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

["Theodore Ts'o" <tytso@mit.edu>]

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....

						- Ted