io_uring: honor original task RLIMIT_FSIZE

io_uring: honor original task RLIMIT_FSIZE

commit 4ed734b0d0913e566a9d871e15d24eb240f269f7 upstream.

With the previous fixes for number of files open checking, I added some
debug code to see if we had other spots where we're checking rlimit()
against the async io-wq workers. The only one I found was file size
checking, which we should also honor.

During write and fallocate prep, store the max file size and override
that for the current ask if we're in io-wq worker context.

Cc: stable@vger.kernel.org # 5.1+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>