Operation will continue without using snapshot provider, because file system 'volname' does not have write permissions.
The source file system for a snapshot should be read-write as by definition a snapshot is a point-in-time snapshot of changing file system. Snapshot creation updates the file system superblock which requires the file system to be read-write
Processing continues without using snapshot provider.
If the volume needs to be backed up via snapshot provider, change its permissions to read-write.