I was fixing a i_size problem in btrfs and I used fsx to reproduce the issue, but I needed to make a few changes to actually reproduce the problem. The individual explanations are in the patch changelogs themselves. One thing that may trip people up is that I've done system("echo 3 > /proc/sys/vm/drop_caches") for dropping caches, but this is consistent with several other tools we have in fstests. These are all small and straightforward fixes, and don't really affect any of the other tests. The only exception is generic/521 which is a soak test, I figure we want that thing to cover as much ground as possible, so enabling the close+open operation is desired there. Thanks, Josef