Browse code
Fix delete a image while saving it, delete successfully but failed to save it
Issue Description:
* 1. Saving more than one images, `docker save -o a.tar aaa bbb`
* 2. Delete the last image which in saving progress. `docker rmi bbb`
Espected:
Saving images operation shouldn't be disturbed. But the real result is that failed to
save image and get an error as below:
`Error response from daemon: open
/var/lib/docker/image/devicemapper/imagedb/content/sha256/7c24e4d533a76e801662ad1b7e6e06bc1204f80110b5623e96ba2877c51479a1:
no such file or directory`
Analysis:
1. While saving more than one images, it will get all the image info from reference/imagestore,
and then using the `cached data` to save the images to a tar file.
2. But this process doesn't have a resource lock, if a deletion operation comes, the image will be deleted,
so saving operation will fail.
Solution:
When begin to save an image, `Get` all the layers first. then the
deletion operation won't delete the layers.
Signed-off-by: Wentao Zhang <zhangwentao234@huawei.com>
Wentao Zhang authored on 2017/05/24 01:40:33Showing 1 changed files
| ... | ... |
@@ -21,8 +21,10 @@ import ( |
| 21 | 21 |
) |
| 22 | 22 |
|
| 23 | 23 |
type imageDescriptor struct {
|
| 24 |
- refs []reference.NamedTagged |
|
| 25 |
- layers []string |
|
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+ refs []reference.NamedTagged |
|
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+ layers []string |
|
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+ image *image.Image |
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+ layerRef layer.Layer |
|
| 26 | 28 |
} |
| 27 | 29 |
|
| 28 | 30 |
type saveSession struct {
|
| ... | ... |
@@ -39,33 +41,47 @@ func (l *tarexporter) Save(names []string, outStream io.Writer) error {
|
| 39 | 39 |
return err |
| 40 | 40 |
} |
| 41 | 41 |
|
| 42 |
+ // Release all the image top layer references |
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+ defer l.releaseLayerReferences(images) |
|
| 42 | 44 |
return (&saveSession{tarexporter: l, images: images}).save(outStream)
|
| 43 | 45 |
} |
| 44 | 46 |
|
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-func (l *tarexporter) parseNames(names []string) (map[image.ID]*imageDescriptor, error) {
|
|
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+// parseNames will parse the image names to a map which contains image.ID to *imageDescriptor. |
|
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+// Each imageDescriptor holds an image top layer reference named 'layerRef'. It is taken here, should be released later. |
|
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+func (l *tarexporter) parseNames(names []string) (desc map[image.ID]*imageDescriptor, rErr error) {
|
|
| 46 | 50 |
imgDescr := make(map[image.ID]*imageDescriptor) |
| 51 |
+ defer func() {
|
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+ if rErr != nil {
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+ l.releaseLayerReferences(imgDescr) |
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+ } |
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+ }() |
|
| 47 | 56 |
|
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- addAssoc := func(id image.ID, ref reference.Named) {
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+ addAssoc := func(id image.ID, ref reference.Named) error {
|
|
| 49 | 58 |
if _, ok := imgDescr[id]; !ok {
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- imgDescr[id] = &imageDescriptor{}
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+ descr := &imageDescriptor{}
|
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+ if err := l.takeLayerReference(id, descr); err != nil {
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+ return err |
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+ } |
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+ imgDescr[id] = descr |
|
| 51 | 64 |
} |
| 52 | 65 |
|
| 53 | 66 |
if ref != nil {
|
| 54 | 67 |
if _, ok := ref.(reference.Canonical); ok {
|
| 55 |
- return |
|
| 68 |
+ return nil |
|
| 56 | 69 |
} |
| 57 | 70 |
tagged, ok := reference.TagNameOnly(ref).(reference.NamedTagged) |
| 58 | 71 |
if !ok {
|
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- return |
|
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+ return nil |
|
| 60 | 73 |
} |
| 61 | 74 |
|
| 62 | 75 |
for _, t := range imgDescr[id].refs {
|
| 63 | 76 |
if tagged.String() == t.String() {
|
| 64 |
- return |
|
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+ return nil |
|
| 65 | 78 |
} |
| 66 | 79 |
} |
| 67 | 80 |
imgDescr[id].refs = append(imgDescr[id].refs, tagged) |
| 68 | 81 |
} |
| 82 |
+ return nil |
|
| 69 | 83 |
} |
| 70 | 84 |
|
| 71 | 85 |
for _, name := range names {
|
| ... | ... |
@@ -78,11 +94,9 @@ func (l *tarexporter) parseNames(names []string) (map[image.ID]*imageDescriptor, |
| 78 | 78 |
// Check if digest ID reference |
| 79 | 79 |
if digested, ok := ref.(reference.Digested); ok {
|
| 80 | 80 |
id := image.IDFromDigest(digested.Digest()) |
| 81 |
- _, err := l.is.Get(id) |
|
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- if err != nil {
|
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| 81 |
+ if err := addAssoc(id, nil); err != nil {
|
|
| 83 | 82 |
return nil, err |
| 84 | 83 |
} |
| 85 |
- addAssoc(id, nil) |
|
| 86 | 84 |
continue |
| 87 | 85 |
} |
| 88 | 86 |
return nil, errors.Errorf("invalid reference: %v", name)
