2020-07-29 07:03:39

by Jaegeuk Kim

[permalink] [raw]
Subject: [PATCH] f2fs: fix deadlock between quota writes and checkpoint

f2fs_write_data_pages(quota_mapping)
__f2fs_write_data_pages f2fs_write_checkpoint
* blk_start_plug(&plug);
* add bio in write_io[DATA]
- block_operations
- skip syncing quota by
>DEFAULT_RETRY_QUOTA_FLUSH_COUNT
- down_write(&sbi->node_write);
- f2fs_write_single_data_page
- f2fs_do_write_data_page
- f2fs_outplace_write_data
- do_write_page
- f2fs_allocate_data_block
- down_write(node_write)
- f2fs_wait_on_all_pages(F2FS_WB_CP_DATA);

Signed-off-by: Daeho Jeong <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>
---
fs/f2fs/checkpoint.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 8c782d3f324f0..99c8061da55b9 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1269,6 +1269,8 @@ void f2fs_wait_on_all_pages(struct f2fs_sb_info *sbi, int type)
if (type == F2FS_DIRTY_META)
f2fs_sync_meta_pages(sbi, META, LONG_MAX,
FS_CP_META_IO);
+ else if (type == F2FS_WB_CP_DATA)
+ f2fs_submit_merged_write(sbi, DATA);
io_schedule_timeout(DEFAULT_IO_TIMEOUT);
}
finish_wait(&sbi->cp_wait, &wait);
--
2.28.0.rc0.142.g3c755180ce-goog


2020-07-29 12:45:44

by Chao Yu

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH] f2fs: fix deadlock between quota writes and checkpoint

On 2020-7-29 15:02, Jaegeuk Kim wrote:
> f2fs_write_data_pages(quota_mapping)
> __f2fs_write_data_pages f2fs_write_checkpoint
> * blk_start_plug(&plug);
> * add bio in write_io[DATA]
> - block_operations
> - skip syncing quota by
> >DEFAULT_RETRY_QUOTA_FLUSH_COUNT
> - down_write(&sbi->node_write);
> - f2fs_write_single_data_page

After commit 79963d967b49 ("f2fs: shrink node_write lock coverage"),
node_write lock was moved to f2fs_write_single_data_page() and
f2fs_write_compressed_pages().

So it needs to update the callstack.

- down_write(node_write)

Otherwise it looks good to me.

Reviewed-by: Chao Yu <[email protected]>

Thanks,

> - f2fs_do_write_data_page
> - f2fs_outplace_write_data
> - do_write_page
> - f2fs_allocate_data_block
> - down_write(node_write)
> - f2fs_wait_on_all_pages(F2FS_WB_CP_DATA);
>
> Signed-off-by: Daeho Jeong <[email protected]>
> Signed-off-by: Jaegeuk Kim <[email protected]>
> ---
> fs/f2fs/checkpoint.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> index 8c782d3f324f0..99c8061da55b9 100644
> --- a/fs/f2fs/checkpoint.c
> +++ b/fs/f2fs/checkpoint.c
> @@ -1269,6 +1269,8 @@ void f2fs_wait_on_all_pages(struct f2fs_sb_info *sbi, int type)
> if (type == F2FS_DIRTY_META)
> f2fs_sync_meta_pages(sbi, META, LONG_MAX,
> FS_CP_META_IO);
> + else if (type == F2FS_WB_CP_DATA)
> + f2fs_submit_merged_write(sbi, DATA);
> io_schedule_timeout(DEFAULT_IO_TIMEOUT);
> }
> finish_wait(&sbi->cp_wait, &wait);
>

2020-07-29 16:24:25

by Jaegeuk Kim

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH] f2fs: fix deadlock between quota writes and checkpoint

