My system has developed a strange defect after a distribution upgrade
(OpenSuSE 12.3 -> 13.2). I have various USB devices that I want to
mount to different top-level directories: the backup drive to /backup,
my USB stick to /usb, and the SD card adapter to /SD. That used to
work without problem by simply naming the device ID and the top-level
directory in /etc/fstab:

```
/dev/disk/by-id/scsi-1TOSHIBA_TransMemory-part1                        /usb       vfat     noauto,user,exec               0 0
/dev/disk/by-id/ata-ST2000LM003_HN-M201RAD_S34RJ9AFA36173-part1        /backup    ext4     noauto,user,exec               0 0
/dev/disk/by-id/usb-Generic-_SD_MMC_MS_PRO_20120926571200000-0:0-part1 /SD        exfat    noauto,user,exec  

```

Now, with the new kernel (3.16.7) and all, the exact /dev/disk/by-id
identifiers have changed, so I adapted them, but mounting fails
nevertheless. It turns out I can mount none of these devices to their
preferred mount points anymore, not even when I give the real name (e.g.,
/dev/sdc1 or the like). Mounting them manually, even as root, gives no
output and returns 0 just like a normal mount, but it doesn't populate
the moint point with the content of the disk, and in fact the `mount`
command claims that the device isn't mounted after all.

However, I *can* mount any of these devices successfully if I choose
the mount point /mnt, or, weirdly, a subdirectory of /mnt. That's
reassuring - it proves that there isn't a hardware or driver problem -
but I'd really like to mount my peripherals to their mnemonic names,
and in particular I'd sometimes like to mount two of them
simultaneously.

Why on Earth would the system care *where* I mount something, as long
as the mount point exists, is accessible, and isn't already mounted?
All three top-level dirs worked fine under the old kernel (3.7.10), and
now they don't. Can I be running into some new security manager or filter
rule that I've never heard about?