"p4 revert -a" equivalent in git?

Hi,

Is there a "p4 revert -a" equivalent in git or should I
whip up a script using git-diff-index and git-update-index?

That is I want to git-update-index --refresh for all
files whose inode may have changed but the actual file
data has not (i.e. git-diff-index is empty).

Thanks,
   Luben