From owner-freebsd-fs Thu Feb 24 5:58:40 2000 Delivered-To: freebsd-fs@freebsd.org Received: from mailman.zeta.org.au (mailman.zeta.org.au [203.26.10.16]) by hub.freebsd.org (Postfix) with ESMTP id B8F6837BBC4; Thu, 24 Feb 2000 05:58:29 -0800 (PST) (envelope-from bde@zeta.org.au) Received: from bde.zeta.org.au (bde.zeta.org.au [203.2.228.102]) by mailman.zeta.org.au (8.8.7/8.8.7) with ESMTP id BAA12804; Fri, 25 Feb 2000 01:02:06 +1100 Date: Fri, 25 Feb 2000 00:57:42 +1100 (EST) From: Bruce Evans X-Sender: bde@alphplex.bde.org To: Alfred Perlstein Cc: Kirk McKusick , Terry Lambert , fs@FreeBSD.ORG, jkh@FreeBSD.ORG Subject: Re: changing mount options still can cause damage? In-Reply-To: <20000222204610.I21720@fw.wintelcom.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Tue, 22 Feb 2000, Alfred Perlstein wrote: > * Kirk McKusick [000222 19:14] wrote: > > ... Appropriate warnings about async are > > called for, however the only warning necessary about cycling > > between sync and async is that the danger of async does not > > go away for several minutes after you have cycled to sync. > > > > ~Kirk > > You're saying the exact opposite of what Bruce and Luoqi said, > they both say that updating the mount from async -> noasync/sync > is safe because of the flush_files call. > > Looking at the code you seem right... > However the async -> noasync/sync doesn't do the same (fsync the > device vp), shouldn't it, and if it did, wouldn't that fix the > problem? It's not like doing a fsync on the whole filesystem > at that point would be a common occurance. Copying the code in sync() and changing MNT_NOWAIT to MNT_WAIT in it should work, modulo locking problems. This applies to both async -> noasync and nosync -> sync. Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message