Merge pull request #118 from willscott/fixup/renameinvalidate

Fixup/renameinvalidate

handler.go

@@ -27,6 +27,8 @@ type Handler interface {
 	// Can be safely implemented via helpers/cachinghandler.
 	ToHandle(fs billy.Filesystem, path []string) []byte
 	FromHandle(fh []byte) (billy.Filesystem, []string, error)
+	InvalidateHandle(billy.Filesystem, []byte) error
+
 	// How many handles can be safely maintained by the handler.
 	HandleLimit() int
 }

helpers/cachinghandler.go

@@ -4,6 +4,7 @@ import (
 	"crypto/sha256"
 	"encoding/binary"
 	"io/fs"
+	"reflect"
 
 	"github.com/willscott/go-nfs"
 
@@ -23,10 +24,12 @@ func NewCachingHandlerWithVerifierLimit(h nfs.Handler, limit int, verifierLimit
 		nfs.Log.Warnf("Caching handler created with insufficient cache to support directory listing", "size", limit, "verifiers", verifierLimit)
 	}
 	cache, _ := lru.New[uuid.UUID, entry](limit)
+	reverseCache := make(map[string][]uuid.UUID)
 	verifiers, _ := lru.New[uint64, verifier](verifierLimit)
 	return &CachingHandler{
 		Handler:         h,
 		activeHandles:   cache,
+		reverseHandles:  reverseCache,
 		activeVerifiers: verifiers,
 		cacheLimit:      limit,
 	}
@@ -36,6 +39,7 @@ func NewCachingHandlerWithVerifierLimit(h nfs.Handler, limit int, verifierLimit
 type CachingHandler struct {
 	nfs.Handler
 	activeHandles   *lru.Cache[uuid.UUID, entry]
+	reverseHandles  map[string][]uuid.UUID
 	activeVerifiers *lru.Cache[uint64, verifier]
 	cacheLimit      int
 }
@@ -49,13 +53,29 @@ type entry struct {
 // In stateless nfs (when it's serving a unix fs) this can be the device + inode
 // but we can generalize with a stateful local cache of handed out IDs.
 func (c *CachingHandler) ToHandle(f billy.Filesystem, path []string) []byte {
+	joinedPath := f.Join(path...)
+
+	if handle := c.searchReverseCache(f, joinedPath); handle != nil {
+		return handle
+	}
+
 	id := uuid.New()
-
-	newPath:=make([]string,len(path))
-
-	copy(newPath,path)
-	c.activeHandles.Add(id, entry{f, newPath})
+
+	newPath := make([]string, len(path))
+
+	copy(newPath, path)
+	evictedKey, evictedPath, ok := c.activeHandles.GetOldest()
+	if evicted := c.activeHandles.Add(id, entry{f, newPath}); evicted && ok {
+		rk := evictedPath.f.Join(evictedPath.p...)
+		c.evictReverseCache(rk, evictedKey)
+	}
+
+	if _, ok := c.reverseHandles[joinedPath]; !ok {
+		c.reverseHandles[joinedPath] = []uuid.UUID{}
+	}
+	c.reverseHandles[joinedPath] = append(c.reverseHandles[joinedPath], id)
 	b, _ := id.MarshalBinary()
+
 	return b
 }
 
@@ -74,14 +94,59 @@ func (c *CachingHandler) FromHandle(fh []byte) (billy.Filesystem, []string, erro
 			}
 		}
 		if ok {
-			newP:=make([]string,len(f.p))
-			copy(newP,f.p)
+			newP := make([]string, len(f.p))
+			copy(newP, f.p)
 			return f.f, newP, nil
 		}
 	}
 	return nil, []string{}, &nfs.NFSStatusError{NFSStatus: nfs.NFSStatusStale}
 }
 
+func (c *CachingHandler) searchReverseCache(f billy.Filesystem, path string) []byte {
+	uuids, exists := c.reverseHandles[path]
+
+	if !exists {
+		return nil
+	}
+
+	for _, id := range uuids {
+		if candidate, ok := c.activeHandles.Get(id); ok {
+			if reflect.DeepEqual(candidate.f, f) {
+				return id[:]
+			}
+		}
+	}
+
+	return nil
+}
+
+func (c *CachingHandler) evictReverseCache(path string, handle uuid.UUID) {
+	uuids, exists := c.reverseHandles[path]
+
+	if !exists {
+		return
+	}
+	for i, u := range uuids {
+		if u == handle {
+			uuids = append(uuids[:i], uuids[i+1:]...)
+			c.reverseHandles[path] = uuids
+			return
+		}
+	}
+}
+
+func (c *CachingHandler) InvalidateHandle(fs billy.Filesystem, handle []byte) error {
+	//Remove from cache
+	id, _ := uuid.FromBytes(handle)
+	entry, ok := c.activeHandles.Get(id)
+	if ok {
+		rk := entry.f.Join(entry.p...)
+		c.evictReverseCache(rk, id)
+	}
+	c.activeHandles.Remove(id)
+	return nil
+}
+
 // HandleLimit exports how many file handles can be safely stored by this cache.
 func (c *CachingHandler) HandleLimit() int {
 	return c.cacheLimit

helpers/nullauthhandler.go

@@ -49,6 +49,10 @@ func (h *NullAuthHandler) FromHandle([]byte) (billy.Filesystem, []string, error)
 	return nil, []string{}, nil
 }
 
+func (c *NullAuthHandler) InvalidateHandle(billy.Filesystem, []byte) error {
+	return nil
+}
+
 // HandleLImit handled by cachingHandler
 func (h *NullAuthHandler) HandleLimit() int {
 	return -1

nfs_onrename.go

@@ -85,6 +85,10 @@ func onRename(ctx context.Context, w *response, userHandle Handler) error {
 		return &NFSStatusError{NFSStatusIO, err}
 	}
 
+	if err := userHandle.InvalidateHandle(fs, from.Handle); err != nil {
+		return &NFSStatusError{NFSStatusServerFault, err}
+	}
+
 	writer := bytes.NewBuffer([]byte{})
 	if err := xdr.Write(writer, uint32(NFSStatusOk)); err != nil {
 		return &NFSStatusError{NFSStatusServerFault, err}