UFS2 limits

Wojciech Puchar wojtek at wojtek.tensor.gdynia.pl
Sun Nov 9 10:32:01 PST 2008

>>  the limit is 32765, just because link count is 2 bytes wide and
>>  each subdir adds two to base directory. you have to change to 2
>>  level hierarchy.
> 	Question (for anyone who has an informed opinion):
> 	If there any technical reason that couldn't be expanded to 32
> bits?  Or is it possible but not done for historical or
> policy reasons, and if so what are they?
looking at /usr/include/ufs/ufs/dinode.h - i see

         int64_t         di_spare[3];

and i have really no idea why time uses as much as 8+4 bytes like that:

         ufs_time_t      di_mtime;       /*  40: Last modified time. */
         int32_t         di_mtimensec;   /*  64: Last modified time. */

i think it is not a problem to make link count 32-bit, and - why "spare" 
space are not just used for more direct/indirect blocks

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