Re: xfstest 531 and unlink of open file

[Jeremy Allison <jra@samba.org>]

On Mon, Jun 24, 2019 at 01:44:53PM +1000, ronnie sahlberg via samba-technical wrote:
> On Mon, Jun 24, 2019 at 1:23 PM Steve French <smfrench@gmail.com> wrote:
> >
> > Xioli created a fairly simple unlink test failure reproducer loosely
> > related to xfstest 531 (see
> > https://bugzilla.kernel.org/show_bug.cgi?id=203271) which unlinks an
> > open file then tries to create a file with the same name before
> > closing the first file (which fails over SMB3/SMB3.11 mounts with
> > STATUS_DELETE_PENDING).
> >
> > Presumably we could work around this by a "silly-rename" trick.
> > During delete we set delete on close for the file, then close it but
> > presumably we could check first if the file is open by another local
> > process and if so try to rename it?
> >
> > Ideas?
> 
> The test is to check "can you unlink and recreate a file while someone
> (else) is holding it open?"
> 
> I don't think you can rename() a file while other folks have it open :-(
> This is likely a place where NTFS is too different from Posix that we
> can't get full 100% posix semantics.

Yeah, this is one of the places you need SMB3+ POSIX extensions
(and even there we fail it if a Windows open exists on the same
handle).