Return-Path: Received: from mail-qy0-f174.google.com ([209.85.216.174]:61788 "EHLO mail-qy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755061Ab1A1RlJ (ORCPT ); Fri, 28 Jan 2011 12:41:09 -0500 Received: by qyj19 with SMTP id 19so1127151qyj.19 for ; Fri, 28 Jan 2011 09:41:07 -0800 (PST) From: Chuck Lever Subject: [PATCH 2/2] NFS: NFSv4 readdir loses entries To: trond.myklebust@netapp.com Cc: linux-nfs@vger.kernel.org Date: Fri, 28 Jan 2011 12:41:05 -0500 Message-ID: <20110128174105.3235.21014.stgit@matisse.1015granger.net> In-Reply-To: <20110128173624.3235.74504.stgit@matisse.1015granger.net> References: <20110128173624.3235.74504.stgit@matisse.1015granger.net> Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On recent 2.6.38-rc kernels, connectathon basic test 6 fails on NFSv4 mounts of OpenSolaris with something like: > ./test6: readdir > ./test6: (/mnt/klimt/matisse.test) didn't read expected 'file.12' dir entry, pass 0 > ./test6: (/mnt/klimt/matisse.test) didn't read expected 'file.82' dir entry, pass 0 > ./test6: (/mnt/klimt/matisse.test) didn't read expected 'file.164' dir entry, pass 0 > ./test6: (/mnt/klimt/matisse.test) Test failed with 3 errors > basic tests failed > Tests failed, leaving /mnt/klimt mounted > [cel@matisse cthon04]$ I narrowed the problem down to nfs4_decode_direct() reporting that the decode buffer had overflowed while decoding the entries for those missing files. verify_attr_len() assumes both it's pointer arguments reside on the same page. When these arguments point to locations on two different pages, verify_attr_len() can report false errors. This can happen now that a large NFSv4 readdir result can span pages. We have reasonably good checking in nfs4_decode_dirent() anyway, so it should be safe to simply remove the extra checking. At a guess, this was introduced by commit 6650239a, "NFS: Don't use vm_map_ram() in readdir". Cc: stable@kernel.org [2.6.37] Signed-off-by: Chuck Lever --- fs/nfs/nfs4xdr.c | 3 --- 1 files changed, 0 insertions(+), 3 deletions(-) diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c index 009aef9..4e2c168 100644 --- a/fs/nfs/nfs4xdr.c +++ b/fs/nfs/nfs4xdr.c @@ -6132,9 +6132,6 @@ int nfs4_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry, if (entry->fattr->valid & NFS_ATTR_FATTR_TYPE) entry->d_type = nfs_umode_to_dtype(entry->fattr->mode); - if (verify_attr_len(xdr, p, len) < 0) - goto out_overflow; - return 0; out_overflow: