This is my problem:

I configured my RPi with Debian:

  • Samba shares a specific folder, that is readable-writeable-executable from my home network: /media/

  • usbmount automount USB devices when inserted in my RPi, in /media/usb

  • No users should be logged in to do this

When I insert an USB device, usbmount mount it correctly, so RPi can write on it and a person can READ it through network. BUT no persons are allowed to WRITE on it through network.

Checking permissions on /media/usb I found that:

  • BEFORE usbmount mount device /media/usb is rwx-rwx-rwx
  • AFTER usbmount mount device /media/usb became rwx-r-r, so only root (usbmount work mounting devices as root) can write on it

So I've tryed to change the FS_MOUNTPOINTS="" line in /etc/usbmount/usbmount.conf file but I don't know how to force usbmount to automount devices rwx-rwx-rwx or with "low-user write permission".

  • Check the MOUNTOPTIONS entry in /etc/usbmount/usbmount.conf. Does it contain ro?
    – Bex
    Apr 17, 2015 at 6:17
  • No it doesen't contain ro. All the line: MOUNTOPTIONS="sync,noexec,nodev,noatime,nodiratime"
    – xdola
    Apr 17, 2015 at 22:05

2 Answers 2


After a lot of test i edited the FS_MOUNTOPTIONS line:



  • vfat is the filesystem
  • umask=0000 is the permission of the file and folder. 0000 means rwx-rwx-rwx

I've had this problem on linux once. It turned out that mounting a drive will apply the root directory permissions to the mount point. A simple chmod 777 /media/usb after mounting should fix it.

You might also want to add ,dmask=000,fmask=000 (or preferably 002 and using a group) to the FS_MOUNTOPTIONS line.

  • The Raspberry should do it automatically, without a person that change the permission. However chmod doesn't work.
    – xdola
    Apr 19, 2015 at 16:08

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