Wenjie

**What would you like to be added**: **Why is this needed**: curvefs is an shared POSIX filesystem on top of S3, and it has own metadata engine.

curvebs: change hostname from required to optional

7

### What problem does this PR solve? Issue Number: #2493 Problem Summary: ### What is changed and how it works? What's Changed: How it Works: Side effects(Breaking backward compatibility? Performance...

[feat]curvefs: client: optimize rmdir

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### What problem does this PR solve? when rmdir, it uses ListDentry to check if dir is empty, which cost to mush. Issue Number: #xxx Problem Summary: ### What is...