Change permition of a mounted external harddrive for all users?

Question

I have set up a RetroPie running on a RaspBerry PI 2 with a the latest RetroPie. I have managed to mount an external harddrive and play all my games from there. I tried playing and saving the games but saving always fail which implies that I don`t have the proper permission set in my HD. I've messed around with chmod but I can only manage to write in this drive with root acess. what do i do to change the permission of this drive and make it writable for any user?

sudo findmnt gives me that

TARGET                           SOURCE    FSTYPE   OPTIONS
/                                /dev/mmcblk0p6
                                           ext4     rw,noatime,data=ordered
├─/dev                           devtmpfs  devtmpfs rw,relatime,size=372312k,nr_
│ ├─/dev/shm                     tmpfs     tmpfs    rw,nosuid,nodev
│ ├─/dev/pts                     devpts    devpts   rw,nosuid,noexec,relatime,gi
│ └─/dev/mqueue                  mqueue    mqueue   rw,relatime
├─/sys                           sysfs     sysfs    rw,nosuid,nodev,noexec,relat
│ ├─/sys/fs/cgroup               tmpfs     tmpfs    ro,nosuid,nodev,noexec,mode=
│ │ ├─/sys/fs/cgroup/systemd     cgroup    cgroup   rw,nosuid,nodev,noexec,relat
│ │ ├─/sys/fs/cgroup/cpuset      cgroup    cgroup   rw,nosuid,nodev,noexec,relat
│ │ ├─/sys/fs/cgroup/cpu,cpuacct cgroup    cgroup   rw,nosuid,nodev,noexec,relat
│ │ ├─/sys/fs/cgroup/blkio       cgroup    cgroup   rw,nosuid,nodev,noexec,relat
│ │ ├─/sys/fs/cgroup/devices     cgroup    cgroup   rw,nosuid,nodev,noexec,relat
│ │ ├─/sys/fs/cgroup/freezer     cgroup    cgroup   rw,nosuid,nodev,noexec,relat
│ │ └─/sys/fs/cgroup/net_cls     cgroup    cgroup   rw,nosuid,nodev,noexec,relat
│ ├─/sys/kernel/debug            debugfs   debugfs  rw,relatime
│ ├─/sys/fs/fuse/connections     fusectl   fusectl  rw,relatime
│ └─/sys/kernel/config           configfs  configfs rw,relatime
├─/proc                          proc      proc     rw,relatime
│ └─/proc/sys/fs/binfmt_misc     systemd-1 autofs   rw,relatime,fd=22,pgrp=1,tim
├─/run                           tmpfs     tmpfs    rw,nosuid,nodev,mode=755
│ ├─/run/lock                    tmpfs     tmpfs    rw,nosuid,nodev,noexec,relat
│ ├─/run/user/0                  tmpfs     tmpfs    rw,nosuid,nodev,relatime,siz
│ └─/run/user/1000               tmpfs     tmpfs    rw,nosuid,nodev,relatime,siz
├─/boot                          /dev/mmcblk0p5
                                           vfat     rw,relatime,fmask=0022,dmask
└─/media/usb0                    /dev/sda5 vfat     rw,nodev,noexec,noatime,nodi

the last entry shows my HD mounted

If I edit /etc/fstab I get the following entry:

proc            /proc           proc    defaults          0       0
/dev/mmcblk0p5  /boot           vfat    defaults          0       2
/dev/mmcblk0p6  /               ext4    defaults,noatime  0       1
# a swapfile is not a swap partition, no line here
#   use  dphys-swapfile swap[on|off]  for that

Answer 1

Run sudo findmnt (with the drive mounted) and paste the output into your question (at least the relevant part).

You can ensure the drive is mounted by editing /etc/fstab. To specify the settings you need to tell us more about the drive.

You are mounting a FAT partition so there are few options. (see https://raspberrypi.stackexchange.com/a/41233/8697 for more explanation.

1. Make a directory to mount in. I suggest /mnt/MYDISK but you can use any name.
2. Change permissions so everyone has access e.g. chmod 755 /mnt/MYDISK

3. Add a line like the following to /etc/fstab

   /dev/sda5 /mnt/MYDISK vfat defaults,noatime,noauto 0 0

(You can change the noauto to auto if you want it automatically mounted)

Answer 2

I have managed to make it work by editting /etc/usbmount/usbmount.conf and add FS_MOUNTOPTIONS="-fstype=vfat,umask=0000" .