From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932147AbaHAN3n (ORCPT ); Fri, 1 Aug 2014 09:29:43 -0400 Received: from mga01.intel.com ([192.55.52.88]:10863 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756014AbaHAN3M (ORCPT ); Fri, 1 Aug 2014 09:29:12 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,780,1400050800"; d="scan'208";a="578740172" From: Matthew Wilcox To: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Jan Kara , willy@linux.intel.com, Matthew Wilcox Subject: [PATCH v9 20/22] ext4: Avoid lock inversion between i_mmap_mutex and transaction start Date: Fri, 1 Aug 2014 09:27:36 -0400 Message-Id: X-Mailer: git-send-email 2.0.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jan Kara When DAX is enabled, it uses i_mmap_mutex as a protection against truncate during page fault. This inevitably forces i_mmap_mutex to rank outside of a transaction start and thus we have to avoid calling pagecache purging operations when transaction is started. Signed-off-by: Jan Kara Signed-off-by: Matthew Wilcox --- fs/ext4/inode.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 8a06473..494a864 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3631,13 +3631,19 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length) if (IS_SYNC(inode)) ext4_handle_sync(handle); - /* Now release the pages again to reduce race window */ + inode->i_mtime = inode->i_ctime = ext4_current_time(inode); + ext4_mark_inode_dirty(handle, inode); + ext4_journal_stop(handle); + + /* + * Now release the pages again to reduce race window. This has to happen + * outside of a transaction to avoid lock inversion on i_mmap_mutex + * when DAX is enabled. + */ if (last_block_offset > first_block_offset) truncate_pagecache_range(inode, first_block_offset, last_block_offset); - - inode->i_mtime = inode->i_ctime = ext4_current_time(inode); - ext4_mark_inode_dirty(handle, inode); + goto out_dio; out_stop: ext4_journal_stop(handle); out_dio: -- 2.0.1