On 09/03/2016 04:35, Fam Zheng wrote: >> > enum BdrvTrackedRequestType { >> > BDRV_TRACKED_READ, >> > BDRV_TRACKED_WRITE, >> > - BDRV_TRACKED_FLUSH, >> > - BDRV_TRACKED_IOCTL, >> > BDRV_TRACKED_DISCARD, > Okay, so flush and ioctl are not needed, but why is discard different?
Discard can modify the contents of the device, so I think it's safer to serialize it against RMW and copy-on-read operations. Paolo