From owner-freebsd-hackers Wed Apr 16 16:39:01 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id QAA28475 for hackers-outgoing; Wed, 16 Apr 1997 16:39:01 -0700 (PDT) Received: from phaeton.artisoft.com (phaeton.Artisoft.COM [198.17.250.50]) by freefall.freebsd.org (8.8.5/8.8.5) with SMTP id QAA28374 for ; Wed, 16 Apr 1997 16:38:53 -0700 (PDT) Received: (from terry@localhost) by phaeton.artisoft.com (8.6.11/8.6.9) id QAA28363; Wed, 16 Apr 1997 16:16:32 -0700 From: Terry Lambert Message-Id: <199704162316.QAA28363@phaeton.artisoft.com> Subject: Re: Feasibility of porting Linux filesystem code? To: spidaman@well.com (Ian Kallen) Date: Wed, 16 Apr 1997 16:16:32 -0700 (MST) Cc: hackers@FreeBSD.org In-Reply-To: from "Ian Kallen" at Apr 16, 97 02:50:55 pm X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@FreeBSD.org X-Loop: FreeBSD.org Precedence: bulk > Come to think of it, I've migrated all of our IRIX filesystems to XFS > which is journaled like JFS. A FreeBSD XFS driver would certainly put a > smile on my face. I just mentioned EFS 'case I knew it existed amongst > the Linux folks. XFS has proved to be very stable under heavy load though > the procession of patches has made me wonder about how well they QA it. > I wish xfsdump had the v switch that Solaris' ufsdump has for verifying > a dump's integrity. Er, I'm drifting. Anyway, if you're interested in > developing an XFS driver for FreeBSD you have my moral support anyway! The Linux VFS interface is not reflexive; it's not cut at the right place for a journalled FS. FreeBSD's is much better, but it's still not there either... I've discussed this in detail with the guy who wrote the read-only NTFS driver for Linux. You need to be able to treat the VFS interface as if it were a transaction interface to do things like event rollback. It helps if the internal treatment is architected as event/responder, too. The same thing would help for Soft Updates, which is basically a transaction order enforcement mechanism, with the dependency graph statically computed (rendering it FFS-specific). Regards, Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.