[LU-14923] do not always take write lock for writable mmap

Mon, 9 Aug 2021 21:12:34 +0000

Currently, Lustre always takes a PW lock when working with a writable mmap. This is not great because it means if multiple nodes map the same file writably and do pure read only, they'll all get write locks.

This is pretty easy to fix - just check we are doing a mkwrite when selecting the lock mode.

Whamcloud Community JIRA

[LU-14923] do not always take write lock for writable mmap