From owner-freebsd-hackers Tue Nov 28 13:36:51 1995 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.6.12/8.6.6) id NAA07587 for hackers-outgoing; Tue, 28 Nov 1995 13:36:51 -0800 Received: from phaeton.artisoft.com (phaeton.Artisoft.COM [198.17.250.211]) by freefall.freebsd.org (8.6.12/8.6.6) with ESMTP id NAA07581 for ; Tue, 28 Nov 1995 13:36:46 -0800 Received: (from terry@localhost) by phaeton.artisoft.com (8.6.11/8.6.9) id OAA22102; Tue, 28 Nov 1995 14:30:12 -0700 From: Terry Lambert Message-Id: <199511282130.OAA22102@phaeton.artisoft.com> Subject: Re: MsDoss FileSystem To: bde@zeta.org.au (Bruce Evans) Date: Tue, 28 Nov 1995 14:30:12 -0700 (MST) Cc: chuck@fang.cs.sunyit.edu, hackers@freebsd.org In-Reply-To: <199511281505.CAA01593@godzilla.zeta.org.au> from "Bruce Evans" at Nov 29, 95 02:05:01 am X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Length: 1204 Sender: owner-hackers@freebsd.org Precedence: bulk > >support? Does BSD/OS, NetBSD, Lites suffer from the same problems? > > NetBSD has kept it up to date better. E.g., in 4.4lite introduced waiting > on VXLOCK in ufs_lock(). This change has propagated to msdosfs_lock() in > NetBSD and not in FreeBSD. I don't know about Lites. Linux has better > msdosfs support in half as much code. This is actually broken. The underlying FS locking, as I said in a previous message, should be moved to the vncalls layer (vfs_syscalls.c in kern in BSD parlance). The problem is in the use of vnode/inode disassociation, which is broken anyway: the buffer chain for a vnode will not be reclaimed even though it is in core if only a partial chain exists. The clustering code (unhappily) does not order the buffers in a cluster in the LRU to be adjacent and in reverse order. The Linux code uses non-vmio, so integration would require a lot of work or using non-vmio. The non-vmio in FreeBSD has not really been kept up to date with the vmio code, so some integration from NetBSD should be done if you choose this path. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.