From mboxrd@z Thu Jan 1 00:00:00 1970 From: Reinoud Zandijk Subject: Re: Some nilfs comments Date: Mon, 22 Dec 2008 14:01:52 +0100 Message-ID: <20081222130152.GA23725@aardappel.13thmonkey.org> References: <1229568775.27170.134.camel@think.oraclecorp.com> <20081222.180719.88488712.ryusuke@osrg.net> Reply-To: NILFS Users mailing list Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20081222.180719.88488712.ryusuke-sG5X7nlA6pw@public.gmane.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: users-bounces-JrjvKiOkagjYtjvyW6yDsg@public.gmane.org Errors-To: users-bounces-JrjvKiOkagjYtjvyW6yDsg@public.gmane.org To: NILFS Users mailing list Cc: chris.mason-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org Hi Ryusuke, Chris, On Mon, Dec 22, 2008 at 06:07:19PM +0900, Ryusuke Konishi wrote: > Well, I feel that the following two matters are particularlly > questionable and need to be checked: > > - struct the_nilfs: > NILFS allows users to mount snapshots without making additional > devices or volumes. This is achieved by sharing a block device > among multiple mount instances (i.e. super_block structs). > the_nilfs struct is used for this sharing. > > This approach seems to be peculiar to nilfs, and I feel it needs > attention. I've dug into this too and decided to use the same mechanism for my implementation. I think its nice to have all the fs's administration centered at one place; i even have all the btree stuff there. One thing indeed is that its not possible to do say `unmount /dev/wd0a' if there are multiple mounts on it... but maybe thats better even ;) or its even a positive thing to just unmount all the mounts in one go. > - ioctl: > Ioctl interface (routines and structures) were implemented in an > own way. These seems to be checked whether to comply with the rules > of ioctl design. I can't comment on that yet since i haven't dug into that... > Thanks, I've also started to read btrfs. > I'll see it during the Christmas holidays ;) Whats your first impression? Want to take over things/ideas? Isn't that a quite different FS structurally since it doesn't have segments? (AFAIK!) With regards, Reinoud Zandijk