From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joel Becker Subject: Re: [RFC 0/13] extents and 48bit ext3 Date: Fri, 9 Jun 2006 14:29:05 -0700 Message-ID: <20060609212905.GK3574@ca-server1.us.oracle.com> References: <1149880865.22124.70.camel@localhost.localdomain> <4489CB42.6020709@garzik.org> <20060609204418.GG3574@ca-server1.us.oracle.com> <20060609211123.GI3574@ca-server1.us.oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Andrew Morton , Jeff Garzik , ext2-devel , linux-kernel@vger.kernel.org, Chase Venters , cmm@us.ibm.com, linux-fsdevel@vger.kernel.org, Andreas Dilger , Alan Cox Return-path: To: Alex Tomas Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: ext2-devel-bounces@lists.sourceforge.net Errors-To: ext2-devel-bounces@lists.sourceforge.net List-Id: linux-fsdevel.vger.kernel.org On Sat, Jun 10, 2006 at 01:20:31AM +0400, Alex Tomas wrote: > two point here: > a) warnings should be made visible at mount time, > something like printk(KERN_CRIT ...) Too late, they're already broken! > b) I don't think you're going to fight all crazy people in the world, > they'll definitely find a way to break something: > data or something else. Certainly not the crazy people. But the random person who's just humming along? We should be nice to them. > PS. in the end, "extents" option affects *new* files only. and one > can boot extents-enabled kernel and convert fs back. I just mentioned to Ted in another mail, since this is a "permanent" change to the on-disk structure, why is this a mount option? Shouldn't it rather be a tunefs(8)/mkfs(8) option? In general, anything you pass to "mount -o" is optional. You can mount with option X, then unmount and mount without option X. Most people "expect" this to work (Principle of Least Surprise). So, when you do: # mount -o extents /fs1 # create_file /fs1/newfile # umount /fs1 # mount /fs1 it breaks. Lease Surprise expects it to work. However, tunefs(8) and mkfs(8) is generally understood to make physical changes. Why not "tunefs -extents" to turn them on? It's completely analogous to "tunefs -J", will fit everyone's expectation, and won't surprise people. "mkfs -extents" does the same thing. Joel -- Life's Little Instruction Book #232 "Keep your promises." Joel Becker Principal Software Developer Oracle E-mail: joel.becker@oracle.com Phone: (650) 506-8127