Having multiple mounted filesystems in one process prints "fuse_remove_signal_handlers: unknown session"

[centic9]

When I start multiple filesystems in one process (e.g. https://github.com/centic9/JGitFS can now do this to save main memory with many different Git repositories being mounted), I get the error message "fuse: fuse_remove_signal_handlers: unknown session" a number of times when I stop the application with CTRL-C, it seems the first unmount works fine and subsequent shutdown-handlers report the warning as I get it 3 times when mounting 4 filesystems in one process.

It still seems to unmount all filesystem, but that may also be done by the Kernel because the process is terminated.

It would be nice to avoid this output as it may confuse users. Is there a way to get rid of it even when having multiple mounts in one process?

Mounting git repository at /opt/poi at mountpoint /fs/poi
Using git repo at /opt/poi/.git
Found user/group id: 1000
Found user/group id: 1000
Mounting git repository at /opt/jenkins/jacoco-plugin at mountpoint /fs/jacoco-plugin
Using git repo at /opt/jenkins/jacoco-plugin/.git
Mounting git repository at /opt/Subversion/git at mountpoint /fs/subversion
Using git repo at /opt/Subversion/git/.git
Mounting git repository at /opt/git-fs/JGitFS at mountpoint /fs/JGitFS
Using git repo at /opt/git-fs/JGitFS/.git
...
^Cfuse: fuse_remove_signal_handlers: unknown session
fuse: fuse_remove_signal_handlers: unknown session
fuse: fuse_remove_signal_handlers: unknown session

[EtiennePerot]

Hi, just commenting here to say that I haven't forgotten this issue, but I am a bit busy at the moment. However, I'd like to say that multiple mounts in one process, while supported, are probably not a good idea if each mount doesn't need to share data between one another (which seems to be the case for you). Having all mounts in one process means that if this process crashes or OOM's, all filesystems become unavailable at the same time (as opposed to just having the one crashed filesystem become unavailable). Similarly, if you do a big bunch of operations in one filesystem, the other filesystems will become unresponsive because the process is busy doing work for the first filesystem. I think saving RAM is not worth those downsides, when RAM is generally cheap and one filesystem instance is probably not using more than 1% of it.

(This doesn't mean your issue is invalid, it just means that I don't think you need to have this problem in your case.)

[centic9]

Yes, I know it's not unix-like to do more than one thing, but Java is quite memory hungry, even more with Java 7, so I need to do multiple mounts in one process if I want to keep memory usage in sane limits when mounting many JGitFS filesystems on one machine.

BTW, it seems to work just fine even when stress-testing the system and re-use of resources is working out nicely.