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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 6A181C433E1 for ; Thu, 20 Aug 2020 13:59:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3F7F3206DA for ; Thu, 20 Aug 2020 13:59:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597931996; bh=yKmAMZWwCOzOAmbAJPyXG2Z9j6Mu8i6EZ/wMCEjEhhM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uDR6bWxS/+QXwgXmVFemiw53zG+8/kjPZb7WkpfBrKwMUHvwVrc49nWEyBZ3lp9bl uLGO5FBddsyh0xP2udAA2JaM30bwSry5OMF1BQkzKp4nL52fL++sCn0SkMAU/RsUlx 15sP/JQYIMKofbRlW0ILhDUR+jEF4bEybyXYXD98= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727047AbgHTN7x (ORCPT ); Thu, 20 Aug 2020 09:59:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:59916 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726735AbgHTJX7 (ORCPT ); Thu, 20 Aug 2020 05:23:59 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B682222D02; Thu, 20 Aug 2020 09:23:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597915439; bh=yKmAMZWwCOzOAmbAJPyXG2Z9j6Mu8i6EZ/wMCEjEhhM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1aMdTWsMzF0+ccw/wp86aOS3twRhTJp/5AGuxev5xrePU4ecc9lsirsCv0H6yj3ad zFX8mOp6wedkpw006Zv1/V9MkjGrTNReiCCB31KzEHWbdrYP7SVBD1KMz62m8PYreB vl7l9DXMHGlIzAMJfvkW31aUipgZyAJn4n/JHPtQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Greed Rong , Josef Bacik , Qu Wenruo , David Sterba Subject: [PATCH 5.8 014/232] btrfs: free anon block device right after subvolume deletion Date: Thu, 20 Aug 2020 11:17:45 +0200 Message-Id: <20200820091613.418255504@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200820091612.692383444@linuxfoundation.org> References: <20200820091612.692383444@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Qu Wenruo commit 082b6c970f02fefd278c7833880cda29691a5f34 upstream. [BUG] When a lot of subvolumes are created, there is a user report about transaction aborted caused by slow anonymous block device reclaim: BTRFS: Transaction aborted (error -24) WARNING: CPU: 17 PID: 17041 at fs/btrfs/transaction.c:1576 create_pending_snapshot+0xbc4/0xd10 [btrfs] RIP: 0010:create_pending_snapshot+0xbc4/0xd10 [btrfs] Call Trace: create_pending_snapshots+0x82/0xa0 [btrfs] btrfs_commit_transaction+0x275/0x8c0 [btrfs] btrfs_mksubvol+0x4b9/0x500 [btrfs] btrfs_ioctl_snap_create_transid+0x174/0x180 [btrfs] btrfs_ioctl_snap_create_v2+0x11c/0x180 [btrfs] btrfs_ioctl+0x11a4/0x2da0 [btrfs] do_vfs_ioctl+0xa9/0x640 ksys_ioctl+0x67/0x90 __x64_sys_ioctl+0x1a/0x20 do_syscall_64+0x5a/0x110 entry_SYSCALL_64_after_hwframe+0x44/0xa9 ---[ end trace 33f2f83f3d5250e9 ]--- BTRFS: error (device sda1) in create_pending_snapshot:1576: errno=-24 unknown BTRFS info (device sda1): forced readonly BTRFS warning (device sda1): Skipping commit of aborted transaction. BTRFS: error (device sda1) in cleanup_transaction:1831: errno=-24 unknown [CAUSE] The anonymous device pool is shared and its size is 1M. It's possible to hit that limit if the subvolume deletion is not fast enough and the subvolumes to be cleaned keep the ids allocated. [WORKAROUND] We can't avoid the anon device pool exhaustion but we can shorten the time the id is attached to the subvolume root once the subvolume becomes invisible to the user. Reported-by: Greed Rong Link: https://lore.kernel.org/linux-btrfs/CA+UqX+NTrZ6boGnWHhSeZmEY5J76CTqmYjO2S+=tHJX7nb9DPw@mail.gmail.com/ CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Josef Bacik Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/inode.c | 2 ++ 1 file changed, 2 insertions(+) --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -4041,6 +4041,8 @@ int btrfs_delete_subvolume(struct inode } } + free_anon_bdev(dest->anon_dev); + dest->anon_dev = 0; out_end_trans: trans->block_rsv = NULL; trans->bytes_reserved = 0;