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SubjectRe: [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);
>
>
>


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