From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262315AbUK3VAc (ORCPT ); Tue, 30 Nov 2004 16:00:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262310AbUK3VAY (ORCPT ); Tue, 30 Nov 2004 16:00:24 -0500 Received: from H190.C26.B96.tor.eicat.ca ([66.96.26.190]:31962 "EHLO moraine.clusterfs.com") by vger.kernel.org with ESMTP id S262320AbUK3U5Z (ORCPT ); Tue, 30 Nov 2004 15:57:25 -0500 Date: Tue, 30 Nov 2004 13:57:22 -0700 From: Andreas Dilger To: Barry Bouwsma Cc: Linux Kernel mailing list Subject: Re: UFS1 filesystem compatibility problem under Linux Message-ID: <20041130205722.GD22547@schnapps.adilger.int> Mail-Followup-To: Barry Bouwsma , Linux Kernel mailing list References: <200411301423.iAUENK601275@Mail.NOSPAM.DynDNS.dK> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="KDt/GgjP6HVcx58l" Content-Disposition: inline In-Reply-To: <200411301423.iAUENK601275@Mail.NOSPAM.DynDNS.dK> User-Agent: Mutt/1.4.1i X-GPG-Key: 1024D/0D35BED6 X-GPG-Fingerprint: 7A37 5D79 BF1B CECA D44F 8A29 A488 39F5 0D35 BED6 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --KDt/GgjP6HVcx58l Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Nov 30, 2004 15:23 +0100, Barry Bouwsma wrote: > I've had absolutely no problems under FreeBSD (apart from possibly > finding one or two bits of code that needed to be fixed) when I've > made regular use of fragment sizes up to and including the block > size (as large as 65536 bytes), so long as fsize is within the range > of bsize/8 to bsize. >=20 > Question: Is there a reason that the Linux UFS code would be unable > to handle frag sizes larger than 4k, or is this simply an arbitrary Linux requires blocksize <=3D PAGE_SIZE, so basically all filesystems use blocksize <=3D 4096 unless they implement support internally for reading/writing partial disk blocks from the page or buffer cache. With ext2/3 it is possible to change the number of inodes allocated without changing the blocksize (less inodes per block group). If you care about mounting under Linux it might be worthwhile seeing if UFS can do the same. > + (REG) Maximum file size depends on the block size on your > filesystem. For ext2 (and UFS, SysVFS and similar > filesystems), the limits are: > Block size Maximum file size (GiBytes) > 512 B 2 > 1 kiB 16 > 2 kiB 128 > 4 kiB 1024 > 8 kiB 8192 (PAGE_SIZE must be >=3D 8 kiB) This is it exactly. > Hmmm, this reference to PAGE_SIZE is interesting -- the reason > I'm asking all these stupid questions is to know whether some > out-of-the-box on-CD-or-similar Linux could be expected to be > able to handle my UFS1 filesystem as described above, with no > need for a custom or tweaked kernel. It seems unlikely (though not impossible, I haven't checked the UFS code) than it is possible to mount your filesystem without serious hacking to the filesystem/VFS/VM, unless of course you are mounting on an ia64 machine (or similar) with 64kB PAGE_SIZE. Sadly, x86_64 does not support a larger PAGE_SIZE than 4096 (until you get to 4MB or something like that). Cheers, Andreas -- Andreas Dilger http://sourceforge.net/projects/ext2resize/ http://members.shaw.ca/adilger/ http://members.shaw.ca/golinux/ --KDt/GgjP6HVcx58l Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) iD8DBQFBrN6ypIg59Q01vtYRAq5WAJ4xr/k1DRa1MvrKwEY2RghRJ03miQCdHaDX woPRvLrpbfv7p6+DNDjpBO4= =gUXd -----END PGP SIGNATURE----- --KDt/GgjP6HVcx58l--