On 07/29, Chao Yu wrote:
> On 2020-7-29 15:02, Jaegeuk Kim wrote:
> > f2fs_write_data_pages(quota_mapping)
> > __f2fs_write_data_pages f2fs_write_checkpoint
> > * blk_start_plug(&plug);
> > * add bio in write_io[DATA]
> > - block_operations
> > - skip syncing quota by
> > >DEFAULT_RETRY_QUOTA_FLUSH_COUNT
> > - down_write(&sbi->node_write);
> > - f2fs_write_single_data_page
>
> After commit 79963d967b49 ("f2fs: shrink node_write lock coverage"),
> node_write lock was moved to f2fs_write_single_data_page() and
> f2fs_write_compressed_pages().
>
> So it needs to update the callstack.
>
> - down_write(node_write)

Yeah, applied. :)

>
> Otherwise it looks good to me.
>
> Reviewed-by: Chao Yu <[email protected]>
>
> Thanks,
>
> > - f2fs_do_write_data_page
> > - f2fs_outplace_write_data
> > - do_write_page
> > - f2fs_allocate_data_block
> > - down_write(node_write)
> > - f2fs_wait_on_all_pages(F2FS_WB_CP_DATA);
> >
> > Signed-off-by: Daeho Jeong <[email protected]>
> > Signed-off-by: Jaegeuk Kim <[email protected]>
> > ---
> > fs/f2fs/checkpoint.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> > index 8c782d3f324f0..99c8061da55b9 100644
> > --- a/fs/f2fs/checkpoint.c
> > +++ b/fs/f2fs/checkpoint.c
> > @@ -1269,6 +1269,8 @@ void f2fs_wait_on_all_pages(struct f2fs_sb_info *sbi, int type)
> > if (type == F2FS_DIRTY_META)
> > f2fs_sync_meta_pages(sbi, META, LONG_MAX,
> > FS_CP_META_IO);
> > + else if (type == F2FS_WB_CP_DATA)
> > + f2fs_submit_merged_write(sbi, DATA);
> > io_schedule_timeout(DEFAULT_IO_TIMEOUT);
> > }
> > finish_wait(&sbi->cp_wait, &wait);
> >

2020-08-01 19:23:58

by Eric Biggers

[permalink] [raw]
Subject: Re: [PATCH] f2fs: fix deadlock between quota writes and checkpoint

On Wed, Jul 29, 2020 at 12:02:44AM -0700, Jaegeuk Kim wrote:
> f2fs_write_data_pages(quota_mapping)
> __f2fs_write_data_pages f2fs_write_checkpoint
> * blk_start_plug(&plug);
> * add bio in write_io[DATA]
> - block_operations
> - skip syncing quota by
> >DEFAULT_RETRY_QUOTA_FLUSH_COUNT
> - down_write(&sbi->node_write);
> - f2fs_write_single_data_page
> - f2fs_do_write_data_page
> - f2fs_outplace_write_data
> - do_write_page
> - f2fs_allocate_data_block
> - down_write(node_write)
> - f2fs_wait_on_all_pages(F2FS_WB_CP_DATA);
>
> Signed-off-by: Daeho Jeong <[email protected]>
> Signed-off-by: Jaegeuk Kim <[email protected]>
> ---
> fs/f2fs/checkpoint.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> index 8c782d3f324f0..99c8061da55b9 100644
> --- a/fs/f2fs/checkpoint.c
> +++ b/fs/f2fs/checkpoint.c
> @@ -1269,6 +1269,8 @@ void f2fs_wait_on_all_pages(struct f2fs_sb_info *sbi, int type)
> if (type == F2FS_DIRTY_META)
> f2fs_sync_meta_pages(sbi, META, LONG_MAX,
> FS_CP_META_IO);
> + else if (type == F2FS_WB_CP_DATA)
> + f2fs_submit_merged_write(sbi, DATA);
> io_schedule_timeout(DEFAULT_IO_TIMEOUT);
> }
> finish_wait(&sbi->cp_wait, &wait);

This patch is causing the following WARNING when I try to run xfstests:

