[saturnero@freesbie.org: Weird behaviour of mount_unionfs with executables]

[Scott Long]

Dario Freni wrote:
> Forwarding a message apparently ignored on -current. Sorry for being
> annoying, but I'm working on FreeSBIE for my Summer of Code project
> and this bug is blocking me.
> 
> Thanks in advance,
> Dario
> 
> ----- Forwarded message from Dario Freni <saturnero at freesbie.org> -----
> 
> Date: Sat, 2 Jul 2005 14:40:48 +0200
> From: Dario Freni <saturnero at freesbie.org>
> To: freebsd-current at freebsd.org
> Cc: freebsd-ppc at freebsd.org
> Subject: Weird behaviour of mount_unionfs with executables
> 
> Hi everybody, I'm working on rewriting FreeSBIE toolkit for my Summer
> of Code project. Before that, I'm trying to adapt actual scripts with
> latest -current (expecially ppc). I noticed a weird behaviour of
> unionfs either in i386 and ppc. Under FreeSBIE, we use to mount memory
> file systems over compressed ones via unionfs. Under -current,
> whenever I recall an rwx file, it is correctly executed the first
> time, then it is copied to the upper layer (why? I haven't modified it
> yet) with wrong permission, so it is unexecutable.
> 
> sberta:/home/satu/tmp# kldload geom_uzip
> sberta:/home/satu/tmp# mdconfig -a -t vnode -f usr.uzip
> md0
> sberta:/home/satu/tmp# ll /dev/md0*
> crw-r-----  1 root  operator   11,  98 Jul  1 12:48 /dev/md0
> crw-r-----  1 root  operator   11,  99 Jul  1 12:48 /dev/md0.uzip
> sberta:/home/satu/tmp# mount -r /dev/md0.uzip compressedusr/
> 
> sberta:/home/satu/tmp# mdmfs -S -s 32m -M md mdmfs/
> sberta:/home/satu/tmp# mtree -PUdr -p mdmfs/ < FreeSBIE.usr.dirs 
> [..snip, reconstructing the directory tree with right permissions..]
> 
> sberta:/home/satu/tmp# mount_unionfs mdmfs/ compressedusr/
> 
> sberta:/home/satu/tmp# cd compressedusr/bin/
> sberta:/home/satu/tmp/compressedusr/bin# ll w
> -r-xr-xr-x  2 root  wheel  11416 Jun 22 23:35 w
> sberta:/home/satu/tmp/compressedusr/bin# ./w
>  2:26PM  up 1 day,  1:38, 9 users, load averages: 3.49, 3.12, 2.26
> USER             TTY      FROM              LOGIN@  IDLE WHAT
> [...]
> sberta:/home/satu/tmp/compressedusr/bin# ll w
> -rw-r--r--  1 root  wheel  11416 Jul  2 14:26 w
> sberta:/home/satu/tmp/compressedusr/bin# ./w
> ./w: Permission denied.
> 
> I'm also afraid that copying files to the upper layer also when
> they're not modified could fill up our mfs entirely. I'm almost sure
> there's a totally different behaviour under RELENG_5, as we haven't
> encountered such problems.
> 
> 

You might very well have found a bug in the vnode pager.  I take it that
this doesn't happen on 5-STABLE, correct?

Scott