K 10
svn:author
V 3
mjg
K 8
svn:date
V 27
2020-11-04T21:18:08.130103Z
K 7
svn:log
V 483
rms: fixup concurrent writer handling and add more features

Previously the code had one wait channel for all pending writers.
This could result in a buggy scenario where after a writer switches
the lock mode form readers to writers goes off CPU, another writer
queues itself and then the last reader wakes up the latter instead
of the former.

Use a separate channel.

While here add features to reliably detect whether curthread has
the lock write-owned. This will be used by ZFS.

END