From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay3.corp.sgi.com [198.149.34.15]) by oss.sgi.com (Postfix) with ESMTP id D1E4F7CA0 for ; Mon, 13 Jun 2016 13:37:36 -0500 (CDT) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by relay3.corp.sgi.com (Postfix) with ESMTP id 4DC65AC003 for ; Mon, 13 Jun 2016 11:37:36 -0700 (PDT) Received: from shadbolt.e.decadent.org.uk (shadbolt.e.decadent.org.uk [88.96.1.126]) by cuda.sgi.com with ESMTP id CuOxzZnAeJ42PQoo (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NO) for ; Mon, 13 Jun 2016 11:37:34 -0700 (PDT) Content-Disposition: inline MIME-Version: 1.0 From: Ben Hutchings Date: Mon, 13 Jun 2016 19:36:37 +0100 Message-ID: Subject: [PATCH 3.16 097/114] xfs: mmap lock needs to be inside freeze protection In-Reply-To: List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jan Kara , Brian Foster , xfs@oss.sgi.com, Dave Chinner , akpm@linux-foundation.org 3.16.36-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Dave Chinner commit ec56b1f1fdc69599963574ce94cc5693d535dd64 upstream. Lock ordering for the new mmap lock needs to be: mmap_sem sb_start_pagefault i_mmap_lock page lock Right now xfs_vm_page_mkwrite gets this the wrong way around, While technically it cannot deadlock due to the current freeze ordering, it's still a landmine that might explode if we change anything in future. Hence we need to nest the locks correctly. Signed-off-by: Dave Chinner Reviewed-by: Jan Kara Reviewed-by: Brian Foster Signed-off-by: Dave Chinner Signed-off-by: Ben Hutchings Cc: Jan Kara Cc: xfs@oss.sgi.com --- fs/xfs/xfs_file.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1441,15 +1441,20 @@ xfs_filemap_page_mkwrite( struct vm_fault *vmf) { struct xfs_inode *ip = XFS_I(vma->vm_file->f_mapping->host); - int error; + int ret; trace_xfs_filemap_page_mkwrite(ip); + sb_start_pagefault(VFS_I(ip)->i_sb); + file_update_time(vma->vm_file); xfs_ilock(ip, XFS_MMAPLOCK_SHARED); - error = block_page_mkwrite(vma, vmf, xfs_get_blocks); + + ret = __block_page_mkwrite(vma, vmf, xfs_get_blocks); + xfs_iunlock(ip, XFS_MMAPLOCK_SHARED); + sb_end_pagefault(VFS_I(ip)->i_sb); - return error; + return block_page_mkwrite_return(ret); } const struct file_operations xfs_file_operations = { _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs