md/bitmap: Fix bitmap chunk size overflow issues
- limit bitmap chunk size internal u64 variable to values not overflowing
the u32 bitmap superblock structure variable stored on persistent media
- assign bitmap chunk size internal u64 variable from unsigned values to
avoid possible sign extension artifacts when assigning from a s32 value
The bug has been there since at least kernel 4.0.
Steps to reproduce it:
1: mdadm -C /dev/mdx -l 1 --bitmap=internal --bitmap-chunk=256M -e 1.2
-n2 /dev/rnbd1 /dev/rnbd2
2 resize member device rnbd1 and rnbd2 to 8 TB
3 mdadm --grow /dev/mdx --size=max
The bitmap_chunksize will overflow without patch.
Cc: stable@vger.kernel.org
Signed-off-by: Florian-Ewald Mueller <florian-ewald.mueller@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Song Liu <song@kernel.org>