Re: [linux-lvm] vgchange acquire an exclusive VG lock for refresh

"wangzhiqiang (Q)" <[email protected]>
Newsgroups dev.linux.lists.linux-lvm
Message-ID <[email protected]>
Thank you for your reply.

According to your review, I reworked a proper patch.

---
 tools/vgchange.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/vgchange.c b/tools/vgchange.c
index e2d3dad02..8c1d605c6 100644
--- a/tools/vgchange.c
+++ b/tools/vgchange.c
@@ -1008,7 +1008,8 @@ int vgchange(struct cmd_context *cmd, int argc, char **argv)

        if (update)
                flags |= READ_FOR_UPDATE;
-       else if (arg_is_set(cmd, activate_ARG))
+       else if (arg_is_set(cmd, activate_ARG) ||
+                arg_is_set(cmd, refresh_ARG))
                flags |= READ_FOR_ACTIVATE;

        if (!(handle = init_processing_handle(cmd, NULL))) {
--
2.33.0

在 2023/8/29 14:36, wangzhiqiang (Q) 写道:
> Patches based on the latest version:
> 
> ---
>  tools/vgchange.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/vgchange.c b/tools/vgchange.c
> index f07b245bd..f35ff4c0e 100644
> --- a/tools/vgchange.c
> +++ b/tools/vgchange.c
> @@ -1003,7 +1003,7 @@ int vgchange(struct cmd_context *cmd, int argc, char **argv)
>                 init_external_device_info_source(DEV_EXT_NONE);
>         }
> 
> -       if (update)
> +       if (update || arg_is_set(cmd, refresh_ARG))
>                 flags |= READ_FOR_UPDATE;
>         else if (arg_is_set(cmd, activate_ARG))
>                 flags |= READ_FOR_ACTIVATE;
> --
> 2.33.0
> 
> 在 2023/8/29 11:53, wangzhiqiang (Q) 写道:
>> I've got an issue while execute vgchange --refresh concurrently, process vgchange and systemd-udevd
>> enters the D state.
>> root        2933  0.0  1.0  54216 31344 pts/1    D<L  11:21   0:00 vgchange --refresh
>> root        2934  0.0  1.1  54216 32788 pts/1    D<L  11:21   0:00 vgchange --refresh
>> root        2935  0.0  1.0  54216 31496 pts/1    D<L  11:21   0:00 vgchange --refresh
>> root        2937  0.0  1.0  54216 31500 pts/1    S<L  11:21   0:00 vgchange --refresh
>> root        2951  0.0  0.0      0     0 ?        D    11:21   0:00 [systemd-udevd]
>> root        2952  0.0  0.0      0     0 ?        D    11:21   0:00 [systemd-udevd]
>>
>> process stack as follows
>> [root@localhost ~]# cat /proc/2937/stack
>> [<0>] dm_wait_for_bios_completion+0x298/0x340 [dm_mod]
>> [<0>] dm_wait_for_completion+0xfe/0x110 [dm_mod]
>> [<0>] __dm_suspend+0xd0/0x310 [dm_mod]
>> [<0>] dm_suspend+0x133/0x180 [dm_mod]
>> [<0>] dev_suspend+0x115/0x150 [dm_mod]
>> [<0>] ctl_ioctl+0x320/0x4c0 [dm_mod]
>> [<0>] dm_ctl_ioctl+0x26/0x40 [dm_mod]
>> [<0>] __se_sys_ioctl+0xeb/0x120
>> [<0>] do_syscall_64+0x30/0x40
>> [<0>] entry_SYSCALL_64_after_hwframe+0x61/0xc6
>> [root@localhost ~]# cat /proc/2935/stack
>> [<0>] dm_suspend+0x2b/0x180 [dm_mod]
>> [<0>] dev_suspend+0x115/0x150 [dm_mod]
>> [<0>] ctl_ioctl+0x320/0x4c0 [dm_mod]
>> [<0>] dm_ctl_ioctl+0x26/0x40 [dm_mod]
