linux-kernel - Re: [PATCH 3/4] ext4: factor out ext4_get

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Message-ID: <piudbprxqkuph4sqlmdqw5mpfvhrygejzotz33nni34sxefqbs@j6bc3vhtkf2c>
Date: Wed, 30 Apr 2025 09:55:34 +0200
From: Jan Kara <jack@...e.cz>
To: Zhang Yi <yi.zhang@...weicloud.com>
Cc: linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org, 
	linux-kernel@...r.kernel.org, tytso@....edu, adilger.kernel@...ger.ca, jack@...e.cz, 
	wanghaichi0403@...il.com, yi.zhang@...wei.com, libaokun1@...wei.com, yukuai3@...wei.com, 
	yangerkun@...wei.com
Subject: Re: [PATCH 3/4] ext4: factor out ext4_get_maxbytes()

On Wed 30-04-25 09:13:00, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@...wei.com>
> 
> There are several locations that get the correct maxbytes value based on
> the inode's block type. It would be beneficial to extract a common
> helper function to make the code more clear.
> 
> Signed-off-by: Zhang Yi <yi.zhang@...wei.com>

Nice. Feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  fs/ext4/ext4.h    | 7 +++++++
>  fs/ext4/extents.c | 7 +------
>  fs/ext4/file.c    | 7 +------
>  fs/ext4/inode.c   | 8 +-------
>  4 files changed, 10 insertions(+), 19 deletions(-)
> 
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 5a20e9cd7184..8664bb5367c5 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -3378,6 +3378,13 @@ static inline unsigned int ext4_flex_bg_size(struct ext4_sb_info *sbi)
>  	return 1 << sbi->s_log_groups_per_flex;
>  }
>  
> +static inline loff_t ext4_get_maxbytes(struct inode *inode)
> +{
> +	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
> +		return inode->i_sb->s_maxbytes;
> +	return EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
> +}
> +
>  #define ext4_std_error(sb, errno)				\
>  do {								\
>  	if ((errno))						\
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index c616a16a9f36..b294d2f35a26 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -4931,12 +4931,7 @@ static const struct iomap_ops ext4_iomap_xattr_ops = {
>  
>  static int ext4_fiemap_check_ranges(struct inode *inode, u64 start, u64 *len)
>  {
> -	u64 maxbytes;
> -
> -	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
> -		maxbytes = inode->i_sb->s_maxbytes;
> -	else
> -		maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
> +	u64 maxbytes = ext4_get_maxbytes(inode);
>  
>  	if (*len == 0)
>  		return -EINVAL;
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index beb078ee4811..b845a25f7932 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -929,12 +929,7 @@ static int ext4_file_open(struct inode *inode, struct file *filp)
>  loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
>  {
>  	struct inode *inode = file->f_mapping->host;
> -	loff_t maxbytes;
> -
> -	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
> -		maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
> -	else
> -		maxbytes = inode->i_sb->s_maxbytes;
> +	loff_t maxbytes = ext4_get_maxbytes(inode);
>  
>  	switch (whence) {
>  	default:
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index f9725e6347c7..9f32af1241ff 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -4006,7 +4006,7 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
>  	struct inode *inode = file_inode(file);
>  	struct super_block *sb = inode->i_sb;
>  	ext4_lblk_t start_lblk, end_lblk;
> -	loff_t max_end;
> +	loff_t max_end = ext4_get_maxbytes(inode) - sb->s_blocksize;
>  	loff_t end = offset + length;
>  	handle_t *handle;
>  	unsigned int credits;
> @@ -4015,12 +4015,6 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
>  	trace_ext4_punch_hole(inode, offset, length, 0);
>  	WARN_ON_ONCE(!inode_is_locked(inode));
>  
> -	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
> -		max_end = sb->s_maxbytes;
> -	else
> -		max_end = EXT4_SB(sb)->s_bitmap_maxbytes;
> -	max_end -= sb->s_blocksize;
> -
>  	/* No need to punch hole beyond i_size */
>  	if (offset >= inode->i_size || offset >= max_end)
>  		return 0;
> -- 
> 2.46.1
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR