From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755320AbdJINjP (ORCPT ); Mon, 9 Oct 2017 09:39:15 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43462 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755045AbdJINTr (ORCPT ); Mon, 9 Oct 2017 09:19:47 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Jan Kara" Date: Mon, 09 Oct 2017 13:44:24 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 037/192] udf: Fix deadlock between writeback and udf_setsize() In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.49-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit f2e95355891153f66d4156bf3a142c6489cd78c6 upstream. udf_setsize() called truncate_setsize() with i_data_sem held. Thus truncate_pagecache() called from truncate_setsize() could lock a page under i_data_sem which can deadlock as page lock ranks below i_data_sem - e. g. writeback can hold page lock and try to acquire i_data_sem to map a block. Fix the problem by moving truncate_setsize() calls from under i_data_sem. It is safe for us to change i_size without holding i_data_sem as all the places that depend on i_size being stable already hold inode_lock. Fixes: 7e49b6f2480cb9a9e7322a91592e56a5c85361f5 Signed-off-by: Jan Kara Signed-off-by: Ben Hutchings --- fs/udf/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/fs/udf/inode.c +++ b/fs/udf/inode.c @@ -1238,8 +1238,8 @@ int udf_setsize(struct inode *inode, lof return err; } set_size: - truncate_setsize(inode, newsize); up_write(&iinfo->i_data_sem); + truncate_setsize(inode, newsize); } else { if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) { down_write(&iinfo->i_data_sem); @@ -1256,9 +1256,9 @@ set_size: udf_get_block); if (err) return err; + truncate_setsize(inode, newsize); down_write(&iinfo->i_data_sem); udf_clear_extent_cache(inode); - truncate_setsize(inode, newsize); udf_truncate_extents(inode); up_write(&iinfo->i_data_sem); }