This week I've implemented release of vnode locks while waiting for
reply from userland, and puffs doesn't panic any more during forced
unmounts Two operations don't drop vnode lock: inactive and reclaim.
These two are special and can't be handled usual way:
unlock-wait-relock. I've also added support for fifos, and extended
pnullfs to allow creation of fifos. It seems there's a bug in original
puffs code that didn't show up because filesystems enabled page cache
by default. I've add workaround for it and plan to try fixing it next
week. I'm also going to start porting psshfs next week.