isofs now uses an in-memory directory listing built on-the-fly instead
of parsing the ISO 9660 data structures over and over for almost every
request. This yields huge performance improvements.
The directory listing is allocated dynamically, but Minix servers aren't
normally supposed to do that because critical servers would crash if the
system runs out of memory. isofs is quite frugal, won't allocate memory
after having the whole directory tree cached and is not that critical
(its most important job is to serve as a root file system during
installation).
The benefits and elegance of this scheme far outweights this small
problem in practice.
Change-Id: I13d070388c07d274cbee0645cbc50295c447c5b6
This patch changes the libminixfs API and implementation such that the
library is at all times aware of how many total and used blocks there
are in the file system. This removes the last upcall of libminixfs
into file systems (fs_blockstats). In the process, make this part of
the libminixfs API a little prettier and more robust. Change file
systems accordingly. Since this change only adds to MFS being unable
to deal with zones and blocks having different sizes, fail to mount
such file systems immediately rather than triggering an assert later.
Change-Id: I078e589c7e1be1fa691cf391bf5dfddd1baf2c86
