rbd: add listsnapshots function

added listsnapshots function for an
rbd image to list all the snapshots
created from an rbd images, This will
list the snapshots which are in trash also.

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

internal/rbd/rbd_util.go

@@ -1137,3 +1137,46 @@ func (rv *rbdVolume) ensureEncryptionMetadataSet(status string) error {
 
 	return nil
 }
+
+// SnapshotInfo holds snapshots details
+type snapshotInfo struct {
+	ID        int    `json:"id"`
+	Name      string `json:"name"`
+	Size      int64  `json:"size"`
+	Protected string `json:"protected"`
+	Timestamp string `json:"timestamp"`
+	Namespace struct {
+		Type         string `json:"type"`
+		OriginalName string `json:"original_name"`
+	} `json:"namespace"`
+}
+
+// TODO: use go-ceph once https://github.com/ceph/go-ceph/issues/300 is available in a release.
+func (rv *rbdVolume) listSnapshots(ctx context.Context, cr *util.Credentials) ([]snapshotInfo, error) {
+	// rbd snap ls <image> --pool=<pool-name> --all --format=json
+	var snapInfo []snapshotInfo
+	stdout, stderr, err := util.ExecCommand("rbd",
+		"-m", rv.Monitors,
+		"--id", cr.ID,
+		"--keyfile="+cr.KeyFile,
+		"-c", util.CephConfigPath,
+		"--format="+"json",
+		"snap",
+		"ls",
+		"--all", rv.String())
+	if err != nil {
+		klog.Errorf(util.Log(ctx, "failed getting information for image (%s): (%s)"), rv, err)
+		if strings.Contains(string(stderr), "rbd: error opening image "+rv.RbdImageName+
+			": (2) No such file or directory") {
+			return snapInfo, ErrImageNotFound{rv.String(), err}
+		}
+		return snapInfo, err
+	}
+
+	err = json.Unmarshal(stdout, &snapInfo)
+	if err != nil {
+		klog.Errorf(util.Log(ctx, "failed to parse JSON output of snapshot info (%s)"), err)
+		return snapInfo, fmt.Errorf("unmarshal failed: %w. raw buffer response: %s", err, string(stdout))
+	}
+	return snapInfo, nil
+}