Evan, > If the backing device for a loop device is a block device, then mirror > the discard properties of the underlying block device into the loop > device. While in there, differentiate between REQ_OP_DISCARD and > REQ_OP_WRITE_ZEROES, which are different for block devices, but which > the loop device had just been lumping together. Bubbling up the queue limits from the backing device is fine. However, I'm not sure why you are requiring a filesystem to be on a discard-capable device for REQ_OP_DISCARD to have an effect? Punching a hole in a file is semantically the same as discarding. -- Martin K. Petersen Oracle Linux Engineering
