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=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 14962C433E4 for ; Thu, 20 Aug 2020 13:23:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E0A5922D07 for ; Thu, 20 Aug 2020 13:22:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597929779; bh=7cAz3Ec2k+7Y8nlZLkYt3m3jyL4YEhx1BCEiANHBXnE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=0Y1401/eK3ZEIEctMpLS2TtrOQje0zPMO/1O2JP+fiDa6nX9TvR09fdOEXBZGm4Bi Ia9naqHYMqOCcSx0d+ixRLYu4zSt5buEoTZiPVJ76J8RBcU61A4z5E1r0MU5pD5x3X 2QQl+V37o6xlrUtCCA85JB9Pwlg0Yo4QhJxYwG04= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730385AbgHTNRq (ORCPT ); Thu, 20 Aug 2020 09:17:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:48070 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728172AbgHTJez (ORCPT ); Thu, 20 Aug 2020 05:34:55 -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 BBC7B20724; Thu, 20 Aug 2020 09:34:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597916095; bh=7cAz3Ec2k+7Y8nlZLkYt3m3jyL4YEhx1BCEiANHBXnE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eVYNB8h6WrwwGG52s+B8KvIB/FgJ9Egxag0xMvTrz32Tnme5EZnbxgYfDjkwYR60R W3dApJnv/kfFdiCGX39329y/OAE/o4pWtEYTlpvzCW4Ra9JQCqzs5KGcNcSTL64yWc uDlOfoSniVhuIhMPs6ma/x7FPUlrVJKgLtRKO4Gw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Johannes Thumshirn , David Sterba Subject: [PATCH 5.7 010/204] btrfs: allow use of global block reserve for balance item deletion Date: Thu, 20 Aug 2020 11:18:27 +0200 Message-Id: <20200820091606.724524770@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200820091606.194320503@linuxfoundation.org> References: <20200820091606.194320503@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: David Sterba commit 3502a8c0dc1bd4b4970b59b06e348f22a1c05581 upstream. On a filesystem with exhausted metadata, but still enough to start balance, it's possible to hit this error: [324402.053842] BTRFS info (device loop0): 1 enospc errors during balance [324402.060769] BTRFS info (device loop0): balance: ended with status: -28 [324402.172295] BTRFS: error (device loop0) in reset_balance_state:3321: errno=-28 No space left It fails inside reset_balance_state and turns the filesystem to read-only, which is unnecessary and should be fixed too, but the problem is caused by lack for space when the balance item is deleted. This is a one-time operation and from the same rank as unlink that is allowed to use the global block reserve. So do the same for the balance item. Status of the filesystem (100GiB) just after the balance fails: $ btrfs fi df mnt Data, single: total=80.01GiB, used=38.58GiB System, single: total=4.00MiB, used=16.00KiB Metadata, single: total=19.99GiB, used=19.48GiB GlobalReserve, single: total=512.00MiB, used=50.11MiB CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Johannes Thumshirn Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/volumes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -3235,7 +3235,7 @@ static int del_balance_item(struct btrfs if (!path) return -ENOMEM; - trans = btrfs_start_transaction(root, 0); + trans = btrfs_start_transaction_fallback_global_rsv(root, 0); if (IS_ERR(trans)) { btrfs_free_path(path); return PTR_ERR(trans);