fusermount: umount failed: Invalid argument

Question

When I try to umount the FUSE file system, I get an error:

root@ubuntu:/home/fufs/src# fusermount -u /tmp/kpfss
fusermount: failed to unmount /tmp/kpfss: Invalid argument
root@ubuntu:/home/fufs/src# fusermount -z -u /tmp/kpfss
fusermount: failed to unmount /tmp/kpfss: Invalid argument

How can I umount the file system? Thanks.

Answer 1

Had this problem before and you may find it helps to use umount thus:

umount -f /tmp/kpfss # or whatever the mount point is

When I've seen this issue, there was a dropped connection to the remote server, and trying to access the mount point locked the shell up. The shell process couldn't even be killed.

Using umount seemed to help sort that.

Answer 2

Often while developing fuse filesystems, I've experienced this when the fuse filesystem locks up in an infinite while loop, or having seg faulted somehow. The only way I know how to free it is to ps -ef | grep name_of_fuse_filesystem_process and kill the corresponding pid.