From e19499710e3728433cdc8348e985f9a825cb2336 Mon Sep 17 00:00:00 2001
From: Michael Crosby <crosbymichael@gmail.com>
Date: Fri, 6 May 2016 14:54:28 -0700
Subject: [PATCH] Remove ref counting from layer store
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
---
layer/layer_store.go | 8 +---
layer/layer_test.go | 17 ---------
layer/migration_test.go | 13 -------
layer/mounted_layer.go | 81 +----------------------------------------
4 files changed, 3 insertions(+), 116 deletions(-)
diff --git a/layer/layer_store.go b/layer/layer_store.go
index f18aff2145..f25ef91ac9 100644
--- a/layer/layer_store.go
+++ b/layer/layer_store.go
@@ -502,15 +502,9 @@ func (ls *layerStore) ReinitRWLayer(l RWLayer) error {
ls.mountL.Lock()
defer ls.mountL.Unlock()
- m, ok := ls.mounts[l.Name()]
- if !ok {
+ if _, ok := ls.mounts[l.Name()]; !ok {
return ErrMountDoesNotExist
}
-
- if err := m.incActivityCount(l); err != nil {
- return err
- }
-
return nil
}
diff --git a/layer/layer_test.go b/layer/layer_test.go
index 85687cebb4..2e4fab5c86 100644
--- a/layer/layer_test.go
+++ b/layer/layer_test.go
@@ -400,14 +400,11 @@ func TestStoreRestore(t *testing.T) {
if err := ioutil.WriteFile(filepath.Join(path, "testfile.txt"), []byte("nothing here"), 0644); err != nil {
t.Fatal(err)
}
- assertActivityCount(t, m, 1)
if err := m.Unmount(); err != nil {
t.Fatal(err)
}
- assertActivityCount(t, m, 0)
-
ls2, err := NewStoreFromGraphDriver(ls.(*layerStore).store, ls.(*layerStore).driver)
if err != nil {
t.Fatal(err)
@@ -438,20 +435,15 @@ func TestStoreRestore(t *testing.T) {
t.Fatalf("Unexpected path %s, expected %s", mountPath, path)
}
- assertActivityCount(t, m2, 1)
-
if mountPath, err := m2.Mount(""); err != nil {
t.Fatal(err)
} else if path != mountPath {
t.Fatalf("Unexpected path %s, expected %s", mountPath, path)
}
- assertActivityCount(t, m2, 2)
if err := m2.Unmount(); err != nil {
t.Fatal(err)
}
- assertActivityCount(t, m2, 1)
-
b, err := ioutil.ReadFile(filepath.Join(path, "testfile.txt"))
if err != nil {
t.Fatal(err)
@@ -464,8 +456,6 @@ func TestStoreRestore(t *testing.T) {
t.Fatal(err)
}
- assertActivityCount(t, m2, 0)
-
if metadata, err := ls2.ReleaseRWLayer(m2); err != nil {
t.Fatal(err)
} else if len(metadata) != 0 {
@@ -674,13 +664,6 @@ func assertReferences(t *testing.T, references ...Layer) {
}
}
-func assertActivityCount(t *testing.T, l RWLayer, expected int) {
- rl := l.(*referencedRWLayer)
- if rl.activityCount != expected {
- t.Fatalf("Unexpected activity count %d, expected %d", rl.activityCount, expected)
- }
-}
-
func TestRegisterExistingLayer(t *testing.T) {
ls, _, cleanup := newTestStore(t)
defer cleanup()
diff --git a/layer/migration_test.go b/layer/migration_test.go
index 7e2e2a6489..50ea6407bb 100644
--- a/layer/migration_test.go
+++ b/layer/migration_test.go
@@ -380,8 +380,6 @@ func TestMountMigration(t *testing.T) {
Kind: archive.ChangeAdd,
})
- assertActivityCount(t, rwLayer1, 1)
-
if _, err := ls.CreateRWLayer("migration-mount", layer1.ChainID(), "", nil, nil); err == nil {
t.Fatal("Expected error creating mount with same name")
} else if err != ErrMountNameConflict {
@@ -401,16 +399,10 @@ func TestMountMigration(t *testing.T) {
t.Fatal(err)
}
