From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Qu Wenruo <wqu@suse.com>, Jeff Mahoney <jeffm@suse.com>,
David Sterba <dsterba@suse.com>, Sasha Levin <sashal@kernel.org>,
linux-btrfs@vger.kernel.org
Subject: [PATCH AUTOSEL 5.4 43/46] btrfs: qgroup: ensure qgroup_rescan_running is only set when the worker is at least queued
Date: Thu, 9 Apr 2020 23:49:06 -0400 [thread overview]
Message-ID: <20200410034909.8922-43-sashal@kernel.org> (raw)
In-Reply-To: <20200410034909.8922-1-sashal@kernel.org>
From: Qu Wenruo <wqu@suse.com>
[ Upstream commit d61acbbf54c612ea9bf67eed609494cda0857b3a ]
[BUG]
There are some reports about btrfs wait forever to unmount itself, with
the following call trace:
INFO: task umount:4631 blocked for more than 491 seconds.
Tainted: G X 5.3.8-2-default #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
umount D 0 4631 3337 0x00000000
Call Trace:
([<00000000174adf7a>] __schedule+0x342/0x748)
[<00000000174ae3ca>] schedule+0x4a/0xd8
[<00000000174b1f08>] schedule_timeout+0x218/0x420
[<00000000174af10c>] wait_for_common+0x104/0x1d8
[<000003ff804d6994>] btrfs_qgroup_wait_for_completion+0x84/0xb0 [btrfs]
[<000003ff8044a616>] close_ctree+0x4e/0x380 [btrfs]
[<0000000016fa3136>] generic_shutdown_super+0x8e/0x158
[<0000000016fa34d6>] kill_anon_super+0x26/0x40
[<000003ff8041ba88>] btrfs_kill_super+0x28/0xc8 [btrfs]
[<0000000016fa39f8>] deactivate_locked_super+0x68/0x98
[<0000000016fcb198>] cleanup_mnt+0xc0/0x140
[<0000000016d6a846>] task_work_run+0xc6/0x110
[<0000000016d04f76>] do_notify_resume+0xae/0xb8
[<00000000174b30ae>] system_call+0xe2/0x2c8
[CAUSE]
The problem happens when we have called qgroup_rescan_init(), but
not queued the worker. It can be caused mostly by error handling.
Qgroup ioctl thread | Unmount thread
----------------------------------------+-----------------------------------
|
btrfs_qgroup_rescan() |
|- qgroup_rescan_init() |
| |- qgroup_rescan_running = true; |
| |
|- trans = btrfs_join_transaction() |
| Some error happened |
| |
|- btrfs_qgroup_rescan() returns error |
But qgroup_rescan_running == true; |
| close_ctree()
| |- btrfs_qgroup_wait_for_completion()
| |- running == true;
| |- wait_for_completion();
btrfs_qgroup_rescan_worker is never queued, thus no one is going to wake
up close_ctree() and we get a deadlock.
All involved qgroup_rescan_init() callers are:
- btrfs_qgroup_rescan()
The example above. It's possible to trigger the deadlock when error
happened.
- btrfs_quota_enable()
Not possible. Just after qgroup_rescan_init() we queue the work.
- btrfs_read_qgroup_config()
It's possible to trigger the deadlock. It only init the work, the
work queueing happens in btrfs_qgroup_rescan_resume().
Thus if error happened in between, deadlock is possible.
We shouldn't set fs_info->qgroup_rescan_running just in
qgroup_rescan_init(), as at that stage we haven't yet queued qgroup
rescan worker to run.
[FIX]
Set qgroup_rescan_running before queueing the work, so that we ensure
the rescan work is queued when we wait for it.
