[f2fs-dev] [PATCH] f2fs: avoid to use a NULL point in destroy_segment_manager

[f2fs-dev] [PATCH] f2fs: avoid to use a NULL point in destroy_segment_manager

[Chao Yu]

A NULL point should avoid to be used in destroy_segment_manager after allocating memory fail for f2fs_sm_info.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
---
 fs/f2fs/segment.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 3d4d5fc..ff363e6
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1744,6 +1744,8 @@ static void destroy_sit_info(struct f2fs_sb_info *sbi)
 void destroy_segment_manager(struct f2fs_sb_info *sbi)
 {
 	struct f2fs_sm_info *sm_info = SM_I(sbi);
+	if (!sm_info)
+		return;
 	destroy_dirty_segmap(sbi);
 	destroy_curseg(sbi);
 	destroy_free_segmap(sbi);
-- 
1.7.9.5

Re: [f2fs-dev] [PATCH] f2fs: avoid to use a NULL point in destroy_segment_manager

[Gu Zheng]

On 11/06/2013 09:12 AM, Chao Yu wrote:

> A NULL point should avoid to be used in destroy_segment_manager after allocating memory fail for f2fs_sm_info.

Though without this patch it still can work well, because if it failed
to allocate f2fs_sm_info, the sit_info, free_info... all were NULL, and
the destory path(e.g. destroy_dirty_segmap) can deal with them well.
IMO, this patch is still a good catch. 

Regards,
Gu

> 
> Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> ---
>  fs/f2fs/segment.c |    2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 3d4d5fc..ff363e6
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1744,6 +1744,8 @@ static void destroy_sit_info(struct f2fs_sb_info *sbi)
>  void destroy_segment_manager(struct f2fs_sb_info *sbi)
>  {
>  	struct f2fs_sm_info *sm_info = SM_I(sbi);
> +	if (!sm_info)
> +		return;
>  	destroy_dirty_segmap(sbi);
>  	destroy_curseg(sbi);
>  	destroy_free_segmap(sbi);

RE: [f2fs-dev] [PATCH] f2fs: avoid to use a NULL point in destroy_segment_manager

[Chao Yu]

Hi Gu,

> -----Original Message-----
> From: Gu Zheng [mailto:guz.fnst@cn.fujitsu.com]
> Sent: Wednesday, November 06, 2013 11:41 AM
> To: Chao Yu
> Cc: ???; linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; linux-f2fs-devel@lists.sourceforge.net; 谭姝
> Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid to use a NULL point in destroy_segment_manager
> 
> On 11/06/2013 09:12 AM, Chao Yu wrote:
> 
> > A NULL point should avoid to be used in destroy_segment_manager after allocating memory fail for f2fs_sm_info.
> 
> Though without this patch it still can work well, because if it failed
> to allocate f2fs_sm_info, the sit_info, free_info... all were NULL, and
> the destory path(e.g. destroy_dirty_segmap) can deal with them well.

I think it could not work well. Without this patch we may got a segment 
fault in DIRTY_I(sbi) at the following code if it failed to allocate 
f2fs_sm_info memory(sbi->sm_info). Right?

static void destroy_dirty_segmap(struct f2fs_sb_info *sbi)
{
	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);

> IMO, this patch is still a good catch.
> 
> Regards,
> Gu
> 
> >
> > Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> > ---
> >  fs/f2fs/segment.c |    2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index 3d4d5fc..ff363e6
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -1744,6 +1744,8 @@ static void destroy_sit_info(struct f2fs_sb_info *sbi)
> >  void destroy_segment_manager(struct f2fs_sb_info *sbi)
> >  {
> >  	struct f2fs_sm_info *sm_info = SM_I(sbi);
> > +	if (!sm_info)
> > +		return;
> >  	destroy_dirty_segmap(sbi);
> >  	destroy_curseg(sbi);
> >  	destroy_free_segmap(sbi);

Re: [f2fs-dev] [PATCH] f2fs: avoid to use a NULL point in destroy_segment_manager

[Gu Zheng]

On 11/06/2013 01:10 PM, Chao Yu wrote:

> Hi Gu,
> 
>> -----Original Message-----
>> From: Gu Zheng [mailto:guz.fnst@cn.fujitsu.com]
>> Sent: Wednesday, November 06, 2013 11:41 AM
>> To: Chao Yu
>> Cc: ???; linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; linux-f2fs-devel@lists.sourceforge.net; 谭姝
>> Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid to use a NULL point in destroy_segment_manager
>>
>> On 11/06/2013 09:12 AM, Chao Yu wrote:
>>
>>> A NULL point should avoid to be used in destroy_segment_manager after allocating memory fail for f2fs_sm_info.
>>
>> Though without this patch it still can work well, because if it failed
>> to allocate f2fs_sm_info, the sit_info, free_info... all were NULL, and
>> the destory path(e.g. destroy_dirty_segmap) can deal with them well.
> 
> I think it could not work well. Without this patch we may got a segment 
> fault in DIRTY_I(sbi) at the following code if it failed to allocate 
> f2fs_sm_info memory(sbi->sm_info). Right?

