Hi,

On 6/1/26 2:33 PM, Al Viro wrote:

On Mon, Jun 01, 2026 at 10:17:23AM -0700, Linus Torvalds wrote:

quoted

TLDR: maybe we could ghet rid of "f_op->splice_read". *That* would be
a big simplification.

FUSE might be interesting - fuse_dev_splice_read() and its ilk.
Communications between the kernel and fuse server at least used to
seriously want that, so that would be one place to look for unhappy
userland...

speaking of fuse_dev_splice……_write actually, this series has broken 
xdg-document-portal!

https://github.com/flatpak/xdg-desktop-portal/issues/2026

Specifically what happens is that the EINVAL is returned due to oh.len 
!= nbytes:

fuse_dev_do_write: oh.len 16400 != nbytes 15526

(where 16400 == 16384 (read len) + 16, 15526 == 15510 (file len) + 16)

After reverting the series, there is no error because oh.len 
becomes 15526 too.


Thanks,
~val