Re: [PATCH] fs/read_write: Enable copy_file_range for block device.

[Dave Chinner]

On Mon, Jul 24, 2023 at 11:33:36AM +0530, Nitesh Shetty wrote:
> From: Anuj Gupta <anuj20.g@xxxxxxxxxxx>
> 
> Change generic_copy_file_checks to use ->f_mapping->host for both inode_in
> and inode_out. Allow block device in generic_file_rw_checks.

Why? copy_file_range() is for copying a range of a regular file to
another regular file - why do we want to support block devices for
somethign that is clearly intended for copying data files?

Also, the copy_file_range man page states:

ERRORS
.....
    EINVAL Either fd_in or fd_out is not a regular file.
.....

If we are changing the behavioru of copy_file_range (why?), then man
page updates need to be done as well, documenting the change, which
kernel versions only support regular files, etc.

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx