Date: Mon, 19 Sep 2005 04:27:31 GMT From: Erez Zadok <ezk@am-utils.org> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/86319: support a "noac" NFS mount flag to turn off the attribute cache Message-ID: <200509190427.j8J4RVTg031506@www.freebsd.org> Resent-Message-ID: <200509190430.j8J4U4iX066875@freefall.freebsd.org>
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>Number: 86319 >Category: kern >Synopsis: support a "noac" NFS mount flag to turn off the attribute cache >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: change-request >Submitter-Id: current-users >Arrival-Date: Mon Sep 19 04:30:03 GMT 2005 >Closed-Date: >Last-Modified: >Originator: Erez Zadok >Release: 5.4 and 6.0 >Organization: Stony Brook University >Environment: All versions of freebsd up to and including 6.0. >Description: To turn off the NFS attribute cache in FreeBSD, one has to set the following four flags to zero in struct nfs_args: nfs_args->acregmin = 0; nfs_args->acregmax = 0; nfs_args->acdirmin = 0; nfs_args->acdirmax = 0; In addition, you have to turn on four flags to tell the kernel that you indeed want it to use your values for the above four flags: nfs_args->flags |= \ (NFSMNT_ACREGMIN|NFSMNT_ACREGMAX|NFSMNT_ACDIRMIN|NFSMNT_ACDIRMAX); This is rather cumbersome and also confusing because some users may be used to what other OSs do: just setting the four fields suffices. For that reason, some OSs like Solaris provide a convenience flag called "noac" that can be set to simply turn off the attribute cache entirely. I would like to ask that FreeBSD support such a convenience flag "noac". In addition, please document this flag and the current behaviour of how one turns off the attribute cache, in the mount_nfs man page. >How-To-Repeat: >Fix: >Release-Note: >Audit-Trail: >Unformatted:
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