Date: Thu, 02 Aug 2001 12:06:02 +0100 From: Ian Dowse <iedowse@maths.tcd.ie> To: David Malone <dwmalone@maths.tcd.ie> Cc: Julian Stacey <jhs@jhs.muc.de>, hackers@freebsd.org Subject: Re: vnconfig + mount removes permission for a second Message-ID: <200108021206.aa93171@salmon.maths.tcd.ie> In-Reply-To: Your message of "Thu, 02 Aug 2001 11:48:35 BST." <20010802114835.A92803@walton.maths.tcd.ie>
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In message <20010802114835.A92803@walton.maths.tcd.ie>, David Malone writes: > >When you do a mount it automatically HUP's mountd which then >re-exports NFS filesystems. I suspect what is happening is that >the the filesystem mountlist is being cleared for a moment and that >is upsetting the cp. Yes, the mountd-kernel interface for updating export lists is a bit stupid; you have to clear all exports and then add each allowed host/net one by one. Any NFS requests that come in after the exports have been deleted but before the entries have been re-added will get rejected. See PRs misc/3980 and kern/9619 for more details. I think NetBSD tried at one point to make mountd incrementally change the export list, but it turned out to be quite hard to get the logic right to keep the mountd and kernel lists in sync. I think they reverted that change eventually. This is certainly a bug that needs to be fixed; mountd should be able to build up a list of all exports for a filesystem and pass them into the kernel in one "replace export list" operation. Maybe nice'ing mountd to run at a higher priority, and/or specifying only IP addresses in /etc/exports would help things a bit now. Ian To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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