fusefs: fix a deadlock caused by daemons that never initializeHEADmain

If a daemon never responds to FUSE_INIT, but some process attempts to
access the mountpoint, and a different process (possibly the daemon
itself) attempts to unmount, a deadlock would result.

Fix this bug by blocking any thread that enters fuse_vfsop_root until
the daemon responds to FUSE_INIT or it times out.  That will block any
thread attempting to lookup a path in the fuse mountpoint, before it
even gets to fuse VOPs.  Remove less thorough initialization checks in
fuse_ticket_fetch and fuse_vnop_access that are no longer necessary.
And add a test case.

PR:		287431
MFC after:	2 weeks
Sponsored by:	ConnectWise
Reviewed by:	js
Differential Revision: https://reviews.freebsd.org/D59737

0 files changed, 0 insertions, 0 deletions