Return-Path: Received: from natasha.panasas.com ([67.152.220.90]:50810 "EHLO natasha.panasas.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756568Ab1H3UbF (ORCPT ); Tue, 30 Aug 2011 16:31:05 -0400 Message-ID: <4E5D46EB.7030102@panasas.com> Date: Tue, 30 Aug 2011 13:24:11 -0700 From: Boaz Harrosh To: Chuck Lever CC: Jeff Layton , "J. Bruce Fields" , Trond Myklebust , Linux NFS Mailing List Subject: Re: [PATCH] NFSD: Add a cache for fs_locations information References: <20110829185115.3413.92459.stgit@matisse.1015granger.net> <20110830151845.4dec5b40@tlielax.poochiereds.net> <852F14A9-7826-47A0-BCD6-D5D46E38A39C@oracle.com> In-Reply-To: <852F14A9-7826-47A0-BCD6-D5D46E38A39C@oracle.com> Content-Type: text/plain; charset="UTF-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On 08/30/2011 01:00 PM, Chuck Lever wrote: <> >> >> Won't the above check be rather expensive? You'll need to do a >> getxattr call on almost every path component of every lookup, >> right? >> >> I may be misremembering your talk from connectathon, but I thought >> you were planning to use a well-known mode for junctions that would >> cut down on the number of unnecessary getxattrs... > > Yes, that's the plan. To reduce overhead, the S_ISVTX bit must be > set before NFSD does the expensive xattr test. from: stat(2) - Linux man page The 'sticky' bit (S_ISVTX) on a directory means that a file in that directory can be renamed or deleted only by the owner of the file, by the owner of the directory, and by a privileged process. Please explain how does it work? Once the junction is followed and mounted then the mode-bits get changed to the destination directory's mode bits? So the Server's junction mode-bits are never exposed, except in a local-fs file access on the server? Thanks Boaz > However, I don't > think this kind of filtering was ever implemented. I got the patch > from here: > > http://git.linux-nfs.org/?p=trondmy/nfs-2.6.git;a=shortlog;h=refs/heads/fedfs-for-2.6.34 > > and that doesn't seem to have it either. I can implement something > and repost these. >