On 05/05/2015 13:49, Paolo Bonzini wrote: > > > On 05/05/2015 13:48, Kevin Wolf wrote: >> It depends. In its basic form, bdrv_discard() just means "I don't care >> about the data any more". Then clearing the dirty bitmap is correct. >> >> The content is only important if the caller used discard to write zeros >> because can_write_zeroes_with_unmap = true. Do we have any such callers >> apart from qemu-img convert? > > Yes, the SCSI command WRITE SAME with UNMAP = 1 (not coincidentially :)) > calls discard too.
s/discard/write_zeroes/ of course! Paolo > Who knows what the guest used it for... > However, write zeroes doesn't go through bdrv_co_discard, does it? > > Paolo > >