|
| ... | ... |
@@ -93,20 +107,26 @@ func (l *tarexporter) parseNames(names []string) (map[image.ID]*imageDescriptor, |
| 93 | 93 |
if err != nil {
|
| 94 | 94 |
return nil, err |
| 95 | 95 |
} |
| 96 |
- addAssoc(imgID, nil) |
|
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+ if err := addAssoc(imgID, nil); err != nil {
|
|
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+ return nil, err |
|
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+ } |
|
| 97 | 99 |
continue |
| 98 | 100 |
} |
| 99 | 101 |
if reference.IsNameOnly(namedRef) {
|
| 100 | 102 |
assocs := l.rs.ReferencesByName(namedRef) |
| 101 | 103 |
for _, assoc := range assocs {
|
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- addAssoc(image.IDFromDigest(assoc.ID), assoc.Ref) |
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+ if err := addAssoc(image.IDFromDigest(assoc.ID), assoc.Ref); err != nil {
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+ return nil, err |
|
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+ } |
|
| 103 | 107 |
} |
| 104 | 108 |
if len(assocs) == 0 {
|
| 105 | 109 |
imgID, err := l.is.Search(name) |
| 106 | 110 |
if err != nil {
|
| 107 | 111 |
return nil, err |
| 108 | 112 |
} |
| 109 |
- addAssoc(imgID, nil) |
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+ if err := addAssoc(imgID, nil); err != nil {
|
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+ return nil, err |
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+ } |
|
| 110 | 116 |
} |
| 111 | 117 |
continue |
| 112 | 118 |
} |
| ... | ... |
@@ -114,12 +134,43 @@ func (l *tarexporter) parseNames(names []string) (map[image.ID]*imageDescriptor, |
| 114 | 114 |
if err != nil {
|
| 115 | 115 |
return nil, err |
| 116 | 116 |
} |
| 117 |
- addAssoc(image.IDFromDigest(id), namedRef) |
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+ if err := addAssoc(image.IDFromDigest(id), namedRef); err != nil {
|
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+ return nil, err |
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+ } |
|
| 118 | 120 |
|
| 119 | 121 |
} |
| 120 | 122 |
return imgDescr, nil |
| 121 | 123 |
} |
| 122 | 124 |
|
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+// takeLayerReference will take/Get the image top layer reference |
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+func (l *tarexporter) takeLayerReference(id image.ID, imgDescr *imageDescriptor) error {
|
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+ img, err := l.is.Get(id) |
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+ if err != nil {
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+ return err |
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+ } |
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+ imgDescr.image = img |
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+ topLayerID := img.RootFS.ChainID() |
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+ if topLayerID == "" {
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+ return nil |
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+ } |
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+ layer, err := l.ls.Get(topLayerID) |
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+ if err != nil {
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+ return err |
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+ } |
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+ imgDescr.layerRef = layer |
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+ return nil |
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+} |
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+ |
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+// releaseLayerReferences will release all the image top layer references |
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+func (l *tarexporter) releaseLayerReferences(imgDescr map[image.ID]*imageDescriptor) error {
|
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+ for _, descr := range imgDescr {
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+ if descr.layerRef != nil {
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+ l.ls.Release(descr.layerRef) |
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+ } |
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+ } |
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+ return nil |
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+} |
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+ |
|
| 123 | 154 |
func (s *saveSession) save(outStream io.Writer) error {
|
| 124 | 155 |
s.savedLayers = make(map[string]struct{})
|
| 125 | 156 |
s.diffIDPaths = make(map[layer.DiffID]string) |
| ... | ... |
@@ -224,11 +275,7 @@ func (s *saveSession) save(outStream io.Writer) error {
|
| 224 | 224 |
} |
| 225 | 225 |
|
| 226 | 226 |
func (s *saveSession) saveImage(id image.ID) (map[layer.DiffID]distribution.Descriptor, error) {
|
| 227 |
- img, err := s.is.Get(id) |
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- if err != nil {
|
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- return nil, err |
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- } |
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- |
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+ img := s.images[id].image |
|
| 232 | 228 |
if len(img.RootFS.DiffIDs) == 0 {
|
| 233 | 229 |
return nil, fmt.Errorf("empty export - not implemented")
|
| 234 | 230 |
} |