add ceph backing store plugin

pkg/scsi/backingstore/cephstore_linux.go

@@ -0,0 +1,151 @@
+/*
+Copyright 2018 The GoStor 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 backingstore
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/gostor/gotgt/pkg/api"
+	"github.com/gostor/gotgt/pkg/scsi"
+
+	log "github.com/Sirupsen/logrus"
+	"github.com/ceph/go-ceph/rados"
+	"github.com/ceph/go-ceph/rbd"
+)
+
+// This ceph-rbd plugin is only for linux
+// path format ceph-rbd:poolname/imagename
+const (
+	CephBackingStorage = "ceph-rbd"
+)
+
+func init() {
+	scsi.RegisterBackingStore(CephBackingStorage, newCeph)
+}
+
+type CephBackingStore struct {
+	scsi.BaseBackingStore
+	poolName  string
+	imageName string
+	conn      *rados.Conn
+	ioctx     *rados.IOContext
+	image     *rbd.Image
+}
+
+func newCeph() (api.BackingStore, error) {
+	return &CephBackingStore{
+		BaseBackingStore: scsi.BaseBackingStore{
+			Name:            CephBackingStorage,
+			DataSize:        0,
+			OflagsSupported: 0,
+		},
+	}, nil
+}
+
+func (bs *CephBackingStore) Open(dev *api.SCSILu, path string) error {
+
+	pathinfo := strings.SplitN(path, "/", 2)
+	if len(pathinfo) != 2 {
+		return fmt.Errorf("invalid device path string:%s", path)
+	}
+	poolName := pathinfo[0]
+	imageName := pathinfo[1]
+	log.Debugf("ceph path = %s", path)
+	if conn, err := rados.NewConn(); err != nil {
+		log.Error(err)
+		return err
+	} else {
+		bs.conn = conn
+	}
+	if err := bs.conn.ReadDefaultConfigFile(); err != nil {
+		log.Error(err)
+		return err
+	}
+
+	if err := bs.conn.Connect(); err != nil {
+		log.Error(err)
+		return err
+	}
+
+	if ioctx, err := bs.conn.OpenIOContext(poolName); err != nil {
+		bs.conn.Shutdown()
+		log.Error(err)
+		return err
+	} else {
+		bs.ioctx = ioctx
+	}
+
+	if image := rbd.GetImage(bs.ioctx, imageName); image == nil {
+		err := fmt.Errorf("rbdGetImage failed:poolName:%s,imageName:%s",
+			poolName, imageName)
+		log.Error(err)
+	} else {
+		bs.image = image
+	}
+
+	if err := bs.image.Open(); err != nil {
+		log.Error(err)
+		return err
+	}
+
+	if dataSize, err := bs.image.GetSize(); err != nil {
+		log.Error(err)
+		return err
+	} else {
+		bs.DataSize = dataSize
+	}
+	return nil
+}
+
+func (bs *CephBackingStore) Close(dev *api.SCSILu) error {
+	err := bs.image.Close()
+	bs.ioctx.Destroy()
+	bs.conn.Shutdown()
+	return err
+}
+
+func (bs *CephBackingStore) Init(dev *api.SCSILu, Opts string) error {
+	return nil
+}
+
+func (bs *CephBackingStore) Exit(dev *api.SCSILu) error {
+	return nil
+}
+
+func (bs *CephBackingStore) Size(dev *api.SCSILu) uint64 {
+	return bs.DataSize
+}
+
+func (bs *CephBackingStore) Read(offset, tl int64) ([]byte, error) {
+	tmpbuf := make([]byte, tl)
+	_, err := bs.image.ReadAt(tmpbuf, offset)
+	return tmpbuf, err
+}
+
+func (bs *CephBackingStore) Write(wbuf []byte, offset int64) error {
+	_, err := bs.image.WriteAt(wbuf, offset)
+	return err
+}
+
+func (bs *CephBackingStore) DataSync() error {
+	err := bs.image.Flush()
+	return err
+}
+
+func (bs *CephBackingStore) DataAdvise(offset, length int64, advise uint32) error {
+	return nil
+}