[Unionfs] unionfs has problems with file permissions

[Erez Zadok]

In message <498721B9.5040103 at msgid.tls.msk.ru>, Michael Tokarev writes:
> Johannes Hirte wrote:
> > Ok second try, since my first mail didn't reached the ML.
> > 
> > I run into write problems with unionfs and nfs and found this thread on
> > the ML:
> > 
> > http://www.fsl.cs.sunysb.edu/pipermail/unionfs/2008-November/005949.html
> > 
> > This describes pretty good my problem. I'm booting from network into an
> > initrd, mounting a tmpfs (rw) and a nfs-export (ro) together with
> > unionfs. The problem is, I can't modify a file from the nfs. Deleting
> > or creating is no problem, only modifying ends in "Permission denied".
> 
> This is not unique to nfs - it also happens when the ro part is on
> a read-only media like CD-rom for example, or squashfs, whatever.
> 
> /mjt

Michael, please see my response to Johannes: any additional info you can
give me will be helpful, including temp remote access, VMware images that
reproduce the problem, live CD images I can try, etc.

My guess is that there's something different about your system and
Johannes's system -- perhaps a difference that common to the two of you.
Whatever is going on, it's not a common setup or issue: after all unionfs's
main premise is to recognize readonly files and copy-up them automatically.

Cheers,
Erez.