ext4: filesystems without casefold feature cannot be mounted with siphash

commit 985b67cd86392310d9e9326de941c22fc9340eec upstream.

When mounting the ext4 filesystem, if the default hash version is set to
DX_HASH_SIPHASH but the casefold feature is not set, exit the mounting.

BUG=b/378072645
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2024-49968 in the Linux kernel.

cos-patch: security-moderate
Reported-by: syzbot+340581ba9dceb7e06fb3@syzkaller.appspotmail.com
Change-Id: I9b49b06dd5899c4e107642cc7431f452e118afe7
Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
Link: https://patch.msgid.link/20240605012335.44086-1-lizhi.xu@windriver.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[cascardo: small conflict fixup]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kevin Berry <kpberry@google.com>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/128501
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Miri Amarilio <mirilio@google.com>