>> [<0>] __se_sys_ioctl+0xeb/0x120
>> [<0>] do_syscall_64+0x30/0x40
>> [<0>] entry_SYSCALL_64_after_hwframe+0x61/0xc6
>> [root@localhost ~]# cat /proc/2951/stack
>> [<0>] __lock_page+0x25a/0x7a0
>> [<0>] truncate_inode_pages_range+0xc52/0x1370
>> [<0>] __blkdev_put+0x15b/0x3f0
>> [<0>] blkdev_close+0x49/0x60
>> [<0>] __fput+0x1b9/0x480
>> [<0>] task_work_run+0xad/0xf0
>> [<0>] do_exit+0x47f/0x810
>> [<0>] do_group_exit+0x77/0x150
>> [<0>] get_signal+0x2a2/0xa60
>> [<0>] arch_do_signal_or_restart+0x1c6/0x310
>> [<0>] exit_to_user_mode_loop+0xdb/0x100
>> [<0>] exit_to_user_mode_prepare+0x7e/0x90
>> [<0>] syscall_exit_to_user_mode+0x12/0x40
>> [<0>] entry_SYSCALL_64_after_hwframe+0x61/0xc6
>>
>> I recommend get an exclusive lock when vgchange --refresh.
>>
>> >From 7ddadf2bbbe0383893ab8f5b7cb8d51ebf7a5ed4 Mon Sep 17 00:00:00 2001
>> From: wangzhiqiang <[email protected]>
>> Date: Tue, 29 Aug 2023 10:28:15 +0800
>> Subject: [PATCH] vgchange acquire an exclusive VG lock for refresh.
>>
>> Let's run the following test cases, we've got hungtask.
>> P2 or P3 can't suspend snap and udevd also can't read
>> device info because real or cow has been suspend.
>>
>>     P1(vgchange)      P2(vgchange)      P3(vgchange)
>> --------------------------------------------------------
>>     suspend real
>>     suspend cow
>>                       suspend snap
>>                                         suspend snap
>>     suspend snap
>>
>> function query()
>> {
>>         while true
>>         do
>>                 vgchange --refresh
>>         done
>> }
>>
>> query 1 &> /dev/null &
>> query 2 &> /dev/null &
>> query 3 &> /dev/null &
>>
>> [  247.250669] INFO: task vgchange:2934 blocked for more than 122 seconds.
>> [  247.251935] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>> [  247.252619] task:vgchange        state:D stack:    0 pid: 2934 ppid:  2930 flags:0x00000080
>> [  247.252626] Call Trace:
>> [  247.252633]  __schedule+0x547/0xe80
>> [  247.252640]  ? io_schedule_timeout+0xb0/0xb0
>> [  247.252647]  ? _raw_spin_lock+0x7a/0xd0
>> [  247.252652]  schedule+0x6f/0x130
>> [  247.252658]  schedule_preempt_disabled+0xa/0x10
>> [  247.252664]  __mutex_lock.constprop.0+0x311/0x700
>> [  247.252673]  ? kernel_text_address.part.0+0xb9/0xc0
>> [  247.252678]  ? ww_mutex_unlock+0x50/0x50
>> [  247.252685]  ? unwind_get_return_address+0x33/0x50
>> [  247.252692]  ? cred_has_capability.isra.0+0x14b/0x220
>> [  247.252698]  ? check_nnp_nosuid.isra.0+0x170/0x170
>> [  247.252704]  mutex_lock+0x114/0x130
>> [  247.252710]  ? __mutex_lock_slowpath+0x10/0x10
>> [  247.252716]  ? rwsem_down_write_slowpath+0x830/0x830
>> [  247.252733]  ? dm_get+0x40/0x70 [dm_mod]
>> [  247.252752]  ? dm_get_md+0xb3/0x120 [dm_mod]
>> [  247.252770]  dm_suspend+0x2b/0x180 [dm_mod]
>> [  247.252788]  dev_suspend+0x115/0x150 [dm_mod]
>> [  247.252805]  ctl_ioctl+0x320/0x4c0 [dm_mod]
>> [  247.252823]  ? dev_set_geometry+0x290/0x290 [dm_mod]
