From patchwork Thu May 20 09:23:08 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 445364 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0BEBAC433B4 for ; Thu, 20 May 2021 11:03:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E7EBF613DF for ; Thu, 20 May 2021 11:03:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235753AbhETLFA (ORCPT ); Thu, 20 May 2021 07:05:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:57206 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238800AbhETLCB (ORCPT ); Thu, 20 May 2021 07:02:01 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 08F9D61436; Thu, 20 May 2021 10:03:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621505040; bh=9giTw0wQ5kVztn1UFDEgT73nxsq2oDRznyPpL6XQJNY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rMwoc8yRzbQn1M75bZKfM70TlgqvfYz+gh39vM97L3/TizKunNawskY3LTT/m3dIT e7vsenGl5m/hvj6Rumw6l0SggUJvrYdz0VAvWMTjg2nnWdsic5PiB2Y3ymjLrM1SxH 1Mmj6b8VTqdyurQtQrn+gBDxpKVH3i0H1MPTqIvY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Trond Myklebust , Sasha Levin Subject: [PATCH 4.9 196/240] NFS: Deal correctly with attribute generation counter overflow Date: Thu, 20 May 2021 11:23:08 +0200 Message-Id: <20210520092115.242539100@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210520092108.587553970@linuxfoundation.org> References: <20210520092108.587553970@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Trond Myklebust [ Upstream commit 9fdbfad1777cb4638f489eeb62d85432010c0031 ] We need to use unsigned long subtraction and then convert to signed in order to deal correcly with C overflow rules. Fixes: f5062003465c ("NFS: Set an attribute barrier on all updates") Signed-off-by: Trond Myklebust Signed-off-by: Sasha Levin --- fs/nfs/inode.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index 6c0035761d17..7a94f5a5f8c8 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -1469,10 +1469,10 @@ EXPORT_SYMBOL_GPL(_nfs_display_fhandle); */ static int nfs_inode_attrs_need_update(const struct inode *inode, const struct nfs_fattr *fattr) { - const struct nfs_inode *nfsi = NFS_I(inode); + unsigned long attr_gencount = NFS_I(inode)->attr_gencount; - return ((long)fattr->gencount - (long)nfsi->attr_gencount) > 0 || - ((long)nfsi->attr_gencount - (long)nfs_read_attr_generation_counter() > 0); + return (long)(fattr->gencount - attr_gencount) > 0 || + (long)(attr_gencount - nfs_read_attr_generation_counter()) > 0; } static int nfs_refresh_inode_locked(struct inode *inode, struct nfs_fattr *fattr) @@ -1882,7 +1882,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr) nfsi->attrtimeo_timestamp = now; } /* Set the barrier to be more recent than this fattr */ - if ((long)fattr->gencount - (long)nfsi->attr_gencount > 0) + if ((long)(fattr->gencount - nfsi->attr_gencount) > 0) nfsi->attr_gencount = fattr->gencount; }