Cache resolved links (#3801)

* Cache resolved node ids for paths

* Add changelog

changelog/unreleased/cache-node-ids.md

@@ -0,0 +1,5 @@
+Enhancement: Cache node ids
+
+decomposedfs now keeps an in-memory cache for node ids, sparing a lot of ReadLink calls.
+
+https://github.com/cs3org/reva/pull/3801

pkg/storage/utils/decomposedfs/tree/tree.go

@@ -32,6 +32,7 @@ import (
  "strings"
  "time"
 
+ "github.com/bluele/gcache"
  provider "github.com/cs3org/go-cs3apis/cs3/storage/provider/v1beta1"
  "github.com/cs3org/reva/v2/pkg/appctx"
  "github.com/cs3org/reva/v2/pkg/errtypes"
@@ -78,6 +79,8 @@ type Tree struct {
  blobstore Blobstore
 
  options *options.Options
+
+ idCache gcache.Cache
 }
 
 // PermissionCheckFunc defined a function used to check resource permissions
@@ -89,6 +92,7 @@ func New(lu PathLookup, bs Blobstore, o *options.Options) *Tree {
  lookup: lu,
  blobstore: bs,
  options: o,
+ idCache: gcache.New(1_000_000).LRU().Build(),
  }
 }
 
@@ -271,6 +275,7 @@ func (t *Tree) Move(ctx context.Context, oldNode *node.Node, newNode *node.Node)
  if err != nil {
  return errors.Wrap(err, "Decomposedfs: could not move child")
  }
+ t.idCache.Remove(filepath.Join(oldNode.ParentPath(), oldNode.Name))
 
  // update target parentid and name
  attribs := node.Attributes{}
@@ -360,9 +365,19 @@ func (t *Tree) ListFolder(ctx context.Context, n *node.Node) ([]*node.Node, erro
  for i := 0; i < numWorkers; i++ {
  g.Go(func() error {
  for name := range work {
- nodeID, err := readChildNodeFromLink(filepath.Join(dir, name))
- if err != nil {
- return err
+ nodeID := ""
+ path := filepath.Join(dir, name)
+ if val, err := t.idCache.Get(path); err == nil {
+ nodeID = val.(string)
+ } else {
+ nodeID, err = readChildNodeFromLink(path)
+ if err != nil {
+ return err
+ }
+ err = t.idCache.Set(path, nodeID)
+ if err != nil {
+ return err
+ }
  }
 
  child, err := node.ReadNode(ctx, t.lookup, n.SpaceID, nodeID, false, n, true)
@@ -481,7 +496,9 @@ func (t *Tree) Delete(ctx context.Context, n *node.Node) (err error) {
  _ = os.Remove(n.LockFilePath())
 
  // finally remove the entry from the parent dir
- err = os.Remove(filepath.Join(n.ParentPath(), n.Name))
+ path := filepath.Join(n.ParentPath(), n.Name)
+ err = os.Remove(path)
+ t.idCache.Remove(path)
  if err != nil {
  // To roll back changes
  // TODO revert the rename