store: ensure lockfile is updated before writes

The lockfile's write record is now updated prior to the actual write operation. This ensures that, in the event of an unexpected termination, other processes are correctly notified of an initiated write operation. Signed-off-by: Giuseppe Scrivano <[email protected]>
containers · May 18, 2023 · 89ddbb8 · 89ddbb8
1 parent 561b148
commit 89ddbb8
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Showing 3 changed files with 19 additions and 16 deletions.
diff --git a/containers.go b/containers.go
@@ -523,6 +523,11 @@ func (r *containerStore) load(lockedForWriting bool) (bool, error) {
 // The caller must hold r.inProcessLock for reading (but usually holds it for writing in order to make the desired changes).
 func (r *containerStore) save(saveLocations containerLocations) error {
 	r.lockfile.AssertLockedForWriting()
+	lw, err := r.lockfile.RecordWrite()
+	if err != nil {
+		return err
+	}
+	r.lastWrite = lw
 	for locationIndex := 0; locationIndex < numContainerLocationIndex; locationIndex++ {
 		location := containerLocationFromIndex(locationIndex)
 		if location&saveLocations == 0 {
@@ -553,11 +558,6 @@ func (r *containerStore) save(saveLocations containerLocations) error {
 			return err
 		}
 	}
-	lw, err := r.lockfile.RecordWrite()
-	if err != nil {
-		return err
-	}
-	r.lastWrite = lw
 	return nil
 }
 

diff --git a/images.go b/images.go
@@ -575,14 +575,14 @@ func (r *imageStore) Save() error {
 	if err != nil {
 		return err
 	}
-	if err := ioutils.AtomicWriteFile(rpath, jdata, 0600); err != nil {
-		return err
-	}
 	lw, err := r.lockfile.RecordWrite()
 	if err != nil {
 		return err
 	}
 	r.lastWrite = lw
+	if err := ioutils.AtomicWriteFile(rpath, jdata, 0600); err != nil {
+		return err
+	}
 	return nil
 }
 

diff --git a/layers.go b/layers.go
@@ -920,6 +920,12 @@ func (r *layerStore) saveLayers(saveLocations layerLocations) error {
 	}
 	r.lockfile.AssertLockedForWriting()
 
+	lw, err := r.lockfile.RecordWrite()
+	if err != nil {
+		return err
+	}
+	r.lastWrite = lw
+
 	for locationIndex := 0; locationIndex < numLayerLocationIndex; locationIndex++ {
 		location := layerLocationFromIndex(locationIndex)
 		if location&saveLocations == 0 {
@@ -949,11 +955,6 @@ func (r *layerStore) saveLayers(saveLocations layerLocations) error {
 		}
 		r.layerspathsModified[locationIndex] = opts.ModTime
 	}
-	lw, err := r.lockfile.RecordWrite()
-	if err != nil {
-		return err
-	}
-	r.lastWrite = lw
 	return nil
 }
 
@@ -982,14 +983,16 @@ func (r *layerStore) saveMounts() error {
 	if err != nil {
 		return err
 	}
-	if err = ioutils.AtomicWriteFile(mpath, jmdata, 0600); err != nil {
-		return err
-	}
+
 	lw, err := r.mountsLockfile.RecordWrite()
 	if err != nil {
 		return err
 	}
 	r.mountsLastWrite = lw
+
+	if err = ioutils.AtomicWriteFile(mpath, jmdata, 0600); err != nil {
+		return err
+	}
 	return r.loadMounts()
 }