From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: [PATCH 5/5] writeback: check skipped pages on WB_SYNC_ALL Date: Tue, 09 Nov 2010 07:09:21 +0800 Message-ID: <20101108231727.275529265@intel.com> References: <20101108230916.826791396@intel.com> Cc: Jan Kara , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Johannes Weiner , Wu Fengguang To: Andrew Morton Return-path: Received: from mga09.intel.com ([134.134.136.24]:15198 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751437Ab0KHXTh (ORCPT ); Mon, 8 Nov 2010 18:19:37 -0500 cc: Christoph Hellwig , Jan Engelhardt Cc: LKML Content-Disposition: inline; filename=writeback-warn-sync-skipped_pages.patch Sender: linux-fsdevel-owner@vger.kernel.org List-ID: In WB_SYNC_ALL mode, filesystems are not expected to skip dirty pages on temporal lock contentions or non fatal errors, otherwise sync() will return without actually syncing the skipped pages. Add a check to catch possible redirty_page_for_writepage() callers that violate this expectation. I'd recommend to keep this check in -mm tree for some time and fixup the possible warnings before pushing it to upstream. Signed-off-by: Wu Fengguang --- fs/fs-writeback.c | 1 + 1 file changed, 1 insertion(+) --- linux-next.orig/fs/fs-writeback.c 2010-11-07 22:01:06.000000000 +0800 +++ linux-next/fs/fs-writeback.c 2010-11-07 22:01:15.000000000 +0800 @@ -527,6 +527,7 @@ static int writeback_sb_inodes(struct su * buffers. Skip this inode for now. */ redirty_tail(inode); + WARN_ON_ONCE(wbc->sync_mode == WB_SYNC_ALL); } spin_unlock(&inode_lock); iput(inode);