Merge pull request #2350 from mheon/lock_renumber

Add lock renumbering

1 files changed, 14 insertions, 0 deletions

diff --git a/libpod/lock/lock.go b/libpod/lock/lock.go
index 1f94171fe..d6841646b 100644
--- a/libpod/lock/lock.go
+++ b/libpod/lock/lock.go
@@ -24,6 +24,20 @@ type Manager interface {
 	// The underlying lock MUST be the same as another other lock with the
 	// same UUID.
 	RetrieveLock(id uint32) (Locker, error)
+	// PLEASE READ FULL DESCRIPTION BEFORE USING.
+	// FreeAllLocks frees all allocated locks, in preparation for lock
+	// reallocation.
+	// As this deallocates all presently-held locks, this can be very
+	// dangerous - if there are other processes running that might be
+	// attempting to allocate new locks and free existing locks, we may
+	// encounter races leading to an inconsistent state.
+	// (This is in addition to the fact that FreeAllLocks instantly makes
+	// the state inconsistent simply by using it, and requires a full
+	// lock renumbering to restore consistency!).
+	// In short, this should only be used as part of unit tests, or lock
+	// renumbering, where reasonable guarantees about other processes can be
+	// made.
+	FreeAllLocks() error
 }
 
 // Locker is similar to sync.Locker, but provides a method for freeing the lock