Re: [Qemu-devel] structured reply behavior for read of 0 bytes

2017-11-06 Thread Eric Blake
On 11/05/2017 01:57 PM, Wouter Verhelst wrote: > > I'd like to take a step back first and wonder what a zero-sized read > would actually mean. "Please read no data at this offset". What good > does that do? I can't see anything useful coming out of that. If the export is some sort of memory-mappe

Re: [Qemu-devel] structured reply behavior for read of 0 bytes

2017-11-05 Thread Wouter Verhelst
Hi Eric, On Fri, Nov 03, 2017 at 05:45:07PM -0500, Eric Blake wrote: > As currently written, structured reply is documented as: > > > NBD_REPLY_TYPE_OFFSET_DATA (1) > > > > This chunk type is in the content chunk category. length MUST be at least > > 9. It represents the contents of length - 8 b

[Qemu-devel] structured reply behavior for read of 0 bytes

2017-11-03 Thread Eric Blake
As currently written, structured reply is documented as: > NBD_REPLY_TYPE_OFFSET_DATA (1) > > This chunk type is in the content chunk category. length MUST be at least 9. > It represents the contents of length - 8 bytes of the file, starting at the > absolute offset from the start of the export