From: Bernd Schubert Subject: Re: Extended file stat: Splitting file- and fs-specific info? Date: Wed, 09 May 2012 14:25:20 +0200 Message-ID: <4FAA6230.7040700@itwm.fraunhofer.de> References: <20120509002420.GL5091@dastard> <20120419140558.17272.74360.stgit@warthog.procyon.org.uk> <16281.1336508382@redhat.com> <20170.1336555274@redhat.com> <20120509111958.GA11345@infradead.org> <4FAA5B24.1020306@itwm.fraunhofer.de> <20120509120544.GA17535@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: David Howells , Dave Chinner , adilger-m1MBpc4rdrD3fQ9qLvQP4Q@public.gmane.org, bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org, smfrench-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, ben-/+tVBieCtBitmTQ+vhA3Yw@public.gmane.org, Trond.Myklebust-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org, roland-/Z5OmTQCD9xF6kxbq+BtvQ@public.gmane.org, jra-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, samba-technical-w/Ol4Ecudpl8XjKLYN78aQ@public.gmane.org, linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, libc-alpha-9JcytcrH/bA+uJoB2kUjGw@public.gmane.org To: Christoph Hellwig Return-path: In-Reply-To: <20120509120544.GA17535-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org> Sender: linux-cifs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-ext4.vger.kernel.org On 05/09/2012 02:05 PM, Christoph Hellwig wrote: > On Wed, May 09, 2012 at 01:55:16PM +0200, Bernd Schubert wrote: >> The basic idea of generation numbers is to check if an inode was >> recycled, so only if the tuple of inode-number and generation-number >> matches we still have the same file. Kernel nfs > > NFS does not and should not look at the inode generation. Except for a > bit of legacy code for the old pre-Linux 2.4 filehandles it looks at the > opaque file handle returned and only interpreted by the filesystem. Any > userspace NFS server should do the same. Ok, I didn't look how kernel NFS does it for quite some time already... User space NFS only can do it beginning with 2.6.39 - given that user space also needs to support older kernels and other OSs, which might not have open_by_handle, userspace unfortunately cannot entirely rely on that feature. Cheers, Bernd