Re: [PATCH RFC 05/20] fs: add vfs_setpos_cookie()

[Jan Kara <jack@suse.cz>]

On Fri 30-08-24 15:04:46, Christian Brauner wrote:
> Add a new helper and make vfs_setpos() call it. We will use it in
> follow-up patches.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Looks good. Feel free to add:

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

								Honza

> ---
>  fs/read_write.c | 31 +++++++++++++++++++++++++------
>  1 file changed, 25 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/read_write.c b/fs/read_write.c
> index 90e283b31ca1..66ff52860496 100644
> --- a/fs/read_write.c
> +++ b/fs/read_write.c
> @@ -40,18 +40,20 @@ static inline bool unsigned_offsets(struct file *file)
>  }
>  
>  /**
> - * vfs_setpos - update the file offset for lseek
> + * vfs_setpos_cookie - update the file offset for lseek and reset cookie
>   * @file:	file structure in question
>   * @offset:	file offset to seek to
>   * @maxsize:	maximum file size
> + * @cookie:	cookie to reset
>   *
> - * This is a low-level filesystem helper for updating the file offset to
> - * the value specified by @offset if the given offset is valid and it is
> - * not equal to the current file offset.
> + * Update the file offset to the value specified by @offset if the given
> + * offset is valid and it is not equal to the current file offset and
> + * reset the specified cookie to indicate that a seek happened.
>   *
>   * Return the specified offset on success and -EINVAL on invalid offset.
>   */
> -loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize)
> +static loff_t vfs_setpos_cookie(struct file *file, loff_t offset,
> +				loff_t maxsize, u64 *cookie)
>  {
>  	if (offset < 0 && !unsigned_offsets(file))
>  		return -EINVAL;
> @@ -60,10 +62,27 @@ loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize)
>  
>  	if (offset != file->f_pos) {
>  		file->f_pos = offset;
> -		file->f_version = 0;
> +		*cookie = 0;
>  	}
>  	return offset;
>  }
> +
> +/**
> + * vfs_setpos - update the file offset for lseek
> + * @file:	file structure in question
> + * @offset:	file offset to seek to
> + * @maxsize:	maximum file size
> + *
> + * This is a low-level filesystem helper for updating the file offset to
> + * the value specified by @offset if the given offset is valid and it is
> + * not equal to the current file offset.
> + *
> + * Return the specified offset on success and -EINVAL on invalid offset.
> + */
> +loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize)
> +{
> +	return vfs_setpos_cookie(file, offset, maxsize, &file->f_version);
> +}
>  EXPORT_SYMBOL(vfs_setpos);
>  
>  /**
> 
> -- 
> 2.45.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR