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=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 8BD19C43215 for ; Fri, 22 Nov 2019 19:50:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5793420726 for ; Fri, 22 Nov 2019 19:50:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574452207; bh=KBWdRp1C0diqcB72JfhHtC2PPDRx4lRZjSBB2xMIzcg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=qQxyLh6hIwLf8BU1apUSUuWyjCpX0z0dVXCG93T0s3468lQGQR3fSXnL5yxsv6umk zutVDHiLucmu1nrsBRAZSxZ5YlZfL2RZZ8921KWbG26Ptcv5Xxiuv7Wp/UA/KK145z zbXT4/g08iBCFsL0+FOYLwTBhZVNvcGI+ipcdo64= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727723AbfKVTuG (ORCPT ); Fri, 22 Nov 2019 14:50:06 -0500 Received: from mail.kernel.org ([198.145.29.99]:50466 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727673AbfKVTuC (ORCPT ); Fri, 22 Nov 2019 14:50:02 -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 9D6F32075B; Fri, 22 Nov 2019 19:50:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574452202; bh=KBWdRp1C0diqcB72JfhHtC2PPDRx4lRZjSBB2xMIzcg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WEgFOJ6jncme/aVhsiDTtx638FHRzn7w+Rytn/6F31R1MHVYqLfSZl8fxwR9xCDDP xf+hqkeqLaWSCxxLOb/KCnUtKXIxEv4hhYk8N6ehPzTIumSVI1MTcjricyb9aSFm1W FHpgHo5+mSvQhPs9XfNlFd0ifblMF6aVGkm3NhWc= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Al Viro , Sasha Levin Subject: [PATCH AUTOSEL 4.9 03/13] exportfs_decode_fh(): negative pinned may become positive without the parent locked Date: Fri, 22 Nov 2019 14:49:48 -0500 Message-Id: <20191122194958.24926-3-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191122194958.24926-1-sashal@kernel.org> References: <20191122194958.24926-1-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 7a7bba7c23284..3706939e5dd5e 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -506,26 +506,33 @@ 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