ntfs: update index root allocated size before shrink

ntfs_ir_truncate() currently shrinks the resident $INDEX_ROOT value first
and only updates index.allocated_size after re-looking up the attribute.
During that relookup, the resident value_length can already be smaller
while index.allocated_size still contains the old larger size.

That leaves a transiently inconsistent $INDEX_ROOT layout and prevents
lookup-time $INDEX_ROOT validation from being enabled: validation can
correctly reject allocated_size extending past the newly shrunk resident
value.

When shrinking, lower index.allocated_size before shrinking value_length.
If the truncate fails, restore the old allocated_size. Keep the existing
grow ordering because the old allocated_size remains within the enlarged
resident value until it is updated after the relookup. The shrink path is
safe because the new value_length still covers struct index_root, so the
index.allocated_size field remains present while it is updated first.

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