Samba on shares with XFS and kernel 2.6.18

[Björn Jacke]

On 2010-11-17 at 11:16 +0100 Volker Lendecke sent off:
> On Wed, Nov 17, 2010 at 11:07:04AM +0100, Stefan Gohmann wrote:
> > No it does not help. From the configure:
> > checking for utimensat... yes
> > 
> > But I found the following debian bug against the coreutils package:
> > http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=515941
> > 
> > So I think it is not a samba bug.
> 
> Well, it would be nice for Samba to behave as if configure
> did not find utimensat in this case. ENOSYS as an error
> message is pretty specific.
> 
> source3/modules/vfs_default.c around line 543ff is the piece
> that does it. It should be a relatively minor change to
> handle ENOSYS to utimensat properly.

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.

Björn
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