From mboxrd@z Thu Jan 1 00:00:00 1970 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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 81720C43331 for ; Mon, 11 Nov 2019 18:50:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 55D7B214E0 for ; Mon, 11 Nov 2019 18:50:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573498210; bh=bBKoEvnOK/hSzQAhfsYEOcnPvPdetAAXiI9F+EJstDk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=pPoy4ZDK4S5OZF4Gk8r5oLoba5ufEwCls+9GzkqEygEeCrjQ97Bx7q8+1/d8dTfel JnGaBi6GFofO4CP/pg7QYiGPAnXahENmkd6JCcFXCMhANGART5oB9eDWPk1FJahRB1 P/gykDjRylbYmw9uxjUki/WILHeR0RWAstKwp7fs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728009AbfKKSuJ (ORCPT ); Mon, 11 Nov 2019 13:50:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:43706 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727468AbfKKSuG (ORCPT ); Mon, 11 Nov 2019 13:50:06 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AF867204FD; Mon, 11 Nov 2019 18:50:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573498206; bh=bBKoEvnOK/hSzQAhfsYEOcnPvPdetAAXiI9F+EJstDk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HKo/06GBQxRFJUy5ijGNpHuH/tybTJWHOBiIzOyimbh4/tZ9tSj4C9S54hSXQSnd7 79eGyVXJYC7e3fwlZmWL+Bmd4SRfmRCh6FV2wHgb2f+LcIFBA35sToY52BF2/ukmER MpeX8nmHzNl4J6V/GeQZqXGGaAdokhenVf4SzlgY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Viro , Jeff Layton , Ilya Dryomov Subject: [PATCH 5.3 052/193] ceph: fix RCU case handling in ceph_d_revalidate() Date: Mon, 11 Nov 2019 19:27:14 +0100 Message-Id: <20191111181504.816035684@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191111181459.850623879@linuxfoundation.org> References: <20191111181459.850623879@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Al Viro commit aa8dd816732b2bab28c54bc4d2ccf3fc8a6e0892 upstream. For RCU case ->d_revalidate() is called with rcu_read_lock() and without pinning the dentry passed to it. Which means that it can't rely upon ->d_inode remaining stable; that's the reason for d_inode_rcu(), actually. Make sure we don't reload ->d_inode there. Cc: stable@vger.kernel.org Signed-off-by: Al Viro Signed-off-by: Jeff Layton Signed-off-by: Ilya Dryomov Signed-off-by: Greg Kroah-Hartman --- fs/ceph/dir.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) --- a/fs/ceph/dir.c +++ b/fs/ceph/dir.c @@ -1553,36 +1553,37 @@ static int ceph_d_revalidate(struct dent { int valid = 0; struct dentry *parent; - struct inode *dir; + struct inode *dir, *inode; if (flags & LOOKUP_RCU) { parent = READ_ONCE(dentry->d_parent); dir = d_inode_rcu(parent); if (!dir) return -ECHILD; + inode = d_inode_rcu(dentry); } else { parent = dget_parent(dentry); dir = d_inode(parent); + inode = d_inode(dentry); } dout("d_revalidate %p '%pd' inode %p offset %lld\n", dentry, - dentry, d_inode(dentry), ceph_dentry(dentry)->offset); + dentry, inode, ceph_dentry(dentry)->offset); /* always trust cached snapped dentries, snapdir dentry */ if (ceph_snap(dir) != CEPH_NOSNAP) { dout("d_revalidate %p '%pd' inode %p is SNAPPED\n", dentry, - dentry, d_inode(dentry)); + dentry, inode); valid = 1; - } else if (d_really_is_positive(dentry) && - ceph_snap(d_inode(dentry)) == CEPH_SNAPDIR) { + } else if (inode && ceph_snap(inode) == CEPH_SNAPDIR) { valid = 1; } else { valid = dentry_lease_is_valid(dentry, flags); if (valid == -ECHILD) return valid; if (valid || dir_lease_is_valid(dir, dentry)) { - if (d_really_is_positive(dentry)) - valid = ceph_is_any_caps(d_inode(dentry)); + if (inode) + valid = ceph_is_any_caps(inode); else valid = 1; }