[f2fs-dev] [PATCH] f2fs: don't set RO when shutting down f2fs

[f2fs-dev] [PATCH] f2fs: don't set RO when shutting down f2fs

[Jaegeuk Kim]

Shutdown does not check the error of thaw_super due to readonly, which
causes a deadlock like below.

f2fs_ioc_shutdown(F2FS_GOING_DOWN_FULLSYNC)        issue_discard_thread
 - bdev_freeze
  - freeze_super
 - f2fs_stop_checkpoint()
  - f2fs_handle_critical_error                     - sb_start_write
    - set RO                                         - waiting
 - bdev_thaw
  - thaw_super_locked
    - return -EINVAL, if sb_rdonly()
 - f2fs_stop_discard_thread
  -> wait for kthread_stop(discard_thread);

Reported-by: "Light Hsieh (謝明燈)" <Light.Hsieh@mediatek.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/super.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index df9765b41dac..ba6288e870c5 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -4135,9 +4135,16 @@ void f2fs_handle_critical_error(struct f2fs_sb_info *sbi, unsigned char reason,
 	if (shutdown)
 		set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
 
-	/* continue filesystem operators if errors=continue */
-	if (continue_fs || f2fs_readonly(sb))
+	/*
+	 * Continue filesystem operators if errors=continue. Should not set
+	 * RO by shutdown, since RO bypasses thaw_super which can hang the
+	 * system.
+	 */
+	if (continue_fs || f2fs_readonly(sb) ||
+				reason == STOP_CP_REASON_SHUTDOWN) {
+		f2fs_warn(sbi, "Stopped filesystem due to readon: %d", reason);
 		return;
+	}
 
 	f2fs_warn(sbi, "Remounting filesystem read-only");
 	/*
-- 
2.44.0.478.gd926399ef9-goog



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Re: [f2fs-dev] [PATCH] f2fs: don't set RO when shutting down f2fs

[Chao Yu]

On 2024/4/5 3:52, Jaegeuk Kim wrote:
> Shutdown does not check the error of thaw_super due to readonly, which
> causes a deadlock like below.
> 
> f2fs_ioc_shutdown(F2FS_GOING_DOWN_FULLSYNC)        issue_discard_thread
>   - bdev_freeze
>    - freeze_super
>   - f2fs_stop_checkpoint()
>    - f2fs_handle_critical_error                     - sb_start_write
>      - set RO                                         - waiting
>   - bdev_thaw
>    - thaw_super_locked
>      - return -EINVAL, if sb_rdonly()
>   - f2fs_stop_discard_thread
>    -> wait for kthread_stop(discard_thread);
> 
> Reported-by: "Light Hsieh (謝明燈)" <Light.Hsieh@mediatek.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>   fs/f2fs/super.c | 11 +++++++++--
>   1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index df9765b41dac..ba6288e870c5 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -4135,9 +4135,16 @@ void f2fs_handle_critical_error(struct f2fs_sb_info *sbi, unsigned char reason,
>   	if (shutdown)
>   		set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
>   
> -	/* continue filesystem operators if errors=continue */
> -	if (continue_fs || f2fs_readonly(sb))
> +	/*
> +	 * Continue filesystem operators if errors=continue. Should not set
> +	 * RO by shutdown, since RO bypasses thaw_super which can hang the
> +	 * system.
> +	 */
> +	if (continue_fs || f2fs_readonly(sb) ||
> +				reason == STOP_CP_REASON_SHUTDOWN) {
> +		f2fs_warn(sbi, "Stopped filesystem due to readon: %d", reason);
>   		return;

Do we need to set RO after bdev_thaw() in f2fs_do_shutdown()?