[ 20.157753] ------------[ cut here ]------------
[ 20.158393] do not call blocking ops when !TASK_RUNNING; state=2 set at [<0000000096354225>] prepare_to_wait+0xcd/0x430
[ 20.159858] WARNING: CPU: 1 PID: 1152 at kernel/sched/core.c:7142 __might_sleep+0x149/0x1a0
[ 20.160762] Modules linked in:
[ 20.161119] CPU: 1 PID: 1152 Comm: umount Not tainted 5.8.0-rc7-next-20200731 #1
[ 20.161924] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20200516_175120-felixonmars2 04/01/2014
[ 20.163110] RIP: 0010:__might_sleep+0x149/0x1a0
[ 20.163709] Code: 65 48 8b 1c 25 c0 ed 01 00 48 8d 7b 10 48 89 fe 48 c1 ee 03 80 3c 06 00 75 2b 48 8b 73 10 48 c7 c7 a0 bc 66 83 e8 0
[ 20.166083] RSP: 0018:ffffc900015a7868 EFLAGS: 00010286
[ 20.166759] RAX: 0000000000000000 RBX: ffff88806805c500 RCX: 0000000000000000
[ 20.167658] RDX: 0000000000000004 RSI: 0000000000000008 RDI: fffff520002b4eff
[ 20.168557] RBP: ffffc900015a7898 R08: 0000000000000001 R09: ffff88806d32f44f
[ 20.169481] R10: ffffed100da65e89 R11: 1ffff1100d00b9a1 R12: ffffffff83674ba0
[ 20.170389] R13: 00000000000005fa R14: 0000000000000000 R15: ffff8880638200a0
[ 20.171291] FS: 00007f3da4b2f080(0000) GS:ffff88806d300000(0000) knlGS:0000000000000000
[ 20.172311] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 20.173061] CR2: 000055734e8b2638 CR3: 0000000067069000 CR4: 00000000003506e0
[ 20.173965] Call Trace:
[ 20.174295] ? lockdep_hardirqs_on_prepare.part.0+0x22f/0x430
[ 20.175022] down_write+0x77/0x150
[ 20.175464] ? rwsem_down_read_slowpath+0xd40/0xd40
[ 20.176110] __submit_merged_write_cond+0x191/0x310
[ 20.176739] f2fs_submit_merged_write+0x18/0x20
[ 20.177323] f2fs_wait_on_all_pages+0x269/0x2d0
[ 20.177899] ? block_operations+0x980/0x980
[ 20.178441] ? __kasan_check_read+0x11/0x20
[ 20.178975] ? finish_wait+0x260/0x260
[ 20.179488] ? percpu_counter_set+0x147/0x230
[ 20.180049] do_checkpoint+0x1757/0x2a50
[ 20.180558] f2fs_write_checkpoint+0x840/0xaf0
[ 20.181126] f2fs_sync_fs+0x287/0x4a0
[ 20.181602] ? kill_f2fs_super+0x310/0x310
[ 20.182127] ? dput+0x3bf/0x570
[ 20.182565] sync_filesystem+0x165/0x200
[ 20.183075] generic_shutdown_super+0x69/0x320
[ 20.183651] kill_block_super+0x97/0xe0
[ 20.184144] kill_f2fs_super+0x21f/0x310
[ 20.184656] ? f2fs_dquot_commit+0xc0/0xc0
[ 20.185179] ? kfree+0xcc/0x320
[ 20.185594] ? unregister_shrinker+0x163/0x220
[ 20.186185] deactivate_locked_super+0x7b/0xf0
[ 20.186763] deactivate_super+0x71/0x80
[ 20.187262] cleanup_mnt+0x362/0x540
[ 20.187722] __cleanup_mnt+0xd/0x10
[ 20.188172] task_work_run+0xca/0x170
[ 20.188647] exit_to_user_mode_loop+0x98/0xa0
[ 20.189226] exit_to_user_mode_prepare+0xb4/0x110
[ 20.189838] syscall_exit_to_user_mode+0x37/0x90
[ 20.190435] do_syscall_64+0x3f/0x50
[ 20.190895] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 20.191539] RIP: 0033:0x7f3da4f55507
[ 20.192000] Code: 19 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 8
[ 20.194359] RSP: 002b:00007ffc043b0018 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
[ 20.195319] RAX: 0000000000000000 RBX: 000055fbd27c6970 RCX: 00007f3da4f55507
[ 20.196239] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000055fbd27cacd0
[ 20.197142] RBP: 0000000000000000 R08: 000055fbd27cac40 R09: 00007f3da4fd6e80
[ 20.198042] R10: 0000000000000000 R11: 0000000000000246 R12: 000055fbd27cacd0
[ 20.198942] R13: 00007f3da507b1c4 R14: 000055fbd27c6a68 R15: 000055fbd27c6b80
[ 20.199866] irq event stamp: 4503
[ 20.200307] hardirqs last enabled at (4511): [<ffffffff81358743>] console_unlock+0x4d3/0x630
[ 20.201381] hardirqs last disabled at (4518): [<ffffffff813583e6>] console_unlock+0x176/0x630
[ 20.202479] softirqs last enabled at (4010): [<ffffffff83200ebf>] asm_call_on_stack+0xf/0x20
[ 20.203556] softirqs last disabled at (3549): [<ffffffff83200ebf>] asm_call_on_stack+0xf/0x20
[ 20.204631] ---[ end trace 6d3d87d9846869f6 ]---

