Disk blocks for long periods

[Joakim Tjernlund]

Hi 

I have noticed that if i copy a "big" file(580K) it sometimes take up to 42 seconds before
it's finished. Normally it takes about 3-4 seconds. When this long copy happen, top reports
that kupdate and the copy(cp) process is in D state, the rest is sleeping.
The FS is a 45% usage. FS is about 63MB in size. Using the stable branch.

Why does it block for so long time?

Also, if I fill the FS up to 100% and later reboots, it kan take 10-15 minutes before
init starts to run. The root fs mount takes about 20 seconds and the system just
stops between the last message from the kernel and when init prints its version.

It is just the first reboot after I fill the FS, once I have gotten past the first reboot and
reboots again, things are back to normal.

Any ideas?

   Jocke