I've been nurturing an interest in storage and filesystems, but have been running into a real drought of high-quality books on the topic. On the database side of the world, we have things like Database Internals, Database Management Systems, or even DDIA. Filesystems, however, don't seem to get as much coverage.

So... yeah. If someone asked you what book to read to really grok filesystems, what would you suggest? Thanks!