Fixes: 8d9eddad1946 ("Btrfs: fix qgroup rescan worker initialization")
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
[ Change subject and cause analyse, use a smaller fix ]
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/btrfs/qgroup.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 286c8c11c8d32..590defdf88609 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1030,6 +1030,7 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info)
ret = qgroup_rescan_init(fs_info, 0, 1);
if (!ret) {
qgroup_rescan_zero_tracking(fs_info);
+ fs_info->qgroup_rescan_running = true;
btrfs_queue_work(fs_info->qgroup_rescan_workers,
&fs_info->qgroup_rescan_work);
}
@@ -3276,7 +3277,6 @@ qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid,
sizeof(fs_info->qgroup_rescan_progress));
fs_info->qgroup_rescan_progress.objectid = progress_objectid;
init_completion(&fs_info->qgroup_rescan_completion);
- fs_info->qgroup_rescan_running = true;
spin_unlock(&fs_info->qgroup_lock);
mutex_unlock(&fs_info->qgroup_rescan_lock);
@@ -3341,8 +3341,11 @@ btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info)
qgroup_rescan_zero_tracking(fs_info);
+ mutex_lock(&fs_info->qgroup_rescan_lock);
+ fs_info->qgroup_rescan_running = true;
btrfs_queue_work(fs_info->qgroup_rescan_workers,
&fs_info->qgroup_rescan_work);
+ mutex_unlock(&fs_info->qgroup_rescan_lock);
return 0;
}
@@ -3378,9 +3381,13 @@ int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
void
btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info)
{
- if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN)
+ if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
+ mutex_lock(&fs_info->qgroup_rescan_lock);
+ fs_info->qgroup_rescan_running = true;
btrfs_queue_work(fs_info->qgroup_rescan_workers,
&fs_info->qgroup_rescan_work);
+ mutex_unlock(&fs_info->qgroup_rescan_lock);
+ }
}
/*
--
2.20.1
next prev parent reply other threads:[~2020-04-10 3:55 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-10 3:48 [PATCH AUTOSEL 5.4 01/46] cpufreq: imx6q: Fixes unwanted cpu overclocking on i.MX6ULL Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 02/46] staging: wilc1000: avoid double unlocking of 'wilc->hif_cs' mutex Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 03/46] media: venus: hfi_parser: Ignore HEVC encoding for V1 Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 04/46] firmware: arm_sdei: fix double-lock on hibernate with shared events Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 05/46] null_blk: Fix the null_add_dev() error path Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 06/46] null_blk: Handle null_add_dev() failures properly Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 07/46] null_blk: fix spurious IO errors after failed past-wp access Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 08/46] media: imx: imx7_mipi_csis: Power off the source when stopping streaming Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 09/46] media: imx: imx7-media-csi: Fix video field handling Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 10/46] xhci: bail out early if driver can't accress host in resume Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 11/46] ACPI: EC: Do not clear boot_ec_is_ecdt in acpi_ec_add() Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 12/46] x86: Don't let pgprot_modify() change the page encryption bit Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 13/46] dma-mapping: Fix dma_pgprot() for unencrypted coherent pages Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 14/46] block: keep bdi->io_pages in sync with max_sectors_kb for stacked devices Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 15/46] debugfs: Check module state before warning in {full/open}_proxy_open() Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 16/46] irqchip/versatile-fpga: Handle chained IRQs properly Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 17/46] time/sched_clock: Expire timer in hardirq context Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 18/46] media: allegro: fix type of gop_length in channel_create message Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 19/46] sched: Avoid scale real weight down to zero Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 20/46] selftests/x86/ptrace_syscall_32: Fix no-vDSO segfault Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 21/46] PCI/switchtec: Fix init_completion race condition with poll_wait() Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 22/46] block, bfq: move forward the getting of an extra ref in bfq_bfqq_move Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 23/46] media: i2c: video-i2c: fix build errors due to 'imply hwmon' Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 24/46] libata: Remove extra scsi_host_put() in ata_scsi_add_hosts() Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 25/46] pstore/platform: fix potential mem leak if pstore_init_fs failed Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 26/46] gfs2: Do log_flush in gfs2_ail_empty_gl even if ail list is empty Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 27/46] gfs2: Don't demote a glock until its revokes are written Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 28/46] cpufreq: imx6q: fix error handling Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 29/46] x86/boot: Use unsigned comparison for addresses Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 30/46] efi/x86: Ignore the memory attributes table on i386 Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 31/46] genirq/irqdomain: Check pointer in irq_domain_alloc_irqs_hierarchy() Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 32/46] blk-mq: Keep set->nr_hw_queues and set->map[].nr_queues in sync Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 33/46] block: Fix use-after-free issue accessing struct io_cq Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 34/46] media: i2c: ov5695: Fix power on and off sequences Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 35/46] usb: dwc3: core: add support for disabling SS instances in park mode Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 36/46] irqchip/gic-v4: Provide irq_retrigger to avoid circular locking dependency Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 37/46] md: check arrays is suspended in mddev_detach before call quiesce operations Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 38/46] firmware: fix a double abort case with fw_load_sysfs_fallback Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 39/46] spi: spi-fsl-dspi: Replace interruptible wait queue with a simple completion Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 40/46] locking/lockdep: Avoid recursion in lockdep_count_{for,back}ward_deps() Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 41/46] block, bfq: fix use-after-free in bfq_idle_slice_timer_body Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 42/46] btrfs: hold a ref on the root in btrfs_recover_relocation Sasha Levin
2020-04-10 3:49 ` Sasha Levin [this message]
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 44/46] btrfs: remove a BUG_ON() from merge_reloc_roots() Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 45/46] btrfs: restart relocate_tree_blocks properly Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 46/46] btrfs: track reloc roots based on their commit root bytenr Sasha Levin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200410034909.8922-43-sashal@kernel.org \
--to=sashal@kernel.org \
--cc=dsterba@suse.com \
--cc=jeffm@suse.com \
--cc=linux-btrfs@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=stable@vger.kernel.org \
--cc=wqu@suse.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).