Re-add locks to volumes.

This will require a 'podman system renumber' after being applied
to get lock numbers for existing volumes.

Add the DB backend code for rewriting volume configs and use it
for updating lock numbers as part of 'system renumber'.

Signed-off-by: Matthew Heon <matthew.heon@pm.me>

1 files changed, 14 insertions, 1 deletions

diff --git a/libpod/runtime_ctr.go b/libpod/runtime_ctr.go
index 92b2faefb..acd317d20 100644
--- a/libpod/runtime_ctr.go
+++ b/libpod/runtime_ctr.go
@@ -253,10 +253,13 @@ func (r *Runtime) setupContainer(ctx context.Context, ctr *Container) (c *Contai
 
 	// Go through named volumes and add them.
 	// If they don't exist they will be created using basic options.
+	// Maintain an array of them - we need to lock them later.
+	ctrNamedVolumes := make([]*Volume, 0, len(ctr.config.NamedVolumes))
 	for _, vol := range ctr.config.NamedVolumes {
 		// Check if it exists already
-		_, err := r.state.Volume(vol.Name)
+		dbVol, err := r.state.Volume(vol.Name)
 		if err == nil {
+			ctrNamedVolumes = append(ctrNamedVolumes, dbVol)
 			// The volume exists, we're good
 			continue
 		} else if errors.Cause(err) != config2.ErrNoSuchVolume {
@@ -275,6 +278,8 @@ func (r *Runtime) setupContainer(ctx context.Context, ctr *Container) (c *Contai
 		if err := ctr.copyWithTarFromImage(vol.Dest, newVol.MountPoint()); err != nil && !os.IsNotExist(err) {
 			return nil, errors.Wrapf(err, "Failed to copy content into new volume mount %q", vol.Name)
 		}
+
+		ctrNamedVolumes = append(ctrNamedVolumes, newVol)
 	}
 
 	if ctr.config.LogPath == "" && ctr.config.LogDriver != JournaldLogging {
@@ -291,6 +296,14 @@ func (r *Runtime) setupContainer(ctx context.Context, ctr *Container) (c *Contai
 		ctr.config.Mounts = append(ctr.config.Mounts, ctr.config.ShmDir)
 	}
 
+	// Lock all named volumes we are adding ourself to, to ensure we can't
+	// use a volume being removed.
+	for _, namedVol := range ctrNamedVolumes {
+		toLock := namedVol
+		toLock.lock.Lock()
+		defer toLock.lock.Unlock()
+	}
+
 	// Add the container to the state
 	// TODO: May be worth looking into recovering from name/ID collisions here
 	if ctr.config.Pod != "" {