On Wed, 10 Mar 2021 at 12:38, Philippe Mathieu-Daudé <phi...@redhat.com> wrote:
> On 3/10/21 1:32 PM, Fam Zheng wrote: > > On Wed, 10 Mar 2021 at 11:44, Philippe Mathieu-Daudé <phi...@redhat.com > > <mailto:phi...@redhat.com>> wrote: > > > > Hi, > > > > This is an alternative approach to changing null-co driver > > default 'read-zeroes' option to true: > > https://www.mail-archive.com/qemu-block@nongnu.org/msg80873.html > > <https://www.mail-archive.com/qemu-block@nongnu.org/msg80873.html> > > > > Instead we introduce yet another block driver with an explicit > > name: 'zeroes-co'. We then clarify in secure-coding-practices.rst > > that security reports have to be sent using this new driver. > > > > The 2nd patch is RFC because I won't spend time converting the > > tests until the first patch is discussed, as I already spent enough > > time doing that in the previous mentioned series. > > > > Regards, > > > > Phil. > > > > Philippe Mathieu-Daudé (3): > > block: Introduce the 'zeroes-co' driver > > tests/test-blockjob: Use zeroes-co instead of > null-co,read-zeroes=on > > docs/secure-coding-practices: Describe null-co/zeroes-co block > drivers > > > > docs/devel/secure-coding-practices.rst | 7 + > > block/zeroes.c | 306 > +++++++++++++++++++++++++ > > > > Why not add another BlockDriver struct to block/null.c and set the > > read_zeroes field in the .bdrv_file_open callback? It would make the > > patch much simpler. > > This is the first patch I wrote but then realized you are listed as > null-co maintainer, so you might be uninterested in having this new > driver in the same file. And declaring the prototypes public to > reuse them seemed overkill. > > I posted a patch for block/null.c to add the same interface, just as an alternative to the first patch. I think we all agree that both zeroed and non-zeroed read mode will be supported going forward, the divergence is on approach: a) -blockdev null-co:// | -blockdev null-co://,read-zeroes=off, if we make read-zeroes=on the default. b) -blockdev null-co:// | -blockdev zero-co://, if we keep the current default of null-co://, but introduce zero-co:// which has a clearer interface. Fam
