Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx2.netapp.com ([216.240.18.37]:33588 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751031Ab3EHSne convert rfc822-to-8bit (ORCPT ); Wed, 8 May 2013 14:43:34 -0400 From: "Myklebust, Trond" To: Steve Dickson CC: "J. Bruce Fields" , "David P. Quigley" , Linux NFS list , "Linux FS devel list" , Linux Security List , SELinux List Subject: Re: [PATCH 09/17] NFSv4: Introduce new label structure Date: Wed, 8 May 2013 18:06:24 +0000 Message-ID: <1368036382.5978.24.camel@leira.trondhjem.org> References: <1367240239-19326-1-git-send-email-SteveD@redhat.com> <1367240239-19326-10-git-send-email-SteveD@redhat.com> <1367434764.4189.33.camel@leira.trondhjem.org> <518A8C3D.9000407@RedHat.com> In-Reply-To: <518A8C3D.9000407@RedHat.com> Content-Type: text/plain; charset=US-ASCII MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Wed, 2013-05-08 at 13:32 -0400, Steve Dickson wrote: > On 01/05/13 14:59, Myklebust, Trond wrote: > >> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h > >> > index 9f2dba3..4d2fdf6 100644 > >> > --- a/include/linux/nfs_xdr.h > >> > +++ b/include/linux/nfs_xdr.h > >> > @@ -351,6 +351,7 @@ struct nfs_openargs { > >> > const u32 * bitmask; > >> > const u32 * open_bitmap; > >> > __u32 claim; > >> > + const struct nfs4_label *label; > >> > }; > >> > > >> > struct nfs_openres { > >> > @@ -360,6 +361,7 @@ struct nfs_openres { > >> > struct nfs4_change_info cinfo; > >> > __u32 rflags; > >> > struct nfs_fattr * f_attr; > >> > + struct nfs4_label *f_label; > >> > struct nfs_seqid * seqid; > >> > const struct nfs_server *server; > >> > fmode_t delegation_type; > >> > @@ -404,6 +406,7 @@ struct nfs_closeres { > >> > struct nfs4_sequence_res seq_res; > >> > nfs4_stateid stateid; > >> > struct nfs_fattr * fattr; > >> > + struct nfs4_label *label; > >> > struct nfs_seqid * seqid; > >> > const struct nfs_server *server; > >> > }; > >> > @@ -477,6 +480,7 @@ struct nfs4_delegreturnargs { > >> > struct nfs4_delegreturnres { > >> > struct nfs4_sequence_res seq_res; > >> > struct nfs_fattr * fattr; > >> > + struct nfs4_label *label; > >> > const struct nfs_server *server; > >> > }; > >> > > >> > @@ -497,6 +501,7 @@ struct nfs_readargs { > >> > struct nfs_readres { > >> > struct nfs4_sequence_res seq_res; > >> > struct nfs_fattr * fattr; > >> > + struct nfs4_label *label; > > Why do we need to check labels on close, delegreturn, read, remove, > > rename, etc? > All of these have GETATTR in the compound they send out. So I'm > assuming to keep consistence, the label bit needs to be set > on all *most* of the GEATTRs. Ones that actually nfs_refresh_inode() > the inode. We need to distinguish between cache consistency GETATTRs, and metadata refresh GETATTRs. Cache consistency GETATTRs are basically all about making sure that we're keeping the change_attribute (and size) up to date so that we know whether or not the data and metadata caches are correct. Metadata refresh GETATTRs are sent if we know or suspect that our cached metadata is incorrect, and we need to _use_ some of that cached data (in a stat() syscall, or as part of a path lookup or an open()). > > Do any of those operations cause our cached labels to change? > Not the label but the inode. The bit is set in ACCESS, LOOKUP, > LINK, OPEN, CREAT, SETATTR which all clearly update the inode. > > So I guess my question is if the bit is not set in any of these > ops how do we know if the label has changed? Should label changes > be synchronized with inode updates? I know that Bruce doesn't like FATTR4_CHANGE_SEC_LABEL, but that is the only option I can see for implementing a cache consistency model for labels. Without it, the choices are: 1) always fetch the label as part of every COMPOUND. 2) assume the label never changes on the server. The main use cases that have been presented for Labeled NFS on Linux would tend to push me towards door number 2, Monty please... -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com