fs.h: fix signed/unsigned issues, from NetBSD

[emaste]

Summary

This will allow us to increase WARNS in at least makefs.

From NetBSD fs.h 1.57, 1.58.

https://github.com/NetBSD/src/commit/e8458667baaf7c856681cef5944a68649ccf1930
https://github.com/NetBSD/src/commit/03c60fb61968c55563c203d2454702610c71cf34

Test Plan

Tinderbox build

[kib]

I dislike the direct use of uint64_t for disk address. Some abstraction is IMO warranted there, off_t use was relatively sane.

Note that our daddr_t type, which represents disk block number, is also signed.

[emaste]

The signedness warning arises because the UFS dinode di_size is u_int64_t. Is the right fix then just to sprinkle casts everywhere?

[kib]

In D10578#219445, @emaste wrote:

The signedness warning arises because the UFS dinode di_size is u_int64_t. Is the right fix then just to sprinkle casts everywhere?

I am not sure, and since I noted that e.g. lblktosize() is legitimately used for extended data blocks, which have negative indexes, I think changing signess there is tricky.
Are there too many relateed warnings in the makefs code ? Does makefs support ext attributes on UFS ?

sys/ufs/ffs/fs.h

577

For this change, please take a look at ufs/ffs/ffs_softdep.c:trunc_pages(). I suspect that it would break the calculation, or at least more consideration is required.

[emaste]

Instead of this change I can use D10589 and some casts sprinkled in makefs.

sys/ufs/ffs/fs.h

611

related issue arises here, where i_size is uint64_t and smallblktosize is signed