Re: [Qemu-devel] [Nbd] [PATCH 1/2] NBD proto: add WRITE_ZEROES extension

2016-03-24 Thread Wouter Verhelst
On Thu, Mar 24, 2016 at 12:37:33PM +0100, Paolo Bonzini wrote: > > > On 24/03/2016 09:26, Wouter Verhelst wrote: > >> > > >> > No, there is no specific reason. Looks like NBD_CMD_FLAG_ZEROES fits the > >> > spec and implementations nicely. So I'll rewrite the extension and add > >> > the flag

Re: [Qemu-devel] [Nbd] [PATCH 1/2] NBD proto: add WRITE_ZEROES extension

2016-03-24 Thread Eric Blake
On 03/24/2016 02:26 AM, Wouter Verhelst wrote: >> No, there is no specific reason. Looks like NBD_CMD_FLAG_ZEROES fits the >> spec and implementations nicely. So I'll rewrite the extension and add >> the flag instead of the whole command. > > Actually, having given this some more thought... > >

Re: [Qemu-devel] [Nbd] [PATCH 1/2] NBD proto: add WRITE_ZEROES extension

2016-03-24 Thread Paolo Bonzini
On 24/03/2016 09:26, Wouter Verhelst wrote: >> > >> > No, there is no specific reason. Looks like NBD_CMD_FLAG_ZEROES fits the >> > spec and implementations nicely. So I'll rewrite the extension and add >> > the flag instead of the whole command. > Actually, having given this some more

Re: [Qemu-devel] [Nbd] [PATCH 1/2] NBD proto: add WRITE_ZEROES extension

2016-03-24 Thread Pavel Borzenkov
On Thu, Mar 24, 2016 at 09:26:41AM +0100, Wouter Verhelst wrote: > On Thu, Mar 24, 2016 at 10:57:06AM +0300, Pavel Borzenkov wrote: > > On Wed, Mar 23, 2016 at 06:21:16PM +0100, Wouter Verhelst wrote: > > > So, the semantics of your proposed WRITE_ZEROES are exactly the same as > > > the WRITE

Re: [Qemu-devel] [Nbd] [PATCH 1/2] NBD proto: add WRITE_ZEROES extension

2016-03-24 Thread Pavel Borzenkov
On Wed, Mar 23, 2016 at 06:21:16PM +0100, Wouter Verhelst wrote: > Hi, > > On Wed, Mar 23, 2016 at 05:16:01PM +0300, Denis V. Lunev wrote: > > From: Pavel Borzenkov > > > > There exist some cases when a client knows that the data it is going to > > write is all zeroes.

Re: [Qemu-devel] [Nbd] [PATCH 1/2] NBD proto: add WRITE_ZEROES extension

2016-03-24 Thread Wouter Verhelst
On Thu, Mar 24, 2016 at 10:57:06AM +0300, Pavel Borzenkov wrote: > On Wed, Mar 23, 2016 at 06:21:16PM +0100, Wouter Verhelst wrote: > > So, the semantics of your proposed WRITE_ZEROES are exactly the same as > > the WRITE command, except that no payload is sent? > > > > In that case, I think it's

Re: [Qemu-devel] [Nbd] [PATCH 1/2] NBD proto: add WRITE_ZEROES extension

2016-03-24 Thread Wouter Verhelst
On Thu, Mar 24, 2016 at 10:16:19AM +0300, Pavel Borzenkov wrote: > So if no one objects, I'll send a patch correcting current spec > ambiguities and than patches with new proposed commands. Yes please. Thank you. -- < ron> I mean, the main *practical* problem with C++, is there's like a dozen

Re: [Qemu-devel] [Nbd] [PATCH 1/2] NBD proto: add WRITE_ZEROES extension

2016-03-23 Thread Wouter Verhelst
On Wed, Mar 23, 2016 at 09:14:10AM -0600, Eric Blake wrote: > On 03/23/2016 08:16 AM, Denis V. Lunev wrote: [...] > [1] Oh, you ARE adding this to the "Experimental extensions" section of > the document, so your wording IS correct. I guess the idea is that we > write up the documentation in the

Re: [Qemu-devel] [Nbd] [PATCH 1/2] NBD proto: add WRITE_ZEROES extension

2016-03-23 Thread Wouter Verhelst
Hi, On Wed, Mar 23, 2016 at 05:16:01PM +0300, Denis V. Lunev wrote: > From: Pavel Borzenkov > > There exist some cases when a client knows that the data it is going to > write is all zeroes. Such cases include mirroring or backing up a device > implemented by a sparse