From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Chinner Subject: Re: i_version vs iversion (Was: Re: [RFC PATCH v2 1/2] Btrfs: add noi_version option to disable MS_I_VERSION) Date: Thu, 25 Jun 2015 09:59:00 +1000 Message-ID: <20150624235900.GC7943@dastard> References: <1434527672-5762-1-git-send-email-bo.li.liu@oracle.com> <20150617153306.GY6761@twin.jikos.cz> <20150617155234.GB7773@localhost.localdomain> <20150617170118.GA6761@twin.jikos.cz> <20150618024607.GA8530@localhost.localdomain> <20150618143856.GG6761@suse.cz> <20150623163241.GA6645@thunk.org> <20150624180215.GC726@suse.cz> <20150624231750.GE14324@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: dsterba-AlSwsSmVLrQ@public.gmane.org, Liu Bo , linux-btrfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, fdmanana-IBi9RG/b67k@public.gmane.org, kzak-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org, linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, mingming.cao-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org To: Theodore Ts'o Return-path: Content-Disposition: inline In-Reply-To: <20150624231750.GE14324-AKGzg7BKzIDYtjvyW6yDsg@public.gmane.org> Sender: linux-nfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-fsdevel.vger.kernel.org On Wed, Jun 24, 2015 at 07:17:50PM -0400, Theodore Ts'o wrote: > On Wed, Jun 24, 2015 at 08:02:15PM +0200, David Sterba wrote: > > > > This sounds similar to what Dave proposed, a per-inode I_VERSION > > attribute that can be changed through chattr. Though the negated meaning > > of the flag could be confusing, I had to reread the paragraph again. > > Dave did not specify an I_VERSION attribute that would be stored on > disk. Instead he talked about a inode flag that would be set when the > struct inode is created by the file system. Right. > This would allow file systems to permanently configure (on a per-inode > basis) whether or not a particular inode would require a forced > i_version update any time the inode's data or metadata is modified. I > suppose you could initialized the inode flag from an on-disk > attribute, but that wasn't implied by Dave's proposal, at least as I > understood it. It enables filesystems to do this. If btrfs want to add an on-disk flag to turn off I_VERSION on a per-inode basis, or imply it from some other on-disk flag, then they are welcome to do so and the above infrastructure change will support it. Cheers, Dave. -- Dave Chinner david-FqsqvQoI3Ljby3iVrkZq2A@public.gmane.org -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html