Date: Fri, 25 Feb 2000 00:57:42 +1100 (EST) From: Bruce Evans <bde@zeta.org.au> To: Alfred Perlstein <bright@wintelcom.net> Cc: Kirk McKusick <mckusick@flamingo.McKusick.COM>, Terry Lambert <tlambert@primenet.com>, fs@FreeBSD.ORG, jkh@FreeBSD.ORG Subject: Re: changing mount options still can cause damage? Message-ID: <Pine.BSF.4.21.0002250039510.7108-100000@alphplex.bde.org> In-Reply-To: <20000222204610.I21720@fw.wintelcom.net>
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On Tue, 22 Feb 2000, Alfred Perlstein wrote: > * Kirk McKusick <mckusick@flamingo.McKusick.COM> [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
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