* Update compatibility maximum cluster size when sector size is larger than 512 bytes.
* Additional validation of values in FsInfo sector.
* next_free_cluster cannot be 0 or 1, as these are reserved clusters
* next_free_cluster must be a valid cluster (using BPB to validate)
* free_cluster_count must be possible value (using BPB to validate)
* Avoid data-loss edge-case on volumes over 138GB in size.
Specifically, if the volume has more
than 0x0FFF_FFF4 clusters, then the FAT
will include an entry for clusters that
are reserved values. Specifically, cluster
number 0x0FFF_FFF7 is defined to mean
BAD_SECTOR, while numbers 0x0FFF_FFF8 ..
0x0FFF_FFFF are defined to mean end-of-chain.
This prevents these clusters from being part
of any valid cluster chain. Therefore:
1. prevent setting these clusters to point to
a valid next cluster
2. prevent reading these clusters as pointing
to a valid next cluster
Instead, always read/write these FAT entries
to have next cluster value of BAD_SECTOR.
* Reduce noisy warnings on FAT32.
* The reserved bits in FAT entry must be preserved on update.
* Change the set() implementation for FAT32 entries to return an actual Err(),
when attempting to set values for cluster numbers that have special meaning.
2a4c01082a