Add fast path for fsmagic supported drivers

crosbymichael · crosbymichael · commit 1ba05cdb6ade · 2016-05-23T15:57:23.000-07:00
For things that we can check if they are mounted by using their fsmagic
we should use that and for others do it the slow way.

Signed-off-by: Michael Crosby &lt;crosbymichael@gmail.com&gt;
diff --git a/daemon/graphdriver/counter.go b/daemon/graphdriver/counter.go
@@ -1,10 +1,6 @@
 package graphdriver
 
-import (
-	"sync"
-
-	"github.com/docker/docker/pkg/mount"
-)
+import "sync"
 
 type minfo struct {
 	check bool
@@ -13,13 +9,20 @@ type minfo struct {
 
 // RefCounter is a generic counter for use by graphdriver Get/Put calls
 type RefCounter struct {
-	counts map[string]*minfo
-	mu     sync.Mutex
+	counts  map[string]*minfo
+	mu      sync.Mutex
+	checker Checker
 }
 
 // NewRefCounter returns a new RefCounter
-func NewRefCounter() *RefCounter {
-	return &RefCounter{counts: make(map[string]*minfo)}
+func NewRefCounter(c Checker) *RefCounter {
+	if c == nil {
+		c = &defaultChecker{}
+	}
+	return &RefCounter{
+		checker: c,
+		counts:  make(map[string]*minfo),
+	}
 }
 
 // Increment increaes the ref count for the given id and returns the current count
@@ -35,8 +38,7 @@ func (c *RefCounter) Increment(path string) int {
 	// count if it is mounted as it is in use.
 	if !m.check {
 		m.check = true
-		mntd, _ := mount.Mounted(path)
-		if mntd {
+		if c.checker.IsMounted(path) {
 			m.count++
 		}
 	}
@@ -58,8 +60,7 @@ func (c *RefCounter) Decrement(path string) int {
 	// count if it is mounted as it is in use.
 	if !m.check {
 		m.check = true
-		mntd, _ := mount.Mounted(path)
-		if mntd {
+		if c.checker.IsMounted(path) {
 			m.count++
 		}
 	}
diff --git a/daemon/graphdriver/devmapper/driver.go b/daemon/graphdriver/devmapper/driver.go
@@ -47,7 +47,7 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap
 		home:      home,
 		uidMaps:   uidMaps,
 		gidMaps:   gidMaps,
-		ctr:       graphdriver.NewRefCounter(),
+		ctr:       graphdriver.NewRefCounter(nil),
 	}
 
 	return graphdriver.NewNaiveDiffDriver(d, uidMaps, gidMaps), nil
diff --git a/daemon/graphdriver/driver_linux.go b/daemon/graphdriver/driver_linux.go
@@ -5,6 +5,8 @@ package graphdriver
 import (
 	"path/filepath"
 	"syscall"
+
+	"github.com/docker/docker/pkg/mount"
 )
 
 const (
@@ -89,6 +91,36 @@ func GetFSMagic(rootpath string) (FsMagic, error) {
 	return FsMagic(buf.Type), nil
 }
 
+// Checker makes checks on specified filesystems.
+type Checker interface {
+	// IsMounted returns true if the provided path is mounted for the specific checker
+	IsMounted(path string) bool
+}
+
+// NewFsChecker returns a checker configured for the provied FsMagic
+func NewFsChecker(t FsMagic) Checker {
+	return &fsChecker{
+		t: t,
+	}
+}
+
+type fsChecker struct {
+	t FsMagic
+}
+
+func (c *fsChecker) IsMounted(path string) bool {
+	m, _ := Mounted(c.t, path)
+	return m
+}
+
+type defaultChecker struct {
+}
+
+func (c *defaultChecker) IsMounted(path string) bool {
+	m, _ := mount.Mounted(path)
+	return m
+}
+
 // Mounted checks if the given path is mounted as the fs type
 func Mounted(fsType FsMagic, mountPath string) (bool, error) {
 	var buf syscall.Statfs_t
diff --git a/daemon/graphdriver/overlay/overlay.go b/daemon/graphdriver/overlay/overlay.go
@@ -141,7 +141,7 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap
 		home:    home,
 		uidMaps: uidMaps,
 		gidMaps: gidMaps,
-		ctr:     graphdriver.NewRefCounter(),
+		ctr:     graphdriver.NewRefCounter(graphdriver.NewFsChecker(graphdriver.FsMagicOverlay)),
 	}
 
 	return NaiveDiffDriverWithApply(d, uidMaps, gidMaps), nil
diff --git a/daemon/graphdriver/zfs/zfs.go b/daemon/graphdriver/zfs/zfs.go
@@ -105,7 +105,7 @@ func Init(base string, opt []string, uidMaps, gidMaps []idtools.IDMap) (graphdri
 		filesystemsCache: filesystemsCache,
 		uidMaps:          uidMaps,
 		gidMaps:          gidMaps,
-		ctr:              graphdriver.NewRefCounter(),
+		ctr:              graphdriver.NewRefCounter(graphdriver.NewFsChecker(graphdriver.FsMagicZfs)),
 	}
 	return graphdriver.NewNaiveDiffDriver(d, uidMaps, gidMaps), nil
 }

Original file line number	Diff line number	Diff line change
`@@ -47,7 +47,7 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap`
`47`	`47`	`home: home,`
`48`	`48`	`uidMaps: uidMaps,`
`49`	`49`	`gidMaps: gidMaps,`
`50`		`- ctr: graphdriver.NewRefCounter(),`
	`50`	`+ ctr: graphdriver.NewRefCounter(nil),`
`51`	`51`	`}`
`52`	`52`
`53`	`53`	`return graphdriver.NewNaiveDiffDriver(d, uidMaps, gidMaps), nil`
Original file line number	Diff line number	Diff line change
`@@ -141,7 +141,7 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap`
`141`	`141`	`home: home,`
`142`	`142`	`uidMaps: uidMaps,`
`143`	`143`	`gidMaps: gidMaps,`
`144`		`- ctr: graphdriver.NewRefCounter(),`
	`144`	`+ ctr: graphdriver.NewRefCounter(graphdriver.NewFsChecker(graphdriver.FsMagicOverlay)),`
`145`	`145`	`}`
`146`	`146`
`147`	`147`	`return NaiveDiffDriverWithApply(d, uidMaps, gidMaps), nil`
Original file line number	Diff line number	Diff line change
`@@ -105,7 +105,7 @@ func Init(base string, opt []string, uidMaps, gidMaps []idtools.IDMap) (graphdri`
`105`	`105`	`filesystemsCache: filesystemsCache,`
`106`	`106`	`uidMaps: uidMaps,`
`107`	`107`	`gidMaps: gidMaps,`
`108`		`- ctr: graphdriver.NewRefCounter(),`
	`108`	`+ ctr: graphdriver.NewRefCounter(graphdriver.NewFsChecker(graphdriver.FsMagicZfs)),`
`109`	`109`	`}`
`110`	`110`	`return graphdriver.NewNaiveDiffDriver(d, uidMaps, gidMaps), nil`
`111`	`111`	`}`