diff --git a/lustre/tests/multiop.c b/lustre/tests/multiop.c
index b42bfb8..f1e69b2 100755
--- a/lustre/tests/multiop.c
+++ b/lustre/tests/multiop.c
@@ -68,6 +68,8 @@ char usage[] =
 "        d  mkdir\n"
 "        D  open(O_DIRECTORY)\n"
 "        f  statfs\n"
+"        G  get grouplock gid\n"
+"        g  put grouplock gid\n"
 "        L  link\n"
 "        l  symlink\n"
 "        m  mknod\n"
@@ -194,6 +196,7 @@ int main(int argc, char **argv)
         int flags;
         int save_errno;
         int verbose = 0;
+        int gid = 0;
 
         if (argc < 3) {
                 fprintf(stderr, usage, argv[0]);
@@ -257,6 +260,22 @@ int main(int argc, char **argv)
                                 exit(save_errno);
                         }
                         break;
+                case 'G':
+                        gid = atoi(commands+1);
+                        if (ioctl(fd, LL_IOC_GROUP_LOCK, gid) == -1) {
+                                save_errno = errno;
+                                perror("ioctl(GROUP_LOCK)");
+                                exit(save_errno);
+                        }
+                        break;
+                case 'g':
+                        gid = atoi(commands+1);
+                        if (ioctl(fd, LL_IOC_GROUP_UNLOCK, gid) == -1) {
+                                save_errno = errno;
+                                perror("ioctl(GROUP_UNLOCK)");
+                                exit(save_errno);
+                        }
+                        break;
                 case 'l':
                         newfile = POP_ARG();
                         if (!newfile)
diff --git a/lustre/tests/sanity.sh b/lustre/tests/sanity.sh
index 052a207..18e0d22 100644
--- a/lustre/tests/sanity.sh
+++ b/lustre/tests/sanity.sh
@@ -2013,6 +2013,20 @@ test_34g() {
 }
 run_test 34g "truncate long file ==============================="
 
+test_34h() {
+    dd if=/dev/zero of=$DIR/$tfile bs=1 count=100
+    GID=10
+    multiop $DIR/$tfile OG${GID}Tg${GID}C &
+    MULTIPID=$!
+    sleep 1
+
+    if [[ `ps h -o comm -p $MULTIPID` == "multiop" ]]; then
+        error "Multiop blocked on ftruncate, pid=$MULTIPID"
+    fi
+    kill -9 $MULTIPID
+}
+run_test 34h "ftruncate file under grouplock, should not block"
+
 test_35a() {
 	cp /bin/sh $DIR/f35a
 	chmod 444 $DIR/f35a