ufs: try to elide the interlock in ufs_itimes

[mjg]

Summary

Especially if the fs is mounted noatime none of the flags tend to be set.

While here dedup code with ufsfifo_close.

[kib]

Then why checking for v_usecount > 1 at all? It can go to 1 at any time.

[mjg]

I'm guessing the original code was avoiding the call, expecting for it to happen in ufs_inactive later. This retains the ultimately racy nature, except avoids the interlock.

[kib]

I agree, it probably was an attempt for micro-optimization, I do not see any other reason. Then, since inactivation is not guaranteed to occur now, while close is, I think the check for v_usecount should be removed.

[mckusick]

With updates, looks good.