On Wed, 03/09 08:43, Paolo Bonzini wrote: > > > 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.
Okay, that makes sense, but ioctl like SG_IO can also modify content, no? Fam