Merge pull request #72 from mheon/file_locking

Move containers to file locks from c/storage

1 files changed, 20 insertions, 14 deletions

diff --git a/libpod/container.go b/libpod/container.go
index 70011963d..fce64b0dd 100644
--- a/libpod/container.go
+++ b/libpod/container.go
@@ -8,7 +8,6 @@ import (
 	"os"
 	"path/filepath"
 	"strconv"
-	"sync"
 	"syscall"
 	"time"
 
@@ -64,9 +63,8 @@ type Container struct {
 
 	state *containerRuntimeInfo
 
-	// TODO move to storage.Locker from sync.Mutex
 	valid   bool
-	lock    sync.Mutex
+	lock    storage.Locker
 	runtime *Runtime
 }
 
@@ -319,6 +317,8 @@ func (c *Container) attachSocketPath() string {
 
 // Sync this container with on-disk state and runc status
 // Should only be called with container lock held
+// This function should suffice to ensure a container's state is accurate and
+// it is valid for use.
 func (c *Container) syncContainer() error {
 	if err := c.runtime.state.UpdateContainer(c); err != nil {
 		return err
@@ -343,7 +343,7 @@ func (c *Container) syncContainer() error {
 }
 
 // Make a new container
-func newContainer(rspec *spec.Spec) (*Container, error) {
+func newContainer(rspec *spec.Spec, lockDir string) (*Container, error) {
 	if rspec == nil {
 		return nil, errors.Wrapf(ErrInvalidArg, "must provide a valid runtime spec to create container")
 	}
@@ -360,6 +360,20 @@ func newContainer(rspec *spec.Spec) (*Container, error) {
 
 	ctr.config.CreatedTime = time.Now()
 
+	// Path our lock file will reside at
+	lockPath := filepath.Join(lockDir, ctr.config.ID)
+	// Ensure there is no conflict - file does not exist
+	_, err := os.Stat(lockPath)
+	if err == nil || !os.IsNotExist(err) {
+		return nil, errors.Wrapf(ErrCtrExists, "lockfile for container ID %s already exists", ctr.config.ID)
+	}
+	// Grab a lockfile at the given path
+	lock, err := storage.GetLockfile(lockPath)
+	if err != nil {
+		return nil, errors.Wrapf(err, "error creating lockfile for new container")
+	}
+	ctr.lock = lock
+
 	return ctr, nil
 }
 
@@ -904,11 +918,7 @@ func (c *Container) mountStorage() (err error) {
 		}
 	}()
 
-	if err := c.runtime.state.SaveContainer(c); err != nil {
-		return errors.Wrapf(err, "error saving container %s state", c.ID())
-	}
-
-	return nil
+	return c.save()
 }
 
 // CleanupStorage unmounts all mount points in container and cleans up container storage
@@ -944,9 +954,5 @@ func (c *Container) cleanupStorage() error {
 	c.state.Mountpoint = ""
 	c.state.Mounted = false
 
-	if err := c.runtime.state.SaveContainer(c); err != nil {
-		return errors.Wrapf(err, "error saving container %s state", c.ID())
-	}
-
-	return nil
+	return c.save()
 }