Subject: Automounter only mounts first partition of USB media (at least in certain cases)

From: Stefan Baur <[email-masked]>
Date: Fri, 10 Jan 2014 14:23:34 +0100

package: x2gousbmount
severity: normal
version: 1.1.0.2-0x2go2~git20131217.483+wheezy.heuler.1

Hi, I have a USB device with several partitions.

It's being detected by the automounter and shows up under /media like so:

ls -lah /media/USB2.0_Mobile_Disk/
total 16K
drwxr-xr-x 5 root           root 100 Jan 10 12:16 .
drwxr-xr-x 4 root           root  80 Jan 10 12:16 ..
drwxr-xr-x 2 root           root  40 Jan 10 12:16 sdb
drwxr-xr-x 4 x2gothinclient root 16K Jan  1  1970 sdb1
drwxr-xr-x 2 root           root  40 Jan 10 12:16 sdb2

As you can already see from the ownership tag, only sdb1 is actually 
mounted.

file -s /dev/sdb1:
/dev/sdb1: sticky x86 boot sector, mkdosfs boot message display, code 
offset 0x3c, OEM-ID " mkdosfs", sectors/cluster 16, root entries 512, 
Media descriptor 0xf8, sectors/FAT 208, heads 17, sectors 802816 
(volumes > 32 MB) , serial number 0x90e07535, label: "           ", FAT 
(16 bit)

I have to admit that the content of sdb2 is a bit unusual - it's an 
ISO9660 filesystem like the one you usually find on a CD.
file -s /dev/sdb2:
/dev/sdb2: sticky # ISO 9660 CD-ROM filesystem data 'Debian wheezy 
20131213-23:56    '

Still, it's perfectly possible to mount it manually:
mount /dev/sdb2 /media/USB2.0_Mobile_Disk/sdb2:
mount: block device /dev/sdb2 is write-protected, mounting read-only

mount
[...]
/dev/sdb1 on /media/USB2.0_Mobile_Disk/sdb1 type vfat 
(ro,relatime,sync,uid=104,fmask=0022,dmask=0022,codepage=cp437,iocharset=utf8,shortname=mixed,uni_xlate,errors=remount-ro)
/dev/sdb2 on /media/USB2.0_Mobile_Disk/sdb2 type iso9660 (ro,relatime)

So this should be supported by the automounter as well.

Note: I haven't tried what happens when you insert USB media with 
several "regulary formatted" (FAT, ext_, ...) partitions, so I don't 
know if the automounter is limited to mounting the first partition in 
general, or if it is simply confused by the fact that this particular 
USB medium contains an ISO9660-formatted partition.

-Stefan