bitmap of filesystem

Scott Long scottl at
Thu Aug 10 00:21:52 UTC 2006

Geeta Khetan wrote:
>   Is there a global bitmap that keeps track of busy/free blocks over the
>   entire file system ? Is there a API or command i can use for that map?
>     Thanks

No, the bitmaps are stored on a per-cylinder group basis.  You can use
cgread() in libufs to read each group and then examine the bitmaps with
the cg* macros in /sys/ufs/ffs/fs.h.


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