btrfs: switch write_buf to kernel_write

Instead of playing with the addressing limits.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Christoph Hellwig 2017-09-01 17:39:19 +02:00 • committed by Al Viro
commit 8e93157bdd