linux-kernel - Re: [PATCH V2] f2fs: fix to adjust appropirate defragment pg

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Message-ID: <8a6b2768-8ab6-4275-8c4e-05b4eca83987@kernel.org>
Date: Tue, 26 Mar 2024 19:11:50 +0800
From: Chao Yu <chao@...nel.org>
To: Zhiguo Niu <zhiguo.niu@...soc.com>, jaegeuk@...nel.org
Cc: linux-f2fs-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
 niuzhiguo84@...il.com, ke.wang@...soc.com, hongyu.jin@...soc.com
Subject: Re: [PATCH V2] f2fs: fix to adjust appropirate defragment pg_end

On 2024/3/25 13:56, Zhiguo Niu wrote:
> A length that exceeds the real size of the inode may be
> specified from user, although these out-of-range areas
> are not mapped, but they still need to be check in
> while loop, which is unnecessary.
> 
> Signed-off-by: Zhiguo Niu <zhiguo.niu@...soc.com>
> ---
> v2: check i_size within inode lock according to Chao's suggestions
> ---
> ---
>   fs/f2fs/file.c | 11 +++++++----
>   1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 128e53d..cf63db7 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -2608,9 +2608,6 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
>   	bool fragmented = false;
>   	int err;
>   
> -	pg_start = range->start >> PAGE_SHIFT;
> -	pg_end = (range->start + range->len) >> PAGE_SHIFT;
> -
>   	f2fs_balance_fs(sbi, true);
>   
>   	inode_lock(inode);
> @@ -2629,10 +2626,16 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,

pg_start = range->start >> PAGE_SHIFT;
pg_end = min_t(pgoff_t, (range->start + range->len) >> PAGE_SHIFT,
			DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE));

>   
>   	/* writeback all dirty pages in the range */
>   	err = filemap_write_and_wait_range(inode->i_mapping, range->start,
> -						range->start + range->len - 1);
> +						min_t(loff_t, range->start + range->len - 1,
> +						i_size_read(inode) - 1));

, pg_start << PAGE_SHIFT - 1, pg_end << PAGE_SHIFT - 1); ?

Thanks,

>   	if (err)
>   		goto out;
>   
> +	pg_start = range->start >> PAGE_SHIFT;
> +	pg_end = min_t(pgoff_t,
> +				(range->start + range->len) >> PAGE_SHIFT,
> +				DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE));
> +
>   	/*
>   	 * lookup mapping info in extent cache, skip defragmenting if physical
>   	 * block addresses are continuous.