ntfs: only alias volume $UpCase to default on exact match

load_and_init_upcase() currently aliases vol->upcase to the global
default upcase whenever the shared prefix matches, and then truncates
vol->upcase_len to that shorter prefix.  The result is correct only by
accident: upcase[] accesses in name collation are gated by upcase_len,
so the prefix-equality alias produces the same fold output as keeping
the volume's own shorter table.

Still, prefix equality is not equality: the volume table is logically
distinct from the default and should not be replaced by it unless they
are byte-for-byte identical.  Use memcmp() to compare the complete table
in one expression and drop the now-redundant upcase_len rewrite.

No user-visible change is expected for compliant volumes whose $UpCase
has exactly default_upcase_len entries; shorter volume tables are no
longer aliased to the default.

Cc: stable@vger.kernel.org # v7.1
Signed-off-by: DaeMyung Kang <charsyam@gmail.com>
Reviewed-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

0 files changed, 0 insertions, 0 deletions