On Mon, Dec 2, 2013 at 4:54 AM, Chunyan Liu <cy...@suse.com> wrote: > 2013/11/25 Kevin Wolf <kw...@redhat.com> >> >> Am 21.11.2013 um 09:51 hat Stefan Hajnoczi geschrieben: >> > On Thu, Nov 21, 2013 at 11:33:56AM +0800, Chunyan Liu wrote: >> > > 2013/11/20 Stefan Hajnoczi <stefa...@gmail.com> >> > > >> > > > On Wed, Nov 20, 2013 at 04:50:29PM +0800, Chunyan Liu wrote: >> > > > > block/cow.c | 22 ++++++++++++++++++++++ >> > > > > block/qcow.c | 22 ++++++++++++++++++++++ >> > > > > block/qcow2.c | 22 ++++++++++++++++++++++ >> > > > >> > > > I think you can avoid modifying all the image formats: >> > > > >> > > > .bdrv_create() functions pass options to bdrv_create_file(). >> > > > Therefore >> > > > an image format like qcow2 does not need to parse the nocow option >> > > > itself. Only raw-posix.c:.bdrv_create() needs to know about the >> > > > nocow >> > > > option. >> > > > >> > > > >> > > In existing code, options passed to bdrv_create_file contains no >> > > option in >> > > fact. >> > > >> > > And if we pass all options to bdrv_create_file directly, raw-posix.c: >> > > .bdrv_create() will get NOCOW option but at the same time get SIZE >> > > option, >> > > it >> > > will create a file with total size. For cow/qcow/qcow2, I suppose it's >> > > not >> > > expected? In current code, bdrv_create_file will create a zero-sized >> > > image >> > > for >> > > cow/qcow/qcow2. >> > >> > I see what the problem is: the loop that parses options does options++. >> > So by the time it has processed them the options pointer will be NULL or >> > point to a terminator option (option->name == NULL). >> > >> > I was confused because there has been a patch series which changes >> > .bdrv_create() option parsing. But I forgot it hasn't been merged. >> > https://lists.gnu.org/archive/html/qemu-devel/2013-08/msg01695.html >> > >> > Kevin: Have you looked at .bdrv_create() QEMUOptionParameter removal >> > recently? Otherwise I'm inclined to merge Chunyan's patch - we can >> > always refactor the code later when QEMUOptionParameter is removed. >> >> No, I haven't. I think the QemuOpts conversion series was relatively >> close, but it seems nobody is working on it any more. Someone should >> probably pick it up and finish it. > > > Hi, Kevin & Stefan, > About the nocow option, according to current status, how should we proceed? > Any > further work needs to do?
We talked on IRC about rebasing the QEMUOptionParameter series. Let's get the in so the 'nocow' change can be made cleanly. Stefan
