Re: Flaky test: generic:269 (EBUSY on umount)

["Darrick J. Wong" <djwong@kernel.org>]

On Thu, Jun 13, 2024 at 10:56:39PM +0100, Theodore Ts'o wrote:
> On Wed, Jun 12, 2024 at 12:41:36PM -0700, Darrick J. Wong wrote:
> > 
> > I don't see this problem; if you apply this to fstests to turn off
> > io_uring:
> > https://lore.kernel.org/fstests/169335095953.3534600.16325849760213190849.stgit@frogsfrogsfrogs/#r
> > 
> > do the problems go away?
> 
> Thanks for pointing out the mail thread; I had a vague memory that
> this had been raised as a problem before.  Looking at the discussion
> (from August 2023, so over 9 months ago), this is a bug that has been
> acknowledged as an io_uring bug, but it still hasn't been fixed.
> 
> Using Zorro's sugestion of adding "-f uring_read=0 -f uring_write=0"
> to the fsstress options makes the EBUSY umount failures go away.  I've
> also created a new test which relaibly reproduces the "fsstress ;
> umount" EBUSY bug (as opposed to the existing test failures which only
> fail 1-10% of the time).  So with that I can with a clean conscience
> suggest that we omit io_uring calls from those tests using fsstress to
> thest some non-io_uring related bug if they run into the umount EBUSY
> bug, since there is now a new bug which reliably shows off the
> problem....

Amusingly enough, I still have that patch (and generic/1220) in my
fstests branch, and I haven't seen this problem happen on g/1220 in
quite a while.

--D
> 
> 						- Ted