Thanks,

> +	}
>   
>   	f2fs_warn(sbi, "Remounting filesystem read-only");
>   	/*


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Re: [f2fs-dev] [PATCH] f2fs: don't set RO when shutting down f2fs

[Daeho Jeong]

On Thu, Apr 4, 2024 at 12:54 PM Jaegeuk Kim <jaegeuk@kernel.org> wrote:
>
> Shutdown does not check the error of thaw_super due to readonly, which
> causes a deadlock like below.
>
> f2fs_ioc_shutdown(F2FS_GOING_DOWN_FULLSYNC)        issue_discard_thread
>  - bdev_freeze
>   - freeze_super
>  - f2fs_stop_checkpoint()
>   - f2fs_handle_critical_error                     - sb_start_write
>     - set RO                                         - waiting
>  - bdev_thaw
>   - thaw_super_locked
>     - return -EINVAL, if sb_rdonly()
>  - f2fs_stop_discard_thread
>   -> wait for kthread_stop(discard_thread);
>
> Reported-by: "Light Hsieh (謝明燈)" <Light.Hsieh@mediatek.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  fs/f2fs/super.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index df9765b41dac..ba6288e870c5 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -4135,9 +4135,16 @@ void f2fs_handle_critical_error(struct f2fs_sb_info *sbi, unsigned char reason,
>         if (shutdown)
>                 set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
>
> -       /* continue filesystem operators if errors=continue */
> -       if (continue_fs || f2fs_readonly(sb))
> +       /*
> +        * Continue filesystem operators if errors=continue. Should not set
> +        * RO by shutdown, since RO bypasses thaw_super which can hang the
> +        * system.
> +        */
> +       if (continue_fs || f2fs_readonly(sb) ||
> +                               reason == STOP_CP_REASON_SHUTDOWN) {

I think we can use "shutdown" variable instead of "reason ==
STOP_CP_REASON_SHUTDOWN" to be concise.

> +               f2fs_warn(sbi, "Stopped filesystem due to readon: %d", reason);

readon -> reason?

>                 return;
> +       }
>
>         f2fs_warn(sbi, "Remounting filesystem read-only");
>         /*
> --
> 2.44.0.478.gd926399ef9-goog
>
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel


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Re: [f2fs-dev] [PATCH v2] f2fs: don't set RO when shutting down f2fs

[Jaegeuk Kim]

Shutdown does not check the error of thaw_super due to readonly, which
causes a deadlock like below.

f2fs_ioc_shutdown(F2FS_GOING_DOWN_FULLSYNC)        issue_discard_thread
 - bdev_freeze
  - freeze_super
 - f2fs_stop_checkpoint()
  - f2fs_handle_critical_error                     - sb_start_write
    - set RO                                         - waiting
 - bdev_thaw
  - thaw_super_locked
    - return -EINVAL, if sb_rdonly()
 - f2fs_stop_discard_thread
  -> wait for kthread_stop(discard_thread);

Reported-by: "Light Hsieh (謝明燈)" <Light.Hsieh@mediatek.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---

 Change log from v1:
  - use better variable
  - fix typo

 fs/f2fs/super.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 8ac4734c2df6..df32573d1f62 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -4159,9 +4159,15 @@ void f2fs_handle_critical_error(struct f2fs_sb_info *sbi, unsigned char reason,
 	if (shutdown)
 		set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
 
-	/* continue filesystem operators if errors=continue */
-	if (continue_fs || f2fs_readonly(sb))
+	/*
+	 * Continue filesystem operators if errors=continue. Should not set
+	 * RO by shutdown, since RO bypasses thaw_super which can hang the
+	 * system.
+	 */
+	if (continue_fs || f2fs_readonly(sb) || shutdown) {
+		f2fs_warn(sbi, "Stopped filesystem due to reason: %d", reason);
 		return;
+	}
 
 	f2fs_warn(sbi, "Remounting filesystem read-only");
 	/*
-- 
2.44.0.478.gd926399ef9-goog



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Re: [f2fs-dev] [PATCH] f2fs: don't set RO when shutting down f2fs

[Jaegeuk Kim]

