Linux – the noauto mount flag for

Ok, it's been a long time, but I'll still answer my question with the best option I found as of now.

The best way is to create a udev rule, associated with some scripts (that will create / remove directories and mount / unmount removable devices), and attached to partition udev device event type.

1 - Creating add / remove scripts

Add this script storage-automount.sh in /lib/udev/ and set it to executable (sudo chmod +x /lib/udev/storage-automount.sh):

#!/bin/sh

# set the mountpoint name according to partition or device name
mount_point=$ID_FS_LABEL
if [ -z $mount_point ]; then
    mount_point=${DEVNAME##*/}
fi

# if a plugdev group exist, retrieve its gid set & it as owner of mountpoint
plugdev_gid="$(grep plugdev /etc/group|cut -f3 -d:)"
if [ -z $plugdev_gid ]; then
    gid=''
else
    chown root:plugdev $mount_point
    gid=",gid=$plugdev_gid"
fi

# create the mountpoint directory in /media/ (if not empty)
if [ -n $mount_point ]; then
    mkdir -p /media/$mount_point
    # other options (breaks POSIX): noatime,nodiratime,nosuid,nodev
    mount -t $ID_FS_TYPE \
      -o rw,flush,user,uid=0$gid,umask=002,dmask=002,fmask=002 \
      $DEVNAME /media/$mount_point
fi

Add this script storage-autounmount.sh in /lib/udev/ and set it to executable (sudo chmod +x /lib/udev/storage-autounmount.sh):

#!/bin/sh

# set the mountpoint name according to partition or device name
mount_point=$ID_FS_LABEL
if [ -z $mount_point ]; then
    mount_point=${DEVNAME##*/}
fi

# remove the mountpoint directory from /media/ (if not empty)
if [ -n $mount_point ]; then
    umount -l /media/$mount_point
    rm -R /media/$mount_point
fi

2 - Creating the udev rule to attach those scripts to events

And finally, add a udev rule in /etc/udev/rules.d, for instance 85-storage-automount.rules:

ENV{DEVTYPE}=="partition", RUN+="/lib/udev/storage-automount.sh", ENV{REMOVE_CMD}="/lib/udev/storage-autounmount.sh"

And that's it.

Now, when you plug a storage device in, a directory will be created in /media/ according to the partition name (I don't remember but I think it's working with NTFS partitions as well) and your partition will be mounted into it. It's R/W for users if you have a plugdev group on your system. Also, the devices are mounted in synchronous mode in order to limit the risks of data loss in case of hot unplugging.

When the device is removed, it's unmounted and the directory is removed from /media.

Also, the tool to monitor the udev events is udevadm monitor, with options like --env or --property:

$ udevadm monitor --env

This is tested and working fine on both Debian and Arch, but probably works on all distributions that rely on udev.

You can do a chmod after you mounted the partition, but that wouldn't be persistent accross reboots.

You should try this fstab line:

/dev/sda1   /media/josiah    vfat    user,umask=0000   0   0

Or this mount options:

mount -t vfat -ouser,umask=0000 /dev/sda1 /media/josiah

That will make the mounted partition world readable and writable.

If you need a less permissive setup, you should create a new group and mount as follows:

mount -t vfat -ouser,gid=1010,umask=0007 /dev/sda1 /media/josiah

It assumes your new group's gid is 1010. All users that need access to the mountpoint will need to be added to the new group.