From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mingming Cao Subject: Re: [RFC][PATCH 06/10] cifs: define inode-level cache object and register them Date: Fri, 25 Jun 2010 17:52:24 -0700 Message-ID: References: <20100625125306.7f9b1966@tlielax.poochiereds.net> <4C24A606.5040001@suse.de> <1277220214-3597-1-git-send-email-sjayaraman@suse.de> <9822.1277312573@redhat.com> <22697.1277470549@redhat.com> <18628.1277502398@redhat.com> <20100625182651.36800d06@tlielax.poochiereds.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: linux-cifs@vger.kernel.org, Jeff Layton , samba-technical@lists.samba.org, linux-kernel@vger.kernel.org, David Howells , linux-fsdevel@vger.kernel.org, "Aneesh Kumar K.V" To: Steve French Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: samba-technical-bounces@lists.samba.org Errors-To: samba-technical-bounces@lists.samba.org List-Id: linux-cifs.vger.kernel.org Steve French wrote on 06/25/2010 04:05:30 PM: > Steve French > 06/25/2010 04:05 PM > > To > > Jeff Layton , "Aneesh Kumar K.V" > , Mingming Cao/Beaverton/IBM@IBMUS > > cc > > David Howells , Suresh Jayaraman > , linux-cifs@vger.kernel.org, linux- > fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, samba- > technical@lists.samba.org, Jeff Layton > > Subject > > Re: [RFC][PATCH 06/10] cifs: define inode-level cache object and > register them > > On Fri, Jun 25, 2010 at 5:26 PM, Jeff Layton wrot= e: > > > > On Fri, 25 Jun 2010 22:46:38 +0100 > > David Howells wrote: > > > > > Jeff Layton wrote: > > > > > > > Looks like it mostly uses the ctime. IMO, the mtime would be a better > > > > choice since it changes less frequently, but I don't guess that= it > > > > matters very much. > > > > > > I'd've thought mtime changes more frequently since that's > altered when data is > > > written. =A0ctime is changed when attributes are changed. > > > > > > > IIUC, updating mtime for a write is also an attribute change, and t= hat > > affects ctime. According to the stat(2) manpage: > > > > =A0 =A0 =A0 The field st_ctime is changed by writing or by setting > =A0inode =A0informa- > > =A0 =A0 =A0 tion (i.e., owner, group, link count, mode, etc.). > > > > > Note that Ext4 appears to have a file creation time field in its inode > > > (struct ext4_inode::i_crtime[_extra]). =A0Can Samba be made to us= e that? > > > > > > > Is it exposed to userspace in any (standard) way? It would be handy= to > > have that. While we're wishing...it might also be nice to have a > > standard way to get at the i_generation from userspace too. > > > > Yes - I have talked with MingMing and Aneesh about those (NFS may > someday be able to use those too).=A0 An obstacle in the past had bee= n > that samba server stores its own fake creation time in an ndr encoded= > xattr which complicates things. > > MingMing/Annesh - > Xattr or other way to get at birth time? > > Not yet, The ext4 file creation time only accesable from the kernel at the mome= nt. There were discussion to make this information avaliable via xattr before, but was rejected, since most people agree that making this info avalibele via stat() is more standard. Howe= ver modifying stat() would imply big interface change. thus no action has been taken yet. > -- > Thanks, > > Steve=