[Lustre-discuss] tunefs.lustre --print fails on mounted mdt/ost with mmp

[Bernd Schubert]

On Wednesday, July 14, 2010, Andreas Dilger wrote:
> On 2010-07-14, at 13:29, Nate Pearlstein wrote:
> > Just checking to be sure this isn't a known bug or problem.  I couldn't
> > find a bz for this, but it would appear that tunefs.lustre --print fails
> > on a lustre mdt or ost device if mounted with mmp.
> > 
> > Is this expected behavior?
> 
> Not really expected...  It is reading the "mountdata" file via debugfs, so
> that should be safe even on a mounted filesystem, but it doesn't work with
> MMP:
> 
> # debugfs -c -R stats /dev/vgbackup/lvtest
> debugfs 1.41.10.sun2 (24-Feb-2010)
> /dev/vgbackup/lvtest: MMP: device currently active while opening filesystem
> stats: Filesystem not open
> 
> This is already fixed in our next release of e2fsprogs, however, thanks to
> a patch Jim Garlick @ LLNL.  It is the first hunk of the patch at:
> 
> https://bugzilla.lustre.org/attachment.cgi?id=30441

Actually not required, as it opens the device read-only. I would recommend the 
first patch from 

https://bugzilla.lustre.org/show_bug.cgi?id=22421 

that also allows to run other e2fs tools, such as "e2fsck -n", "dumpe2fs -h" 
and "tunefs.lustre --print" on mounted devices.

Cheers,
Bernd