Hey, question: What's a convincing use case for a union filesystem?
Also, what I don't think union filesystems are a valid argument. They're not real filesystems in the way NTFS/FAT/extfs/reiserfs or whatever are — there's a lot less work to be done, and I could see the falling under the "toy" category that Linus was talking about...
I'd love to use them for VM image building, something I'm doing quite a lot of at the moment. Having an editable FS overlay on top of a pristine root image without having to futz with qcow2 and nbd would make the process a lot simpler.
Also, what I don't think union filesystems are a valid argument. They're not real filesystems in the way NTFS/FAT/extfs/reiserfs or whatever are — there's a lot less work to be done, and I could see the falling under the "toy" category that Linus was talking about...