[FOLLOW UP] lockmgr rewriting -- round 1

Attilio Rao attilio at freebsd.org
Sat Mar 1 22:50:45 UTC 2008

Starting from the end of december, a serie of commits hit the tree in
order to prepare current CVS stock kernel to be ready for an eventual
newly implemented lockmgr locking primitive inclusion.
The commits included various fixes to lockmgr(9) consumers, mostly the
VFS locks and buffer cache objects locks. A detailed, tecnical, list
of all modifies provided will be released soon, in order to maintain
interested developers up-to-date, but it worths mentioning that for
any commit modifying KPI, manpages and __FreeBSD_version bumping
happened very closely.

Due to the vfs and buffer cache involvement, modifies propagated to a
lot of different filesystems, and some bugs show up: all the known one
have been alredy fixed, with the exception of LORs reported by
WITNESS, which hopefully will be analyzed and solved soon.
The "consumers" are now in a good shape in order to accept the new,
optimized, implementation, so we can consider an ideal "round 1" as
closed. The new implementation should follow in a few of weeks, just
in time to find any eventual bug and tweak exiting work in order to be
in sync with the new KPI.

If any user is experiencing any strange behaviour and he thinks VFS
can be involved, please let me know as it is likely bugs can show up
in this time-frame and it is better to solve them before the new
implementation cames in.

As last step let me thank people which deserved many thanks during
this "round 1":
- Konstantin Belousov submitted code and found time for reviewing
almost all the relevant patches, as long as finding time for
discussing approaches to follow
- Kris Kennaway, Peter Holm, Matteo Riondato and Andrea Barberio
tested, together, almost all patches before to be committed
- Jeff Roberson, Stephan Uphoff and John Baldwin offered time for
revisions and discussions
- Yar Tikhiy, Doug Barton, Scot Hetzel and Bryan Venteicher found time
to help in resolving specific filesystems bugs
- Christian Brueffer and Gabor Kovesdan helped in updating manpages
and docs/ bits


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