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  2. Commit 1272f90eaed080537f7904282d383f54b91c536b
Browse code

Sequence non-persistent objects in cache

Since the datastore interface is common for persistent and
non-persistent objects we need to provide the same kind of sequencing
and atomicity guarantess to non-persistent data operations as we do for
persistent operations. So added sequencing and atomicity checks in the
data cache layer.

Signed-off-by: Jana Radhakrishnan <mrjana@docker.com>

Jana Radhakrishnan authored on 2016/06/14 15:53:05
Showing 2 changed files
libnetwork/datastore/cache.go
History View file @ 1272f90
... ... 
@@ -86,25 +86,52 @@ out:
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 	return kmap, nil
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 }
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-func (c *cache) add(kvObject KVObject) error {
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+func (c *cache) add(kvObject KVObject, atomic bool) error {
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 	kmap, err := c.kmap(kvObject)
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 	if err != nil {
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 		return err
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 	}
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 	c.Lock()
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+	// If atomic is true, cache needs to maintain its own index
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+	// for atomicity and the add needs to be atomic.
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+	if atomic {
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+		if prev, ok := kmap[Key(kvObject.Key()...)]; ok {
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+			if prev.Index() != kvObject.Index() {
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+				c.Unlock()
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+				return ErrKeyModified
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+			}
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+		}
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+
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+		// Increment index
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+		index := kvObject.Index()
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+		index++
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+		kvObject.SetIndex(index)
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+	}
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+
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 	kmap[Key(kvObject.Key()...)] = kvObject
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 	c.Unlock()
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 	return nil
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 }
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-func (c *cache) del(kvObject KVObject) error {
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+func (c *cache) del(kvObject KVObject, atomic bool) error {
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 	kmap, err := c.kmap(kvObject)
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 	if err != nil {
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 		return err
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 	}
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 	c.Lock()
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+	// If atomic is true, cache needs to maintain its own index
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+	// for atomicity and del needs to be atomic.
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+	if atomic {
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+		if prev, ok := kmap[Key(kvObject.Key()...)]; ok {
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+			if prev.Index() != kvObject.Index() {
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+				c.Unlock()
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+				return ErrKeyModified
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+			}
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+		}
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+	}
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+
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 	delete(kmap, Key(kvObject.Key()...))
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 	c.Unlock()
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 	return nil
libnetwork/datastore/datastore.go
History View file @ 1272f90
... ... 
@@ -410,7 +410,9 @@ func (ds *datastore) PutObjectAtomic(kvObject KVObject) error {
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 add_cache:
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 	if ds.cache != nil {
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-		return ds.cache.add(kvObject)
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+		// If persistent store is skipped, sequencing needs to
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+		// happen in cache.
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+		return ds.cache.add(kvObject, kvObject.Skip())
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 	}
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 	return nil
... ... 
@@ -435,7 +437,9 @@ func (ds *datastore) PutObject(kvObject KVObject) error {
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 add_cache:
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 	if ds.cache != nil {
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-		return ds.cache.add(kvObject)
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+		// If persistent store is skipped, sequencing needs to
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+		// happen in cache.
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+		return ds.cache.add(kvObject, kvObject.Skip())
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 	}
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 	return nil
... ... 
@@ -537,7 +541,9 @@ func (ds *datastore) DeleteObject(kvObject KVObject) error {
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 	// cleaup the cache first
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 	if ds.cache != nil {
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-		ds.cache.del(kvObject)
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+		// If persistent store is skipped, sequencing needs to
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+		// happen in cache.
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+		ds.cache.del(kvObject, kvObject.Skip())
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 	}
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 	if kvObject.Skip() {
... ... 
@@ -572,7 +578,9 @@ func (ds *datastore) DeleteObjectAtomic(kvObject KVObject) error {
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 del_cache:
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 	// cleanup the cache only if AtomicDelete went through successfully
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 	if ds.cache != nil {
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-		return ds.cache.del(kvObject)
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+		// If persistent store is skipped, sequencing needs to
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+		// happen in cache.
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+		return ds.cache.del(kvObject, kvObject.Skip())
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 	}
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 	return nil
... ... 
@@ -585,7 +593,9 @@ func (ds *datastore) DeleteTree(kvObject KVObject) error {
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 	// cleaup the cache first
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 	if ds.cache != nil {
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-		ds.cache.del(kvObject)
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+		// If persistent store is skipped, sequencing needs to
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+		// happen in cache.
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+		ds.cache.del(kvObject, kvObject.Skip())
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 	}
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 	if kvObject.Skip() {