From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gu Zheng Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid to use a NULL point in destroy_segment_manager Date: Wed, 06 Nov 2013 13:15:36 +0800 Message-ID: <5279D078.8080803@cn.fujitsu.com> References: <000001ceda8d$5b185bd0$11491370$@samsung.com> <5279BA67.4040906@cn.fujitsu.com> <000101cedaae$bb7ed820$327c8860$@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <000101cedaae$bb7ed820$327c8860$@samsung.com> Sender: linux-kernel-owner@vger.kernel.org To: Chao Yu Cc: '???' , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, =?GB2312?B?J8y35q0n?= List-Id: linux-f2fs-devel.lists.sourceforge.net On 11/06/2013 01:10 PM, Chao Yu wrote: > Hi Gu, >=20 >> -----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; =CC=B7=E6=AD >> Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid to use a NULL point in d= estroy_segment_manager >> >> On 11/06/2013 09:12 AM, Chao Yu wrote: >> >>> A NULL point should avoid to be used in destroy_segment_manager aft= er allocating memory fail for f2fs_sm_info. >> >> Though without this patch it still can work well, because if it fail= ed >> 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. >=20 > I think it could not work well. Without this patch we may got a segme= nt=20 > fault in DIRTY_I(sbi) at the following code if it failed to allocate=20 > 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 >=20 > static void destroy_dirty_segmap(struct f2fs_sb_info *sbi) > { > struct dirty_seglist_info *dirty_i =3D DIRTY_I(sbi); >=20 >> IMO, this patch is still a good catch. >> >> Regards, >> Gu >> >>> >>> Signed-off-by: Chao Yu >>> --- >>> 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_i= nfo *sbi) >>> void destroy_segment_manager(struct f2fs_sb_info *sbi) >>> { >>> struct f2fs_sm_info *sm_info =3D SM_I(sbi); >>> + if (!sm_info) >>> + return; >>> destroy_dirty_segmap(sbi); >>> destroy_curseg(sbi); >>> destroy_free_segmap(sbi); >=20 >=20 >=20