Cross-platform acltype

The acltype property is currently hidden on FreeBSD and does not
reflect the NFSv4 style ZFS ACLs used on the platform.  This makes it
difficult to observe that a pool imported from FreeBSD on Linux has a
different type of ACL that is being ignored, and vice versa.

Add an nfsv4 acltype and expose the property on FreeBSD.

Make the default acltype nfsv4 on FreeBSD.

Setting acltype to an unhanded style is treated the same as setting
it to off.  The ACLs will not be removed, but they will be ignored.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #10520

module/os/freebsd/zfs/zfs_vfsops.c

@@ -592,6 +592,14 @@ acl_inherit_changed_cb(void *arg, uint64_t newval)
 	zfsvfs->z_acl_inherit = newval;
 }
 
+static void
+acl_type_changed_cb(void *arg, uint64_t newval)
+{
+	zfsvfs_t *zfsvfs = arg;
+
+	zfsvfs->z_acl_type = newval;
+}
+
 static int
 zfs_register_callbacks(vfs_t *vfsp)
 {
@@ -722,6 +730,8 @@ zfs_register_callbacks(vfs_t *vfsp)
 	    zfs_prop_to_name(ZFS_PROP_EXEC), exec_changed_cb, zfsvfs);
 	error = error ? error : dsl_prop_register(ds,
 	    zfs_prop_to_name(ZFS_PROP_SNAPDIR), snapdir_changed_cb, zfsvfs);
+	error = error ? error : dsl_prop_register(ds,
+	    zfs_prop_to_name(ZFS_PROP_ACLTYPE), acl_type_changed_cb, zfsvfs);
 	error = error ? error : dsl_prop_register(ds,
 	    zfs_prop_to_name(ZFS_PROP_ACLMODE), acl_mode_changed_cb, zfsvfs);
 	error = error ? error : dsl_prop_register(ds,
@@ -797,6 +807,11 @@ zfsvfs_init(zfsvfs_t *zfsvfs, objset_t *os)
 		return (error);
 	zfsvfs->z_case = (uint_t)val;
 
+	error = zfs_get_zplprop(os, ZFS_PROP_ACLTYPE, &val);
+	if (error != 0)
+		return (error);
+	zfsvfs->z_acl_type = (uint_t)val;
+
 	/*
 	 * Fold case on file systems that are always or sometimes case
 	 * insensitive.
@@ -1232,6 +1247,10 @@ zfs_domount(vfs_t *vfsp, char *osname)
 		    "xattr", &pval, NULL)))
 			goto out;
 		xattr_changed_cb(zfsvfs, pval);
+		if ((error = dsl_prop_get_integer(osname,
+		    "acltype", &pval, NULL)))
+			goto out;
+		acl_type_changed_cb(zfsvfs, pval);
 		zfsvfs->z_issnap = B_TRUE;
 		zfsvfs->z_os->os_sync = ZFS_SYNC_DISABLED;
 
@@ -2220,6 +2239,9 @@ zfs_get_zplprop(objset_t *os, zfs_prop_t prop, uint64_t *value)
 		case ZFS_PROP_CASE:
 			*value = ZFS_CASE_SENSITIVE;
 			break;
+		case ZFS_PROP_ACLTYPE:
+			*value = ZFS_ACLTYPE_NFSV4;
+			break;
 		default:
 			return (error);
 		}