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

[Eric Sandeen <sandeen@redhat.com>]

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?

-Eric