spack/lib
Todd Gamblin 3d8d8d3644 Fix bug with lock upgrades.
- Closing and re-opening to upgrade to write will lose all existing read
  locks on this process.
  - If we didn't allow ranges, sleeping until no reads would work.
  - With ranges, we may never be able to take some legal write locks
    without invalidating all reads. e.g., if a write lock has distinct
    range from all reads, it should just work, but we'd have to close the
    file, reopen, and re-take reads.

- It's easier to just check whether the file is writable in the first
  place and open for writing from the start.

- Lock now only opens files read-only if we *can't* write them.
2016-10-11 01:55:33 -07:00
..
spack Fix bug with lock upgrades. 2016-10-11 01:55:33 -07:00