UNMAP: propagate request to backing store

pkg/scsi/backingstore/cephstore_linux.go

@@ -150,6 +150,6 @@ func (bs *CephBackingStore) DataAdvise(offset, length int64, advise uint32) erro
 	return nil
 }
 
-func (bs *CephBackingStore) Unmap() error {
+func (bs *CephBackingStore) Unmap([]api.UnmapBlockDescriptor) error {
 	return nil
 }

pkg/scsi/backingstore/common.go

@@ -114,6 +114,6 @@ func (bs *FileBackingStore) DataAdvise(offset, length int64, advise uint32) erro
 	return util.Fadvise(bs.file, offset, length, advise)
 }
 
-func (bs *FileBackingStore) Unmap() error {
+func (bs *FileBackingStore) Unmap([]api.UnmapBlockDescriptor) error {
 	return nil
 }

pkg/scsi/backingstore/null.go

@@ -75,6 +75,6 @@ func (bs *NullBackingStore) DataAdvise(offset, length int64, advise uint32) erro
 	return nil
 }
 
-func (bs *NullBackingStore) Unmap() error {
+func (bs *NullBackingStore) Unmap([]api.UnmapBlockDescriptor) error {
 	return nil
 }