refresh partition table

[David Henderson]

On 05/16/2011 10:52 AM, David Henderson wrote:
> On 05/15/2011 04:27 PM, Sergey Naumov wrote:
>> blockdev --rereadpt
>>
>> Sergey Naumov.
>
> I've run into an interesting problem by using the above syntax.  
> Apparently when I issue that command "blockdev --rereadpt /dev/sde", 
> it removes all the device's partition files (e.g. /dev/sde1) and 
> leaves the one for the drive itself (e.g. /dev/sde).  If I unplug the 
> device and plug it back in, the correct device files populate again.  
> So it appears that mdev is working right, but the blockdev is not.  
> Any ideas why blockdev would be doing this?
>
> Dave

Just to add a few more details.  I have a card reader that occupies 
/dev/sda through /dev/sdd.  If I insert an SD card with 2 partitions and 
wait for mdev to populate the device files, wait a few seconds, then 
issue the blockdev command, it wipes out those partition files too (e.g. 
/dev/sdb1).  If I issue the blockdev command on the device files for the 
card reader that don't have any inserted media, I get the error message 
"blockdev: can't open '/dev/sda': No medium found".  This tells me that 
blockdev can actually see if a device is present and that the devices 
files are populated correctly.  I just have no idea why it wouldn't be 
working correctly.  I've also tried:

# hdparm -z /dev/sde

/dev/sde:

So you can see that it's failing too.  I think, however, hdparm isn't 
the best choice to use for USB attached devices.  Thoughts anyone?

Dave