On Fri, 25 Jun 2010 17:52:24 -0700, Mingming Cao <mcao@xxxxxxxxxx> wrote: > > > Steve French <smfrench@xxxxxxxxx> wrote on 06/25/2010 04:05:30 PM: > > > Steve French <smfrench@xxxxxxxxx> > > 06/25/2010 04:05 PM > > > > To > > > > Jeff Layton <jlayton@xxxxxxxxx>, "Aneesh Kumar K.V" > > <aneesh.kumar@xxxxxxxxxxxxxxxxxx>, Mingming Cao/Beaverton/IBM@IBMUS > > > > cc > > > > David Howells <dhowells@xxxxxxxxxx>, Suresh Jayaraman > > <sjayaraman@xxxxxxx>, linux-cifs@xxxxxxxxxxxxxxx, linux- > > fsdevel@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, samba- > > technical@xxxxxxxxxxxxxxx, Jeff Layton <jlayton@xxxxxxxxxx> > > > > 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 <jlayton@xxxxxxxxx> wrote: > > > > > > On Fri, 25 Jun 2010 22:46:38 +0100 > > > David Howells <dhowells@xxxxxxxxxx> wrote: > > > > > > > Jeff Layton <jlayton@xxxxxxxxx> 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. ctime is changed when attributes are changed. > > > > > > > > > > IIUC, updating mtime for a write is also an attribute change, and that > > > affects ctime. According to the stat(2) manpage: > > > > > > The field st_ctime is changed by writing or by setting > > inode informa- > > > 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]). Can Samba be made to use > 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). An obstacle in the past had been > > 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 moment. > 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. However > modifying stat() would imply > big interface change. thus no action has been taken yet. NFS ganesha pNFS also had a requirement for getting i_generation and inode number in userspace. So may be we should now look at updating stat or add a variant syscall that include i_generation and create time in the return value -aneesh -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
