Samba on shares with XFS and kernel 2.6.18

[Björn JACKE]

On 2010-11-19 at 09:37 +0100 Janek Walkenhorst sent off:
> Am 2010-11-19 06:16:38 schrieb Stefan Gohmann:
> > Am Mittwoch 17 November 2010 schrieb Björn Jacke:
> > > but doing that correct would be a bit tricky. In
> > > vfswrap_fs_capabilities() we also need to know that utimensat() doesn't
> > > work to initialize p_ts_res correctly. A test utimensat() call would
> > > actually be required to set p_ts_res right, too. POSIX does not even
> > > mention that this call may fail with ENOSYS.
> > >
> > > I would prefer that people with utimensat resulting in ENOSYS should get
> > > a big warning in the log files: "never us a glibc which is much more
> > > recent than your kernel." This is a well known problem of Debian systems
> > > with a way too old XEN kernel. Old kernels with new glibc are not
> > > supported by their maintainers. People should just not do this - the lack
> > > of utimensat() is just the most obvious place of brokenness, I guess
> > > there are more, more subtle brokennesses waiting to be discovered.
> >
> > You are right, the results are not known if the kernel is too old for the
> > glibc. Janek will create a new patch which adds the warning and he will
> > also check vfswrap_fs_capabilities. I think this would be the best.
> This is the patch with the check in vfswrap_fs_capabilities and a log message 
> added.

I really meant that we should issue a big warning and not do any workaround
because such a setup is unsupported by glibc and kernel maintainers. Working
around this issue will encourage users to keep the broken setup running and for
other problems that arise due to the ancient XEN kernel/recent glibc
combination people will start to look for the bugs in Samba again. We should
not try to fix broken setups at the very wrong place. Therefore I'd prefer the
attached short patch without any fallback code.

Björn
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