Corrupted git repository?

Hi,

it looks like my git repository got corrupted today.

git status shows no changes,
git cherry-pick says "error: Your local changes to the following files
would be overwritten by merge:",
git fsck starts checking objects but hangs on one "Checking tree"

Other commands (gc, checkout, reset) seem to work correctly.

I've tried hard resetting to HEAD, didn't help.

What can I do? Cloning is very expensive operation here.

-- 
Piotrek