Date: Sun, 18 Sep 2005 21:06:12 -0600 From: Scott Long <scottl@samsco.org> To: Erez Zadok <ezk@cs.sunysb.edu> Cc: freebsd-fs@freebsd.org, christos@zoulas.com, Kris Kennaway <kris@obsecurity.org> Subject: Re: turning off the NFS attribute cache Message-ID: <432E2B24.5040607@samsco.org> In-Reply-To: <200509190225.j8J2PclG016625@agora.fsl.cs.sunysb.edu> References: <200509190225.j8J2PclG016625@agora.fsl.cs.sunysb.edu>
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Erez Zadok wrote: > Good news! > > After browsing the 6.0 kernel sources, I found out that freebsd DOES indeed > have a way of turning off the attribute cache. It's not enough to just set > nfs_args->acregmin and friends, but you also need to > > nfs_args->flags |= NFSMNT_ACREGMIN > > Otherwise, the kernel ignores what you set in the ->acregmin field. So, to > completely turn off the attrcache on freebsd, you have to set four fields in > struct nfs_args to 0, and turn four flags on in ->flags. > > It's cumbersome, but it works. You may still want to consider offering a > "noac" flag for convenience, which'd set all eight values as needed (as some > OSs do). At the very least, please document specifically in the mount_nfs > man page how one turns off the attribute cache completely. > > Anyway, I was able to verify this in 5.4 and 6.0 (SNAP001). And it looks > like the NFSMNT_ACREGMIN type of flags have existed as far back as 4.x, so I > suspect that as long as the implementation was correct, even old versions of > BSD should work well now with Amd. > > I'll release a quick new version of am-utils (6.1.2.1) with this fix, > specifically because I have a few freebsd users who complained about this > bug. > > I would like to ask whomever is responsible for maintaining am-utils for > FreeBSD to consider importing 6.1.2.1 into your ports tree. Currently > you're stuck at an ancient 6.0.10. 6.1.x fixes numerous bugs other than > this latest one, plus it offers a host of new performance and security > features. > > Thanks, > Erez. Thanks for looking into this and adapting am-utils for it. Would you mind submitting a report to the bug database so that we can track this? http://www.freebsd.org/send-pr.html. As for importing a newer am-utils, it's been talked about, but I don't expect it to happen for 6.0. Thanks! Scott
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