8.0-RC3 USB lock up on mounting two partitions from one USB drive

[Guojun Jin]

When mounting two partitions from a USB dirve, it can cause the drive access lock up for a long time.
Details:

Terminal 1 --
term1# mount /dev/da0s3d  /mnt
term1# cd /mnt ; rm -fr *

when rm starts, go to terminal 2 and do:

term2# mount /dev/da0s3e /dist ### this will hanging for a long time and USB hard drive activity light is off.
After more than 1-2 minutes, mount returns, and the drive activity light is blinking, thus removing is going on.

term2# ls /dist   ### this will cause dUSB dirve hanging again -- no avtivity.
Similarly, ls will finish in a couple of miniutes or longer, the rm command continues; but for a while, the drive
activity will stop again.

Reboot machine, repeat the above steps, and result will be the same. Reboot machine again, and just mount one
partition, then doing "rm -rf *" without involve the second partition, rm will finish quickly.

Has anyone obseved this behave on 8.0-RC?

-Jin