LFS is currently carrying around both support for the historical quota format ("quota1") and the recent newer 64-bit in-volume quota format ("quota2") from FFS, but neither is actually connected up or works. In fact, neither has ever worked -- there is no reason to worry about compatibility.

Define a new on-disk quota format that shares some of the properties of both the FFS formats:

Implement the quota system by folding together the existing copies of the quota1 and quota2 code and writing as little new code as possible. Note that while the "ulfs" code should have more or less complete quota support and all the necessary hooks in place, you'll have to add quota hooks to the native lfs code.

You will also need to figure out (before you start coding) what if any special steps need to be taken to make sure that the quota files on disk end up consistent as segments are written out. This may require additional logic like the existing DIROP logic, which would likely be a pain.

Add an option to newfs_lfs to enable quotas. Then add code to fsck_lfs to crosscheck and correct the usage amounts. Also add logic in tunefs_lfs to turn quotas on and off. (It's ok to require a fsck afterwards when turning quotas on to compute the current usage amounts.)

(Note that as of this writing no tunefs_lfs program exists -- that will have to be corrected too.)