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

[Chao Yu]

Hi Gu, 

Thanks for your reviewing!

Regards
Yu

> -----Original Message-----
> From: Gu Zheng [mailto:guz.fnst@xxxxxxxxxxxxxx]
> Sent: Wednesday, November 06, 2013 1:16 PM
> To: Chao Yu
> Cc: '???'; linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx; '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@xxxxxxxxxxxxxx]
> >> Sent: Wednesday, November 06, 2013 11:41 AM
> >> To: Chao Yu
> >> Cc: ???; linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx; 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@xxxxxxxxxxx>
> >>> ---
> >>>  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);
> >
> >
> >
> 
> 
> =

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