cleanup: move core functions to core pkg

as we are refractoring the cephfs code,
Moving all the core functions to a new folder
/pkg called core. This will make things easier
to implement. For now onwards all the core
functionalities will be added to the core
package.

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

internal/cephfs/core/snapshot.go

@@ -0,0 +1,233 @@
+/*
+Copyright 2020 The Ceph-CSI Authors.
+
+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 core
+
+import (
+	"context"
+	"errors"
+	"time"
+
+	cerrors "github.com/ceph/ceph-csi/internal/cephfs/errors"
+	fsutil "github.com/ceph/ceph-csi/internal/cephfs/util"
+	"github.com/ceph/ceph-csi/internal/util/log"
+
+	"github.com/ceph/go-ceph/cephfs/admin"
+	"github.com/ceph/go-ceph/rados"
+	"github.com/golang/protobuf/ptypes/timestamp"
+)
+
+// autoProtect points to the snapshot auto-protect feature of
+// the subvolume.
+const (
+	autoProtect = "snapshot-autoprotect"
+)
+
+// CephfsSnapshot represents a CSI snapshot and its cluster information.
+type CephfsSnapshot struct {
+	NamePrefix string
+	Monitors   string
+	// MetadataPool & Pool fields are not used atm. But its definitely good to have it in this struct
+	// so keeping it here
+	MetadataPool string
+	Pool         string
+	ClusterID    string
+	RequestName  string
+	// ReservedID represents the ID reserved for a snapshot
+	ReservedID string
+}
+
+func (vo *VolumeOptions) CreateSnapshot(ctx context.Context, snapID, volID fsutil.VolumeID) error {
+	fsa, err := vo.conn.GetFSAdmin()
+	if err != nil {
+		log.ErrorLog(ctx, "could not get FSAdmin: %s", err)
+
+		return err
+	}
+
+	err = fsa.CreateSubVolumeSnapshot(vo.FsName, vo.SubvolumeGroup, string(volID), string(snapID))
+	if err != nil {
+		log.ErrorLog(ctx, "failed to create subvolume snapshot %s %s in fs %s: %s",
+			string(snapID), string(volID), vo.FsName, err)
+
+		return err
+	}
+
+	return nil
+}
+
+func (vo *VolumeOptions) DeleteSnapshot(ctx context.Context, snapID, volID fsutil.VolumeID) error {
+	fsa, err := vo.conn.GetFSAdmin()
+	if err != nil {
+		log.ErrorLog(ctx, "could not get FSAdmin: %s", err)
+
+		return err
+	}
+
+	err = fsa.ForceRemoveSubVolumeSnapshot(vo.FsName, vo.SubvolumeGroup, string(volID), string(snapID))
+	if err != nil {
+		log.ErrorLog(ctx, "failed to delete subvolume snapshot %s %s in fs %s: %s",
+			string(snapID), string(volID), vo.FsName, err)
+
+		return err
+	}
+
+	return nil
+}
+
+type SnapshotInfo struct {
+	CreatedAt        time.Time
+	CreationTime     *timestamp.Timestamp
+	HasPendingClones string
+	Protected        string
+}
+
+func (vo *VolumeOptions) GetSnapshotInfo(ctx context.Context, snapID, volID fsutil.VolumeID) (SnapshotInfo, error) {
+	snap := SnapshotInfo{}
+	fsa, err := vo.conn.GetFSAdmin()
+	if err != nil {
+		log.ErrorLog(ctx, "could not get FSAdmin: %s", err)
+
+		return snap, err
+	}
+
+	info, err := fsa.SubVolumeSnapshotInfo(vo.FsName, vo.SubvolumeGroup, string(volID), string(snapID))
+	if err != nil {
+		if errors.Is(err, rados.ErrNotFound) {
