Apparently Linus has made another of his grand pronouncements, on a subject relevant to this project (thanks to Pete Zaitcev for bringing it to my attention). People who think that userspace filesystems are realistic for anything but toys are just misguided.I beg to differ, on the basis that many people are deploying user-space filesystems in production to good effect, and that by definition means they're not toys. Besides the obvious example of GlusterFS, PVFS2 is almost entirely in user space and it has been used to solve some very serious problems on some seriously large systems for years. Everything Linus has worked on is a toy compared to this. There are several other examples, but that one should be sufficient.So where does Linus's dismissive attitude come from?