You cannot do all your changes in free blocks. That would trash file
system performance really fast (can you say "100% fragmentation"?).
There may not even _be_ a 'consistent' state on a busy file system that's
used, eg., for a database. There may literally be months without a single
second in which no transaction is outstanding and no blocks are queued for
writing. But that's a problem no file system can solve without help from
the application.
--
A businessman is a hybrid of a dancer and a calculator.
-- Paul Valery
--
Matthias Urlichs \ noris network GmbH / Xlink-POP Nürnberg
Schleiermacherstraße 12 \ Linux+Internet / EMail: urlichs@noris.de
90491 Nürnberg (Germany) \ Consulting+Programming+Networking+etc'ing
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Click <A HREF="http://info.noris.de/~smurf/finger">here</A>. 42