Operation not permitted with sshfs

[hsiktas]

Hello,

I have installed Syncthing on my VPS and it is running under the syncthing user. I have added additional storage space with a Storage Box and mounted it via sshfs. Its file permissions look like this:

drwxr-xr-x 1 syncthing syncthing 4B Sep 5 15:20 storagebox

I have used the -o idmap=user -o uid=foo -o gid=bar option for sshfs in order to map the remote Storage Box user to my local syncthing user’s uid and gid.
Unfortunately this does not work. When I try to create a folder there the webinterface responds with:

2018-09-05 15:50:22: Loading ignores: open /mnt/storagebox/somefolder/.stignore: operation not permitted

2018-09-05 15:50:22: Creating folder marker: stat /mnt/storagebox/somefolder/: operation not permitted

2018-09-05 15:50:22: Error on folder “somefolder” (foobar): stat /mnt/storagebox/somefolder/: operation not permitted

How can I make this work? The remote user for sshfs does not exist on my VPS and I hoped that just mapping it over would be enough.
Even running sudo -u syncthing touch /mnt/storagebox/testfile fails but it works as root.

[calmh (Jakob Borg)]

I have no idea, but your touch test is a step in the right direction. When you get that to work as the user you want, Syncthing should also work. Until then it’s not really a Syncthing question.

[hsiktas]

I was not aware of the -o allow_other FUSE option for sshfs which enables access to the mount point to all the other UNIX users besides the one who initiated the mount command.

Syncthing already transferred a couple of GBs to the VPS and its StorageBox without any errors.