Re: [Qemu-devel] [PATCH 1/1] nbd: increase maximum size of the PWRITE_ZERO request

On 02/08/2018 07:23 AM, Edgar Kaziakhmedov wrote: Upstream NBD protocol implementation supports an efficient zero out mechanism over the wire, along with the ability to check whether a client allows using a hole. Accordingly, since PWRITE_ZERO doesn't involve any payload on the wire, increase a

Re: [Qemu-devel] [PATCH 1/1] nbd: increase maximum size of the PWRITE_ZERO request

> On 10 Feb 2018, at 18:43, Alex Bligh wrote: > > So I think a reasonable logic for Qemu would be to try NBD_CMD_INFO and find > the maximum write size, and if that's unsupported use 0x (capping at > export size, or export size minus write offset). Ur actually

Re: [Qemu-devel] [PATCH 1/1] nbd: increase maximum size of the PWRITE_ZERO request

> On 8 Feb 2018, at 16:28, Eric Blake wrote: > > On 02/08/2018 07:23 AM, Edgar Kaziakhmedov wrote: >> Upstream NBD protocol implementation supports an efficient zero out >> mechanism over the wire, along with the ability to check whether a >> client allows using a hole. >>

Re: [Qemu-devel] [PATCH 1/1] nbd: increase maximum size of the PWRITE_ZERO request

On 02/08/2018 06:55 PM, Eric Blake wrote: On 02/08/2018 09:28 AM, Edgar Kaziakhmedov wrote: We've got a potential problem.  Unless you have out-of-band communication of the maximum NBD_CMD_WRITE_ZEROES sizing (or if the NBD protocol is enhanced to advertise that as an additional piece of

Re: [Qemu-devel] [PATCH 1/1] nbd: increase maximum size of the PWRITE_ZERO request

On 02/08/2018 09:28 AM, Edgar Kaziakhmedov wrote: We've got a potential problem.  Unless you have out-of-band communication of the maximum NBD_CMD_WRITE_ZEROES sizing (or if the NBD protocol is enhanced to advertise that as an additional piece of block size information during NBD_OPT_GO),

Re: [Qemu-devel] [PATCH 1/1] nbd: increase maximum size of the PWRITE_ZERO request

[resending with correct NBD list address] On 02/08/2018 07:23 AM, Edgar Kaziakhmedov wrote: Upstream NBD protocol implementation supports an efficient zero out mechanism over the wire, along with the ability to check whether a client allows using a hole. Accordingly, since PWRITE_ZERO doesn't

Re: [Qemu-devel] [PATCH 1/1] nbd: increase maximum size of the PWRITE_ZERO request

On 02/08/2018 05:54 PM, Eric Blake wrote: On 02/08/2018 07:23 AM, Edgar Kaziakhmedov wrote: Upstream NBD protocol implementation supports an efficient zero out mechanism over the wire, along with the ability to check whether a client allows using a hole. Accordingly, since PWRITE_ZERO

Re: [Qemu-devel] [PATCH 1/1] nbd: increase maximum size of the PWRITE_ZERO request

On 02/08/2018 07:23 AM, Edgar Kaziakhmedov wrote: Upstream NBD protocol implementation supports an efficient zero out mechanism over the wire, along with the ability to check whether a client allows using a hole. Accordingly, since PWRITE_ZERO doesn't involve any payload on the wire, increase a