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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 690DDC3276C for ; Thu, 2 Jan 2020 22:45:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3F1C5217F4 for ; Thu, 2 Jan 2020 22:45:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578005118; bh=QVQNXYhm774xEJ0esdujKP+OZHgv/yx5eUykMewmE/w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uYTmqieT73SP2B8M5gz46SNLXtwXsme+hPmYWfrVQErpdQH9K/1sftbVDGR/wrI/N 4EQ12EKPIwzNyhhpDuhadFVwvUNP9OM1Xe+NLdhAMH2LMl5oM0iY4UgdDkCc0nxoxC oXso4a7i4z69REUpllSAD2y7GTROD73+L3I1duKk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730852AbgABWpR (ORCPT ); Thu, 2 Jan 2020 17:45:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:38698 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730409AbgABWcZ (ORCPT ); Thu, 2 Jan 2020 17:32:25 -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 59307222C3; Thu, 2 Jan 2020 22:32:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578004344; bh=QVQNXYhm774xEJ0esdujKP+OZHgv/yx5eUykMewmE/w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XD4QRki4isF9c9yxpr/3VIg1wWtQlzRggTGA2MaxEAAUT2B+PYSc0Ym2d06xecokS Kj5RFGTuLjCxe4cLQuxqEOaendq2tJGDaqx2IfQ/5kDW2O3HQY8ubj8G/mrCIMDPKb jTb3K6Nsk6EAmgM+R9axrlOE7BtoioIpEDNwjB6Q= 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 , Sasha Levin Subject: [PATCH 4.9 140/171] ext4: work around deleting a file with i_nlink == 0 safely Date: Thu, 2 Jan 2020 23:07:51 +0100 Message-Id: <20200102220606.559791102@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200102220546.960200039@linuxfoundation.org> References: <20200102220546.960200039@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 [ Upstream commit c7df4a1ecb8579838ec8c56b2bb6a6716e974f37 ] 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: Sasha Levin --- fs/ext4/namei.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 6608cc01a3db..f0ce535d514c 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -3082,18 +3082,17 @@ static int ext4_unlink(struct inode *dir, struct dentry *dentry) 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 = ext4_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 = ext4_current_time(inode); -- 2.20.1