %s: property '%s' does not "
+				    "apply to datasets of this type\n"),
+				    fsname, name);
+				continue;
+			}
+			/*
 			 * We do this only if the property is not already
 			 * locally-set, in which case its value will take
 			 * priority over the received anyway.
@@ -4024,6 +4016,24 @@ zfs_setup_cmdline_props(libzfs_handle_t *hdl, zfs_type_t type,
 				fnvlist_add_nvpair(*oxprops, nvp);
 			break;
 		case DATA_TYPE_STRING: /* -o property=value */
+			/*
+			 * we're trying to override a property that does not
+			 * make sense for this type of dataset, but we don't
+			 * want to fail if the receive is recursive: this comes
+			 * in handy when the send stream contains, for
+			 * instance, a child ZVOL and we're trying to receive
+			 * it with "-o atime=on"
+			 */
+			if (!zfs_prop_valid_for_type(prop, type, B_FALSE) &&
+			    !zfs_prop_user(name)) {
+				if (recursive)
+					continue;
+				zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
+				    "property '%s' does not apply to datasets "
+				    "of this type"), name);
+				ret = zfs_error(hdl, EZFS_BADPROP, errbuf);
+				goto error;
+			}
 			fnvlist_add_nvpair(oprops, nvp);
 			break;
 		default:

tests/zfs-tests/tests/functional/cli_root/zfs_receive/receive-o-x_props_override.ksh

@@ -259,16 +259,21 @@ log_must zfs destroy -r -f $orig
 log_must zfs destroy -r -f $dest
 
 #
-# 3.7 Verify we can't receive a send stream overriding or excluding properties
+# 3.7 Verify we can receive a send stream excluding but not overriding
-#     invalid for the dataset type unless the stream it's recursive, in which
+#     properties invalid for the dataset type, in which case only the
-#     case only the appropriate properties are set on the destination.
+#     appropriate properties are set on the destination.
-#
 log_must zfs create -V 128K -s $orig
 log_must zfs snapshot $orig@snap1
 log_must eval "zfs send $orig@snap1 > $streamfile_full"
-log_mustnot eval "zfs receive -x atime $dest < $streamfile_full"
 log_mustnot eval "zfs receive -o atime=off $dest < $streamfile_full"
+log_mustnot eval "zfs receive -o atime=off -x canmount $dest < $streamfile_full"
+log_must eval "zfs receive -x atime -x canmount $dest < $streamfile_full"
+log_must eval "check_prop_source $dest type volume -"
+log_must eval "check_prop_source $dest atime - -"
+log_must eval "check_prop_source $dest canmount - -"
 log_must_busy zfs destroy -r -f $orig
+log_must_busy zfs destroy -r -f $dest
+# Recursive sends also accept (and ignore) such overrides
 log_must zfs create $orig
 log_must zfs create -V 128K -s $origsub
 log_must zfs snapshot -r $orig@snap1