Return-Path: Received: from mx2.netapp.com ([216.240.18.37]:1509 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753145Ab0K0SYG convert rfc822-to-8bit (ORCPT ); Sat, 27 Nov 2010 13:24:06 -0500 Subject: Re: [REGRESSION] git commit d1bacf9e "NFS: add readdir cache array" is bad From: Trond Myklebust To: Simon Kirby Cc: Guennadi Liakhovetski , linux-nfs@vger.kernel.org, "J. Bruce Fields" , Neil Brown , Bryan Schumaker , rees@umich.edu In-Reply-To: <20101127102732.GD12175@hostway.ca> References: <1290794726.4905.8.camel@heimdal.trondhjem.org> <20101127002548.GA20008@hostway.ca> <20101127102732.GD12175@hostway.ca> Content-Type: text/plain; charset="UTF-8" Date: Sat, 27 Nov 2010 13:24:00 -0500 Message-ID: <1290882240.3415.5.camel@heimdal.trondhjem.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Sat, 2010-11-27 at 02:27 -0800, Simon Kirby wrote: > Ok, so I tracked them down, and they didn't seem to be particularly > unusual, so I tried a not-particularly-unusual thing that I figured might > work, and reproduced it: > > server: echo test > a > client: ls -l > server: echo test > b ; mv b a > client: ls -l > > That's it. The kernel (2.6.37-rc3), on the final "ls -l", says: > > [12814.611197] NFS: server 10.10.52.228 error: fileid changed > [12814.611200] fsid 0:3f: expected fileid 0x122efbf1, got 0x122efc15 > > "ls -li" shows the inode updated, so maybe this isn't even a bug? Ah! I think I see it now, and yes it is a bug... Does the following patch fix it? Cheers Trond ------------------------------------------------------------------------------------- NFS: Fix a readdirplus bug From: Trond Myklebust When comparing filehandles in the helper nfs_same_file(), we should not be using 'strncmp()': filehandles are not null terminated strings. Instead, we should just use the existing helper nfs_compare_fh(). Signed-off-by: Trond Myklebust --- fs/nfs/dir.c | 6 +----- 1 files changed, 1 insertions(+), 5 deletions(-) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 8ea4a41..f0a384e 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -395,13 +395,9 @@ int xdr_decode(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry, struct x static int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry) { - struct nfs_inode *node; if (dentry->d_inode == NULL) goto different; - node = NFS_I(dentry->d_inode); - if (node->fh.size != entry->fh->size) - goto different; - if (strncmp(node->fh.data, entry->fh->data, node->fh.size) != 0) + if (nfs_compare_fh(entry->fh, NFS_FH(dentry->d_inode)) != 0) goto different; return 1; different: -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com