80a35e0bd4
Add a mutex to protect concurrent access to mountedLayer.references map.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
(cherry picked from commit f73b5cb4e8)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
112 lines
2.3 KiB
Go
112 lines
2.3 KiB
Go
package layer // import "github.com/docker/docker/layer"
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import (
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"io"
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"sync"
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"github.com/docker/docker/pkg/archive"
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"github.com/docker/docker/pkg/containerfs"
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)
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type mountedLayer struct {
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name string
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mountID string
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initID string
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parent *roLayer
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path string
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layerStore *layerStore
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sync.Mutex
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references map[RWLayer]*referencedRWLayer
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}
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func (ml *mountedLayer) cacheParent() string {
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if ml.initID != "" {
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return ml.initID
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}
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if ml.parent != nil {
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return ml.parent.cacheID
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}
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return ""
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}
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func (ml *mountedLayer) TarStream() (io.ReadCloser, error) {
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return ml.layerStore.driver.Diff(ml.mountID, ml.cacheParent())
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}
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func (ml *mountedLayer) Name() string {
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return ml.name
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}
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func (ml *mountedLayer) Parent() Layer {
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if ml.parent != nil {
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return ml.parent
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}
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// Return a nil interface instead of an interface wrapping a nil
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// pointer.
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return nil
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}
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func (ml *mountedLayer) Size() (int64, error) {
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return ml.layerStore.driver.DiffSize(ml.mountID, ml.cacheParent())
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}
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func (ml *mountedLayer) Changes() ([]archive.Change, error) {
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return ml.layerStore.driver.Changes(ml.mountID, ml.cacheParent())
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}
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func (ml *mountedLayer) Metadata() (map[string]string, error) {
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return ml.layerStore.driver.GetMetadata(ml.mountID)
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}
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func (ml *mountedLayer) getReference() RWLayer {
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ref := &referencedRWLayer{
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mountedLayer: ml,
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}
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ml.Lock()
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ml.references[ref] = ref
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ml.Unlock()
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return ref
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}
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func (ml *mountedLayer) hasReferences() bool {
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ml.Lock()
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ret := len(ml.references) > 0
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ml.Unlock()
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return ret
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}
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func (ml *mountedLayer) deleteReference(ref RWLayer) error {
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ml.Lock()
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defer ml.Unlock()
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if _, ok := ml.references[ref]; !ok {
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return ErrLayerNotRetained
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}
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delete(ml.references, ref)
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return nil
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}
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func (ml *mountedLayer) retakeReference(r RWLayer) {
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if ref, ok := r.(*referencedRWLayer); ok {
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ml.Lock()
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ml.references[ref] = ref
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ml.Unlock()
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}
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}
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type referencedRWLayer struct {
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*mountedLayer
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}
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func (rl *referencedRWLayer) Mount(mountLabel string) (containerfs.ContainerFS, error) {
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return rl.layerStore.driver.Get(rl.mountedLayer.mountID, mountLabel)
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}
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// Unmount decrements the activity count and unmounts the underlying layer
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// Callers should only call `Unmount` once per call to `Mount`, even on error.
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func (rl *referencedRWLayer) Unmount() error {
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return rl.layerStore.driver.Put(rl.mountedLayer.mountID)
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}
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