On 04/09, Chao Yu wrote:
> On 2024/4/5 3:52, Jaegeuk Kim wrote:
> > Shutdown does not check the error of thaw_super due to readonly, which
> > causes a deadlock like below.
> > 
> > f2fs_ioc_shutdown(F2FS_GOING_DOWN_FULLSYNC)        issue_discard_thread
> >   - bdev_freeze
> >    - freeze_super
> >   - f2fs_stop_checkpoint()
> >    - f2fs_handle_critical_error                     - sb_start_write
> >      - set RO                                         - waiting
> >   - bdev_thaw
> >    - thaw_super_locked
> >      - return -EINVAL, if sb_rdonly()
> >   - f2fs_stop_discard_thread
> >    -> wait for kthread_stop(discard_thread);
> > 
> > Reported-by: "Light Hsieh (謝明燈)" <Light.Hsieh@mediatek.com>
> > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> > ---
> >   fs/f2fs/super.c | 11 +++++++++--
> >   1 file changed, 9 insertions(+), 2 deletions(-)
> > 
> > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > index df9765b41dac..ba6288e870c5 100644
> > --- a/fs/f2fs/super.c
> > +++ b/fs/f2fs/super.c
> > @@ -4135,9 +4135,16 @@ void f2fs_handle_critical_error(struct f2fs_sb_info *sbi, unsigned char reason,
> >   	if (shutdown)
> >   		set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
> > -	/* continue filesystem operators if errors=continue */
> > -	if (continue_fs || f2fs_readonly(sb))
> > +	/*
> > +	 * Continue filesystem operators if errors=continue. Should not set
> > +	 * RO by shutdown, since RO bypasses thaw_super which can hang the
> > +	 * system.
> > +	 */
> > +	if (continue_fs || f2fs_readonly(sb) ||
> > +				reason == STOP_CP_REASON_SHUTDOWN) {
> > +		f2fs_warn(sbi, "Stopped filesystem due to readon: %d", reason);
> >   		return;
> 
> Do we need to set RO after bdev_thaw() in f2fs_do_shutdown()?

IIRC, shutdown doesn't need to set RO as we stopped the checkpoint.
I'm more concerned on any side effect caused by this RO change.

> 
> Thanks,
> 
> > +	}
> >   	f2fs_warn(sbi, "Remounting filesystem read-only");
> >   	/*


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Re: [f2fs-dev] [PATCH v2] f2fs: don't set RO when shutting down f2fs

[Daeho Jeong]

On Tue, Apr 9, 2024 at 9:21 AM Jaegeuk Kim <jaegeuk@kernel.org> wrote:
>
> Shutdown does not check the error of thaw_super due to readonly, which
> causes a deadlock like below.
>
> f2fs_ioc_shutdown(F2FS_GOING_DOWN_FULLSYNC)        issue_discard_thread
>  - bdev_freeze
>   - freeze_super
>  - f2fs_stop_checkpoint()
>   - f2fs_handle_critical_error                     - sb_start_write
>     - set RO                                         - waiting
>  - bdev_thaw
>   - thaw_super_locked
>     - return -EINVAL, if sb_rdonly()
>  - f2fs_stop_discard_thread
>   -> wait for kthread_stop(discard_thread);
>
> Reported-by: "Light Hsieh (謝明燈)" <Light.Hsieh@mediatek.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>
>  Change log from v1:
>   - use better variable
>   - fix typo
>
>  fs/f2fs/super.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 8ac4734c2df6..df32573d1f62 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -4159,9 +4159,15 @@ void f2fs_handle_critical_error(struct f2fs_sb_info *sbi, unsigned char reason,
>         if (shutdown)
>                 set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
>
> -       /* continue filesystem operators if errors=continue */
> -       if (continue_fs || f2fs_readonly(sb))
> +       /*
> +        * Continue filesystem operators if errors=continue. Should not set
> +        * RO by shutdown, since RO bypasses thaw_super which can hang the
> +        * system.
> +        */
> +       if (continue_fs || f2fs_readonly(sb) || shutdown) {
> +               f2fs_warn(sbi, "Stopped filesystem due to reason: %d", reason);
>                 return;
> +       }
>
>         f2fs_warn(sbi, "Remounting filesystem read-only");
>         /*
> --
> 2.44.0.478.gd926399ef9-goog
>
>

Reviewed-by: Daeho Jeong <daehojeong@google.com>


>
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> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel


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Re: [f2fs-dev] [PATCH] f2fs: don't set RO when shutting down f2fs

[Chao Yu]

