I verified that all reported failures pass locally. In backporting, all conflicts I resolved were due to the fact that the FSDirectory#resolvePath change were made to some code not existing in branch-2.7. I made notes on related JIRAs that if they were to be backported to branch-2.7, the backporter should pay attention to
HDFS-10744. And actually since in this change we updated the signature of resolvePath, it's pretty hard to miss without failing the build.
I also made another pass of more tricky changes in FSDirectory. They were all clean in the backport and I think the branch-2.7 patch is making the same logical changes as the branch-2.8 patch.
Pinging Daryn Sharp and Kihwal Lee to take another look at the branch-2.7 patch. If there's no objection I will commit tomorrow night. Thanks!