support fibre channel volume

Signed-off-by: Huamin Chen <hchen@redhat.com>

pkg/volume/fc/fc_util.go

@@ -0,0 +1,200 @@
+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package fc
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+
+	"github.com/golang/glog"
+	"k8s.io/kubernetes/pkg/volume"
+)
+
+type ioHandler interface {
+	ReadDir(dirname string) ([]os.FileInfo, error)
+	Lstat(name string) (os.FileInfo, error)
+	EvalSymlinks(path string) (string, error)
+	WriteFile(filename string, data []byte, perm os.FileMode) error
+}
+
+type osIOHandler struct{}
+
+func (handler *osIOHandler) ReadDir(dirname string) ([]os.FileInfo, error) {
+	return ioutil.ReadDir(dirname)
+}
+func (handler *osIOHandler) Lstat(name string) (os.FileInfo, error) {
+	return os.Lstat(name)
+}
+func (handler *osIOHandler) EvalSymlinks(path string) (string, error) {
+	return filepath.EvalSymlinks(path)
+}
+func (handler *osIOHandler) WriteFile(filename string, data []byte, perm os.FileMode) error {
+	return ioutil.WriteFile(filename, data, perm)
+}
+
+// given a disk path like /dev/sdx, find the devicemapper parent
+func findMultipathDeviceMapper(disk string, io ioHandler) string {
+	sys_path := "/sys/block/"
+	if dirs, err := io.ReadDir(sys_path); err == nil {
+		for _, f := range dirs {
+			name := f.Name()
+			if strings.HasPrefix(name, "dm-") {
+				if _, err1 := io.Lstat(sys_path + name + "/slaves/" + disk); err1 == nil {
+					return "/dev/" + name
+				}
+			}
+		}
+	}
+	return ""
+}
+
+// given a wwn and lun, find the device and associated devicemapper parent
+func findDisk(wwn, lun string, io ioHandler) (string, string) {
+	fc_path := "-fc-0x" + wwn + "-lun-" + lun
+	dev_path := "/dev/disk/by-path/"
+	if dirs, err := io.ReadDir(dev_path); err == nil {
+		for _, f := range dirs {
+			name := f.Name()
+			if strings.Contains(name, fc_path) {
+				if disk, err1 := io.EvalSymlinks(dev_path + name); err1 == nil {
+					arr := strings.Split(disk, "/")
+					l := len(arr) - 1
+					dev := arr[l]
+					dm := findMultipathDeviceMapper(dev, io)
+					return disk, dm
+				}
+			}
+		}
+	}
+	return "", ""
+}
+
+func createMultipathConf(path string, io ioHandler) {
+	if _, err := os.Lstat(path); err != nil {
+		data := []byte(`defaults {
+	find_multipaths yes
+	user_friendly_names yes
+}
+
+
+blacklist {
+}
+`)
+		io.WriteFile(path, data, 0664)
+	}
+}
+
+// rescan scsi bus
+func scsiHostRescan(io ioHandler) {
+	scsi_path := "/sys/class/scsi_host/"
+	if dirs, err := io.ReadDir(scsi_path); err == nil {
+		for _, f := range dirs {
+			name := scsi_path + f.Name() + "/scan"
+			data := []byte("- - -")
+			io.WriteFile(name, data, 0666)
+		}
+	}
+}
+
+// make a directory like /var/lib/kubelet/plugins/kubernetes.io/pod/fc/target-lun-0
+func makePDNameInternal(host volume.VolumeHost, wwns []string, lun string) string {
+	return path.Join(host.GetPluginDir(fcPluginName), wwns[0]+"-lun-"+lun)
+}
+
+type FCUtil struct{}
+
+func (util *FCUtil) MakeGlobalPDName(fc fcDisk) string {
+	return makePDNameInternal(fc.plugin.host, fc.wwns, fc.lun)
+}
+
+func searchDisk(wwns []string, lun string, io ioHandler) (string, string) {
+	disk := ""
+	dm := ""
+
+	rescaned := false
+	// two-phase search:
+	// first phase, search existing device path, if a multipath dm is found, exit loop
+	// otherwise, in second phase, rescan scsi bus and search again, return with any findings
+	for true {
+		for _, wwn := range wwns {
+			disk, dm = findDisk(wwn, lun, io)
+			// if multipath device is found, break
+			if dm != "" {
+				break
+			}
+		}
+		// if a dm is found, exit loop
+		if rescaned || dm != "" {
+			break
+		}
+		// rescan and search again
+		// create multipath conf if it is not there
+		createMultipathConf("/etc/multipath.conf", io)
+		// rescan scsi bus
+		scsiHostRescan(io)
+		rescaned = true
+	}
+	return disk, dm
+}
+
+func (util *FCUtil) AttachDisk(b fcDiskBuilder) error {
+	devicePath := ""
+	wwns := b.wwns
+	lun := b.lun
+	io := b.io
+	disk, dm := searchDisk(wwns, lun, io)
+	// if no disk matches input wwn and lun, exit
+	if disk == "" && dm == "" {
+		return fmt.Errorf("no fc disk found")
+	}
+
+	// if multipath devicemapper device is found, use it; otherwise use raw disk
+	if dm != "" {
+		devicePath = dm
+	} else {
+		devicePath = disk
+	}
+	// mount it
+	globalPDPath := b.manager.MakeGlobalPDName(*b.fcDisk)
+	noMnt, err := b.mounter.IsLikelyNotMountPoint(globalPDPath)
+	if !noMnt {
+		glog.Infof("fc: %s already mounted", globalPDPath)
+		return nil
+	}
+
+	if err := os.MkdirAll(globalPDPath, 0750); err != nil {
+		return fmt.Errorf("fc: failed to mkdir %s, error", globalPDPath)
+	}
+
+	err = b.mounter.Mount(devicePath, globalPDPath, b.fsType, nil)
+	if err != nil {
+		return fmt.Errorf("fc: failed to mount fc volume %s [%s] to %s, error %v", devicePath, b.fsType, globalPDPath, err)
+	}
+
+	return err
+}
+
+func (util *FCUtil) DetachDisk(c fcDiskCleaner, mntPath string) error {
+	if err := c.mounter.Unmount(mntPath); err != nil {
+		return fmt.Errorf("fc detach disk: failed to unmount: %s\nError: %v", mntPath, err)
+	}
+	return nil
+}