[price]

Your data is fine -- it's hidden while something else is mounted on top of the folder.

Rebooting will fix it. But you should be able to just unmount the filesystem, which will also fix it. Does 'mount' list something mounted there? Does 'df /path/to/folder/' reflect the FUSE filesystem rather than the underlying filesystem? The input/output error sounds like the FUSE filesystem being mounted indeed, and just being broken.

[lisper]

> Your data is fine -- it's hidden while something else is mounted on top of the folder.

I thought that was the case. But the truth is I don't really understand how mount points work under the hood. Where is the mount point information actually stored? I'm guessing it's in kernel memory somewhere, but I don't really know, and Googling hasn't been much help. Is there an article somewhere that explains this?

> Rebooting will fix it.

Good to know.

> But you should be able to just unmount the filesystem

Yeah, you'd think. But everything I try to do to that directory results in "Input/output error".

> Does 'mount' list something mounted there?

Yes:

Python@fuse0 on /Users/ron/devel (fusefs, nodev, nosuid, synchronous, mounted by ron)

> Does 'df /path/to/folder/' reflect the FUSE filesystem rather than the underlying filesystem?

  [ron@mickey:~]$ df devel
  df: devel: Input/output error
  [ron@mickey:~]$ umount devel
  umount: devel: not currently mounted
  [ron@mickey:~]$ ls devel
  ls: devel: Input/output error

You can hopefully see why I'm puzzled. I would really like to understand why this is happening.

[lisper]

Figured it out. umount wanted an absolute path.