From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423799AbcFMSyz (ORCPT ); Mon, 13 Jun 2016 14:54:55 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43690 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161321AbcFMShb (ORCPT ); Mon, 13 Jun 2016 14:37:31 -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" , "Dave Chinner" , xfs@oss.sgi.com, "Dave Chinner" , "Brian Foster" Date: Mon, 13 Jun 2016 19:36:37 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 092/114] xfs: use i_mmaplock on read faults 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 3.16.36-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Dave Chinner commit de0e8c20ba3a65b0f15040aabbefdc1999876e6b upstream. Take the i_mmaplock over read page faults. These come through the ->fault callout, so we need to wrap the generic implementation with the i_mmaplock. While there, add tracepoints for the read fault as it passes through XFS. This gives us a lock order of mmap_sem -> i_mmaplock -> page_lock -> i_lock. Signed-off-by: Dave Chinner 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 | 28 +++++++++++++++++++++++++++- fs/xfs/xfs_trace.h | 2 ++ 2 files changed, 29 insertions(+), 1 deletion(-) --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1417,6 +1417,32 @@ xfs_file_llseek( } } +/* + * Locking for serialisation of IO during page faults. This results in a lock + * ordering of: + * + * mmap_sem (MM) + * i_mmap_lock (XFS - truncate serialisation) + * page_lock (MM) + * i_lock (XFS - extent map serialisation) + */ +STATIC int +xfs_filemap_fault( + struct vm_area_struct *vma, + struct vm_fault *vmf) +{ + struct xfs_inode *ip = XFS_I(vma->vm_file->f_mapping->host); + int error; + + trace_xfs_filemap_fault(ip); + + xfs_ilock(ip, XFS_MMAPLOCK_SHARED); + error = filemap_fault(vma, vmf); + xfs_iunlock(ip, XFS_MMAPLOCK_SHARED); + + return error; +} + const struct file_operations xfs_file_operations = { .llseek = xfs_file_llseek, .read = new_sync_read, @@ -1449,7 +1475,7 @@ const struct file_operations xfs_dir_fil }; static const struct vm_operations_struct xfs_file_vm_ops = { - .fault = filemap_fault, + .fault = xfs_filemap_fault, .map_pages = filemap_map_pages, .page_mkwrite = xfs_vm_page_mkwrite, .remap_pages = generic_file_remap_pages, --- a/fs/xfs/xfs_trace.h +++ b/fs/xfs/xfs_trace.h @@ -684,6 +684,8 @@ DEFINE_INODE_EVENT(xfs_inode_set_eofbloc DEFINE_INODE_EVENT(xfs_inode_clear_eofblocks_tag); DEFINE_INODE_EVENT(xfs_inode_free_eofblocks_invalid); +DEFINE_INODE_EVENT(xfs_filemap_fault); + DECLARE_EVENT_CLASS(xfs_iref_class, TP_PROTO(struct xfs_inode *ip, unsigned long caller_ip), TP_ARGS(ip, caller_ip),