Well, the anime has roughly covered up through chapter 342, which I think is right after Hidan and Kakuzu die. We recently had the 435th, so that's about 93 chapters.
By way of contrast, Bleach was about 39 chapters behind before filler began again. Of course, this probably means that Naruto's filler will not be nearly as long...
As to whether it's justified, I'm not clear on pacing, though I know some have felt that at times it's been waaaaay too slow. So if filler now means good pacing for certain big fights later...maybe.
Blast, I have to start watching again.