From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 137EAC4167D for ; Mon, 20 Sep 2021 18:04:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 07B6E613B5 for ; Mon, 20 Sep 2021 18:04:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357926AbhITSFO (ORCPT ); Mon, 20 Sep 2021 14:05:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:58466 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347903AbhITR7A (ORCPT ); Mon, 20 Sep 2021 13:59:00 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2BF7163218; Mon, 20 Sep 2021 17:15:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1632158121; bh=N01rFWMIESTbGlmm3z6+y+F94ZscUPhe8NXzPUvifdw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IOmAueTxi50CFCqqX7WOK3JzRsuC5VmwzpB9nzrG61V6+41TP3d4laCQo6e99epIi M/e8O0wYa3yo/sjeqH6T9D7Mlf5WzKLQyAtjcjf/aPE27cTk96iWDU9kQtjj7c/3fQ WlHB2TPQYq6r8Zt2ONq/Q/DH0wNI9YNeMKyQ2LCo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nikolay Borisov , Josef Bacik , David Sterba Subject: [PATCH 5.4 002/260] btrfs: wake up async_delalloc_pages waiters after submit Date: Mon, 20 Sep 2021 18:40:20 +0200 Message-Id: <20210920163931.207132508@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210920163931.123590023@linuxfoundation.org> References: <20210920163931.123590023@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Josef Bacik commit ac98141d140444fe93e26471d3074c603b70e2ca upstream. We use the async_delalloc_pages mechanism to make sure that we've completed our async work before trying to continue our delalloc flushing. The reason for this is we need to see any ordered extents that were created by our delalloc flushing. However we're waking up before we do the submit work, which is before we create the ordered extents. This is a pretty wide race window where we could potentially think there are no ordered extents and thus exit shrink_delalloc prematurely. Fix this by waking us up after we've done the work to create ordered extents. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Nikolay Borisov Signed-off-by: Josef Bacik Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/inode.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -1200,11 +1200,6 @@ static noinline void async_cow_submit(st nr_pages = (async_chunk->end - async_chunk->start + PAGE_SIZE) >> PAGE_SHIFT; - /* atomic_sub_return implies a barrier */ - if (atomic_sub_return(nr_pages, &fs_info->async_delalloc_pages) < - 5 * SZ_1M) - cond_wake_up_nomb(&fs_info->async_submit_wait); - /* * ->inode could be NULL if async_chunk_start has failed to compress, * in which case we don't have anything to submit, yet we need to @@ -1213,6 +1208,11 @@ static noinline void async_cow_submit(st */ if (async_chunk->inode) submit_compressed_extents(async_chunk); + + /* atomic_sub_return implies a barrier */ + if (atomic_sub_return(nr_pages, &fs_info->async_delalloc_pages) < + 5 * SZ_1M) + cond_wake_up_nomb(&fs_info->async_submit_wait); } static noinline void async_cow_free(struct btrfs_work *work)