When running on ZFS or UFS with NFSv4 ACL support enabled, "rsync -A" fails due to acl_get_file(3)
returning EINVAL.  EINVAL is caused by improper use of this routine - rsync doesn't bother to check
if POSIX.1e ACLs are supported, and blindly requests ACL_TYPE_ACCESS, which is invalid for files
with NFSv4 ACLs.

Patch below makes rsync properly recognize EINVAL as lack of support for the requested ACL type.

--- acls.c.orig 2010-12-23 10:45:21.344757361 +0100
+++ acls.c      2010-12-23 10:44:33.000000000 +0100
@@ -1082,6 +1082,10 @@ int default_perms_for_dir(const char *di
                case ENOTSUP:
 #endif
                case ENOSYS:
+#ifdef __FreeBSD__
+               /* Workaround for improper NFSv4 ACL handling in rsync. */
+               case EINVAL:
+#endif
                        /* No ACLs are available. */
                        break;
                case ENOENT:

--- lib/sysacls.c.orig  2010-12-23 10:47:02.945461082 +0100
+++ lib/sysacls.c       2010-12-23 10:44:52.000000000 +0100
@@ -2771,6 +2771,13 @@ int no_acl_syscall_error(int err)
        if (err == ENOENT)
                return 1; /* Weird problem with directory ACLs. */
 #endif
+#ifdef __FreeBSD__
+       if (err == EINVAL)
+               /*
+                * Workaround for improper NFSv4 ACL handling in rsync.
+                */
+               return 1;
+#endif
 #if defined(ENOSYS)
        if (err == ENOSYS) {
                return 1;