From: Jeff Layton Subject: Re: [fuse-devel] [PATCH 01/25] VFS: move attr_kill logic from notify_change into helper function Date: Mon, 6 Aug 2007 14:13:33 -0400 Message-ID: <20070806141333.0f54ab17.jlayton@redhat.com> References: <200708061354.l76Ds6sq002260@dantu.rdu.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: codalist@TELEMANN.coda.cs.cmu.edu, dhowells@redhat.com, jfs-discussion@lists.sourceforge.net, jffs-dev@axis.com, reiserfs-devel@vger.kernel.org, zippel@linux-m68k.org, user-mode-linux-user@lists.sourceforge.net, linux-kernel@vger.kernel.org, wli@holomorphy.com, xfs@oss.sgi.com, cluster-devel@redhat.com, fuse-devel@lists.sourceforge.net, joel.becker@oracle.com, mikulas@artax.karlin.mff.cuni.cz, linux-fsdevel@vger.kernel.org, v9fs-developer@lists.sourceforge.net, linux-ext4@vger.kernel.org, linux-cifs-client@lists.samba.org, ocfs2-devel@oss.oracle.com, bfennema@falcon.csc.calpoly.edu To: Miklos Szeredi Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: cluster-devel-bounces@redhat.com Errors-To: cluster-devel-bounces@redhat.com List-Id: linux-ext4.vger.kernel.org On Mon, 06 Aug 2007 19:43:46 +0200 Miklos Szeredi wrote: > > Separate the handling of the local ia_valid bitmask from the one in > > attr->ia_valid. This allows us to hand off the actual handling of the > > ATTR_KILL_* flags to the .setattr i_op when one is defined. > > > > notify_change still needs to process those flags for the local ia_valid > > variable, since it uses that to decide whether to return early, and to pass > > a (hopefully) appropriate bitmask to fsnotify_change. > > I agree with this change and fuse will make use of it as well. > > Maybe instead of unconditionally moving attr_kill_to_mode() inside > ->setattr() it could be made conditional based on an inode flag > similarly to S_NOCMTIME. Advantages: > > - no need to modify a lot of in-tree filesystems > - no silent breakage of out-of-tree fs > > Actually I think the new flag would be used by exacly the same > filesystems as S_NOCMTIME, so maybe it would make sense to rename > S_NOCMTIME to something more generic (S_NOATTRUPDATE or whatever) and > use that. > > But that could still break out-of-tree fs, so a separate flag is > probably better. > In the past I've been told that adding new flags is something of a "last resort". Since it's not strictly necessary to fix this then it may be best to avoid that. That said, if the concensus is that we need a transition mechanism, then I'd be open to such a suggestion. -- Jeff Layton