>> [  247.252841]  ? copy_params+0x2e0/0x2e0 [dm_mod]
>> [  247.252846]  ? locks_dispose_list+0xa0/0xd0
>> [  247.252851]  ? locks_remove_posix+0x24f/0x340
>> [  247.252856]  ? locks_remove_flock+0x1e6/0x250
>> [  247.252865]  ? ioctl_fiemap.isra.0+0x110/0x1e0
>> [  247.252872]  ? vfs_write+0x2a5/0x440
>> [  247.252877]  ? selinux_file_ioctl+0x89/0x1c0
>> [  247.252895]  ? ctl_ioctl+0x4c0/0x4c0 [dm_mod]
>> [  247.252912]  dm_ctl_ioctl+0x26/0x40 [dm_mod]
>> [  247.252918]  __se_sys_ioctl+0xeb/0x120
>> [  247.252923]  do_syscall_64+0x30/0x40
>> [  247.252929]  entry_SYSCALL_64_after_hwframe+0x61/0xc6
>>
>> [  247.252967] INFO: task vgchange:2935 blocked for more than 122 seconds.
>> [  247.254242] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>> [  247.254909] task:vgchange        state:D stack:    0 pid: 2935 ppid:  2931 flags:0x00000080
>> [  247.254922] Call Trace:
>> [  247.254929]  __schedule+0x547/0xe80
>> [  247.254935]  ? io_schedule_timeout+0xb0/0xb0
>> [  247.254942]  ? _raw_spin_lock+0x7a/0xd0
>> [  247.254947]  schedule+0x6f/0x130
>> [  247.254953]  schedule_preempt_disabled+0xa/0x10
>> [  247.254959]  __mutex_lock.constprop.0+0x311/0x700
>> [  247.254965]  ? kernel_text_address.part.0+0xb9/0xc0
>> [  247.254976]  ? ww_mutex_unlock+0x50/0x50
>> [  247.254981]  ? unwind_get_return_address+0x33/0x50
>> [  247.254988]  ? cred_has_capability.isra.0+0x14b/0x220
>> [  247.254995]  ? check_nnp_nosuid.isra.0+0x170/0x170
>> [  247.255000]  mutex_lock+0x114/0x130
>> [  247.255006]  ? __mutex_lock_slowpath+0x10/0x10
>> [  247.255012]  ? rwsem_down_write_slowpath+0x830/0x830
>> [  247.255029]  ? dm_get+0x40/0x70 [dm_mod]
>> [  247.255052]  ? dm_get_md+0xb3/0x120 [dm_mod]
>> [  247.255069]  dm_suspend+0x2b/0x180 [dm_mod]
>> [  247.255088]  dev_suspend+0x115/0x150 [dm_mod]
>> [  247.255113]  ctl_ioctl+0x320/0x4c0 [dm_mod]
>> [  247.255142]  ? dev_set_geometry+0x290/0x290 [dm_mod]
>> [  247.255160]  ? copy_params+0x2e0/0x2e0 [dm_mod]
>> [  247.255175]  ? nohz_balance_exit_idle+0x2b/0x160
>> [  247.255187]  ? rb_insert_color+0x2a/0x280
>> [  247.255196]  ? ioctl_fiemap.isra.0+0x110/0x1e0
>> [  247.255202]  ? selinux_file_ioctl+0x89/0x1c0
>> [  247.255219]  ? ctl_ioctl+0x4c0/0x4c0 [dm_mod]
>> [  247.255238]  dm_ctl_ioctl+0x26/0x40 [dm_mod]
>> [  247.255250]  __se_sys_ioctl+0xeb/0x120
>> [  247.255255]  do_syscall_64+0x30/0x40
>> [  247.255262]  entry_SYSCALL_64_after_hwframe+0x61/0xc6
>>
>> [  493.015195] INFO: task systemd-udevd:2951 blocked for more than 122 seconds.
>> [  493.016461] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>> [  493.017131] task:systemd-udevd   state:D stack:    0 pid: 2951 ppid:   719 flags:0x000043a6
>> [  493.017138] Call Trace:
>> [  493.017145]  __schedule+0x547/0xe80
>> [  493.017152]  ? io_schedule_timeout+0xb0/0xb0
>> [  493.017157]  ? orc_find.part.0+0x240/0x240
>> [  493.017163]  ? get_stack_info_noinstr+0x16/0x140
>> [  493.017171]  ? bpf_ksym_find+0xc0/0x110
>> [  493.017189]  schedule+0x6f/0x130
>> [  493.017195]  io_schedule+0x6d/0xa0
>> [  493.017202]  __lock_page+0x25a/0x7a0
>> [  493.017209]  ? wait_on_page_bit_killable+0x6c0/0x6c0
>> [  493.017216]  ? __lock_page_or_retry+0x3e0/0x3e0
>> [  493.017222]  ? add_to_page_cache_lru+0x370/0x370
>> [  493.017231]  truncate_inode_pages_range+0xc52/0x1370
>> [  493.017242]  ? generic_error_remove_page+0x90/0x90
>> [  493.017248]  ? __filemap_fdatawait_range+0x179/0x270
>> [  493.017256]  ? filemap_range_has_page+0x170/0x170
>> [  493.017264]  ? __bitmap_or_equal+0x89/0x120
>> [  493.017271]  ? _find_next_bit.constprop.0+0xde/0x120
>> [  493.017279]  ? cpumask_next+0x2c/0x40
>> [  493.017287]  ? smp_call_function_many_cond+0x430/0x5f0
>> [  493.017295]  ? touch_buffer+0xa0/0xa0
>> [  493.017305]  ? __find_get_block+0x110/0x110
>> [  493.017311]  ? __find_get_block+0x110/0x110
>> [  493.017316]  ? touch_buffer+0xa0/0xa0
>> [  493.017322]  __blkdev_put+0x15b/0x3f0
>> [  493.017328]  ? blkdev_put+0x1c0/0x1c0
>> [  493.017333]  blkdev_close+0x49/0x60
>> [  493.017339]  __fput+0x1b9/0x480
>> [  493.017346]  task_work_run+0xad/0xf0
>> [  493.017354]  do_exit+0x47f/0x810
>> [  493.017361]  ? exit_mm+0x450/0x450
>> [  493.017371]  ? _raw_spin_lock_irq+0x7b/0xd0
>> [  493.017377]  do_group_exit+0x77/0x150
>> [  493.017384]  get_signal+0x2a2/0xa60
>> [  493.017393]  arch_do_signal_or_restart+0x1c6/0x310
>> [  493.017399]  ? get_sigframe_size+0x20/0x20
>> [  493.017405]  ? vfs_read+0x1f6/0x2d0
>> [  493.017411]  ? unroll_tree_refs+0x18a/0x1e0
>> [  493.017424]  exit_to_user_mode_loop+0xdb/0x100
>> [  493.017430]  exit_to_user_mode_prepare+0x7e/0x90
>> [  493.017438]  syscall_exit_to_user_mode+0x12/0x40
>> [  493.017445]  entry_SYSCALL_64_after_hwframe+0x61/0xc6
>>
>> cat /proc/2937/stack
>> [<0>] dm_wait_for_bios_completion+0x298/0x340 [dm_mod]
>> [<0>] dm_wait_for_completion+0xfe/0x110 [dm_mod]
>> [<0>] __dm_suspend+0xd0/0x310 [dm_mod]
>> [<0>] dm_suspend+0x133/0x180 [dm_mod]
>> [<0>] dev_suspend+0x115/0x150 [dm_mod]
>> [<0>] ctl_ioctl+0x320/0x4c0 [dm_mod]
>> [<0>] dm_ctl_ioctl+0x26/0x40 [dm_mod]
>> [<0>] __se_sys_ioctl+0xeb/0x120
>> [<0>] do_syscall_64+0x30/0x40
>> [<0>] entry_SYSCALL_64_after_hwframe+0x61/0xc6
>>
>> Signed-off-by: wangzhiqiang <[email protected]>
>> ---
>>  tools/vgchange.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/tools/vgchange.c b/tools/vgchange.c
>> index e4b57db..eb3096d 100644
>> --- a/tools/vgchange.c
>> +++ b/tools/vgchange.c
>> @@ -837,7 +837,7 @@ int vgchange(struct cmd_context *cmd, int argc, char **argv)
>>                         cmd->lockd_vg_enforce_sh = 1;
>>         }
>>
>> -       if (update)
>> +       if (update || arg_is_set(cmd, refresh_ARG))
>>                 flags |= READ_FOR_UPDATE;
>>         else if (arg_is_set(cmd, activate_ARG))
>>                 flags |= READ_FOR_ACTIVATE;
>> --
>> 2.33.0
>>

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