NV+ V2 stalling when 80%+ full (20047616)

hauser wrote:

chirpa wrote: But even with a factory default (not possible for many people), what happens when they hit fragmentation down the road again? Seems like a short term solution. exactly and for me fragmentation should be low as I've hit this problem just in copying data back to the device from one computer with single thread copy after a factory default many times.... normally fragmentation is "bad" if you copy & delete files randomly large amounts of files over time.

You are right, and when I try it with switchover ext3 <> ext4 with absolutely identical data (i mean 100%) - ext4 driver always lockup NAS completely.
There is no fragmentation and volume is mounted in backward compatibility with ext3 then IO kills all! So I can remount same partition with ext3 driver back and problem is gone.
That's why I am asking what is changed, because I saw some new kernel patches to ext4.

a) it's a driver bug
b) 256MB is not enough for ext4 of this volume size

if it's b) then some tuning may solve this problem.
But I don't understand why ext4 driver fails when have absolutely same conditions as ext3 (disabled extents, same data, everything is 100% same...)