linux-kernel - RE: [f2fs-dev] [PATCH 2/2] f2fs: no need to lock for update_inode

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Message-id: <009901d0f143$28f593b0$7ae0bb10$@samsung.com>
Date:	Thu, 17 Sep 2015 20:19:06 +0800
From:	Chao Yu <chao2.yu@...sung.com>
To:	'Jaegeuk Kim' <jaegeuk@...nel.org>
Cc:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	linux-f2fs-devel@...ts.sourceforge.net
Subject: RE: [f2fs-dev] [PATCH 2/2] f2fs: no need to lock for update_inode_page
	all the time

Hi Jaegeuk,

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@...nel.org]
> Sent: Wednesday, September 16, 2015 12:56 AM
> To: linux-kernel@...r.kernel.org; linux-fsdevel@...r.kernel.org;
> linux-f2fs-devel@...ts.sourceforge.net
> Cc: Jaegeuk Kim
> Subject: [f2fs-dev] [PATCH 2/2] f2fs: no need to lock for update_inode_page all the time
> 
> As comment says, we don't need to call f2fs_lock_op in write_inode to prevent
> from producing dirty node pages all the time.
> That happens only when there is not enough free sections and we can avoid that
> by calling balance_fs in prior to that.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
> ---
>  fs/f2fs/inode.c | 10 +++-------
>  1 file changed, 3 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> index 35aae65..0fc4d02 100644
> --- a/fs/f2fs/inode.c
> +++ b/fs/f2fs/inode.c
> @@ -296,16 +296,12 @@ int f2fs_write_inode(struct inode *inode, struct writeback_control *wbc)
>  		return 0;
> 
>  	/*
> -	 * We need to lock here to prevent from producing dirty node pages
> +	 * We need to balance fs here to prevent from producing dirty node pages
>  	 * during the urgent cleaning time when runing out of free sections.
>  	 */
> -	f2fs_lock_op(sbi);
> -	update_inode_page(inode);
> -	f2fs_unlock_op(sbi);
> -
> -	if (wbc)
> -		f2fs_balance_fs(sbi);

f2fs_balance_fs was moved here intentionally by Jin Xu in commit 92c4342fb72a
("f2fs: avoid writing inode redundantly when creating a file") to avoid
redundantly inode page submitting, I was confused since I didn't know all
history here. So, should we change the position of f2fs_balance_fs?

Thanks,

> +	f2fs_balance_fs(sbi);
> 
> +	update_inode_page(inode);
>  	return 0;
>  }
> 
> --
> 2.1.1
> 
> 
> ------------------------------------------------------------------------------
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@...ts.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

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