On 2024/4/10 0:21, Jaegeuk Kim wrote:
> On 04/09, Chao Yu wrote:
>> On 2024/4/5 3:52, Jaegeuk Kim wrote:
>>> Shutdown does not check the error of thaw_super due to readonly, which
>>> causes a deadlock like below.
>>>
>>> f2fs_ioc_shutdown(F2FS_GOING_DOWN_FULLSYNC)        issue_discard_thread
>>>    - bdev_freeze
>>>     - freeze_super
>>>    - f2fs_stop_checkpoint()
>>>     - f2fs_handle_critical_error                     - sb_start_write
>>>       - set RO                                         - waiting
>>>    - bdev_thaw
>>>     - thaw_super_locked
>>>       - return -EINVAL, if sb_rdonly()
>>>    - f2fs_stop_discard_thread
>>>     -> wait for kthread_stop(discard_thread);
>>>
>>> Reported-by: "Light Hsieh (謝明燈)" <Light.Hsieh@mediatek.com>
>>> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
>>> ---
>>>    fs/f2fs/super.c | 11 +++++++++--
>>>    1 file changed, 9 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>> index df9765b41dac..ba6288e870c5 100644
>>> --- a/fs/f2fs/super.c
>>> +++ b/fs/f2fs/super.c
>>> @@ -4135,9 +4135,16 @@ void f2fs_handle_critical_error(struct f2fs_sb_info *sbi, unsigned char reason,
>>>    	if (shutdown)
>>>    		set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
>>> -	/* continue filesystem operators if errors=continue */
>>> -	if (continue_fs || f2fs_readonly(sb))
>>> +	/*
>>> +	 * Continue filesystem operators if errors=continue. Should not set
>>> +	 * RO by shutdown, since RO bypasses thaw_super which can hang the
>>> +	 * system.
>>> +	 */
>>> +	if (continue_fs || f2fs_readonly(sb) ||
>>> +				reason == STOP_CP_REASON_SHUTDOWN) {
>>> +		f2fs_warn(sbi, "Stopped filesystem due to readon: %d", reason);
>>>    		return;
>>
>> Do we need to set RO after bdev_thaw() in f2fs_do_shutdown()?
> 
> IIRC, shutdown doesn't need to set RO as we stopped the checkpoint.
> I'm more concerned on any side effect caused by this RO change.

Okay, I just wonder whether we need to follow semantics of errors=remount-ro
semantics, but it looks fine since shutdown operation simulated by ioctl
could not be treated as an inner critical error,

errors=%s                Specify f2fs behavior on critical errors. This supports modes:
                          "panic", "continue" and "remount-ro", respectively, trigger
                          panic immediately, continue without doing anything, and remount
                          the partition in read-only mode. By default it uses "continue"
                          mode.

Also, it keeps the behavior consistent w/ what we do for errors=panic case.

	if (F2FS_OPTION(sbi).errors == MOUNT_ERRORS_PANIC &&
				!shutdown && !system_going_down() &&
				^^^^^^^^^
				!is_sbi_flag_set(sbi, SBI_IS_SHUTDOWN))
		panic("F2FS-fs (device %s): panic forced after error\n",
							sb->s_id);

Thanks,

> 
>>
>> Thanks,
>>
>>> +	}
>>>    	f2fs_warn(sbi, "Remounting filesystem read-only");
>>>    	/*


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Re: [f2fs-dev] [PATCH v2] f2fs: don't set RO when shutting down f2fs

[Chao Yu]

On 2024/4/10 0:20, Jaegeuk Kim wrote:
> Shutdown does not check the error of thaw_super due to readonly, which
> causes a deadlock like below.
> 
> f2fs_ioc_shutdown(F2FS_GOING_DOWN_FULLSYNC)        issue_discard_thread
>   - bdev_freeze
>    - freeze_super
>   - f2fs_stop_checkpoint()
>    - f2fs_handle_critical_error                     - sb_start_write
>      - set RO                                         - waiting
>   - bdev_thaw
>    - thaw_super_locked
>      - return -EINVAL, if sb_rdonly()
>   - f2fs_stop_discard_thread
>    -> wait for kthread_stop(discard_thread);
> 
> Reported-by: "Light Hsieh (謝明燈)" <Light.Hsieh@mediatek.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,


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