Comment 11 for bug 607632

Okay, quick and dirty workaround that proves its an fsync issue:

//nosync.c:
void sync() { }
int fsync(int fildes) { return 0; }

//build it:
gcc -shared -fPIC -O2 -g nosync.c -o /usr/local/lib/libnosync.so

//use it as preload with dpkg/apt
LD_PRELOAD=/usr/local/lib/libnosync.so apt-get install $package

dpkg should work 'rather' quickly now