- assertActivityCount(t, rwLayer2, 1)
- assertActivityCount(t, rwLayer1, 1)
-
if _, err := rwLayer2.Mount(""); err != nil {
t.Fatal(err)
}
- assertActivityCount(t, rwLayer2, 2)
- assertActivityCount(t, rwLayer1, 1)
-
if metadata, err := ls.Release(layer1); err != nil {
t.Fatal(err)
} else if len(metadata) > 0 {
@@ -420,8 +412,6 @@ func TestMountMigration(t *testing.T) {
if err := rwLayer1.Unmount(); err != nil {
t.Fatal(err)
}
- assertActivityCount(t, rwLayer2, 2)
- assertActivityCount(t, rwLayer1, 0)
if _, err := ls.ReleaseRWLayer(rwLayer1); err != nil {
t.Fatal(err)
@@ -430,9 +420,6 @@ func TestMountMigration(t *testing.T) {
if err := rwLayer2.Unmount(); err != nil {
t.Fatal(err)
}
- if _, err := ls.ReleaseRWLayer(rwLayer2); err == nil {
- t.Fatal("Expected error deleting active mount")
- }
if err := rwLayer2.Unmount(); err != nil {
t.Fatal(err)
}
diff --git a/layer/mounted_layer.go b/layer/mounted_layer.go
index 5a07fd08ea..62189c8c20 100644
--- a/layer/mounted_layer.go
+++ b/layer/mounted_layer.go
@@ -2,7 +2,6 @@ package layer
import (
"io"
- "sync"
"github.com/docker/docker/pkg/archive"
)
@@ -83,106 +82,30 @@ func (ml *mountedLayer) hasReferences() bool {
return len(ml.references) > 0
}
-func (ml *mountedLayer) incActivityCount(ref RWLayer) error {
- rl, ok := ml.references[ref]
- if !ok {
- return ErrLayerNotRetained
- }
-
- if err := rl.acquire(); err != nil {
- return err
- }
- return nil
-}
-
func (ml *mountedLayer) deleteReference(ref RWLayer) error {
- rl, ok := ml.references[ref]
- if !ok {
+ if _, ok := ml.references[ref]; !ok {
return ErrLayerNotRetained
}
-
- if err := rl.release(); err != nil {
- return err
- }
delete(ml.references, ref)
-
return nil
}
func (ml *mountedLayer) retakeReference(r RWLayer) {
if ref, ok := r.(*referencedRWLayer); ok {
- ref.activityCount = 0
ml.references[ref] = ref
}
}
type referencedRWLayer struct {
*mountedLayer
-
- activityL sync.Mutex
- activityCount int
-}
-
-func (rl *referencedRWLayer) acquire() error {
- rl.activityL.Lock()
- defer rl.activityL.Unlock()
-
- rl.activityCount++
-
- return nil
-}
-
-func (rl *referencedRWLayer) release() error {
- rl.activityL.Lock()
- defer rl.activityL.Unlock()
-
- if rl.activityCount > 0 {
- return ErrActiveMount
- }
-
- rl.activityCount = -1
-
- return nil
}
func (rl *referencedRWLayer) Mount(mountLabel string) (string, error) {
- rl.activityL.Lock()
- defer rl.activityL.Unlock()
-
- if rl.activityCount == -1 {
- return "", ErrLayerNotRetained
- }
-
- if rl.activityCount > 0 {
- rl.activityCount++
- return rl.path, nil
- }
-
- m, err := rl.mountedLayer.Mount(mountLabel)
- if err == nil {
- rl.activityCount++
- rl.path = m
- }
- return m, err
+ return rl.mountedLayer.Mount(mountLabel)
}
// Unmount decrements the activity count and unmounts the underlying layer
// Callers should only call `Unmount` once per call to `Mount`, even on error.
func (rl *referencedRWLayer) Unmount() error {
- rl.activityL.Lock()
- defer rl.activityL.Unlock()
-
- if rl.activityCount == 0 {
- return ErrNotMounted
- }
- if rl.activityCount == -1 {
- return ErrLayerNotRetained
- }
-
- rl.activityCount--
- if rl.activityCount > 0 {
- return nil
- }
-
return rl.mountedLayer.Unmount()
}