randomizing next file handle id

weed/mount/filehandle_map.go

@@ -1,6 +1,7 @@
 package mount
 
 import (
+	"github.com/seaweedfs/seaweedfs/weed/util"
 	"sync"
 
 	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
@@ -17,7 +18,7 @@ func NewFileHandleToInode() *FileHandleToInode {
 	return &FileHandleToInode{
 		inode2fh: make(map[uint64]*FileHandle),
 		fh2inode: make(map[FileHandleId]uint64),
-		nextFh:   0,
+		nextFh:   FileHandleId(util.RandomUint64()),
 	}
 }
 
@@ -44,7 +45,7 @@ func (i *FileHandleToInode) AcquireFileHandle(wfs *WFS, inode uint64, entry *fil
 	fh, found := i.inode2fh[inode]
 	if !found {
 		fh = newFileHandle(wfs, i.nextFh, inode, entry)
-		i.nextFh++
+		i.nextFh = FileHandleId(util.RandomUint64())
 		i.inode2fh[inode] = fh
 		i.fh2inode[fh.fh] = inode
 	} else {

weed/mount/weedfs_dir_read.go

@@ -6,6 +6,7 @@ import (
 	"github.com/seaweedfs/seaweedfs/weed/filer"
 	"github.com/seaweedfs/seaweedfs/weed/glog"
 	"github.com/seaweedfs/seaweedfs/weed/mount/meta_cache"
+	"github.com/seaweedfs/seaweedfs/weed/util"
 	"math"
 	"sync"
 )
@@ -45,7 +46,7 @@ func NewDirectoryHandleToInode() *DirectoryHandleToInode {
 func (wfs *WFS) AcquireDirectoryHandle() (DirectoryHandleId, *DirectoryHandle) {
 	wfs.fhmap.Lock()
 	fh := wfs.fhmap.nextFh
-	wfs.fhmap.nextFh++
+	wfs.fhmap.nextFh = FileHandleId(util.RandomUint64())
 	wfs.fhmap.Unlock()
 
 	wfs.dhmap.Lock()

weed/util/bytes.go

@@ -148,6 +148,12 @@ func RandomInt32() int32 {
 	return int32(BytesToUint32(buf))
 }
 
+func RandomUint64() int32 {
+	buf := make([]byte, 8)
+	rand.Read(buf)
+	return int32(BytesToUint64(buf))
+}
+
 func RandomBytes(byteCount int) []byte {
 	buf := make([]byte, byteCount)
 	rand.Read(buf)