kern/85503: panic: wrong dirclust using msdosfs in RELENG_6

[Bruce Evans]

On Sat, 3 Sep 2005, Dmitry Pryanishnikov wrote:

> On Sat, 3 Sep 2005, Dmitry Pryanishnikov wrote:
>>> I think I said that the inode number in msdosfs should be the cluster
>>> number of the first cluster in the file.  This would be broken by
>>> variable-sized clusters (unlikely, and even less useful) or new file
>>> types like symlinks (useful and not so unlikely -- FreeBSD could add
>>> them as an extension).
>> 
>> Yes, I agree with this. While this fs has being called FAT32,
>> it's cluster number will fit in 32-bit word.
>
> Ups, how about empty files? They haven't any allocated clusters, have
> they? So, alas, we can't go this route.

Urk.  It also doesn't work for cd9660.  So the block number can be
used at most as a hint getting a unique fake inode number, and in
msdosfs file systems don't have to be much larger than 128GB to have
>= 4G files -- a 128+GB file system can consist of 128GB of directories
all containing empty files :-).

Bruce