issue-2936: NodePublishVolume must return error if FS was remounted t…

…o RO (#2937)

cloud/blockstore/tests/csi_driver/e2e_tests_part2/test.py

@@ -168,3 +168,36 @@ def test_node_volume_expand_vm_mode():
         raise
     finally:
         csi.cleanup_after_test(env, volume_name, access_type, [pod_id])
+
+
+def test_publish_volume_must_fail_after_fs_error():
+    env, run = csi.init()
+    try:
+        volume_name = "example-disk"
+        volume_size = 1024 ** 3
+        pod_name = "example-pod"
+        pod_id = "deadbeef1"
+        access_type = "mount"
+        env.csi.create_volume(name=volume_name, size=volume_size)
+        env.csi.stage_volume(volume_name, access_type)
+        env.csi.publish_volume(pod_id, volume_name, pod_name, access_type)
+
+        with open('/sys/fs/ext4/nbd0/trigger_fs_error', 'w') as f:
+            f.write("test error")
+
+        env.csi.unpublish_volume(pod_id, volume_name, access_type)
+
+        stage_path = "/var/lib/kubelet/plugins/kubernetes.io/csi/nbs.csi.nebius.ai/a/globalmount"
+        assert "ro" == get_access_mode(stage_path)
+
+        try:
+            env.csi.publish_volume(pod_id, volume_name, pod_name, access_type)
+            assert False
+        except subprocess.CalledProcessError:
+            pass
+
+    except subprocess.CalledProcessError as e:
+        csi.log_called_process_error(e)
+        raise
+    finally:
+        csi.cleanup_after_test(env, volume_name, access_type, [pod_id])

cloud/blockstore/tools/csi_driver/internal/driver/node.go

@@ -623,6 +623,13 @@ func (s *nodeService) nodePublishDiskAsFilesystem(
 			"Staging target path is not mounted: %w", req.VolumeId)
 	}
 
+	readOnly, _ := s.mounter.IsFilesystemRemountedAsReadonly(req.StagingTargetPath)
+	if readOnly {
+		return s.statusErrorf(
+			codes.Internal,
+			"Filesystem was remounted as readonly")
+	}
+
 	mounted, _ = s.mounter.IsMountPoint(req.TargetPath)
 	if !mounted {
 		targetPerm := os.FileMode(0775)

cloud/blockstore/tools/csi_driver/internal/driver/node_test.go

@@ -545,6 +545,7 @@ func TestPublishUnpublishDiskForInfrakuber(t *testing.T) {
 
 	mounter.On("IsMountPoint", stagingTargetPath).Return(true, nil)
 	mounter.On("IsMountPoint", targetPath).Return(false, nil)
+	mounter.On("IsFilesystemRemountedAsReadonly", stagingTargetPath).Return(false, nil)
 
 	mounter.On("Mount", stagingTargetPath, targetPath, "", []string{"bind"}).Return(nil)
 

cloud/blockstore/tools/csi_driver/internal/mounter/iface.go

@@ -12,6 +12,7 @@ type Interface interface {
 	HasBlockDevice(device string) (bool, error)
 
 	IsFilesystemExisted(device string) (bool, error)
+	IsFilesystemRemountedAsReadonly(mountPoint string) (bool, error)
 	MakeFilesystem(device string, fsType string) ([]byte, error)
 
 	NeedResize(devicePath string, deviceMountPath string) (bool, error)

cloud/blockstore/tools/csi_driver/internal/mounter/mock.go

@@ -40,6 +40,11 @@ func (c *Mock) IsFilesystemExisted(device string) (bool, error) {
 	return args.Get(0).(bool), args.Error(1)
 }
 
+func (c *Mock) IsFilesystemRemountedAsReadonly(mountPoint string) (bool, error) {
+	args := c.Called(mountPoint)
+	return args.Get(0).(bool), args.Error(1)
+}
+
 func (c *Mock) MakeFilesystem(device string, fsType string) ([]byte, error) {
 	args := c.Called(device, fsType)
 	return args.Get(0).([]byte), args.Error(1)

cloud/blockstore/tools/csi_driver/internal/mounter/mounter.go

@@ -78,6 +78,39 @@ func (m *mounter) IsFilesystemExisted(device string) (bool, error) {
 	return err == nil && string(out) != "", nil
 }
 
+func (m *mounter) IsFilesystemRemountedAsReadonly(mountPoint string) (bool, error) {
+	mountInfoList, err := mount.ParseMountInfo("/proc/self/mountinfo")
+	if err != nil {
+		return false, err
+	}
+
+	for _, mountInfo := range mountInfoList {
+		if mountInfo.MountPoint == mountPoint {
+			// The filesystem was remounted as read-only
+			// if the mount options included a read-write option, while
+			// the superblock options specified a read-only option.
+			var readWriteFs = false
+			for _, mountOption := range mountInfo.MountOptions {
+				if mountOption == "rw" {
+					readWriteFs = true
+					break
+				}
+			}
+
+			if !readWriteFs {
+				return false, nil
+			}
+
+			for _, superOption := range mountInfo.SuperOptions {
+				if superOption == "ro" {
+					return true, nil
+				}
+			}
+		}
+	}
+	return false, nil
+}
+
 func (m *mounter) MakeFilesystem(device string, fsType string) ([]byte, error) {
 	options := []string{"-t", fsType}
 	if fsType == "ext4" {