On Tue, Sep 25, 2007 at 10:25:50PM +0200, Kay Sievers wrote:
> On Tue, 2007-09-25 at 14:34 +0200, Karel Zak wrote:
> > On Tue, Sep 25, 2007 at 12:11:23PM +0200, Kay Sievers wrote:
> > > On Tue, 2007-09-25 at 11:14 +0200, Karel Zak wrote:
> > > > Now we duplicate a lot of FS probe code in libblkid, libvolume_id and
> > > > libdisk.
> > > >
> > > > Yes, it's long-term task, but it's good direction (IMHO).
> > >
> > > It is, and we are not providing a real value to the users by providing
> > > both of these libs at the same time. :)
> > >
> > > But udev has a very different requirement for probing filesystems.
> > > Unlike non-udev systems, we can't accept any hidden policy inside a
> > > library. We just want to pass a byte stream to the lib, and get back
> > > what exactly is in _this_ byte stream. There must be no chaching, no
> > > devmapper logic, no stat()'ing in /dev, no reading of /proc/partitions,
> > > no ioctl()'s, no hidden decisions, nothing. None of these actions is
> > > acceptable to be done by the library itself, if udev is used. We need
> > > pure mechanics, no policy. We also need an API that allows to specify
> > > the size of the stream and the probing offset. And we don't want to
> > > iterate over tags, need the filesystem version information, the raid
> > > metadata probing, and the classification volume_id provides.
> >
> > Technical details :-)
>
> What do you miss, these are all technical details. :) In simple words,
> we need a completely policy-free, not try-to-be-smart in any sense set
> of functions to identify a bytestream by magic bytes.
Yes, I've read libvolume_id code and I good understand what you mean.
> > Cool. I'd like to create libfsprobe as an independent project. Or is
> > there any advantage to merge everything to util-linux-ng? I don't
> > think so.
>
> Hmm, only if you reaqlly don't want to pull it in util-linux, we could
> have it as a separate tree. I still think util-linux is the best place,
> because the most important user of it is mount/fsck. It's your call, I
> would have no problem sending patches against util-linux. :)
OK, Ted has same opinion and I'm not so stubborn... Let's use
util-linux-ng.
(I think we can continue with this topic at util-linux-ng mailing
list only.)
Karel
--
Karel Zak <kzak@xxxxxxxxxx>
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