Re: [bug] Wrong data from smartctl if disk is 'readonly' / in use

Martijn wrote:
> I've found that smartmontools 6.3 outputs wrong data about a disk, if 
> the disk is in use by another process. This includes wrong data about 
> the serial number of the drive, which surprised me (after it scared me 
> ;-)). I've tested this on a Windows host.
>
> Attached are two files with the output of smartctl.exe --xall of the 
> very same disk, once when it is in use by a VirtualBox virtual 
> machine, and once without.
>
> There are three important things to notice:
> 1. "Serial Number: 20202020202020203431"
> I'm not sure what causes smartmontools to think this particular string 
> is the serial number, but this is not the actual serial number ;-)
> It scared me at first, because I thought this serial number was causes 
> by some sort of problem with the firmware.
>
> 2. "Warning: Limited functionality due to missing admin rights" and 
> "Function requires admin rights"
>
> This is not accurate: I did have admin rights for that particular 
> shell. Both attached files where created in the same shell, with the 
> same rights. I would highly recommend a better description of possible 
> causes, or seperate error messages for seperate cases.

The messages about missing admin rights are printed if Windows does not 
allow full raw R/W access to the disk. Full R/W access is required for 
the ATA pass-through I/O-controls used to access SMART info.

When used by a VirtualBox VM, Windows apparently locks raw R/W access 
from other programs (which is good). Then the admin rights are not 
effective for this disk.

If the raw device could only be opened in non R/W mode, smartctl uses 
replacement functions (IOCTL_STORAGE_QUERY_PROPERTY, WMI). These provide 
only very limited (and sometimes incorrect) info.

Thanks,
Christian


------------------------------------------------------------------------------