linux-kernel - Re: [PATCH] f2fs: prevent meta updates while checkpoint is in progress

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Message-ID: <20200331090608.GZ20234@codeaurora.org>
Date:   Tue, 31 Mar 2020 14:36:08 +0530
From:   Sahitya Tummala <stummala@...eaurora.org>
To:     Jaegeuk Kim <jaegeuk@...nel.org>
Cc:     Chao Yu <yuchao0@...wei.com>,
        linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, stummala@...eaurora.org
Subject: Re: [PATCH] f2fs: prevent meta updates while checkpoint is in
 progress

On Mon, Mar 30, 2020 at 08:54:19PM -0700, Jaegeuk Kim wrote:
> On 03/26, Sahitya Tummala wrote:
> > allocate_segment_for_resize() can cause metapage updates if
> > it requires to change the current node/data segments for resizing.
> > Stop these meta updates when there is a checkpoint already
> > in progress to prevent inconsistent CP data.
> 
> I'd prefer to use f2fs_lock_op() in bigger coverage.

Do you mean to cover the entire free_segment_range() function within
f2fs_lock_op()? Please clarify.

Thanks,

> 
> > 
> > Signed-off-by: Sahitya Tummala <stummala@...eaurora.org>
> > ---
> >  fs/f2fs/gc.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> > index 5bca560..6122bad 100644
> > --- a/fs/f2fs/gc.c
> > +++ b/fs/f2fs/gc.c
> > @@ -1399,8 +1399,10 @@ static int free_segment_range(struct f2fs_sb_info *sbi, unsigned int start,
> >  	int err = 0;
> >  
> >  	/* Move out cursegs from the target range */
> > +	f2fs_lock_op(sbi);
> >  	for (type = CURSEG_HOT_DATA; type < NR_CURSEG_TYPE; type++)
> >  		allocate_segment_for_resize(sbi, type, start, end);
> > +	f2fs_unlock_op(sbi);
> >  
> >  	/* do GC to move out valid blocks in the range */
> >  	for (segno = start; segno <= end; segno += sbi->segs_per_sec) {
> > -- 
> > Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
> > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.

-- 
--
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.