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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 CA3C7C433DB for ; Mon, 18 Jan 2021 14:38:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7C29C221FB for ; Mon, 18 Jan 2021 14:38:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392804AbhAROiE (ORCPT ); Mon, 18 Jan 2021 09:38:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:37986 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390367AbhARLnJ (ORCPT ); Mon, 18 Jan 2021 06:43:09 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 486FD22227; Mon, 18 Jan 2021 11:42:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610970165; bh=SW8pekvyeoZLTf4z4Px0rpMAaFdnyZ0SHKFlEoYSM0E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nnnNn+RMdQ4Wq/TKK4+BTDuekM7i+XWLUtfE240xsbI7YyXLuH51ggiPcOMU5CAId 63+jjpop3zXgRoKsnU8VD7pDTnlmn14Hok/WFQVHOERNeysHhsLnqn/IKUXoUYaBHs RGHhvAJ7KSDxGtzVwh5FIwIuwi5w1RXuKhlgMnm8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josef Bacik , Pavel Begunkov , David Sterba , Sasha Levin Subject: [PATCH 5.10 063/152] btrfs: fix async discard stall Date: Mon, 18 Jan 2021 12:33:58 +0100 Message-Id: <20210118113355.813131517@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210118113352.764293297@linuxfoundation.org> References: <20210118113352.764293297@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: Pavel Begunkov [ Upstream commit ea9ed87c73e87e044b2c58d658eb4ba5216bc488 ] Might happen that bg->discard_eligible_time was changed without rescheduling, so btrfs_discard_workfn() wakes up earlier than that new time, peek_discard_list() returns NULL, and all work halts and goes to sleep without further rescheduling even there are block groups to discard. It happens pretty often, but not so visible from the userspace because after some time it usually will be kicked off anyway by someone else calling btrfs_discard_reschedule_work(). Fix it by continue rescheduling if block group discard lists are not empty. Reviewed-by: Josef Bacik Signed-off-by: Pavel Begunkov Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/discard.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/fs/btrfs/discard.c b/fs/btrfs/discard.c index 741c7e19c32f2..d1a5380e8827d 100644 --- a/fs/btrfs/discard.c +++ b/fs/btrfs/discard.c @@ -199,16 +199,15 @@ static struct btrfs_block_group *find_next_block_group( static struct btrfs_block_group *peek_discard_list( struct btrfs_discard_ctl *discard_ctl, enum btrfs_discard_state *discard_state, - int *discard_index) + int *discard_index, u64 now) { struct btrfs_block_group *block_group; - const u64 now = ktime_get_ns(); spin_lock(&discard_ctl->lock); again: block_group = find_next_block_group(discard_ctl, now); - if (block_group && now > block_group->discard_eligible_time) { + if (block_group && now >= block_group->discard_eligible_time) { if (block_group->discard_index == BTRFS_DISCARD_INDEX_UNUSED && block_group->used != 0) { if (btrfs_is_block_group_data_only(block_group)) @@ -222,12 +221,11 @@ again: block_group->discard_state = BTRFS_DISCARD_EXTENTS; } discard_ctl->block_group = block_group; + } + if (block_group) { *discard_state = block_group->discard_state; *discard_index = block_group->discard_index; - } else { - block_group = NULL; } - spin_unlock(&discard_ctl->lock); return block_group; @@ -429,13 +427,18 @@ static void btrfs_discard_workfn(struct work_struct *work) int discard_index = 0; u64 trimmed = 0; u64 minlen = 0; + u64 now = ktime_get_ns(); discard_ctl = container_of(work, struct btrfs_discard_ctl, work.work); block_group = peek_discard_list(discard_ctl, &discard_state, - &discard_index); + &discard_index, now); if (!block_group || !btrfs_run_discard_work(discard_ctl)) return; + if (now < block_group->discard_eligible_time) { + btrfs_discard_schedule_work(discard_ctl, false); + return; + } /* Perform discarding */ minlen = discard_minlen[discard_index]; -- 2.27.0