Add sync flag to flatfs

Enabled for the paranoid

Author: rht

flatfs/flatfs.go

@@ -34,18 +34,20 @@ type Datastore struct {
 	path string
 	// length of the dir splay prefix, in bytes of hex digits
 	hexPrefixLen int
+	sync         bool
 }
 
 var _ datastore.Datastore = (*Datastore)(nil)
 
-func New(path string, prefixLen int) (*Datastore, error) {
+func New(path string, prefixLen int, sync bool) (*Datastore, error) {
 	if prefixLen <= 0 || prefixLen > maxPrefixLen {
 		return nil, ErrBadPrefixLen
 	}
 	fs := &Datastore{
 		path: path,
 		// convert from binary bytes to bytes of hex encoding
 		hexPrefixLen: prefixLen * hex.EncodedLen(1),
+		sync:         sync,
 	}
 	return fs, nil
 }
@@ -77,12 +79,12 @@ func (fs *Datastore) makePrefixDir(dir string) error {
 		return err
 	}
 
-	// In theory, if we create a new prefix dir and add a file to
-	// it, the creation of the prefix dir itself might not be
-	// durable yet. Sync the root dir after a successful mkdir of
-	// a prefix dir, just to be paranoid.
-	if err := syncDir(fs.path); err != nil {
-		return err
+	if fs.sync {
+		// In theory, if we create a new prefix dir and add a file to
+		// it, the creation of the prefix dir itself might not be
+		// durable yet. Sync the root dir after a successful mkdir of
+		// a prefix dir, just to be paranoid.
+		return syncDir(fs.path)
 	}
 	return nil
 }
@@ -149,8 +151,10 @@ func (fs *Datastore) doPut(key datastore.Key, val []byte) error {
 	if _, err := tmp.Write(val); err != nil {
 		return err
 	}
-	if err := tmp.Sync(); err != nil {
-		return err
+	if fs.sync {
+		if err := tmp.Sync(); err != nil {
+			return err
+		}
 	}
 	if err := tmp.Close(); err != nil {
 		return err
@@ -163,8 +167,8 @@ func (fs *Datastore) doPut(key datastore.Key, val []byte) error {
 	}
 	removed = true
 
-	if err := syncDir(dir); err != nil {
-		return err
+	if fs.sync {
+		return syncDir(dir)
 	}
 	return nil
 }
@@ -214,8 +218,10 @@ func (fs *Datastore) putMany(data map[datastore.Key]interface{}) error {
 	// Now we sync everything
 	// sync and close files
 	for fi, _ := range files {
-		if err := fi.Sync(); err != nil {
-			return err
+		if fs.sync {
+			if err := fi.Sync(); err != nil {
+				return err
+			}
 		}
 
 		if err := fi.Close(); err != nil {
@@ -237,15 +243,15 @@ func (fs *Datastore) putMany(data map[datastore.Key]interface{}) error {
 	}
 
 	// now sync the dirs for those files
-	for _, dir := range dirsToSync {
-		if err := syncDir(dir); err != nil {
-			return err
+	if fs.sync {
+		for _, dir := range dirsToSync {
+			if err := syncDir(dir); err != nil {
+				return err
+			}
 		}
-	}
 
-	// sync top flatfs dir
-	if err := syncDir(fs.path); err != nil {
-		return err
+		// sync top flatfs dir
+		return syncDir(fs.path)
 	}
 
 	return nil