From patchwork Fri Mar 11 07:38:02 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naohiro Aota X-Patchwork-Id: 12777530 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D45CEC4332F for ; Fri, 11 Mar 2022 07:38:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347161AbiCKHjp (ORCPT ); Fri, 11 Mar 2022 02:39:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42968 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231806AbiCKHjo (ORCPT ); Fri, 11 Mar 2022 02:39:44 -0500 Received: from esa3.hgst.iphmx.com (esa3.hgst.iphmx.com [216.71.153.141]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 17F154F9C8; Thu, 10 Mar 2022 23:38:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1646984321; x=1678520321; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=jeCPpho/pRrNLIRebS5xYxPYkhodGWGJai8/U6MxEg0=; b=K2J5PQMoLtr09xbq2HPiT4ErkAs9dMU6YUQx0/twaU7NLnQ1ivLp8g+h R7/V2IOCPr+h0DWhcJioye7l21XA4bv7x/PZiLrQ2sBQGFlGHKOWgUmY7 26bF13hE3dK8l+kFu8Jb1FwZPS59ptWDMoUWrA4f8UnxjCb+GOsaeQbmf FkWBbjxfpbc8PDRueamjIg3tvi1AJYXzeTeVnLSdOQE8HEXQQFadyaC+9 yhRmOh6cv612Wh1WUH93qw2FBEV4aSwx/XCYUDhs5zs5NRyloAdwhtowY 9EVqVzfE0he+uB1LE7cgY/aGAMF7rJYvMXN4zEiPlCykCq9spKVj3Dq4u g==; X-IronPort-AV: E=Sophos;i="5.90,173,1643644800"; d="scan'208";a="199899084" Received: from uls-op-cesaip01.wdc.com (HELO uls-op-cesaep01.wdc.com) ([199.255.45.14]) by ob1.hgst.iphmx.com with ESMTP; 11 Mar 2022 15:38:41 +0800 IronPort-SDR: sp0LjSXM2j1NgRZJga5DojHNsBS8sGX+Uip2fixd92nAnGYwBP3iZG/Sr/fLxQicCn00eHIEJf xEJhrXS5lhO0o8jAB72BMpW9XRLkypbvdEmC8kfGPI3ILXqdUdfKvFHKkN3dRHe4ZQ0sX7PxZK AMNrLu9DtfF4osrPci8briBs9vC8cr8TnF0s9au4tBsVmM/eRxahcjPB2DkTdHXRUjypplqCaM JRMb5uSZ+VCUIYqw3j2i+kfLXs7ocIP2ul7IgyLwTbqDsrjLXRvq9iTe0+MR9ItKTCzqOaVG/l L+a6xRJUJrckQChKnstAcyo+ Received: from uls-op-cesaip02.wdc.com ([10.248.3.37]) by uls-op-cesaep01.wdc.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Mar 2022 23:10:54 -0800 IronPort-SDR: i9t84WH50XF/cEm+tBgwkGRKmJboI6Ud0p/+ICQ5JpYy3XuyW8XPsAT+q6HIskkMqs9TlsYnW9 r6NgrzRnLtSKFPXLK3PyJ+nxK4AyIHcAIK61vSAONhh7dvVatTx4ixCljHf0Rfkj8yKiCWZnHt YsJd6U3hC+AMWBqrhq8PPOcCgvYKKgVC/9bbBlqPAEUWA1wbQpDtT5vpS5Uld5JP/9mLQ6+bXR tCyxorqZRiLvhI2J2eJfDAlgEaqB9akm8VYaAbS/97UNRNz+Ev9QCvN7ErQyrkkKDP4T6s0HES YgQ= WDCIronportException: Internal Received: from dyv5jr2.ad.shared (HELO naota-xeon.wdc.com) ([10.225.50.231]) by uls-op-cesaip02.wdc.com with ESMTP; 10 Mar 2022 23:38:41 -0800 From: Naohiro Aota To: linux-btrfs@vger.kernel.org Cc: johannes.thumshirn@wdc.com, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, david@fromorbit.com, Naohiro Aota Subject: [PATCH 1/4] btrfs: mark resumed async balance as writing Date: Fri, 11 Mar 2022 16:38:02 +0900 Message-Id: <65730df62341500bfcbde7d86eeaa3e9b15f1bcb.1646983176.git.naohiro.aota@wdc.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org When btrfs balance is interrupted with umount, the background balance resumes on the next mount. There is a potential deadlock with FS freezing here like as described in commit 26559780b953 ("btrfs: zoned: mark relocation as writing"). Mark the process as sb_writing. To preserve the order of sb_start_write() (or mnt_want_write_file()) and btrfs_exclop_start(), call sb_start_write() at btrfs_resume_balance_async() before taking fs_info->super_lock. Fixes: 5accdf82ba25 ("fs: Improve filesystem freezing handling") Cc: stable@vger.kernel.org Signed-off-by: Naohiro Aota --- fs/btrfs/volumes.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 1be7cb2f955f..0d27d8d35c7a 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4443,6 +4443,7 @@ static int balance_kthread(void *data) if (fs_info->balance_ctl) ret = btrfs_balance(fs_info, fs_info->balance_ctl, NULL); mutex_unlock(&fs_info->balance_mutex); + sb_end_write(fs_info->sb); return ret; } @@ -4463,6 +4464,7 @@ int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info) return 0; } + sb_start_write(fs_info->sb); spin_lock(&fs_info->super_lock); ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED); fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE;