Alexander Viro <viro@math.psu.edu> wrote:
> > /overlay has all files / filesystem has, plus many more. For example,
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> What for? Why do you want to do it for every bloody file?
I assume it's not a copy, those are pointers.
Another application than transparent unarchiving, etc, could be:
cat /overlay/file
if /file exists, it display /file. If it doesn't, it call the user
process to generate file, e.g. unmigrate from remote storage.
I have precizely done that, but not with podfuk, but with FIST instead.
The concept works, but it is not finished yet.
http://www-internal.alphanet.ch/~schaefer/mfs.html
However with mfs *you always have the inodes on disk*, ie the inodes
ALSO exist on the virtual file system. But they are empty, and they
use a flag to say `I am migrated'. So the user-level process is
only activated for stat(), open(), write() (if the fs overfulls only),
unlink(), rename(). Once it's unmigrated, the inode number doesn't change,
and I/O is done directly to fs.
Keeping resident inodes was the only easy way to make sure things
like NFS work (and made everything easier).
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This archive was generated by hypermail 2b29 : Sun Apr 23 2000 - 21:00:16 EST