From 689329f7495c1fc4f035fe3f39be28375987faf8 Mon Sep 17 00:00:00 2001 From: Matthew Heon Date: Mon, 2 Dec 2019 23:06:00 -0500 Subject: Ensure volumes reacquire locks on state refresh After a restart, pods and containers both run a refresh() function to prepare to run after a reboot. Until now, volumes have not had a similar function, because they had no per-boot setup to perform. Unfortunately, this was not noticed when in-memory locking was introduced to volumes. The refresh() routine is, among other things, responsible for ensuring that locks are reserved after a reboot, ensuring they cannot be taken by a freshly-created container, pod, or volume. If this reservation is not done, we can end up with two objects using the same lock, potentially needing to lock each other for some operations - classic recipe for deadlocks. Add a refresh() function to volumes to perform lock reservation and ensure it is called as part of overall refresh(). Fixes #4605 Fixes #4621 Signed-off-by: Matthew Heon --- libpod/volume_internal.go | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'libpod/volume_internal.go') diff --git a/libpod/volume_internal.go b/libpod/volume_internal.go index 42b935e7c..e89b3484d 100644 --- a/libpod/volume_internal.go +++ b/libpod/volume_internal.go @@ -5,6 +5,7 @@ import ( "path/filepath" "github.com/containers/libpod/libpod/define" + "github.com/pkg/errors" ) // Creates a new volume @@ -46,3 +47,14 @@ func (v *Volume) update() error { func (v *Volume) save() error { return v.runtime.state.SaveVolume(v) } + +// Refresh volume state after a restart. +func (v *Volume) refresh() error { + lock, err := v.runtime.lockManager.AllocateAndRetrieveLock(v.config.LockID) + if err != nil { + return errors.Wrapf(err, "error acquiring lock %d for volume %s", v.config.LockID, v.Name()) + } + v.lock = lock + + return nil +} -- cgit v1.2.3-54-g00ecf