2020-08-04 03:02:35

by Chao Yu

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH] f2fs: fix deadlock between quota writes and checkpoint

On 2020/7/29 15:02, Jaegeuk Kim wrote:
> f2fs_write_data_pages(quota_mapping)
> __f2fs_write_data_pages f2fs_write_checkpoint
> * blk_start_plug(&plug);
> * add bio in write_io[DATA]
> - block_operations
> - skip syncing quota by
> >DEFAULT_RETRY_QUOTA_FLUSH_COUNT
> - down_write(&sbi->node_write);

f2fs_flush_merged_writes() will be called after block_operations(), why this doesn't
help?

> - f2fs_write_single_data_page
> - f2fs_do_write_data_page
> - f2fs_outplace_write_data
> - do_write_page
> - f2fs_allocate_data_block
> - down_write(node_write)
> - f2fs_wait_on_all_pages(F2FS_WB_CP_DATA);
>
> Signed-off-by: Daeho Jeong <[email protected]>
> Signed-off-by: Jaegeuk Kim <[email protected]>
> ---
> fs/f2fs/checkpoint.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> index 8c782d3f324f0..99c8061da55b9 100644
> --- a/fs/f2fs/checkpoint.c
> +++ b/fs/f2fs/checkpoint.c
> @@ -1269,6 +1269,8 @@ void f2fs_wait_on_all_pages(struct f2fs_sb_info *sbi, int type)
> if (type == F2FS_DIRTY_META)
> f2fs_sync_meta_pages(sbi, META, LONG_MAX,
> FS_CP_META_IO);
> + else if (type == F2FS_WB_CP_DATA)
> + f2fs_submit_merged_write(sbi, DATA);
> io_schedule_timeout(DEFAULT_IO_TIMEOUT);
> }
> finish_wait(&sbi->cp_wait, &wait);
>

2020-08-04 03:55:09

by Jaegeuk Kim

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH] f2fs: fix deadlock between quota writes and checkpoint

On 08/04, Chao Yu wrote:
> On 2020/7/29 15:02, Jaegeuk Kim wrote:
> > f2fs_write_data_pages(quota_mapping)
> > __f2fs_write_data_pages f2fs_write_checkpoint
> > * blk_start_plug(&plug);
> > * add bio in write_io[DATA]
> > - block_operations
> > - skip syncing quota by
> > >DEFAULT_RETRY_QUOTA_FLUSH_COUNT
> > - down_write(&sbi->node_write);
>
> f2fs_flush_merged_writes() will be called after block_operations(), why this doesn't
> help?

