Re: [PATCH fs/locks 2 of 3] Use proper tgid in locks_remove_posix

[Olaf Kirch <okir@suse.de>]

On Mon, Jul 11, 2005 at 08:16:57AM -0400, Trond Myklebust wrote:
> m=E5 den 11.07.2005 Klokka 12:32 (+0200) skreiv Olaf Kirch:
> > # Subject: [NFS] Use proper tgid in locks_remove_posix
> > #=20
> > # This patch fixes a problem with lost unlock calls in multithreaded
> > # applications. locks_remove_posix would send a single unlock call wi=
th
> > # the task group ID of the current process, which may not be the same=
 as
> > # the tgid of the lock. This patch ensures that we send separate unlo=
ck
> > # calls for different fl_pid values.
>=20
> This doesn't look right. Why should a thread be killing locks that
> belong to a different process?

locks_remove_posix is called when we close a file, i.e. when it is remove=
d
from current->files. The problem arises when the files struct is shared
by several threads with different tgid (which seems to be the default
when using pthreads) - in this case we must make sure we send the
unlock call with the right tgid. Previously we would send the unlock call
using fl_pid =3D current->tgid.

Olaf
--=20
Olaf Kirch   |  --- o --- Nous sommes du soleil we love when we play
okir@suse.de |    / | \   sol.dhoop.naytheet.ah kin.ir.samse.qurax


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