On Sat, Aug 03, 2024 at 03:04:30PM GMT, Wouter Verhelst wrote: > The NBD protocol defines a message for zeroing out a region of an export > > Add support to the kernel driver for that message. > > Signed-off-by: Wouter Verhelst <w@xxxxxxx> > --- > drivers/block/nbd.c | 8 ++++++++ > include/uapi/linux/nbd.h | 5 ++++- > 2 files changed, 12 insertions(+), 1 deletion(-) > > diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c > index 5b1811b1ba5f..215e7ea9a3c3 100644 > --- a/drivers/block/nbd.c > +++ b/drivers/block/nbd.c > @@ -352,6 +352,8 @@ static int __nbd_set_size(struct nbd_device *nbd, loff_t bytesize, > } > if (nbd->config->flags & NBD_FLAG_ROTATIONAL) > lim.features |= BLK_FEAT_ROTATIONAL; > + if (nbd->config->flags & NBD_FLAG_SEND_WRITE_ZEROES) > + lim.max_write_zeroes_sectors = UINT_MAX; Is that number accurate, when the kernel has not yet been taught to use 64-bit transactions and can therefore only request a 32-bit byte length on any one transaction? Would a better limit be UINT_MAX/blksize? -- Eric Blake, Principal Software Engineer Red Hat, Inc. Virtualization: qemu.org | libguestfs.org
