Trick with USB drives

[Matt Patterson]

I tried all of the available options from umount and pumount. It can't 
remount the file system because the device is no longer present in the 
/dev/ folder. I always recieve a warning that the device is busy (for 
any invocation of umount/pumount). Dmesg shows it as having a bunch of 
failed writes. It never stops that behavior either. The scsi handler for 
hte device remains as a process until the system reboots. I have tried 
using fuser and lsof to determine the process using it, but I think it 
is just an innappropriate error message. This was the only solution 
besides rebooting.

Matt


ZIYAD A. M. AL-BATLY wrote:

>On Mon, 2005-04-04 at 01:50 -0400, Matt Patterson wrote:
>  
>
>>I don't know if anyone has ever had this, but...If you have for example 
>>a usb stick drive plugged in and mounted, but you forget and unplug it, 
>>then sometimes you can't unmount it. You definitely can't unmount it 
>>unless you plug the stick back in. The trick is to use the mknod command 
>>to create in the /dev/ directory a node identical to the one that was 
>>there when the device was connected, then unmount the drive. Then you 
>>can delete the node you created.
>>
>>I have a flky usb card so I have this a lot, this is the best solution I 
>>have found.
>>
>>Matt
>>    
>>
>
>I don't think this is a good thing to do in such cases.  If this ever
>happened to you again, try 'umount -r -l /dev/media_node'.
>
>>From the "umount" manual:
>
>-r
>        In case unmounting fails, try to remount read-only.
>
>-l
>        Lazy  unmount.  Detach the filesystem from the filesystem
>        hierarchy now, and cleanup all references to the filesystem as
>        soon as it is not busy anymore.  (Requires kernel 2.4.11 or
>        later.)
>
>
>Ziyad.
>
>
>  
>