I had 25Tb of data and many directories of 100 000 files, when i try "ls -all" it's too long ..... I'd enough time to take a coffee :)
Just a hint:
'ls' sorts it's output, so you won't see anything until the 'getdents-loop' finished.
You could try using 'find', it should be a lot faster than ls (because it doesn't sort) but it will still take some time to complete.
Regards, Adrian