[Fedora-livecd-list] Patch for BZ# 509427

[Jasper Hartline]

On Fri, Jul 23, 2010 at 9:41 PM, Bruno Wolff III <bruno at wolff.to> wrote:
> It looks like it can cause problems in the general case, but I think where
> it isn't expected that outside processes will be using stuff, as is the
> case for livecd creator, it shouldn't hurt.

It doesn't hurt in the general case for livecd-creator, and from my testing
allows livecd-creator to clean up after it's self properly when exceptions
sprout up from deeper within buildTransaction() which causes the
domino effect, and
finally also causes livecd-creator to not be able to clean up properly.

> Do you know if the issue is umounting in the wrong order or missing umounts?
> I would expect this patch to fix umounting stuff in the wrong order, but
> if a umount is missed, then I wouldn't expect the umount to succeed without
> manual intervention. That would be no worse than today, but wouldn't be
> a big help either.

No. livecd-creator does everything in the correct order, at the correct times
except when exceptions bubble up from deep within buildTransaction().
cleanup() in livecd-creator already works fine, until something deeper
causes an exception
which with Python and livecd-creator holding on to filedescriptors
until it exits, cannot unmount
when it catches those exceptions because the filesystem is busy.

Using the lazy umount fixes the problem that livecd-creator cannot
clean up properly when it
runs into a problem, and this maybe the only way to handle this
scenario properly for
umount/cleanup.