snapshots. With this policy in place:
- Separate the snapshot vnode lock from the snapshot common lock.
Snapshots no longer need recursive vnode locks.
- Use a mutex (si_snaplock) to serialize creation, deletion, reading and
writing of snapshots.
- Move ffs_read() for snapshots into ffs_snapshot.c.
Reviewed by: Jason Thorpe <thorpej@netbsd.org>
While here change ffs_copyonwrite() to fail requests from pagedaemon that need
to copy-on-write.
93d3ff0e45