Re: [PATCH-RFC-RESEND 1/9] vfs: pull btrfs clone API to vfs layer

[Dave Chinner <david@fromorbit.com>]

On Wed, Aug 26, 2015 at 04:16:42PM +0800, Peng Tao wrote:
> Now that a few file systems are adding clone functionality, namingly
> btrfs, NFS (later in the series) and XFS
> (ttp://oss.sgi.com/archives/xfs/2015-06/msg00407.html), it makes sense
> to pull the ioctl to common code.
> 
> Add vfs_file_clone_range() helper and .clone_range file operation interface
> to allow underlying filesystems to clone between regular files.
> 
> The change in do_vfs_ioctl() is defered to next patch where btrfs
> .clone_range is added, just so that we don't break btrfs CLONE ioctl
> with this patch.
> 
> Signed-off-by: Peng Tao <tao.peng@primarydata.com>
> ---
>  fs/ioctl.c              | 24 ++++++++++++++++++++++++
>  fs/read_write.c         | 45 +++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/fs.h      |  4 ++++
>  include/uapi/linux/fs.h |  9 +++++++++
>  4 files changed, 82 insertions(+)
.....
> +int vfs_file_clone_range(struct file *src_file, struct file *dst_file,
> +			 loff_t off, size_t len, loff_t dstoff)
> +{
> +	struct inode *src_ino;
> +	struct inode *dst_ino;
> +	ssize_t ret;
> +
> +	if (!(src_file->f_mode & FMODE_READ) ||
> +	    !(dst_file->f_mode & FMODE_WRITE) ||
> +	    (dst_file->f_flags & O_APPEND) ||
> +	    !src_file->f_op || !src_file->f_op->clone_range)
> +		return -EINVAL;
> +
> +	src_ino = file_inode(src_file);
> +	dst_ino = file_inode(dst_file);
> +
> +        if (S_ISDIR(src_ino->i_mode) || S_ISDIR(dst_ino->i_mode))
> +                return -EISDIR;

Whacky whitespace.

Also, shouldn't this call be restricted to S_ISREG() inodes? This
only checks for directories...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com