Re: [PATCH] xfstests: unmount scratch mnt in test 307

[Dave Chinner <david@fromorbit.com>]

On Fri, May 03, 2013 at 03:15:01PM -0500, Eric Sandeen wrote:
> On 5/3/13 3:11 PM, Josef Bacik wrote:
> > So if you have a mount command that doesn't use /etc/mtab then it will spit out
> > a different device for the mounted device.  So say we have
> > 
> > SCRATCH_DEV_POOL="/dev/sda /dev/sdb /dev/sdc"
> > 
> > we will turn this into
> > 
> > SCRATCH_DEV="/dev/sda"
> > SCRATCH_DEV_POOL="/dev/sdb /dev/sdc"
> > 
> > and then when you mkfs this you do _scratch_mkfs $SCRATCH_DEV_POOL which turns
> > into this
> > 
> > mkfs.btrfs /dev/sdb /dev/sdc /dev/sda
> > 
> > becuase we do
> > 
> > mkfs $* $SCRATCH_DEV
> > 
> > Then btrfs will always show the lowest devid in /proc/mounts to maintain
> > consistency, so even though we do mount /dev/sda $SCRATCH_MNT, you will see
> > /dev/sdb as the mounted device in /proc/mounts.  So then say the next test wants
> > to just use $SCRATCH_DEV, it will do _require_scratchdev which will check to see
> > if $SCRATCH_DEV is mounted, which it will look like it is not because
> > /proc/mounts shows /dev/sdb instead of /dev/sda, and so it won't umount
> > $SCRATCH_MNT, and then that test will fail because we can't mkfs the device
> > because it is busy.  I reproduced this on a box that doesn't use /etc/mtab by
> > doing
> > 
> > ./check btrfs/307 generic/015
> > 
> > and 015 would fail.  With this patch it passes now.  Thanks,
> > 
> > Signed-off-by: Josef Bacik <jbacik@fusionio.com>
> > ---
> >  tests/btrfs/307 |    1 +
> >  1 files changed, 1 insertions(+), 0 deletions(-)
> > 
> > diff --git a/tests/btrfs/307 b/tests/btrfs/307
> > index 87314c6..15157b3 100644
> > --- a/tests/btrfs/307
> > +++ b/tests/btrfs/307
> > @@ -35,6 +35,7 @@ _cleanup()
> >  {
> >      cd /
> >      rm -f $tmp.*
> > +    umount $SCRATCH_MNT
> >  }
> >  
> >  # get standard environment, filters and checks
> > 
> 
> This seems fine for this particular test.
> 
> Is it really a hard requirement that each test unmount SCRATCH_[DEV|MNT] if it used it?
> If so, fine... the README does indicate this.
> 
> But I wonder if we can make it a little more foolproof by updating _require_scratch
> to handle this situation more gracefully?

It already tries to unmount $SCRATCH_DEV, and will through an error
if it's not mounted on $SCRATCH_MNT. I guess the opposite checks are
necessary in this case i.e. check that SCRATCH_MNT is not mounted,
and through an error if it's not SCRATCH_DEV that is mounted
there...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com