diff --git a/src/fdcache.cpp b/src/fdcache.cpp
index cd56603..d57c1d1 100644
--- a/src/fdcache.cpp
+++ b/src/fdcache.cpp
@@ -623,14 +623,16 @@ int FdEntity::FillFile(int fd, unsigned char byte, off_t size, off_t start)
 // FdEntity methods
 //------------------------------------------------
 FdEntity::FdEntity(const char* tpath, const char* cpath)
-        : is_lock_init(false), refcnt(0), path(SAFESTRPTR(tpath)), cachepath(SAFESTRPTR(cpath)), mirrorpath(""),
-          fd(-1), pfile(NULL), is_modify(false), size_orgmeta(0), upload_id(""), mp_start(0), mp_size(0)
+        : is_lock_init(false), refcnt(0), path(SAFESTRPTR(tpath)),
+          fd(-1), pfile(NULL), size_orgmeta(0), upload_id(""), mp_start(0), mp_size(0), is_modify(false),
+          cachepath(SAFESTRPTR(cpath)), mirrorpath("")
 {
   try{
     pthread_mutexattr_t attr;
     pthread_mutexattr_init(&attr);
     pthread_mutexattr_settype(&attr, S3FS_MUTEX_RECURSIVE);   // recursive mutex
     pthread_mutex_init(&fdent_lock, &attr);
+    pthread_mutex_init(&fdent_data_lock, &attr);
     is_lock_init = true;
   }catch(exception& e){
     S3FS_PRN_CRIT("failed to init mutex");
@@ -643,6 +645,7 @@ FdEntity::~FdEntity()
 
   if(is_lock_init){
     try{
+      pthread_mutex_destroy(&fdent_data_lock);
       pthread_mutex_destroy(&fdent_lock);
     }catch(exception& e){
       S3FS_PRN_CRIT("failed to destroy mutex");
@@ -654,6 +657,7 @@ FdEntity::~FdEntity()
 void FdEntity::Clear()
 {
   AutoLock auto_lock(&fdent_lock);
+  AutoLock auto_data_lock(&fdent_data_lock);
 
   if(-1 != fd){
     if(!cachepath.empty()){
@@ -696,6 +700,7 @@ void FdEntity::Close()
       abort();
     }
     if(0 == refcnt){
+      AutoLock auto_data_lock(&fdent_data_lock);
       if(!cachepath.empty()){
         CacheFileStat cfstat(path.c_str());
         if(!pagelist.Serialize(cfstat, true)){
@@ -796,6 +801,7 @@ int FdEntity::Open(headers_t* pmeta, off_t size, time_t time, bool no_fd_lock_wa
     return -EIO;
   }
 
+  AutoLock auto_data_lock(&fdent_data_lock);
   if(-1 != fd){
     // already opened, needs to increment refcnt.
     Dup();
@@ -993,7 +999,7 @@ bool FdEntity::OpenAndLoadAll(headers_t* pmeta, off_t* size, bool force_load)
       return false;
     }
   }
-  AutoLock auto_lock(&fdent_lock);
+  AutoLock auto_lock(&fdent_data_lock);
 
   if(force_load){
     SetAllStatusUnloaded();
@@ -1172,7 +1178,7 @@ int FdEntity::Load(off_t start, off_t size)
   if(-1 == fd){
     return -EBADF;
   }
-  AutoLock auto_lock(&fdent_lock);
+  AutoLock auto_lock(&fdent_data_lock);
 
   int result = 0;
 
@@ -1474,7 +1480,7 @@ int FdEntity::RowFlush(const char* tpath, bool force_sync)
   if(-1 == fd){
     return -EBADF;
   }
-  AutoLock auto_lock(&fdent_lock);
+  AutoLock auto_lock(&fdent_data_lock);
 
   if(!force_sync && !is_modify){
     // nothing to update.
@@ -1628,7 +1634,7 @@ ssize_t FdEntity::Read(char* bytes, off_t start, size_t size, bool force_load)
   if(-1 == fd){
     return -EBADF;
   }
-  AutoLock auto_lock(&fdent_lock);
+  AutoLock auto_lock(&fdent_data_lock);
 
   if(force_load){
     pagelist.SetPageLoadedStatus(start, size, false);
@@ -1691,7 +1697,7 @@ ssize_t FdEntity::Write(const char* bytes, off_t start, size_t size)
   if(FdManager::IsCacheDir() && !FdManager::IsSafeDiskSpace(NULL, size)){
     FdManager::get()->CleanupCacheDir();
   }
-  AutoLock auto_lock(&fdent_lock);
+  AutoLock auto_lock(&fdent_data_lock);
 
   // check file size
   if(pagelist.Size() < start){
diff --git a/src/fdcache.h b/src/fdcache.h
index d96a020..0296550 100644
--- a/src/fdcache.h
+++ b/src/fdcache.h
@@ -112,22 +112,23 @@ class FdEntity
   private:
     pthread_mutex_t fdent_lock;
     bool            is_lock_init;
-    PageList        pagelist;
     int             refcnt;         // reference count
     std::string     path;           // object path
-    std::string     cachepath;      // local cache file path
-                                    // (if this is empty, does not load/save pagelist.)
-    std::string     mirrorpath;     // mirror file path to local cache file path
     int             fd;             // file descriptor(tmp file or cache file)
     FILE*           pfile;          // file pointer(tmp file or cache file)
-    bool            is_modify;      // if file is changed, this flag is true
     headers_t       orgmeta;        // original headers at opening
     off_t           size_orgmeta;   // original file size in original headers
 
+    pthread_mutex_t fdent_data_lock;// protects the following members
+    PageList        pagelist;
     std::string     upload_id;      // for no cached multipart uploading when no disk space
     etaglist_t      etaglist;       // for no cached multipart uploading when no disk space
     off_t           mp_start;       // start position for no cached multipart(write method only)
     off_t           mp_size;        // size for no cached multipart(write method only)
+    bool            is_modify;      // if file is changed, this flag is true
+    std::string     cachepath;      // local cache file path
+                                    // (if this is empty, does not load/save pagelist.)
+    std::string     mirrorpath;     // mirror file path to local cache file path
 
   private:
     static int FillFile(int fd, unsigned char byte, off_t size, off_t start);