Subject: FFS soft dependencies code available
To: None <firstname.lastname@example.org, email@example.com>
From: Frank van der Linden <firstname.lastname@example.org>
Date: 10/19/1999 21:06:21
Kirk McKusick's FFS soft updates/dependency code has been around for quite
a bit, and has been in an "almost ready" state for NetBSD for close
to 2 years now. Which is a big shame, we really need to get this
So, I have put it on a branch in our CVS tree, for the adventurous to
use and debug.
1) Get the code. For example, using anoncvs and ssh, set CVS_RSH
to 'ssh', and do:
cvs -d email@example.com:/cvsroot co -r fvdl-softdep src-nocrypto
This will create a directory called "src" with all that you need
in it. This includes all of src/sys, and a few bits living in
sbin/. I did not tag the rest of the sources, so they will not
be checked out; they are not needed for testing (you can just
use the rest of -current for that).
If you want a complete tree, checking out the whole
"src-nocrypto" without "-r fvdl-softdep", and then
doing a cvs update using the -r flag of that tree
2) Compile a kernel as you always would, in the checked out tree.
3) Compile the userland utilities (fsck_ffs, tunefs, mount)
Note that these will grab the wrong <sys/foo.h> include
files if you compile them, it's easiest to add a line
..to the Makefiles.
4) You can remove "update" from /etc/rc.conf if you want
to do some more permanent testing, since it's no longer
needed with the "trickle sync" code that comes with
the softdep code.
5) Boot the new kernel.
6) Find a crash & burn filesystem. Run the new tunefs binary
on it as:
tunefs -n enable /dev/rXdXX
7) Mess around with the filesystem.
Note that there is a known bug currently, which makes unmounting filesystems
with soft dependencies, that have been used moderately, hang.
I wouldn't advise using this yet if you're not willing to deal with
hanging unmounts and possible other problems. However, I would really
appreciate it if people could test it. Even if it's just a new kernel
without any filesystems that use soft dependencies (this should be
a lot more stable).
One final note: the file ffs_softdep.c appears on the branch, but will
not appear in the main tree if the code gets merged eventually. This is
because of copyright issues. However, the code is set up in such a way
that there is a stubfile for this one, and the "real" file can be dropped
in without a hitch. That way, the kernel can still be completely BSD-style
licensed, and people can grab ffs_softdep.c and drop it in if they