I know there are related issues, but none of them seem to apply to my case. Below is iotop output. jbd2 is constantly above 90% usage. It's been grinding away for 2 days. It stops for a while after a reboot, but then starts again after some time. I'm using 32bit Ubuntu 13.04. 200GB WD disk. Smart disabled in bios. No raid configs.
Total DISK READ: 0.00 B/s | Total DISK WRITE: 1997.25 K/s
TID PRIO USER DISK READ DISK WRITE SWAPIN IO> COMMAND
307 be/3 root 0.00 B/s 811.58 B/s 0.00 % 93.68 % [jbd2/sda1-8]
15454 be/4 curvv 0.00 B/s 1623.16 B/s 0.00 % 0.88 % firefox
4305 be/4 curvv 0.00 B/s 721.23 K/s 0.00 % 0.70 % gvfsd-metadata
2048 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % console-kit-daemon --no-daemon
1 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % init
2 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [kthreadd]
3 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [ksoftirqd/0]
...
gvfsd-metadata is a daemon acting as a write serialiser to the internal gvfs metadata storage. It is autostarted by GIO clients when they make metadata changes. Read operations are done by client-side GIO code directly, and don't require the daemon to be running. The gvfs metadata capabilities are used by the nautilus file manager, for example.– Curvian Vynes Jun 26 '13 at 18:41