From patchwork Wed Mar 16 13:22:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naohiro Aota X-Patchwork-Id: 12782691 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 108E0C433EF for ; Wed, 16 Mar 2022 13:23:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244037AbiCPNYX (ORCPT ); Wed, 16 Mar 2022 09:24:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40018 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238918AbiCPNYW (ORCPT ); Wed, 16 Mar 2022 09:24:22 -0400 Received: from esa2.hgst.iphmx.com (esa2.hgst.iphmx.com [68.232.143.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8836CA188; Wed, 16 Mar 2022 06:23:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1647436987; x=1678972987; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=kCqIT6QE4X6rjqZGfyRVMUMbl6cnDFW78z03eIIrjMY=; b=nE1f0ZxYzkW4mhBTvgSz+l/quHxF2TrrSxIehT6vT9tjZBzL+uCSsUDw Ayxh81Jn5YdTZmN78gyI6HEw1yDv2WBlK2kmDquN+QZfoU1oZLFyNLRSK 1Nfy69yUsEQXzlYER65E1aKXKiRZIzV7ZM3GAzApQexUMpFY+7aUjd+vu SrnuNOlOfqtLKBKUMPmUU5cxuO8Wn8jf4LFYIq21JMzvl6YL32RKHnE3f ZGLTaIb7+lGegglZ3YxMI4EVRWgrI0XsTRlC6utbEfxPCdnxPIVQ2zUe7 WCUufyZ1XU46VsniVMgznXYeSUEx+tcI2nrBwE3UkmdgPO5728XlqZLqJ g==; X-IronPort-AV: E=Sophos;i="5.90,186,1643644800"; d="scan'208";a="299654875" Received: from uls-op-cesaip02.wdc.com (HELO uls-op-cesaep02.wdc.com) ([199.255.45.15]) by ob1.hgst.iphmx.com with ESMTP; 16 Mar 2022 21:23:07 +0800 IronPort-SDR: KZaIeq9tbwICFt4rR1PhVvJ0cgLtAVWn1gthIG8yDHMw1j/Z/Svoti2BS7pdcttAZ2yAswgemm NhhDuSxQIjl6h9VwwfYw46BExCn7+U67CUTkLYJEIx5vylhZ8tBHatkAVAJ8dzNX0NHpd4SSoJ K9PabBnj+/xE+HjZzt5VV7VnQBB24SVItS3FwP4hOiwtAP0sMNBYB5y0CiJW3PRHlgDF7FqQuu +JwLKIkXIVgh0VR+Mim7wwTpDIrWQfNfhia31PAqUv2zBocW+y8jAOiNKc9Bd7WqvITs1wWERV yUzcgL+DFiy5g/FLexwuh3cp Received: from uls-op-cesaip01.wdc.com ([10.248.3.36]) by uls-op-cesaep02.wdc.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Mar 2022 05:54:13 -0700 IronPort-SDR: h6pANHya6cNJa88DC1iwMORVk1t0Z8B8LtArPceHg4/YDHusZQRsHTopJVcfBLjNEgAKBLC9s7 vRFfQrslHKWv+DjIGaZO3sXCp154mYZstC46dBPLKmwOd9EzELnJrcoq1sG1rQpX2guq/0Dm/m ikfGZYO9mbEwHqD2ikSoBaKXda/+9FDhBIi1fdv0xA6Saw6zFOPaqFHoMGDt5DgZ2ctQ9Ccwf0 fubirgoV1fjxA5ei3Kudto/Gu//YByWevcAtSjtj5hDXW6Qrc0b8IeGqOE7eEPb306I8i8899s grk= WDCIronportException: Internal Received: from d2bbl13.ad.shared (HELO naota-xeon.wdc.com) ([10.225.55.209]) by uls-op-cesaip01.wdc.com with ESMTP; 16 Mar 2022 06:23:06 -0700 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 v2 1/4] btrfs: mark resumed async balance as writing Date: Wed, 16 Mar 2022 22:22:37 +0900 Message-Id: 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. Cc: stable@vger.kernel.org # 4.9+ Signed-off-by: Naohiro Aota Reviewed-by: Filipe Manana --- fs/btrfs/volumes.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 3fd17e87815a..3471698fd831 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4430,10 +4430,12 @@ static int balance_kthread(void *data) struct btrfs_fs_info *fs_info = data; int ret = 0; + sb_start_write(fs_info->sb); mutex_lock(&fs_info->balance_mutex); 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; }