Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752629AbdGYTXK (ORCPT ); Tue, 25 Jul 2017 15:23:10 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:35234 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753254AbdGYTW2 (ORCPT ); Tue, 25 Jul 2017 15:22:28 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Kara Subject: [PATCH 4.9 102/125] udf: Fix deadlock between writeback and udf_setsize() Date: Tue, 25 Jul 2017 12:20:17 -0700 Message-Id: <20170725192019.976211077@linuxfoundation.org> X-Mailer: git-send-email 2.13.3 In-Reply-To: <20170725192014.314851996@linuxfoundation.org> References: <20170725192014.314851996@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1571 Lines: 51 4.9-stable 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: Greg Kroah-Hartman --- fs/udf/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/fs/udf/inode.c +++ b/fs/udf/inode.c @@ -1243,8 +1243,8 @@ 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); @@ -1261,9 +1261,9 @@ 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); }