On Sat, Jan 08, 2022 at 09:12:08AM -0800, Hugh Dickins wrote:
> On Fri, 7 Jan 2022, Matthew Wilcox wrote:
> > On Sun, Jan 02, 2022 at 05:34:05PM -0800, Hugh Dickins wrote:
> > > xfstests generic 098 214 263 286 412 used to pass on huge tmpfs (well,
> > > three of those _require_odirect, enabled by a shmem_direct_IO() stub),
> > > but still fail even with the partial_end fix.
> > >
> > > generic/098 output mismatch shows actual data loss:
> > > --- tests/generic/098.out
> > > +++ /home/hughd/xfstests/results//generic/098.out.bad
> > > @@ -4,9 +4,7 @@
> > > wrote 32768/32768 bytes at offset 262144
> > > XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> > > File content after remount:
> > > -0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
> > > -*
> > > -0400000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> > > +0000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> > > ...
> >
> > generic/098 is passing for me ;-( I'm using 'always' for THPs.
> > I'll have to try harder. Regardless, I think your fix is good ...
>
> Worrying that the test behaves differently. Your 'always':
> you have '-o huge=always' in the exported TMPFS_MOUNT_OPTIONS?
> That should be enough, but I admit to belt and braces by also
> echo force > /sys/kernel/mm/transparent_hugepage/shmem_enabled
Ah, I hadn't done TMPFS_MOUNT_OPTIONS, just the
echo always >/sys/kernel/mm/transparent_hugepage/shmem_enabled
Adding TMPFS_MOUNT_OPTIONS and retrying with what I originally posted
reproduces the bug. Retrying with the current for-next branch doesn't.
So now I can confirm that there was a bug and your patch fixed it.
And maybe I can avoid introducing more bugs of this nature in the future.
