From: Steve Dickson Subject: Re: [PATCH] nfs(5): document new local_lock option Date: Wed, 29 Sep 2010 07:16:16 -0400 Message-ID: <4CA32000.8040906@RedHat.com> References: <4C9BA266.1040102@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: Linux NFS mailing list , trond.myklebust@netapp.com To: Suresh Jayaraman Return-path: Received: from mx1.redhat.com ([209.132.183.28]:42188 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753260Ab0I2LQU (ORCPT ); Wed, 29 Sep 2010 07:16:20 -0400 In-Reply-To: <4C9BA266.1040102@suse.de> Sender: linux-nfs-owner@vger.kernel.org List-ID: On 09/23/2010 02:54 PM, Suresh Jayaraman wrote: > Kernel 2.6.37 would most likely add a new mount option: local_lock. > Document the new option in the nfs(5) man page. > > Signed-off-by: Suresh Jayaraman Committed... steved. > --- > utils/mount/nfs.man | 44 ++++++++++++++++++++++++++++++++++++++++++++ > 1 files changed, 44 insertions(+), 0 deletions(-) > > diff --git a/utils/mount/nfs.man b/utils/mount/nfs.man > index 55d4b55..d2a4c5f 100644 > --- a/utils/mount/nfs.man > +++ b/utils/mount/nfs.man > @@ -717,6 +717,50 @@ If this option is not specified, the NFS client uses READDIRPLUS requests > on NFS version 3 mounts to read small directories. > Some applications perform better if the client uses only READDIR requests > for all directories. > +.TP 1.5i > +.BR local_lock= mechanism > +Specifies whether to use local locking for any or both of the flock and the > +POSIX locking mechanisms. > +.I mechanism > +can be one of > +.BR all , > +.BR flock , > +.BR posix , > +or > +.BR none . > +This option is supported in kernels 2.6.37 and later. > +.IP > +The Linux NFS client provides a way to make locks local. This means, the > +applications can lock files, but such locks provide exclusion only against > +other applications running on the same client. Remote applications are not > +affected by these locks. > +.IP > +If this option is not specified, or if > +.B none > +is specified, the client assumes that the locks are not local. > +.IP > +If > +.BR all > +is specified, the client assumes that both flock and POSIX locks are local. > +.IP > +If > +.BR flock > +is specified, the client assumes that only flock locks are local and uses > +NLM sideband protocol to lock files when POSIX locks are used. > +.IP > +If > +.BR posix > +is specified, the client assumes that POSIX locks are local and uses NLM > +sideband protocol to lock files when flock locks are used. > +.IP > +To support legacy flock behavior similar to that of NFS clients < 2.6.12, use > +'local_lock=flock'. This option is required when exporting NFS mounts via > +Samba as Samba maps Windows share mode locks as flock. Since NFS clients > > +2.6.12 implement flock by emulating POSIX locks, this will result in > +conflicting locks. > +.IP > +NOTE: When used together, the 'local_lock' mount option will be overridden > +by 'nolock'/'lock' mount option. > .SS "Options for version 4 only" > Use these options, along with the options in the first subsection above, > for NFSv4 only. They will be ignored with older versions.