On Sat, Jul 14, 2018 at 11:41:05AM +1000, Dave Chinner wrote: > On Tue, Jul 10, 2018 at 04:09:42PM -0600, Ross Zwisler wrote: > > This adds a regression test for the following series: > > > > https://lists.01.org/pipermail/linux-nvdimm/2018-July/016842.html > > > > which adds synchronization between DAX DMA in ext4 and truncate/hole-punch. > > The intention of the test is to test those specific changes, but it runs > > fine both with XFS and without DAX so I've put it in the generic tests > > instead of ext4 and not restricted it to only DAX configurations. > > > > When run with v4.18-rc4 + DAX + ext4, this test will hit the following > > WARN_ON_ONCE() in dax_disassociate_entry(): > > > > WARN_ON_ONCE(trunc && page_ref_count(page) > 1); > > > > If you change this to a WARN_ON() instead, you can see that each of the > > four paths being exercised in this test hits that condition many times in > > the one second that the subtest is being run. > > > > Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> > > just a FWIW: > > > +int main(int argc, char *argv[]) > > +{ > > + int err; > > + > > + if (argc != 3) { > > + printf("Usage: %s <dax file> <non-dax file>\n", > > + basename(argv[0])); > > + exit(0); > > + } > > This is an example of why we should be supporting per-inode DAX > enablement in all filesystems, not a global mount option.... > > > +_supported_fs generic > > +_supported_os Linux > > +_require_test > > +_require_test_program "t_mmap_collision" > > + > > +# To get the failure we turn off DAX on our SCRATCH_MNT so we can get O_DIRECT > > +# behavior. We will continue to use unmodified mount options for the test > > +# TEST_DIR. The failures fixed by the above mentioned kernel patch trigger > > +# when those mount options include "-o dax", but the test runs fine without > > +# that option so we don't require it. > > +export MOUNT_OPTIONS="" > > +_scratch_unmount >> $seqres.full 2>&1 > > +_scratch_mount >> $seqres.full 2>&1 > > And then all this crap would go away.... Yep, I totally agree. :)
