runtime_vm: Create deleteContainer() helper

deleteContainer() function is a helper that can be used for cleaning up
containers in case of error. Instead of taking the risk of duplicating
code, let's take the relevant part out of the DeleteContainer(), and
make it available for future uses.

It's important to note that other functions cannot just call
DeleteContainer() directly if they're holding a container's opLock, as
DeleteContainer() would try to acquire the very same lock, causing then
a happy little accident called "deadlock".

Signed-off-by: Fabiano Fidêncio <fidencio@redhat.com>
(cherry picked from commit d785c14)
(cherry picked from commit bdfe05c)

internal/oci/runtime_vm.go

@@ -530,22 +530,30 @@ func (r *runtimeVM) DeleteContainer(c *Container) error {
 	c.opLock.Lock()
 	defer c.opLock.Unlock()
 
+	return r.deleteContainer(c, false)
+}
+
+// deleteContainer performs all the operations needed to delete a container.
+// force must only be used on clean-up cases.
+// It does **not** Lock the container, thus it's the caller responsibility to do so, when needed.
+func (r *runtimeVM) deleteContainer(c *Container, force bool) error {
 	r.Lock()
 	cInfo, ok := r.ctrs[c.ID()]
 	r.Unlock()
-	if !ok {
+	if !ok && !force {
 		return errors.New("Could not retrieve container information")
 	}
 
-	if err := cInfo.cio.Close(); err != nil {
+	if err := cInfo.cio.Close(); err != nil && !force {
 		return err
 	}
 
-	if err := r.remove(r.ctx, c.ID(), ""); err != nil {
+	if err := r.remove(r.ctx, c.ID(), ""); err != nil && !force {
 		return err
 	}
 
-	if _, err := r.task.Shutdown(r.ctx, &task.ShutdownRequest{ID: c.ID()}); err != nil && err != ttrpc.ErrClosed {
+	_, err := r.task.Shutdown(r.ctx, &task.ShutdownRequest{ID: c.ID()})
+	if err != nil && err != ttrpc.ErrClosed && !force {
 		return err
 	}