When we try to create a volume from image, we attach the volume to the host and perform qemu-img convert command to convert the image and write it into the volume.

In a iSCSI environment, the following error is observed when performing the qemu-img operation.

2024-05-02 16:40:38.189 8 ERROR cinder.volume.volume_utils Stderr: 'qemu-img: /dev/dm-7: error while converting raw: Cannot grow device files\n'

This happens because the multipath device is not ready for I/O and we try to write data into it.

We require a check in os-brick to verify the multipath device is ready for read/write before returning the call to cinder/nova/glance for writing data into the volume.