Hello, Our automated test infrastructure has been throwing errors while running generic/388 on upstream kernels for a little bit. We run the same tests on our internal kernels and it doesn't fail on any of our variations, the most recent of which is 4.16 based, so it's relatively new. I reproduced locally to make sure it wasn't a fluke, and it took 3 runs but I hit it as well. The test passes but fails with the follow up fsck, generally with messages like the following eck_generic_filesystem: filesystem on /dev/sdb is inconsistent *** fsck.ext4 output *** fsck from util-linux 2.30.2 e2fsck 1.43.5 (04-Aug-2017) Pass 1: Checking inodes, blocks, and sizes Inode 28049719 extent tree (at level 1) could be shorter. Fix? no Inode 30146767 extent tree (at level 1) could be shorter. Fix? no Deleted inode 45875333 has zero dtime. Fix? no Inode 45875468 extent tree (at level 1) could be shorter. Fix? no Inode 85459211, i_size is 3090400, should be 3846144. Fix? no Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information Block bitmap differences: -(230555--230583) -(231110--231130) -(231322--231370) -(232783--232920) -(235484--235501) -(235656--235659) -183533625 Fix? no Inode bitmap differences: -45875333 Fix? no /dev/sdb: ********** WARNING: Filesystem still has errors ********** The other things I see commonly are Inode 398211, i_blocks is 1464, should be 1304. Fix? no Inode 396011, end of extent exceeds allowed value (logical block 379, physical block 1626963, len 20) Clear? no I'm not sure where it got introduced, I'm running a bisect now to try and figure out where it happened but I wanted to let you know ASAP. Thanks, Josef