Re: [PATCH v2 6/6] tests/9p: Test `Tsetattr` can truncate unlinked file

[Christian Schoenebeck <qemu_oss@crudebyte.com>]

On Wednesday, March 12, 2025 3:25:20 PM CET Greg Kurz wrote:
> On Wed, 12 Mar 2025 15:11:41 +0100
> Christian Schoenebeck <qemu_oss@crudebyte.com> wrote:
> 
> > On Tuesday, March 11, 2025 6:28:09 PM CET Greg Kurz wrote:
> > > Enhance the `use-after-unlink` test with a new check for the
> > > case where the client wants to alter the size of an unlinked
> > > file for which it still has an active fid.
> > > 
> > > Suggested-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
> > > Signed-off-by: Greg Kurz <groug@kaod.org>
> > > ---
> > >  tests/qtest/virtio-9p-test.c | 8 ++++++++
> > >  1 file changed, 8 insertions(+)
> > > 
> > > diff --git a/tests/qtest/virtio-9p-test.c b/tests/qtest/virtio-9p-test.c
> > > index f515a9bb157b..20c0d744fa56 100644
> > > --- a/tests/qtest/virtio-9p-test.c
> > > +++ b/tests/qtest/virtio-9p-test.c
> > > @@ -736,6 +736,14 @@ static void fs_use_after_unlink(void *obj, void *data,
> > >          .data = buf
> > >      }).count;
> > >      g_assert_cmpint(count, ==, write_count);
> > > +
> > > +    /* truncate file to (arbitrarily chosen) size 2001 */
> > > +    tsetattr({
> > > +        .client = v9p, .fid = fid_file, .attr = (v9fs_attr) {
> > > +            .valid = P9_SETATTR_SIZE,
> > > +            .size = 2001
> > > +        }
> > > +     });
> > >  }
> > >  
> > >  static void cleanup_9p_local_driver(void *data)
> > > 
> > 
> > Ah, I just meant the code snippet as a starting point, like I would have also
> > checked with a stat() call whether 9p server really did what it promised.
> > 
> > But OK, better some test coverage than nothing. :)
> > 
> 
> FWIW the server returns ENOENT if it doesn't have the fix which causes
> the check to fail. I was assuming this would be enough but I'm fine with
> adding an extra check if you want.

Yeah, that's why I wasn't really anxious about it. If you have some cycles,
fine, I'll guess you can just copy & paste existing stat() code from another
test, otherwise deferred into future, NP.

Thanks!

/Christian