error: packfile size changed

I was just about to push out a branch to a remote repo, and got a quite worrying error message:

$ git push kusma work/git-svn-autocrlf
Counting objects: 3475, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (1132/1132), done.
Writing objects: 100% (2503/2503), 933.82 KiB, done.
Total 2503 (delta 1909), reused 1927 (delta 1362)
error: packfile
./objects/pack/pack-165dacbd05ac0aa1634eb220f2b6d3be05b2bd3c.pack size
changed
error: packfile
./objects/pack/pack-165dacbd05ac0aa1634eb220f2b6d3be05b2bd3c.pack
cannot be accessed
error: unpack should have generated
83d114b6781e06b422a2062854dd3dede3795079, but I can't find it!
To ssh://kusma@repo.or.cz/srv/git/git/kusma.git
 ! [remote rejected] work/git-svn-autocrlf -> work/git-svn-autocrlf (bad pack)
error: failed to push some refs to
'ssh://kusma@repo.or.cz/srv/git/git/kusma.git'

The push was attempted with git v1.7.0.rc2. It fails with v1.6.6.1 (and msysgit's devel-branch, 1.6.5.1.1375.gc836) as well.

I tried running "git fsck --full", but it didn't report anything apart from dangling objects.

Any ideas, anyone?