Return-Path: Received: from mx2.netapp.com ([216.240.18.37]:5591 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756921Ab1FJBbI (ORCPT ); Thu, 9 Jun 2011 21:31:08 -0400 From: Trond Myklebust To: linux-nfs@vger.kernel.org Subject: [PATCH 2/5] NFSv4.1: Fix an off-by-one error in pnfs_generic_pg_test Date: Thu, 9 Jun 2011 21:30:59 -0400 Message-Id: <1307669462-15764-2-git-send-email-Trond.Myklebust@netapp.com> In-Reply-To: <1307669462-15764-1-git-send-email-Trond.Myklebust@netapp.com> References: <1307669462-15764-1-git-send-email-Trond.Myklebust@netapp.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: Content-Type: text/plain MIME-Version: 1.0 And document what is going on there... Signed-off-by: Trond Myklebust --- fs/nfs/pnfs.c | 21 ++++++++++++++++----- 1 files changed, 16 insertions(+), 5 deletions(-) diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index 12b53ef..9a4ce7c 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -1073,11 +1073,22 @@ pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev, return true; } - if (req_offset(req) > end_offset(pgio->pg_lseg->pls_range.offset, - pgio->pg_lseg->pls_range.length)) - return false; - - return true; + /* + * Test if a nfs_page is fully contained in the pnfs_layout_range. + * Note that this test makes several assumptions: + * - that the previous nfs_page in the struct nfs_pageio_descriptor + * is known to lie within the range. + * - that the nfs_page being tested is known to be contiguous with the + * previous nfs_page. + * - Layout ranges are page aligned, so we only have to test the + * start offset of the request. + * + * Please also note that 'end_offset' is actually the offset of the + * first byte that lies outside the pnfs_layout_range. FIXME? + * + */ + return req_offset(req) < end_offset(pgio->pg_lseg->pls_range.offset, + pgio->pg_lseg->pls_range.length); } EXPORT_SYMBOL_GPL(pnfs_generic_pg_test); -- 1.7.5.2