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 7C78FC43603 for ; Mon, 16 Dec 2019 18:22:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 501D520717 for ; Mon, 16 Dec 2019 18:22:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576520561; bh=9qlUL9FC7N+k1z+E4k4mGKZs9S4CLnnOmFfX4VzFhWY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=O7x9j0zOgPFiUz5E+hub7q2ohcFPekRXv2rabRPzEF3wD+O8vOH8Xq0Oo7M8+IiGH V1fokHX+Komzoxb8U+ZACVXBbT8Guf+gcL4LoVi2/VEA/r6J5c8+oikvHPZ8b34M4/ i6ojRW2F+edEwqFG0mF7sztkcVBDfe0mZtM1/hQ8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732150AbfLPSWk (ORCPT ); Mon, 16 Dec 2019 13:22:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:54186 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732203AbfLPSVL (ORCPT ); Mon, 16 Dec 2019 13:21:11 -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 0AC7E20717; Mon, 16 Dec 2019 18:21:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576520470; bh=9qlUL9FC7N+k1z+E4k4mGKZs9S4CLnnOmFfX4VzFhWY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NEuz8JvLZC1bMG63dWrK4WAoWMxclgtxIpaF/bbsZUXKElkCtCoxD6rfj1Ye68Qlf QEcw1KY+BZXqnN09nR9Dk+/zI7r/ZF7P0vcH1n+zcq4Z3XVKxAo2e7R94jmGY3LxSP uIhcRfgHrl9WX4dEVBAEQelS7tb1oHy4wtb7kAMQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Theodore Tso , stable@kernel.org, Andreas Dilger Subject: [PATCH 5.4 167/177] ext4: work around deleting a file with i_nlink == 0 safely Date: Mon, 16 Dec 2019 18:50:23 +0100 Message-Id: <20191216174849.936839083@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191216174811.158424118@linuxfoundation.org> References: <20191216174811.158424118@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: Theodore Ts'o commit c7df4a1ecb8579838ec8c56b2bb6a6716e974f37 upstream. If the file system is corrupted such that a file's i_links_count is too small, then it's possible that when unlinking that file, i_nlink will already be zero. Previously we were working around this kind of corruption by forcing i_nlink to one; but we were doing this before trying to delete the directory entry --- and if the file system is corrupted enough that ext4_delete_entry() fails, then we exit with i_nlink elevated, and this causes the orphan inode list handling to be FUBAR'ed, such that when we unmount the file system, the orphan inode list can get corrupted. A better way to fix this is to simply skip trying to call drop_nlink() if i_nlink is already zero, thus moving the check to the place where it makes the most sense. https://bugzilla.kernel.org/show_bug.cgi?id=205433 Link: https://lore.kernel.org/r/20191112032903.8828-1-tytso@mit.edu Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Reviewed-by: Andreas Dilger Signed-off-by: Greg Kroah-Hartman --- fs/ext4/namei.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -3182,18 +3182,17 @@ static int ext4_unlink(struct inode *dir if (IS_DIRSYNC(dir)) ext4_handle_sync(handle); - if (inode->i_nlink == 0) { - ext4_warning_inode(inode, "Deleting file '%.*s' with no links", - dentry->d_name.len, dentry->d_name.name); - set_nlink(inode, 1); - } retval = ext4_delete_entry(handle, dir, de, bh); if (retval) goto end_unlink; dir->i_ctime = dir->i_mtime = current_time(dir); ext4_update_dx_flag(dir); ext4_mark_inode_dirty(handle, dir); - drop_nlink(inode); + if (inode->i_nlink == 0) + ext4_warning_inode(inode, "Deleting file '%.*s' with no links", + dentry->d_name.len, dentry->d_name.name); + else + drop_nlink(inode); if (!inode->i_nlink) ext4_orphan_add(handle, inode); inode->i_ctime = current_time(inode);