From patchwork Thu Feb 10 05:59:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naohiro Aota X-Patchwork-Id: 541731 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 9503FC43217 for ; Thu, 10 Feb 2022 06:00:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231366AbiBJGAa (ORCPT ); Thu, 10 Feb 2022 01:00:30 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:49576 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234925AbiBJGA1 (ORCPT ); Thu, 10 Feb 2022 01:00:27 -0500 X-Greylist: delayed 64 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Wed, 09 Feb 2022 22:00:29 PST Received: from esa4.hgst.iphmx.com (esa4.hgst.iphmx.com [216.71.154.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B2581C5; Wed, 9 Feb 2022 22:00:29 -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=1644472829; x=1676008829; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=BskrxKkk4ZgB0vbGwHcFCr4Bnt7JqRs+SAZMxpuzF6U=; b=IlICHxOt5IVJiJsg7T2C7Mnr6SjDWwOBzGtXSO+4Zgg1XI3nmQaKHNh3 NiqY/T9hywLMYZ5rUEaKKQMTPncAKr1VxpfztTxzFAj97TN1WvDbnPlWN OVgs/rmLWnm6P+0i2QdBXeKEzKmILVXMQ9ISBfSgJPdG7TjClehDut2AL n004u/izmAueymMC8MunGda7uBeaBnIWkdib/aVbWTg1QgEUUHsIUqJI3 d7NmLLQKmxdJ0dx46UzoAUpDbJMWmmsEmELAtQcDyFi6hqkzWZpbrrx55 /pHsHljzLL3DE4B25SN+hNV9OXrm5VOnitZi/Op0mzF67Crgb1B0AP0+Y A==; X-IronPort-AV: E=Sophos;i="5.88,357,1635177600"; d="scan'208";a="191512599" Received: from uls-op-cesaip01.wdc.com (HELO uls-op-cesaep01.wdc.com) ([199.255.45.14]) by ob1.hgst.iphmx.com with ESMTP; 10 Feb 2022 13:59:23 +0800 IronPort-SDR: 4eFZiF35f47U4Jvn8873x1hapHzSxj3uJoA7HR8P+RqLdwZ2OWFJp7JOCgi0Jz74fw51qZikVl P3OTMFkjlDc4/Iyr+GLx76x4L/RiPDarQFOqxKuj9LG6fzvgTpvVAhQ0eUQO7Mb4vCdJP5ByDq TrjE0CDLximwvFUmaIYjnIxQK0ONsowwG6NZ+ra3y++tOBAQ9eAIdHdLe3IU8qTUFtwY26v53x wN+zJ99T/LmCiYsXcwi8ZsK+hWc4s1Mp/LgxZNPhH9THNkD+vR6Ss5X1LUqvxM044sW83qxawD LktA7yOKqPzFcu8BGF2mccxx 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; 09 Feb 2022 21:32:21 -0800 IronPort-SDR: EhaxfJoriGF0CnzQ2z5+VDI7p/jAwtYYk7HME3QWqhk2ud4vsK8HpojGeEwopOHe3q1JAxT6LK ICdYBK+C8x3lE8G+D4wDP5IxIoGpoU2WOI4mbO3LvD2N/uhqp/VBzwAwsgi+gwGrYnjjSt8VrR yAv3/0ir0XiChz7e+KApJvr202xnT/M1x/OGUeFiIu0G4zJ9Urjg6fKCUCXNIQ9/K3D/k6S+tr TBpmnYLshQblEmYcYBpLICsUg0uGQT9TZS6VRT+MgHqs6p1RfmCfJeYLVuNPK8zkKsZKInWn4E wiY= WDCIronportException: Internal Received: from chmc3h2.ad.shared (HELO naota-xeon.wdc.com) ([10.225.51.94]) by uls-op-cesaip02.wdc.com with ESMTP; 09 Feb 2022 21:59:24 -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, Naohiro Aota , stable@vger.kernel.org Subject: [PATCH v2 2/2] btrfs: zoned: mark relocation as writing Date: Thu, 10 Feb 2022 14:59:05 +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: stable@vger.kernel.org There is a hung_task issue with running generic/068 on an SMR device. The hang occurs while a process is trying to thaw the filesystem. The process is trying to take sb->s_umount to thaw the FS. The lock is held by fsstress, which calls btrfs_sync_fs() and is waiting for an ordered extent to finish. However, as the FS is frozen, the ordered extent never finish. Having an ordered extent while the FS is frozen is the root cause of the hang. The ordered extent is initiated from btrfs_relocate_chunk() which is called from btrfs_reclaim_bgs_work(). This commit add sb_*_write() around btrfs_relocate_chunk() call site. For the usual "btrfs balance" command, we already call it with mnt_want_file() in btrfs_ioctl_balance(). Additionally, add an ASSERT in btrfs_relocate_chunk() to check it is properly called. Fixes: 18bb8bbf13c1 ("btrfs: zoned: automatically reclaim zones") Cc: stable@vger.kernel.org # 5.13+ Link: https://github.com/naota/linux/issues/56 Signed-off-by: Naohiro Aota --- fs/btrfs/block-group.c | 8 +++++++- fs/btrfs/volumes.c | 6 ++++++ 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c index 68feabc83a27..f9ca58a90630 100644 --- a/fs/btrfs/block-group.c +++ b/fs/btrfs/block-group.c @@ -1513,8 +1513,12 @@ void btrfs_reclaim_bgs_work(struct work_struct *work) if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags)) return; - if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE)) + sb_start_write(fs_info->sb); + + if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE)) { + sb_end_write(fs_info->sb); return; + } /* * Long running balances can keep us blocked here for eternity, so @@ -1522,6 +1526,7 @@ void btrfs_reclaim_bgs_work(struct work_struct *work) */ if (!mutex_trylock(&fs_info->reclaim_bgs_lock)) { btrfs_exclop_finish(fs_info); + sb_end_write(fs_info->sb); return; } @@ -1596,6 +1601,7 @@ void btrfs_reclaim_bgs_work(struct work_struct *work) spin_unlock(&fs_info->unused_bgs_lock); mutex_unlock(&fs_info->reclaim_bgs_lock); btrfs_exclop_finish(fs_info); + sb_end_write(fs_info->sb); } void btrfs_reclaim_bgs(struct btrfs_fs_info *fs_info) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index b07d382d53a8..e415fb4a698e 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -3251,6 +3251,9 @@ int btrfs_relocate_chunk(struct btrfs_fs_info *fs_info, u64 chunk_offset) u64 length; int ret; + /* Assert we called sb_start_write(), not to race with FS freezing */ + sb_assert_write_started(fs_info->sb); + /* * Prevent races with automatic removal of unused block groups. * After we relocate and before we remove the chunk with offset @@ -8299,10 +8302,12 @@ static int relocating_repair_kthread(void *data) target = cache->start; btrfs_put_block_group(cache); + sb_start_write(fs_info->sb); if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE)) { btrfs_info(fs_info, "zoned: skip relocating block group %llu to repair: EBUSY", target); + sb_end_write(fs_info->sb); return -EBUSY; } @@ -8330,6 +8335,7 @@ static int relocating_repair_kthread(void *data) btrfs_put_block_group(cache); mutex_unlock(&fs_info->reclaim_bgs_lock); btrfs_exclop_finish(fs_info); + sb_end_write(fs_info->sb); return ret; }