[ Upstream commit 933a3752babcf6513117d5773d2b70782d6ad149 ] the callers rely upon having any iov_iter_truncate() done inside ->direct_IO() countered by iov_iter_reexpand(). Reported-by: Qian Cai <cai@redhat.com> Tested-by: Qian Cai <cai@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Sasha Levin <sashal@kernel.org>