Well, I think bio can be added after f2fs_flush_merged_writes() as well.

>
> > - f2fs_write_single_data_page
> > - f2fs_do_write_data_page
> > - f2fs_outplace_write_data
> > - do_write_page
> > - f2fs_allocate_data_block
> > - down_write(node_write)
> > - f2fs_wait_on_all_pages(F2FS_WB_CP_DATA);
> >
> > Signed-off-by: Daeho Jeong <[email protected]>
> > Signed-off-by: Jaegeuk Kim <[email protected]>
> > ---
> > fs/f2fs/checkpoint.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> > index 8c782d3f324f0..99c8061da55b9 100644
> > --- a/fs/f2fs/checkpoint.c
> > +++ b/fs/f2fs/checkpoint.c
> > @@ -1269,6 +1269,8 @@ void f2fs_wait_on_all_pages(struct f2fs_sb_info *sbi, int type)
> > if (type == F2FS_DIRTY_META)
> > f2fs_sync_meta_pages(sbi, META, LONG_MAX,
> > FS_CP_META_IO);
> > + else if (type == F2FS_WB_CP_DATA)
> > + f2fs_submit_merged_write(sbi, DATA);
> > io_schedule_timeout(DEFAULT_IO_TIMEOUT);
> > }
> > finish_wait(&sbi->cp_wait, &wait);
> >

2020-08-04 07:58:54

by Chao Yu

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH] f2fs: fix deadlock between quota writes and checkpoint

On 2020/8/4 11:54, Jaegeuk Kim wrote:
> On 08/04, Chao Yu wrote:
>> On 2020/7/29 15:02, Jaegeuk Kim wrote:
>>> f2fs_write_data_pages(quota_mapping)
>>> __f2fs_write_data_pages f2fs_write_checkpoint
>>> * blk_start_plug(&plug);
>>> * add bio in write_io[DATA]
>>> - block_operations
>>> - skip syncing quota by
>>> >DEFAULT_RETRY_QUOTA_FLUSH_COUNT
>>> - down_write(&sbi->node_write);
>>
>> f2fs_flush_merged_writes() will be called after block_operations(), why this doesn't
>> help?
>
> Well, I think bio can be added after f2fs_flush_merged_writes() as well.

- down_read(node_write)
- f2fs_do_write_data_page
- f2fs_trylock_op
- f2fs_outplace_write_data
- f2fs_submit_page_write

bio only be added under node_write lock? during f2fs_flush_merged_writes(), node_write
should have been held by checkpoint() avoiding quota data writeback & bio submission.

>
>>
>>> - f2fs_write_single_data_page
>>> - f2fs_do_write_data_page
>>> - f2fs_outplace_write_data
>>> - do_write_page
>>> - f2fs_allocate_data_block
>>> - down_write(node_write)
>>> - f2fs_wait_on_all_pages(F2FS_WB_CP_DATA);
>>>
>>> Signed-off-by: Daeho Jeong <[email protected]>
>>> Signed-off-by: Jaegeuk Kim <[email protected]>
>>> ---
>>> fs/f2fs/checkpoint.c | 2 ++
>>> 1 file changed, 2 insertions(+)
>>>
>>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
>>> index 8c782d3f324f0..99c8061da55b9 100644
>>> --- a/fs/f2fs/checkpoint.c
>>> +++ b/fs/f2fs/checkpoint.c
>>> @@ -1269,6 +1269,8 @@ void f2fs_wait_on_all_pages(struct f2fs_sb_info *sbi, int type)
>>> if (type == F2FS_DIRTY_META)
>>> f2fs_sync_meta_pages(sbi, META, LONG_MAX,
>>> FS_CP_META_IO);
>>> + else if (type == F2FS_WB_CP_DATA)
>>> + f2fs_submit_merged_write(sbi, DATA);
>>> io_schedule_timeout(DEFAULT_IO_TIMEOUT);
>>> }
>>> finish_wait(&sbi->cp_wait, &wait);
>>>
> .
>