FBSD: Avoid holding AFS_GLOCK during vinvalbuf
Currently we call vinvalbuf(9) in a few places while holding
AFS_GLOCK, but AFS_GLOCK is a non-sleepable lock (struct mtx), and
vinvalbuf can sleep. This can trigger a panic in some rare conditions,
with the message:
Sleeping thread (tid 100179, pid 95481) owns a non-sleepable lock
To avoid this, drop AFS_GLOCK around a few places that call
vinvalbuf().
Change-Id: I58acb144b6ffa007675402e7639b63ff3745dec5
Reviewed-on: https://gerrit.openafs.org/13970
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: BuildBot <buildbot@rampaginggeek.com>