+			return snap, cerrors.ErrSnapNotFound
+		}
+		log.ErrorLog(
+			ctx,
+			"failed to get subvolume snapshot info %s %s in fs %s with error %s",
+			string(volID),
+			string(snapID),
+			vo.FsName,
+			err)
+
+		return snap, err
+	}
+	snap.CreatedAt = info.CreatedAt.Time
+	snap.HasPendingClones = info.HasPendingClones
+	snap.Protected = info.Protected
+
+	return snap, nil
+}
+
+func (vo *VolumeOptions) ProtectSnapshot(ctx context.Context, snapID, volID fsutil.VolumeID) error {
+	// If "snapshot-autoprotect" feature is present, The ProtectSnapshot
+	// call should be treated as a no-op.
+	if checkSubvolumeHasFeature(autoProtect, vo.Features) {
+		return nil
+	}
+	fsa, err := vo.conn.GetFSAdmin()
+	if err != nil {
+		log.ErrorLog(ctx, "could not get FSAdmin: %s", err)
+
+		return err
+	}
+
+	err = fsa.ProtectSubVolumeSnapshot(vo.FsName, vo.SubvolumeGroup, string(volID),
+		string(snapID))
+	if err != nil {
+		if errors.Is(err, rados.ErrObjectExists) {
+			return nil
+		}
+		log.ErrorLog(
+			ctx,
+			"failed to protect subvolume snapshot %s %s in fs %s with error: %s",
+			string(volID),
+			string(snapID),
+			vo.FsName,
+			err)
+
+		return err
+	}
+
+	return nil
+}
+
+func (vo *VolumeOptions) UnprotectSnapshot(ctx context.Context, snapID, volID fsutil.VolumeID) error {
+	// If "snapshot-autoprotect" feature is present, The UnprotectSnapshot
+	// call should be treated as a no-op.
+	if checkSubvolumeHasFeature(autoProtect, vo.Features) {
+		return nil
+	}
+	fsa, err := vo.conn.GetFSAdmin()
+	if err != nil {
+		log.ErrorLog(ctx, "could not get FSAdmin: %s", err)
+
+		return err
+	}
+
+	err = fsa.UnprotectSubVolumeSnapshot(vo.FsName, vo.SubvolumeGroup, string(volID),
+		string(snapID))
+	if err != nil {
+		// In case the snap is already unprotected we get ErrSnapProtectionExist error code
+		// in that case we are safe and we could discard this error.
+		if errors.Is(err, rados.ErrObjectExists) {
+			return nil
+		}
+		log.ErrorLog(
+			ctx,
+			"failed to unprotect subvolume snapshot %s %s in fs %s with error: %s",
+			string(volID),
+			string(snapID),
+			vo.FsName,
+			err)
+
+		return err
+	}
+
+	return nil
+}
+
+func (vo *VolumeOptions) cloneSnapshot(
+	ctx context.Context,
+	volID, snapID, cloneID fsutil.VolumeID,
+	cloneVolOptions *VolumeOptions,
+) error {
+	fsa, err := vo.conn.GetFSAdmin()
+	if err != nil {
+		log.ErrorLog(ctx, "could not get FSAdmin: %s", err)
+
+		return err
+	}
+	co := &admin.CloneOptions{
+		TargetGroup: cloneVolOptions.SubvolumeGroup,
+	}
+	if cloneVolOptions.Pool != "" {
+		co.PoolLayout = cloneVolOptions.Pool
+	}
+
+	err = fsa.CloneSubVolumeSnapshot(vo.FsName, vo.SubvolumeGroup, string(volID), string(snapID), string(cloneID), co)
+	if err != nil {
+		log.ErrorLog(
+			ctx,
+			"failed to clone subvolume snapshot %s %s in fs %s with error: %s",
+			string(volID),
+			string(snapID),
+			string(cloneID),
+			vo.FsName,
+			err)
+		if errors.Is(err, rados.ErrNotFound) {
+			return cerrors.ErrVolumeNotFound
+		}
+
+		return err
+	}
+
+	return nil
+}