linux-kernel - OFD ("file private") locks and NFS

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 29 Apr 2014 10:38:54 +0200
From:	"Michael Kerrisk (man-pages)" <mtk.manpages@...il.com>
To:	Jeff Layton <jlayton@...hat.com>
CC:	mtk.manpages@...il.com,
	Ganesha NFS List <nfs-ganesha-devel@...ts.sourceforge.net>,
	lkml <linux-kernel@...r.kernel.org>,
	Linux-Fsdevel <linux-fsdevel@...r.kernel.org>,
	Trond Myklebust <trond.myklebust@....uio.no>,
	"J. Bruce Fields" <bfields@...ldses.org>,
	Neil Brown <neilb@...e.de>, samba-technical@...ts.samba.org,
	"Michael Kerrisk (gmail)" <mtk.manpages@...il.com>
Subject: OFD ("file private") locks and NFS

Hi Jeff,

I've been looking a bit at the fcntl() documentation of traditional 
(F_SETLK) record locking, and a question just jumped out at me. Is 
it worth considering some future-proofing in the design of OFD locks
("open file description locks", formerly known as "file-private locks")?

What I am thinking of here is that on some systems, the traditional
'struct flock' has a nonstandard field, l_sysid, that is used on F_GETLK 
to identify the remote system on which a lock is held. Should the design
of OFD locks allow for such a field (now, or in the future), which might 
be useful in the context of locking on network file systems such as NFS.

Put more simply, should the new OFD locking system be using a new
structure for describing locks, rather than the traditional 'struct
flock'? Defining a new structure, might be useful to allow for
future extensions to the API.

Cheers,

Michael

-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/