From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.11] helo=sc8-sf-mx1.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1BBWF3-0000Cc-9j for user-mode-linux-devel@lists.sourceforge.net; Thu, 08 Apr 2004 02:54:37 -0700 Received: from userbb201.dsl.pipex.com ([62.190.241.201] helo=irishsea.home.craig-wood.com) by sc8-sf-mx1.sourceforge.net with esmtp (Exim 4.30) id 1BBWF2-00063f-7E for user-mode-linux-devel@lists.sourceforge.net; Thu, 08 Apr 2004 02:54:36 -0700 From: Nick Craig-Wood Subject: Re: [uml-devel] A quick humfs HOWTO Message-ID: <20040408095432.GA10043@axis.demon.co.uk> References: <200404080207.i3827rbe009294@ccure.user-mode-linux.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200404080207.i3827rbe009294@ccure.user-mode-linux.org> Sender: user-mode-linux-devel-admin@lists.sourceforge.net Errors-To: user-mode-linux-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: The user-mode Linux development list List-Post: List-Help: List-Subscribe: , List-Archive: Date: Thu, 8 Apr 2004 10:54:32 +0100 To: Jeff Dike Cc: user-mode-linux-devel@lists.sourceforge.net On Wed, Apr 07, 2004 at 10:07:52PM -0400, Jeff Dike wrote: > As the readers of uml-devel are aware by now, there is a new virtual UML > filesystem called humfs. Sounds like a good solution to lots of problems to me ;-) Do you think it is easy / possible to make UML boot off a loop mounted filesystem which is stored in humfs? This would be an easy migration path... > The superblock file has the format > "version \nused \ntotal \n" > > The version is currently 1. used is set to the disk space consumed by > everything in the data directory. total is set arbitrarily when you set > up the filesystem. It is the size of the filesystem as seen within > UML. Does uml actually obey this total in the superblock? Ie does this setting act as a quota? And an idea... Why not make each of the files in the metadata directory a symlink and store the metadata in the symlink itself? I believe that there is room in the inode for short symlinks so you'll save inodes there. Lots of dangling symlinks might look a bit untidy, but its a technique thats been used before (eg emacs session files). See http://www.charmed.com/txt/ext2.txt and in particular Symbolic links are also filesystem objects with inodes. They deserve special mention because the data for them is stored within the inode itself if the symlink is less than 60 bytes long. It uses the fields which would normally be used to store the pointers to data blocks. This is a worthwhile optimisation as it we avoid allocating a full block for the symlink, and most symlinks are less than 60 characters long. -- Nick Craig-Wood ncw1@axis.demon.co.uk ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel