From patchwork Thu Jan 13 10:40:29 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shinichiro Kawasaki X-Patchwork-Id: 12712555 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 144EFC433EF for ; Thu, 13 Jan 2022 10:40:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229693AbiAMKke (ORCPT ); Thu, 13 Jan 2022 05:40:34 -0500 Received: from esa3.hgst.iphmx.com ([216.71.153.141]:17679 "EHLO esa3.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229675AbiAMKkb (ORCPT ); Thu, 13 Jan 2022 05:40:31 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1642070430; x=1673606430; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=uPzGB/RhTvH6knRpVAabr39025CX7WDm2IV9oJgpohk=; b=LDvS0Bbm7BKaV55IQ7aSpUsfqvx6sC8UJqH/ClkoU5+8sKgNKu0Unb0E ZV/FfBKoz7KC17YNwrocfXze0H00AmnbLXWDvruTs4l3aQT4OJ95T0tXn HkJcHA/SFOtb7DSfOUYYVMXlXEY2dZ0YOHInalGg+wuYKtwGym1at09za qEx5gL0aA0GFK2wDuv8xwVBsEZ2M0FBO+ujqhgo9IwB3rptDLckKM8kop KbKVwMAIfdChEyfPilJulILtWPK85dPxxF8G/o913VDmE1NchhpU0dcMZ XHBpFr28jMdT20eu4cHcKyHpXfmXyA8Y06Fnxt7Azw0HhNsVmcc9fBG33 w==; X-IronPort-AV: E=Sophos;i="5.88,284,1635177600"; d="scan'208";a="195154496" Received: from uls-op-cesaip01.wdc.com (HELO uls-op-cesaep01.wdc.com) ([199.255.45.14]) by ob1.hgst.iphmx.com with ESMTP; 13 Jan 2022 18:40:30 +0800 IronPort-SDR: eKYpAIaSeTQwJx9beOLYyc+KKK9eS1nL961bkvt9YKWKyxxlIJMA+lGIZzzSyl7SoXIDoUmTNL c6eO52cOxLnI9WaeFgEOmF5mkctIfx9iXIwo4qR4l5nPox8b30dX5Cotlfqjj39MlzI0zPhZPL b+o4Wv9WKeoZ/DrEJrGhTrbJfPKXcrs0lv4oOYsWp3/r8whrEavzqtpvfJcfXm7KYMwrMdP+QC yqoUaqYLT/rvojSV2n2iwpF4fnkQOCjBFQmdb97L8NKxzgc5P65INOrb/j6o8wANox0LkIS6AF FLUgKHa+Dbi2PmCuuT5y8no+ Received: from uls-op-cesaip01.wdc.com ([10.248.3.36]) by uls-op-cesaep01.wdc.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Jan 2022 02:14:10 -0800 IronPort-SDR: 5L+0PROCb4k9+6H4nCBPfsvMEQClkOsJPa1lBsalUDS3dJld7YaynskT9VeC5RbYlVn2SF/PGA KXQAc6qmZafZgHf6MvBCzY2/IcUPPfeNpowOh7Aczc1fB/8hRamuSmnrlD6fuyvEl8ghPnfZ6V CsXHbEcFtUlM++Z3hyLpYKaXAYHMs/aj3NtIfyWE/kciByWvIiX5+C+JXGZ6/ez7js3KyMtEQ6 gU7tzwkyLKAipS9NYduQ9YiT3sp8mS5IPJKowKhH4INeDt2IhZnbOCNZp9dxCDBMTHAJMiMSXi FfE= WDCIronportException: Internal Received: from shindev.dhcp.fujisawa.hgst.com (HELO shindev.fujisawa.hgst.com) ([10.149.52.173]) by uls-op-cesaip01.wdc.com with ESMTP; 13 Jan 2022 02:40:30 -0800 From: Shin'ichiro Kawasaki To: linux-btrfs@vger.kernel.org, David Sterba Cc: Naohiro Aota , Johannes Thumshirn , Damien Le Moal , Shin'ichiro Kawasaki Subject: [PATCH] btrfs: fix deadlock between quota disable and qgroup rescan worker Date: Thu, 13 Jan 2022 19:40:29 +0900 Message-Id: <20220113104029.902200-1-shinichiro.kawasaki@wdc.com> X-Mailer: git-send-email 2.33.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Quota disable ioctl starts a transaction before waiting for the qgroup rescan worker completes. However, this wait can be infinite and results in deadlock because of circular dependency among the quota disable ioctl, the qgroup rescan worker and the other task with transaction such as block group relocation task. The deadlock happens with the steps following: 1) Task A calls ioctl to disable quota. It starts a transaction and waits for qgroup rescan worker completes. 2) Task B such as block group relocation task starts a transaction and joins to the transaction that task A started. Then task B commits to the transaction. In this commit, task B waits for a commit by task A. 3) Task C as the qgroup rescan worker starts its job and starts a transaction. In this transaction start, task C waits for completion of the transaction that task A started and task B committed. This deadlock was found with fstests test case block/115 and a zoned null_blk device. The test case enables and disables quota, and the block group reclaim was triggered during the quota disable by chance. The deadlock was also observed by running quota enable and disable in parallel with 'btrfs balance' command on regular null_blk devices. An example report of the deadlock: [ 372.469894] INFO: task kworker/u16:6:103 blocked for more than 122 seconds. [ 372.479944] Not tainted 5.16.0-rc8 #7 [ 372.485067] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 372.493898] task:kworker/u16:6 state:D stack: 0 pid: 103 ppid: 2 flags:0x00004000 [ 372.503285] Workqueue: btrfs-qgroup-rescan btrfs_work_helper [btrfs] [ 372.510782] Call Trace: [ 372.514092] [ 372.521684] __schedule+0xb56/0x4850 [ 372.530104] ? io_schedule_timeout+0x190/0x190 [ 372.538842] ? lockdep_hardirqs_on+0x7e/0x100 [ 372.547092] ? _raw_spin_unlock_irqrestore+0x3e/0x60 [ 372.555591] schedule+0xe0/0x270 [ 372.561894] btrfs_commit_transaction+0x18bb/0x2610 [btrfs] [ 372.570506] ? btrfs_apply_pending_changes+0x50/0x50 [btrfs] [ 372.578875] ? free_unref_page+0x3f2/0x650 [ 372.585484] ? finish_wait+0x270/0x270 [ 372.591594] ? release_extent_buffer+0x224/0x420 [btrfs] [ 372.599264] btrfs_qgroup_rescan_worker+0xc13/0x10c0 [btrfs] [ 372.607157] ? lock_release+0x3a9/0x6d0 [ 372.613054] ? btrfs_qgroup_account_extent+0xda0/0xda0 [btrfs] [ 372.620960] ? do_raw_spin_lock+0x11e/0x250 [ 372.627137] ? rwlock_bug.part.0+0x90/0x90 [ 372.633215] ? lock_is_held_type+0xe4/0x140 [ 372.639404] btrfs_work_helper+0x1ae/0xa90 [btrfs] [ 372.646268] process_one_work+0x7e9/0x1320 [ 372.652321] ? lock_release+0x6d0/0x6d0 [ 372.658081] ? pwq_dec_nr_in_flight+0x230/0x230 [ 372.664513] ? rwlock_bug.part.0+0x90/0x90 [ 372.670529] worker_thread+0x59e/0xf90 [ 372.676172] ? process_one_work+0x1320/0x1320 [ 372.682440] kthread+0x3b9/0x490 [ 372.687550] ? _raw_spin_unlock_irq+0x24/0x50 [ 372.693811] ? set_kthread_struct+0x100/0x100 [ 372.700052] ret_from_fork+0x22/0x30 [ 372.705517] [ 372.709747] INFO: task btrfs-transacti:2347 blocked for more than 123 seconds. [ 372.729827] Not tainted 5.16.0-rc8 #7 [ 372.745907] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 372.767106] task:btrfs-transacti state:D stack: 0 pid: 2347 ppid: 2 flags:0x00004000 [ 372.787776] Call Trace: [ 372.801652] [ 372.812961] __schedule+0xb56/0x4850 [ 372.830011] ? io_schedule_timeout+0x190/0x190 [ 372.852547] ? lockdep_hardirqs_on+0x7e/0x100 [ 372.871761] ? _raw_spin_unlock_irqrestore+0x3e/0x60 [ 372.886792] schedule+0xe0/0x270 [ 372.901685] wait_current_trans+0x22c/0x310 [btrfs] [ 372.919743] ? btrfs_put_transaction+0x3d0/0x3d0 [btrfs] [ 372.938923] ? finish_wait+0x270/0x270 [ 372.959085] ? join_transaction+0xc75/0xe30 [btrfs] [ 372.977706] start_transaction+0x938/0x10a0 [btrfs] [ 372.997168] transaction_kthread+0x19d/0x3c0 [btrfs] [ 373.013021] ? btrfs_cleanup_transaction.isra.0+0xfc0/0xfc0 [btrfs] [ 373.031678] kthread+0x3b9/0x490 [ 373.047420] ? _raw_spin_unlock_irq+0x24/0x50 [ 373.064645] ? set_kthread_struct+0x100/0x100 [ 373.078571] ret_from_fork+0x22/0x30 [ 373.091197] [ 373.105611] INFO: task btrfs:3145 blocked for more than 123 seconds. [ 373.114147] Not tainted 5.16.0-rc8 #7 [ 373.120401] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 373.130393] task:btrfs state:D stack: 0 pid: 3145 ppid: 3141 flags:0x00004000 [ 373.140998] Call Trace: [ 373.145501] [ 373.149654] __schedule+0xb56/0x4850 [ 373.155306] ? io_schedule_timeout+0x190/0x190 [ 373.161965] ? lockdep_hardirqs_on+0x7e/0x100 [ 373.168469] ? _raw_spin_unlock_irqrestore+0x3e/0x60 [ 373.175468] schedule+0xe0/0x270 [ 373.180814] wait_for_commit+0x104/0x150 [btrfs] [ 373.187643] ? test_and_set_bit+0x20/0x20 [btrfs] [ 373.194772] ? kmem_cache_free+0x124/0x550 [ 373.201191] ? btrfs_put_transaction+0x69/0x3d0 [btrfs] [ 373.208738] ? finish_wait+0x270/0x270 [ 373.214704] ? __btrfs_end_transaction+0x347/0x7b0 [btrfs] [ 373.222342] btrfs_commit_transaction+0x44d/0x2610 [btrfs] [ 373.230233] ? join_transaction+0x255/0xe30 [btrfs] [ 373.237334] ? btrfs_record_root_in_trans+0x4d/0x170 [btrfs] [ 373.245251] ? btrfs_apply_pending_changes+0x50/0x50 [btrfs] [ 373.253296] relocate_block_group+0x105/0xc20 [btrfs] [ 373.260533] ? mutex_lock_io_nested+0x1270/0x1270 [ 373.267516] ? btrfs_wait_nocow_writers+0x85/0x180 [btrfs] [ 373.275155] ? merge_reloc_roots+0x710/0x710 [btrfs] [ 373.283602] ? btrfs_wait_ordered_extents+0xd30/0xd30 [btrfs] [ 373.291934] ? kmem_cache_free+0x124/0x550 [ 373.298180] btrfs_relocate_block_group+0x35c/0x930 [btrfs] [ 373.306047] btrfs_relocate_chunk+0x85/0x210 [btrfs] [ 373.313229] btrfs_balance+0x12f4/0x2d20 [btrfs] [ 373.320227] ? lock_release+0x3a9/0x6d0 [ 373.326206] ? btrfs_relocate_chunk+0x210/0x210 [btrfs] [ 373.333591] ? lock_is_held_type+0xe4/0x140 [ 373.340031] ? rcu_read_lock_sched_held+0x3f/0x70 [ 373.346910] btrfs_ioctl_balance+0x548/0x700 [btrfs] [ 373.354207] btrfs_ioctl+0x7f2/0x71b0 [btrfs] [ 373.360774] ? lockdep_hardirqs_on_prepare+0x410/0x410 [ 373.367957] ? lockdep_hardirqs_on_prepare+0x410/0x410 [ 373.375327] ? btrfs_ioctl_get_supported_features+0x20/0x20 [btrfs] [ 373.383841] ? find_held_lock+0x2c/0x110 [ 373.389993] ? lock_release+0x3a9/0x6d0 [ 373.395828] ? mntput_no_expire+0xf7/0xad0 [ 373.402083] ? lock_is_held_type+0xe4/0x140 [ 373.408249] ? vfs_fileattr_set+0x9f0/0x9f0 [ 373.414486] ? selinux_file_ioctl+0x349/0x4e0 [ 373.420938] ? trace_raw_output_lock+0xb4/0xe0 [ 373.427442] ? selinux_inode_getsecctx+0x80/0x80 [ 373.434224] ? lockdep_hardirqs_on+0x7e/0x100 [ 373.440660] ? force_qs_rnp+0x2a0/0x6b0 [ 373.446534] ? lock_is_held_type+0x9b/0x140 [ 373.452763] ? __blkcg_punt_bio_submit+0x1b0/0x1b0 [ 373.459732] ? security_file_ioctl+0x50/0x90 [ 373.466089] __x64_sys_ioctl+0x127/0x190 [ 373.472022] do_syscall_64+0x3b/0x90 [ 373.477513] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 373.484823] RIP: 0033:0x7f8f4af7e2bb [ 373.490493] RSP: 002b:00007ffcbf936178 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 373.500197] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f8f4af7e2bb [ 373.509451] RDX: 00007ffcbf936220 RSI: 00000000c4009420 RDI: 0000000000000003 [ 373.518659] RBP: 00007ffcbf93774a R08: 0000000000000013 R09: 00007f8f4b02d4e0 [ 373.527872] R10: 00007f8f4ae87740 R11: 0000000000000246 R12: 0000000000000001 [ 373.537222] R13: 00007ffcbf936220 R14: 0000000000000000 R15: 0000000000000002 [ 373.546506] [ 373.550878] INFO: task btrfs:3146 blocked for more than 123 seconds. [ 373.559383] Not tainted 5.16.0-rc8 #7 [ 373.565748] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 373.575748] task:btrfs state:D stack: 0 pid: 3146 ppid: 2168 flags:0x00000000 [ 373.586314] Call Trace: [ 373.590846] [ 373.595121] __schedule+0xb56/0x4850 [ 373.600901] ? __lock_acquire+0x23db/0x5030 [ 373.607176] ? io_schedule_timeout+0x190/0x190 [ 373.613954] schedule+0xe0/0x270 [ 373.619157] schedule_timeout+0x168/0x220 [ 373.625170] ? usleep_range_state+0x150/0x150 [ 373.631653] ? mark_held_locks+0x9e/0xe0 [ 373.637767] ? do_raw_spin_lock+0x11e/0x250 [ 373.643993] ? lockdep_hardirqs_on_prepare+0x17b/0x410 [ 373.651267] ? _raw_spin_unlock_irq+0x24/0x50 [ 373.657677] ? lockdep_hardirqs_on+0x7e/0x100 [ 373.664103] wait_for_completion+0x163/0x250 [ 373.670437] ? bit_wait_timeout+0x160/0x160 [ 373.676585] btrfs_quota_disable+0x176/0x9a0 [btrfs] [ 373.683979] ? btrfs_quota_enable+0x12f0/0x12f0 [btrfs] [ 373.691340] ? down_write+0xd0/0x130 [ 373.696880] ? down_write_killable+0x150/0x150 [ 373.703352] btrfs_ioctl+0x3945/0x71b0 [btrfs] [ 373.710061] ? find_held_lock+0x2c/0x110 [ 373.716192] ? lock_release+0x3a9/0x6d0 [ 373.722047] ? __handle_mm_fault+0x23cd/0x3050 [ 373.728486] ? btrfs_ioctl_get_supported_features+0x20/0x20 [btrfs] [ 373.737032] ? set_pte+0x6a/0x90 [ 373.742271] ? do_raw_spin_unlock+0x55/0x1f0 [ 373.748506] ? lock_is_held_type+0xe4/0x140 [ 373.754792] ? vfs_fileattr_set+0x9f0/0x9f0 [ 373.761083] ? selinux_file_ioctl+0x349/0x4e0 [ 373.767521] ? selinux_inode_getsecctx+0x80/0x80 [ 373.774247] ? __up_read+0x182/0x6e0 [ 373.780026] ? count_memcg_events.constprop.0+0x46/0x60 [ 373.787281] ? up_write+0x460/0x460 [ 373.792932] ? security_file_ioctl+0x50/0x90 [ 373.799232] __x64_sys_ioctl+0x127/0x190 [ 373.805237] do_syscall_64+0x3b/0x90 [ 373.810947] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 373.818102] RIP: 0033:0x7f1383ea02bb [ 373.823847] RSP: 002b:00007fffeb4d71f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 [ 373.833641] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1383ea02bb [ 373.842961] RDX: 00007fffeb4d7210 RSI: 00000000c0109428 RDI: 0000000000000003 [ 373.852179] RBP: 0000000000000003 R08: 0000000000000003 R09: 0000000000000078 [ 373.861408] R10: 00007f1383daec78 R11: 0000000000000202 R12: 00007fffeb4d874a [ 373.870647] R13: 0000000000493099 R14: 0000000000000001 R15: 0000000000000000 [ 373.879838] [ 373.884018] Showing all locks held in the system: [ 373.894250] 3 locks held by kworker/4:1/58: [ 373.900356] 1 lock held by khungtaskd/63: [ 373.906333] #0: ffffffff8945ff60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 [ 373.917307] 3 locks held by kworker/u16:6/103: [ 373.923938] #0: ffff888127b4f138 ((wq_completion)btrfs-qgroup-rescan){+.+.}-{0:0}, at: process_one_work+0x712/0x1320 [ 373.936555] #1: ffff88810b817dd8 ((work_completion)(&work->normal_work)){+.+.}-{0:0}, at: process_one_work+0x73f/0x1320 [ 373.951109] #2: ffff888102dd4650 (sb_internal#2){.+.+}-{0:0}, at: btrfs_qgroup_rescan_worker+0x1f6/0x10c0 [btrfs] [ 373.964027] 2 locks held by less/1803: [ 373.969982] #0: ffff88813ed56098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 [ 373.981295] #1: ffffc90000b3b2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x9e2/0x1060 [ 373.992969] 1 lock held by btrfs-transacti/2347: [ 373.999893] #0: ffff88813d4887a8 (&fs_info->transaction_kthread_mutex){+.+.}-{3:3}, at: transaction_kthread+0xe3/0x3c0 [btrfs] [ 374.015872] 3 locks held by btrfs/3145: [ 374.022298] #0: ffff888102dd4460 (sb_writers#18){.+.+}-{0:0}, at: btrfs_ioctl_balance+0xc3/0x700 [btrfs] [ 374.034456] #1: ffff88813d48a0a0 (&fs_info->reclaim_bgs_lock){+.+.}-{3:3}, at: btrfs_balance+0xfe5/0x2d20 [btrfs] [ 374.047646] #2: ffff88813d488838 (&fs_info->cleaner_mutex){+.+.}-{3:3}, at: btrfs_relocate_block_group+0x354/0x930 [btrfs] [ 374.063295] 4 locks held by btrfs/3146: [ 374.069647] #0: ffff888102dd4460 (sb_writers#18){.+.+}-{0:0}, at: btrfs_ioctl+0x38b1/0x71b0 [btrfs] [ 374.081601] #1: ffff88813d488bb8 (&fs_info->subvol_sem){+.+.}-{3:3}, at: btrfs_ioctl+0x38fd/0x71b0 [btrfs] [ 374.094283] #2: ffff888102dd4650 (sb_internal#2){.+.+}-{0:0}, at: btrfs_quota_disable+0xc8/0x9a0 [btrfs] [ 374.106885] #3: ffff88813d489800 (&fs_info->qgroup_ioctl_lock){+.+.}-{3:3}, at: btrfs_quota_disable+0xd5/0x9a0 [btrfs] [ 374.126780] ============================================= To avoid the deadlock, wait for the qgroup rescan worker to complete before starting the transaction for the quota disable ioctl. With current implementation, BTRFS_FS_QUOTA_ENABLE flag is cleared to request the qgroup rescan worker to complete. However, this flag can not be cleared before the transaction for quota disable. Then add and use a new flag BTRFS_FS_STATE_QUOTA_DISABLING instead. To avoid another new qgroup rescan worker to start after the previous qgroup worker completed, check the BTRFS_FS_STATE_QUOTA_DISABLING flag in qgroup_rescan_init. Suggested-by: Naohiro Aota Signed-off-by: Shin'ichiro Kawasaki --- fs/btrfs/ctree.h | 2 ++ fs/btrfs/qgroup.c | 20 ++++++++++++++++++-- 2 files changed, 20 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index b4a9b1c58d22..fe275697e3eb 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -145,6 +145,8 @@ enum { BTRFS_FS_STATE_DUMMY_FS_INFO, BTRFS_FS_STATE_NO_CSUMS, + /* Quota is in disabling process */ + BTRFS_FS_STATE_QUOTA_DISABLING, }; #define BTRFS_BACKREF_REV_MAX 256 diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index 8928275823a1..6f94da4896bc 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -1188,6 +1188,17 @@ int btrfs_quota_disable(struct btrfs_fs_info *fs_info) mutex_lock(&fs_info->qgroup_ioctl_lock); if (!fs_info->quota_root) goto out; + /* + * Request qgroup rescan worker to complete and wait for it. This wait + * must be done before transaction start for quota disable since it may + * deadlock with transaction by the qgroup rescan worker. + */ + if (test_and_set_bit(BTRFS_FS_STATE_QUOTA_DISABLING, + &fs_info->fs_state)) { + ret = -EBUSY; + goto busy; + } + btrfs_qgroup_wait_for_completion(fs_info, false); mutex_unlock(&fs_info->qgroup_ioctl_lock); /* @@ -1212,7 +1223,6 @@ int btrfs_quota_disable(struct btrfs_fs_info *fs_info) goto out; clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags); - btrfs_qgroup_wait_for_completion(fs_info, false); spin_lock(&fs_info->qgroup_lock); quota_root = fs_info->quota_root; fs_info->quota_root = NULL; @@ -1244,6 +1254,8 @@ int btrfs_quota_disable(struct btrfs_fs_info *fs_info) btrfs_put_root(quota_root); out: + clear_bit(BTRFS_FS_STATE_QUOTA_DISABLING, &fs_info->fs_state); +busy: mutex_unlock(&fs_info->qgroup_ioctl_lock); if (ret && trans) btrfs_end_transaction(trans); @@ -3277,7 +3289,8 @@ static void btrfs_qgroup_rescan_worker(struct btrfs_work *work) err = PTR_ERR(trans); break; } - if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) { + if (test_bit(BTRFS_FS_STATE_QUOTA_DISABLING, + &fs_info->fs_state)) { err = -EINTR; } else { err = qgroup_rescan_leaf(trans, path); @@ -3378,6 +3391,9 @@ qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid, btrfs_warn(fs_info, "qgroup rescan is already in progress"); ret = -EINPROGRESS; + } else if (test_bit(BTRFS_FS_STATE_QUOTA_DISABLING, + &fs_info->fs_state)) { + ret = -EBUSY; } else if (!(fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON)) { btrfs_warn(fs_info,