I tested with 2 USB devices: a Kingston USB stick with FAT32, and an ADATA external USB3 hard drive with NTFS.
test1@linux-3776:~> mount | grep -i udisks
/dev/sdb1 on /run/media/test1/KINGSTON type vfat (rw,nosuid,nodev,relatime,uid=1000,gid=100,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,showexec,utf8,flush,errors=remount-ro,uhelper=udisks2)
/dev/sdc1 on /run/media/test1/ADATA type fuseblk (rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions,allow_other,blksize=4096,uhelper=udisks2)
Can’t understand very well the output for the external hard disk, but “ls -la” revealed that everything had permissions 0777, at least as expected.
However, in the USB stick case, it says “fmask=0022”, and yet all files were 0644 and all directories 0755! WTH with this?
Also, there’s certainly nothing inside directory /etc/udisks2. So, for not having udisks 2.9, is the only way to change default mount options setting udev rules?
Finally, I tried the mounting stuff with udisksctl and ISO files.
To mount (it always uses default /dev/loop0):
udisksctl loop-setup -r -f file.iso && udisksctl mount -b /dev/loop0
udisksctl unmount -b /dev/loop0 && udisksctl loop-delete -b /dev/loop0
Seemingly works, yet some limitations at least from my point of view:
–Couldn’t find a way to specify custom mount points, unlike plain “mount” command
–Perhaps it’s by good design, but I found slightly pity that it needs 2 steps to mount ISOs, instead of just one with “mount” command
–No additional messages when mounting in “read-only” mode; wondering if “-r” or “-rf” switches really work…
Besides, can ISOs really be mounted as “writable”? Aren’t they read-only by design?
–After using commands to mount ISOs, 8 loop0-7 devices are created under /etc, which even after no longer being used, they’re not gone until a reboot