From: Trond Myklebust <Trond.Myklebust@netapp.com>
To: Suresh Jayaraman <sjayaraman@suse.de>
Cc: Jeff Layton <jlayton@redhat.com>,
Linux NFS mailing list <linux-nfs@vger.kernel.org>,
Neil Brown <neilb@suse.de>
Subject: Re: [PATCH] nfs: introduce mount option '-olocal_lock' to make locks local
Date: Thu, 09 Sep 2010 21:44:23 -0400 [thread overview]
Message-ID: <1284083063.2764.12.camel@heimdal.trondhjem.org> (raw)
In-Reply-To: <4C896A59.8060903@suse.de>
On Fri, 2010-09-10 at 04:44 +0530, Suresh Jayaraman wrote:
> On 09/10/2010 01:50 AM, Jeff Layton wrote:
> > On Fri, 10 Sep 2010 01:06:38 +0530
> > Suresh Jayaraman <sjayaraman@suse.de> wrote:
> >
> >> NFS clients since 2.6.12 support flock locks by emulating fcntl byte-range
> >> locks. Due to this, some windows applications which seem to use both flock
> >> (share mode lock mapped as flock by Samba) and fcntl locks sequentially on
> >> the same file, can't lock as they falsely assume the file is already locked.
> >> The problem was reported on a setup with windows clients accessing excel files
> >> on a Samba exported share which is originally a NFS mount from a NetApp filer.
> >>
> >> Older NFS clients (< 2.6.12) did not see this problem as flock locks were
> >> considered local. To support legacy flock behavior, this patch adds a mount
> >> option "-olocal_lock=" which can take the following values:
> >>
> >> 'none' - Neither flock locks or fcntl/posix locks are local
> >> 'flock'/'posix' - flock locks are local
> > ^^^^^^^
> > "posix" ought to be synonymous with "fcntl". "flock" was a BSD-ism.
>
> Oops, that should have read 'fcntl/posix' (though the code gets it right)..
Yup. It appears to be a changelog bug...
> > It may be better to keep it simple though and drop either "posix" or
> > "fcntl". No need to add unneeded synonyms on a brand new mount option.
>
> Makes sense.. Trond: which one is more consistent?
I have a slight preference for 'posix'. fcntl is an extensible
interface, which currently supports at least two different types of lock
('posix' and 'lease').
> >> 'fcntl' - fcntl locks are local
> >> 'all' - Both flock locks and fcntl/posix locks are local
> >>
Cheers
Trond
next prev parent reply other threads:[~2010-09-10 1:44 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-09 19:36 [PATCH] nfs: introduce mount option '-olocal_lock' to make locks local Suresh Jayaraman
2010-09-09 20:20 ` Jeff Layton
2010-09-09 23:14 ` Suresh Jayaraman
2010-09-10 1:44 ` Trond Myklebust [this message]
2010-09-10 4:07 ` Suresh Jayaraman
2010-09-10 4:24 ` Neil Brown
2010-09-10 6:09 ` Suresh Jayaraman
2010-09-14 5:06 ` Suresh Jayaraman
-- strict thread matches above, loose matches on Subject: below --
2010-09-16 6:14 Suresh Jayaraman
2010-09-17 22:15 ` Trond Myklebust
2010-09-20 9:27 ` Suresh Jayaraman
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