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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 AF669C432C0 for ; Fri, 22 Nov 2019 19:54:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7AF582071F for ; Fri, 22 Nov 2019 19:54:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574452496; bh=1onni7qI1StNp13OOOaMTO2TDuBSUXH5Q66vVgyAGyo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gUvZq/NXzO/YjaKuf1pPoAIKESfaf8g5xiQD5OYNNuHRY6bFyNAtm4dWmXEsCM+cA bmfX7rknEA+lK8TavZA9PACcGmI0WMvgwTNJf/LLCUeqrXKue1YirO+DxS4pDsJ6xg iInIc9bVbvQYAyvW67lwaj06XktEdd9K4lknWPko= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727724AbfKVTyz (ORCPT ); Fri, 22 Nov 2019 14:54:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:48046 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727116AbfKVTtF (ORCPT ); Fri, 22 Nov 2019 14:49:05 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DFE9420726; Fri, 22 Nov 2019 19:49:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574452145; bh=1onni7qI1StNp13OOOaMTO2TDuBSUXH5Q66vVgyAGyo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wN31UCefoEKR4KMDNPCTHqbnvsUX+BqOAin7dU9rmoFQ2seKGql/eIHTsFxrF2s0o V8+MQZ5jCRFz+276T+51/VVghrld+iGbjuBS8XA3RowSXfKonmxxnOnbQAhEiOvVVb kW3VZe8+GqQ5KBPr3QA8tvdgdmNTZK6MO6vvspG0= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Al Viro , Sasha Levin Subject: [PATCH AUTOSEL 4.19 05/25] exportfs_decode_fh(): negative pinned may become positive without the parent locked Date: Fri, 22 Nov 2019 14:48:38 -0500 Message-Id: <20191122194859.24508-5-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191122194859.24508-1-sashal@kernel.org> References: <20191122194859.24508-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 [ Upstream commit a2ece088882666e1dc7113744ac912eb161e3f87 ] Signed-off-by: Al Viro Signed-off-by: Sasha Levin --- fs/exportfs/expfs.c | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-) diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index 63707abcbeb3e..808cae6d5f50f 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -517,26 +517,33 @@ struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid, * inode is actually connected to the parent. */ err = exportfs_get_name(mnt, target_dir, nbuf, result); - if (!err) { - inode_lock(target_dir->d_inode); - nresult = lookup_one_len(nbuf, target_dir, - strlen(nbuf)); - inode_unlock(target_dir->d_inode); - if (!IS_ERR(nresult)) { - if (nresult->d_inode) { - dput(result); - result = nresult; - } else - dput(nresult); - } + if (err) { + dput(target_dir); + goto err_result; } + inode_lock(target_dir->d_inode); + nresult = lookup_one_len(nbuf, target_dir, strlen(nbuf)); + if (!IS_ERR(nresult)) { + if (unlikely(nresult->d_inode != result->d_inode)) { + dput(nresult); + nresult = ERR_PTR(-ESTALE); + } + } + inode_unlock(target_dir->d_inode); /* * At this point we are done with the parent, but it's pinned * by the child dentry anyway. */ dput(target_dir); + if (IS_ERR(nresult)) { + err = PTR_ERR(nresult); + goto err_result; + } + dput(result); + result = nresult; + /* * And finally make sure the dentry is actually acceptable * to NFSD. -- 2.20.1