linux-kernel - Re: [PATCH] f2fs: fix to account IO correctly

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Message-ID: <20181019231212.GB11541@jaegeuk-macbookpro.roam.corp.google.com>
Date:   Fri, 19 Oct 2018 16:12:12 -0700
From:   Jaegeuk Kim <jaegeuk@...nel.org>
To:     Chao Yu <yuchao0@...wei.com>
Cc:     linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, chao@...nel.org
Subject: Re: [PATCH] f2fs: fix to account IO correctly

On 10/19, Chao Yu wrote:
> On 2018/10/19 3:06, Jaegeuk Kim wrote:
> > 
> > On 10/17, Chao Yu wrote:
> >> Below race can cause reversed reference on F2FS_RD_DATA, there is
> >> the same issue in f2fs_submit_page_bio(), fix them by relocate
> >> __submit_bio() and inc_page_count.
> >>
> >> Thread A			Thread B
> >> - f2fs_write_begin
> >>  - f2fs_submit_page_read
> >>  - __submit_bio
> >> 				- f2fs_read_end_io
> >> 				 - __read_end_io
> >> 				 - dec_page_count(, F2FS_RD_DATA)
> >>  - inc_page_count(, F2FS_RD_DATA)
> > 
> > Let me integrate the change into the original patch and test a bit.
> 
> IMO, it will be better to split this change into two, we can fix the
> location of inc_page_count(, F2FS_RD_DATA) directly in your patch,
> meanwhile we can add one more patch to fix the same issue in
> f2fs_submit_page_bio(), in where the problem exists for long time, it needs
> to send fixing patch to stable kernel mailing list.

How about this?

https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git/commit/?h=dev&id=3cca724d115fc1590c46585e264a391da06c345a
https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git/commit/?h=dev&id=8e3eed6f80c9c4cfe875f995b38dde590e444dc6

> 
> Thanks,
> 
> > 
> > Thanks,
> > 
> >>
> >> Signed-off-by: Chao Yu <yuchao0@...wei.com>
> >> ---
> >>  fs/f2fs/data.c | 6 +++---
> >>  1 file changed, 3 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> >> index c03bd0c2ed22..8b9240762156 100644
> >> --- a/fs/f2fs/data.c
> >> +++ b/fs/f2fs/data.c
> >> @@ -480,10 +480,10 @@ int f2fs_submit_page_bio(struct f2fs_io_info *fio)
> >>  	}
> >>  	bio_set_op_attrs(bio, fio->op, fio->op_flags);
> >>  
> >> -	__submit_bio(fio->sbi, bio, fio->type);
> >> -
> >>  	inc_page_count(fio->sbi, is_read_io(fio->op) ?
> >>  			__read_io_type(page): WB_DATA_TYPE(fio->page));
> >> +
> >> +	__submit_bio(fio->sbi, bio, fio->type);
> >>  	return 0;
> >>  }
> >>  
> >> @@ -612,8 +612,8 @@ static int f2fs_submit_page_read(struct inode *inode, struct page *page,
> >>  		return -EFAULT;
> >>  	}
> >>  	ClearPageError(page);
> >> -	__submit_bio(F2FS_I_SB(inode), bio, DATA);
> >>  	inc_page_count(F2FS_I_SB(inode), F2FS_RD_DATA);
> >> +	__submit_bio(F2FS_I_SB(inode), bio, DATA);
> >>  	return 0;
> >>  }
> >>  
> >> -- 
> >> 2.18.0.rc1
> > 
> > .
> >