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Cc: freebsd-hackers@freebsd.org
Subject: Re: BIO_DELETE equivalent for file on FFS filesystem
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>> file to take 900MB or... can i call some system function to "punch"
>> holes?
>
> I think you can only truncate the file at this time, pretty much like
> brk() works for memory.


BAD. suppose i keep windoze VM image on filesystem which takes 10GB but 
uses 5GB.

i could write simple program to find out what blocks are unused and 
then...do nothing.