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: [email protected]

Signed-off-by: Florian-Ewald Mueller <[email protected]>
Signed-off-by: Jack Wang <[email protected]>
Signed-off-by: Song Liu <[email protected]>

0 files changed, 0 insertions, 0 deletions