/proc/mdstat logic (Linux 6.7)

NOTE

# md_seq_show
- printf("%s: %sactive", dev, active ? "" : "in")
- if active 
    - if rdonly then printf(" (read-only)")
    - if autoread then printf(" (auto-read-only)")
    - printf(" %s", raidtype)
- for each dev
    - printf(" %pg[%d]", dev, nr)
    - * NOTE: %pg is a special format that prints the device name
    - if writemostly then printf("(W)")
    - if journal then printf("(J)")
    - if faulty then printf("(F)")
    - if spare then printf("(S)")
    - if replacement then printf("(R)")
- if has disks then printf("\n      %llu blocks", sectors/2)
- if persistent then printf(" super %d.%d", major, minor)
  elif external then printf(" super external:%s")
  else printf(" super non-persistent")
- if active
    - personality status()
    - printf("\n      ")
    (don't care about the rest output)
- else printf("\n       ")
(don't care about the rest output)

# Personality status

## RAID0

printf(" %dk chunks")

## RAID1

- printf(" [%d/%d] [", disks, disks - degraded)
- for each dev'
    - The order of dev' might be different from "dev" above.
    - printf("%s", is_sync ? "U" : "_")
- printf("]")

## RAID10

- if near_copies < geo.raid_disks then printf(" %dK chunks")
- if near_copies > 1 then printf(" %d near-copies")
- if far_copies > 1 then
    - if far_offset then printf(" %d offset-copies")
    - else printf(" %d far-copies")
    - if far_set_size != raid_disks then printf(" %d devices per set")
- printf(" [%d/%d] [")
- for each dev'
    - printf("%s", is_sync ? "U" : "_")
- printf("]")

## RAID5

- printf(" level %d, %dk chunk, algorithm %d")
- printf(" [%d/%d] [")
- for each dev'
    - printf("%s", is_sync ? "U" : "_")
- printf("]")

## Linear

printf(" %dk rounding")

## Multipath

- printf(" [%d/%d] [")
- for each dev'
    - printf("%s", is_sync ? "U" : "_")
- printf("]")