On Fri, Jan 22, 2021 at 9:21 PM harshad shirwadkar
[off-list ref] wrote:

Thanks Amir for pointing that out. Yes we are missing fast commit
tracking in whiteout. I'll send out a fix for that.

quoted

But I must say it would have been very hard to catch missing ext4_fc_track_*
without specialized fs fuzzer such as the CrashMonkey generated tests.

I agree, it's been on my to-do list to run CrashMonkey tests with fast
commits. I'm curious what kind of CrashMonkey tests you ran that
helped you catch this? Were you running Overlayfs on top of Ext4 with
fast commits?

Neither. I just guessed RENAME_WHITEOUT might be missed as
developers are rarely aware of it.
I never ran CrashMonkey tests myself.
I found a few crash consistency bugs using xfstest generic/455.
I suggest that you run it with fast commits
and try using NUM_OPS and NUM_FILES larger than the test defaults
to let the test run for a longer time.

Thanks,
Amir.