I recently started getting errors on a fairly new USB connected SATA
drive. Aside from the errors, the system was locking up as any process
attempting to access the drive would lock up in disk uninterruptible
wait ("D" in ps). I could not shut down the system and had to power it
off. (It's a laptop.) After a reboot, I tried to fsck it and that locked
up, too. I was able to recover by telling fsck to not fix the truncated
inode and fix everything else. Then I ran fsck again and it was
successful in fixing the inode. This happened several times.

I then bought a new drive and got the identical behavior! It was not the
drive. I rolled my kernel back to 9/13/08 and tried again. This time it just
worked! No errors or lock up.

I suspect that there are two issues. One results in the lock-up when the
disk had errors and the other caused the purported disk errors. The
latter has been introduced since 9/13/08. The kernel that produced the
errors was from 10/21. I also ran a kernel from 10/8 which did not cause
me problems, but I'm not sure that I used the USB drive with this
kernel.

I'll be building a 10/8 kernel later, after I have backed up some data
from a failing drive (PATA, not USB, and SMART confirms that the this
disk is sick). I will try to track down exactly which change triggered
this ugly behavior, but that will take a number of kernel builds, so it
will take a while.

Has anyone else seen this? Any ideas on what changes might be the most
likely cause. Could be USB, CAM, or something else, I guess.
--
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman@es.net Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751

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