Yes, you're right. SIT_I generates sit_info from f2fs_sm_info.
Sorry for my mistake.:(

Regards,
Gu

> 
> static void destroy_dirty_segmap(struct f2fs_sb_info *sbi)
> {
> 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
> 
>> IMO, this patch is still a good catch.
>>
>> Regards,
>> Gu
>>
>>>
>>> Signed-off-by: Chao Yu <chao2.yu@samsung.com>
>>> ---
>>>  fs/f2fs/segment.c |    2 ++
>>>  1 file changed, 2 insertions(+)
>>>
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index 3d4d5fc..ff363e6
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -1744,6 +1744,8 @@ static void destroy_sit_info(struct f2fs_sb_info *sbi)
>>>  void destroy_segment_manager(struct f2fs_sb_info *sbi)
>>>  {
>>>  	struct f2fs_sm_info *sm_info = SM_I(sbi);
>>> +	if (!sm_info)
>>> +		return;
>>>  	destroy_dirty_segmap(sbi);
>>>  	destroy_curseg(sbi);
>>>  	destroy_free_segmap(sbi);
> 
> 
> 

RE: [f2fs-dev] [PATCH] f2fs: avoid to use a NULL point in destroy_segment_manager

[Chao Yu]

Hi Gu, 

Thanks for your reviewing!

Regards
Yu

> -----Original Message-----
> From: Gu Zheng [mailto:guz.fnst@cn.fujitsu.com]
> Sent: Wednesday, November 06, 2013 1:16 PM
> To: Chao Yu
> Cc: '???'; linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; linux-f2fs-devel@lists.sourceforge.net; '谭姝'
> Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid to use a NULL point in destroy_segment_manager
> 
> On 11/06/2013 01:10 PM, Chao Yu wrote:
> 
> > Hi Gu,
> >
> >> -----Original Message-----
> >> From: Gu Zheng [mailto:guz.fnst@cn.fujitsu.com]
> >> Sent: Wednesday, November 06, 2013 11:41 AM
> >> To: Chao Yu
> >> Cc: ???; linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; linux-f2fs-devel@lists.sourceforge.net; 谭姝
> >> Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid to use a NULL point in destroy_segment_manager
> >>
> >> On 11/06/2013 09:12 AM, Chao Yu wrote:
> >>
> >>> A NULL point should avoid to be used in destroy_segment_manager after allocating memory fail for f2fs_sm_info.
> >>
> >> Though without this patch it still can work well, because if it failed
> >> to allocate f2fs_sm_info, the sit_info, free_info... all were NULL, and
> >> the destory path(e.g. destroy_dirty_segmap) can deal with them well.
> >
> > I think it could not work well. Without this patch we may got a segment
> > fault in DIRTY_I(sbi) at the following code if it failed to allocate
> > f2fs_sm_info memory(sbi->sm_info). Right?
> 
> Yes, you're right. SIT_I generates sit_info from f2fs_sm_info.
> Sorry for my mistake.:(
> 
> Regards,
> Gu
> 
> >
> > static void destroy_dirty_segmap(struct f2fs_sb_info *sbi)
> > {
> > 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
> >
> >> IMO, this patch is still a good catch.
> >>
> >> Regards,
> >> Gu
> >>
> >>>
> >>> Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> >>> ---
> >>>  fs/f2fs/segment.c |    2 ++
> >>>  1 file changed, 2 insertions(+)
> >>>
> >>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> >>> index 3d4d5fc..ff363e6
> >>> --- a/fs/f2fs/segment.c
> >>> +++ b/fs/f2fs/segment.c
> >>> @@ -1744,6 +1744,8 @@ static void destroy_sit_info(struct f2fs_sb_info *sbi)
> >>>  void destroy_segment_manager(struct f2fs_sb_info *sbi)
> >>>  {
> >>>  	struct f2fs_sm_info *sm_info = SM_I(sbi);
> >>> +	if (!sm_info)
> >>> +		return;
> >>>  	destroy_dirty_segmap(sbi);
> >>>  	destroy_curseg(sbi);
> >>>  	destroy_free_segmap(sbi);
> >
> >
> >
> 
> 
> =