From patchwork Mon Dec 24 09:57:19 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miao Xie X-Patchwork-Id: 1908461 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 3EC4C40061 for ; Mon, 24 Dec 2012 09:56:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752982Ab2LXJ4z (ORCPT ); Mon, 24 Dec 2012 04:56:55 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:25826 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752841Ab2LXJ4x (ORCPT ); Mon, 24 Dec 2012 04:56:53 -0500 X-IronPort-AV: E=Sophos;i="4.84,346,1355068800"; d="scan'208";a="6463484" Received: from unknown (HELO tang.cn.fujitsu.com) ([10.167.250.3]) by song.cn.fujitsu.com with ESMTP; 24 Dec 2012 17:54:56 +0800 Received: from fnstmail02.fnst.cn.fujitsu.com (tang.cn.fujitsu.com [127.0.0.1]) by tang.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id qBO9urBM014494; Mon, 24 Dec 2012 17:56:54 +0800 Received: from [10.167.225.199] ([10.167.225.199]) by fnstmail02.fnst.cn.fujitsu.com (Lotus Domino Release 8.5.3) with ESMTP id 2012122417564338-580669 ; Mon, 24 Dec 2012 17:56:43 +0800 Message-ID: <50D826FF.8040202@cn.fujitsu.com> Date: Mon, 24 Dec 2012 17:57:19 +0800 From: Miao Xie Reply-To: miaox@cn.fujitsu.com User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Linux Btrfs CC: Josef Bacik Subject: [PATCH V2] Btrfs: flush all dirty inodes if writeback can not start References: <50D2F42D.7070600@cn.fujitsu.com> In-Reply-To: <50D2F42D.7070600@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/12/24 17:56:43, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/12/24 17:56:43, Serialize complete at 2012/12/24 17:56:43 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org We may try to flush some dirty pages when there is no enough space to reserve. But it is possible that this operation fails, in order to get enough space to reserve successfully, we will sync all the delalloc file. This operation is safe, we needn't worry about the case that the filesystem goes from r/w to r/o. because the filesystem should guarantee all the dirty pages have been written into the disk after it becomes readonly, so the sync operation will do nothing if the filesystem is already readonly. Though it may waste lots of time, as a corner case, we needn't care. Signed-off-by: Miao Xie --- Changelog v1 -> v2: - make the function static --- fs/btrfs/extent-tree.c | 40 +++++++++++++++++++++++++++++++--------- 1 file changed, 31 insertions(+), 9 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index b6ed965..2d9fe27 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -3695,12 +3695,15 @@ static int can_overcommit(struct btrfs_root *root, return 0; } -static int writeback_inodes_sb_nr_if_idle_safe(struct super_block *sb, - unsigned long nr_pages, - enum wb_reason reason) +static inline int writeback_inodes_sb_nr_if_idle_safe(struct super_block *sb, + unsigned long nr_pages, + enum wb_reason reason) { - if (!writeback_in_progress(sb->s_bdi) && - down_read_trylock(&sb->s_umount)) { + /* the flusher is dealing with the dirty inodes now. */ + if (writeback_in_progress(sb->s_bdi)) + return 1; + + if (down_read_trylock(&sb->s_umount)) { writeback_inodes_sb_nr(sb, nr_pages, reason); up_read(&sb->s_umount); return 1; @@ -3709,6 +3712,28 @@ static int writeback_inodes_sb_nr_if_idle_safe(struct super_block *sb, return 0; } +static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root, + unsigned long nr_pages) +{ + struct super_block *sb = root->fs_info->sb; + int started; + + /* If we can not start writeback, just sync all the delalloc file. */ + started = writeback_inodes_sb_nr_if_idle_safe(sb, nr_pages, + WB_REASON_FS_FREE_SPACE); + if (!started) { + /* + * We needn't worry the filesystem going from r/w to r/o though + * we don't acquire ->s_umount mutex, because the filesystem + * should guarantee the delalloc inodes list be empty after + * the filesystem is readonly(all dirty pages are written to + * the disk). + */ + btrfs_start_delalloc_inodes(root, 0); + btrfs_wait_ordered_extents(root, 0); + } +} + /* * shrink metadata reservation for delalloc */ @@ -3741,10 +3766,7 @@ static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig, while (delalloc_bytes && loops < 3) { max_reclaim = min(delalloc_bytes, to_reclaim); nr_pages = max_reclaim >> PAGE_CACHE_SHIFT; - writeback_inodes_sb_nr_if_idle_safe(root->fs_info->sb, - nr_pages, - WB_REASON_FS_FREE_SPACE); - + btrfs_writeback_inodes_sb_nr(root, nr_pages); /* * We need to wait for the async pages to actually start before * we do anything.