Re: [PATCH] f2fs: fix ref of discard command

From	Jaegeuk Kim <jaegeuk@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] f2fs: fix ref of discard command
Date	2017-06-14 16:30 +0200
Message-ID	<tSht0-6j2-11@gated-at.bofh.it> (permalink)
References	<tRnTQ-58j-3@gated-at.bofh.it> <tRvy2-1qM-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 06/12, Chao Yu wrote:
> Hi Jaegeuk,
> 
> On 2017/6/12 11:04, Jaegeuk Kim wrote:
> > This patch resolves kernel panic for xfstests/081, caused by recent f2fs_bug_on
> > 
> >   f2fs: add f2fs_bug_on in __remove_discard_cmd
> > 
> > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> > ---
> >  fs/f2fs/segment.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index 86a0c1095939..a6d77388a806 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -1025,6 +1025,8 @@ static void __wait_discard_cmd(struct f2fs_sb_info *sbi, bool wait_cond)
> >  	list_for_each_entry_safe(dc, tmp, wait_list, list) {
> >  		if (!wait_cond || (dc->state == D_DONE && !dc->ref)) {
> >  			wait_for_completion_io(&dc->wait);
> > +			if (dc->state == D_DONE && dc->ref)
> > +				dc->ref--;
> 
> Should set dc->ref to 0 to avoid panic once we add other referrers?

Sorry, could you please explain this in more detail?

Thanks,

> 
> Thanks,
> 
> >  			__remove_discard_cmd(sbi, dc);
> >  		} else {
> >  			dc->ref++;
> >

Thread

[PATCH] f2fs: fix ref of discard command Jaegeuk Kim <jaegeuk@kernel.org> - 2017-06-12 05:10 +0200
  Re: [PATCH] f2fs: fix ref of discard command Chao Yu <yuchao0@huawei.com> - 2017-06-12 13:20 +0200
    Re: [PATCH] f2fs: fix ref of discard command Jaegeuk Kim <jaegeuk@kernel.org> - 2017-06-14 16:30 +0200
      Re: [f2fs-dev] [PATCH] f2fs: fix ref of discard command Chao Yu <chao@kernel.org> - 2017-06-14 17:00 +0200
        Re: [f2fs-dev] [PATCH] f2fs: fix ref of discard command Jaegeuk Kim <jaegeuk@kernel.org> - 2017-06-14 17:30 +0200
          Re: [f2fs-dev] [PATCH] f2fs: fix ref of discard command Chao Yu <chao@kernel.org> - 2017-06-14 17:50 +0200

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