Check files
d5a0ed0305c8df4180cb2bf975ecffe8 SCRATCH_MNT/file1
d5a0ed0305c8df4180cb2bf975ecffe8 SCRATCH_MNT/file2
-Inject error
CoW a few blocks
+Inject error
FS should be shut down, touch will fail
touch: cannot touch 'SCRATCH_MNT/badfs': Input/output error
Remount to replay log