Il 02/07/2013 12:56, Peter Lieven ha scritto: > > Am 02.07.2013 um 12:49 schrieb Paolo Bonzini <pbonz...@redhat.com>: > >> Il 02/07/2013 12:36, Peter Lieven ha scritto: >>>>>> Perhaps we can have a new "discard_zeroes" field in bdrv_get_info, and >>>>>> the unmap functionality can be moved up to qemu-img convert? >>>>> >>>>> Is there any other storage protocol out there that could benefit from it? >>>> >>>> Definitely LVM. Perhaps in the future gluster too, though right now it >>>> only supports discard on files, not block devices. >>> >>> Is discards on LVM sth that is already implemented in qemu? >> >> Yes, it supports BLKDISCARD (see handle_aiocb_discard in >> block/raw-posix.c). Of course there is no way to query the host >> discard_zeroes setting yet. > > No way in qemu or no way at all?
No way in QEMU. Linux has the BLKDISCARDZEROES ioctl, it takes an int* as the third argument and puts 0/1 in it. Paolo
