From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o4PAqZCm242762 for ; Tue, 25 May 2010 05:52:36 -0500 Received: from mail.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 6FD4736D26E for ; Tue, 25 May 2010 03:54:57 -0700 (PDT) Received: from mail.internode.on.net (bld-mail13.adl6.internode.on.net [150.101.137.98]) by cuda.sgi.com with ESMTP id hlOgvMi29z7qR3d8 for ; Tue, 25 May 2010 03:54:57 -0700 (PDT) From: Dave Chinner Subject: [PATCH 6/6] writeback: limit write_cache_pages integrity scanning to current EOF Date: Tue, 25 May 2010 20:54:12 +1000 Message-Id: <1274784852-30502-7-git-send-email-david@fromorbit.com> In-Reply-To: <1274784852-30502-1-git-send-email-david@fromorbit.com> References: <1274784852-30502-1-git-send-email-david@fromorbit.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, jens.axboe@oracle.com, linux-ext4@vger.kernel.org, tytso@mit.edu, xfs@oss.sgi.com From: Dave Chinner sync can currently take a really long time if a concurrent writer is extending a file. The problem is that the dirty pages on the address space grow in the same direction as write_cache_pages scans, so if the writer keeps ahead of writeback, the writeback will not terminate until the writer stops adding dirty pages. For a data integrity sync, we only need to write the pages dirty at the time we start the writeback, so we can stop scanning once we get to the page that was at the end of the file at the time the scan started. This will prevent operations like copying a large file preventing sync from completing as it will not write back pages that were dirtied after the sync was started. This does not impact the existing integrity guarantees, as any dirty page (old or new) within the EOF range at the start of the scan will still be captured. Signed-off-by: Dave Chinner --- mm/page-writeback.c | 15 +++++++++++++++ 1 files changed, 15 insertions(+), 0 deletions(-) diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 0fe713d..c97e973 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -855,7 +855,22 @@ int write_cache_pages(struct address_space *mapping, if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) range_whole = 1; cycled = 1; /* ignore range_cyclic tests */ + + /* + * If this is a data integrity sync, cap the writeback to the + * current end of file. Any extension to the file that occurs + * after this is a new write and we don't need to write those + * pages out to fulfil our data integrity requirements. If we + * try to write them out, we can get stuck in this scan until + * the concurrent writer stops adding dirty pages and extending + * EOF. + */ + if (wbc->sync_mode == WB_SYNC_ALL && + wbc->range_end == LLONG_MAX) { + end = i_size_read(mapping->host) >> PAGE_CACHE_SHIFT; + } } + retry: done_index = index; while (!done && (index <= end)) { -- 1.5.6.5 _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs