diff --git a/src/fdcache_entity.cpp b/src/fdcache_entity.cpp
index 86c78e5..d087d96 100644
--- a/src/fdcache_entity.cpp
+++ b/src/fdcache_entity.cpp
@@ -1384,7 +1384,7 @@ off_t FdEntity::BytesModified()
 // Files smaller than the minimum part size will not be multipart uploaded,
 // but will be uploaded as single part(normally).
 //
-int FdEntity::RowFlush(int fd, const char* tpath, bool force_sync)
+int FdEntity::RowFlush(int fd, const char* tpath, AutoLock::Type type, bool force_sync)
 {
     S3FS_PRN_INFO3("[tpath=%s][path=%s][pseudo_fd=%d][physical_fd=%d]", SAFESTRPTR(tpath), path.c_str(), fd, physical_fd);
 
@@ -1392,7 +1392,7 @@ int FdEntity::RowFlush(int fd, const char* tpath, bool force_sync)
         return -EBADF;
     }
 
-    AutoLock auto_lock(&fdent_lock);
+    AutoLock auto_lock(&fdent_lock, type);
 
     // check pseudo fd and its flag
     fdinfo_map_t::iterator miter = pseudo_fd_map.find(fd);
@@ -1594,7 +1594,7 @@ int FdEntity::RowFlushMultipart(PseudoFdInfo* pseudo_obj, const char* tpath)
             S3FS_PRN_ERR("failed to truncate file(physical_fd=%d) to zero, but continue...", physical_fd);
         }
         // put pending headers or create new file
-        if(0 != (result = UploadPending(-1))){
+        if(0 != (result = UploadPending(-1, AutoLock::ALREADY_LOCKED))){
             return result;
         }
     }
@@ -1722,7 +1722,7 @@ int FdEntity::RowFlushMixMultipart(PseudoFdInfo* pseudo_obj, const char* tpath)
             S3FS_PRN_ERR("failed to truncate file(physical_fd=%d) to zero, but continue...", physical_fd);
         }
         // put pending headers or create new file
-        if(0 != (result = UploadPending(-1))){
+        if(0 != (result = UploadPending(-1, AutoLock::ALREADY_LOCKED))){
             return result;
         }
     }
@@ -1901,7 +1901,7 @@ int FdEntity::RowFlushStreamMultipart(PseudoFdInfo* pseudo_obj, const char* tpat
         pseudo_obj->ClearUploadInfo();         // clear multipart upload info
 
         // put pending headers or create new file
-        if(0 != (result = UploadPending(-1))){
+        if(0 != (result = UploadPending(-1, AutoLock::ALREADY_LOCKED))){
             return result;
         }
     }
@@ -2384,8 +2384,9 @@ bool FdEntity::MergeOrgMeta(headers_t& updatemeta)
 // global function in s3fs.cpp
 int put_headers(const char* path, headers_t& meta, bool is_copy, bool use_st_size = true);
 
-int FdEntity::UploadPending(int fd)
+int FdEntity::UploadPending(int fd, AutoLock::Type type)
 {
+    AutoLock auto_lock(&fdent_lock, type);
     int result;
 
     if(NO_UPDATE_PENDING == pending_status){
@@ -2410,7 +2411,7 @@ int FdEntity::UploadPending(int fd)
             S3FS_PRN_ERR("could not create a new file(%s), because fd is not specified.", path.c_str());
             result = -EBADF;
         }else{
-            result = Flush(fd, true);
+            result = Flush(fd, AutoLock::ALREADY_LOCKED, true);
             if(0 != result){
                 S3FS_PRN_ERR("failed to flush for file(%s) by(%d).", path.c_str(), result);
             }else{
diff --git a/src/fdcache_entity.h b/src/fdcache_entity.h
index 9362ad5..fc0201f 100644
--- a/src/fdcache_entity.h
+++ b/src/fdcache_entity.h
@@ -114,7 +114,7 @@ class FdEntity
         int GetPhysicalFd() const { return physical_fd; }
         bool IsModified() const;
         bool MergeOrgMeta(headers_t& updatemeta);
-        int UploadPending(int fd);
+        int UploadPending(int fd, AutoLock::Type type);
 
         bool GetStats(struct stat& st, bool lock_already_held = false);
         int SetCtime(struct timespec time, bool lock_already_held = false);
@@ -137,8 +137,8 @@ class FdEntity
         int Load(off_t start, off_t size, AutoLock::Type type, bool is_modified_flag = false);  // size=0 means loading to end
 
         off_t BytesModified();
-        int RowFlush(int fd, const char* tpath, bool force_sync = false);
-        int Flush(int fd, bool force_sync = false) { return RowFlush(fd, NULL, force_sync); }
+        int RowFlush(int fd, const char* tpath, AutoLock::Type type, bool force_sync = false);
+        int Flush(int fd, AutoLock::Type type, bool force_sync = false) { return RowFlush(fd, NULL, type, force_sync); }
 
         ssize_t Read(int fd, char* bytes, off_t start, size_t size, bool force_load = false);
         ssize_t Write(int fd, const char* bytes, off_t start, size_t size);
diff --git a/src/s3fs.cpp b/src/s3fs.cpp
index 1d5071f..d6c46e5 100644
--- a/src/s3fs.cpp
+++ b/src/s3fs.cpp
@@ -1155,7 +1155,7 @@ static int s3fs_symlink(const char* _from, const char* _to)
             }
         }
         // upload
-        if(0 != (result = ent->Flush(autoent.GetPseudoFd(), true))){
+        if(0 != (result = ent->Flush(autoent.GetPseudoFd(), AutoLock::NONE, true))){
             S3FS_PRN_WARN("could not upload tmpfile(result=%d)", result);
         }
     }
@@ -1287,7 +1287,7 @@ static int rename_object_nocopy(const char* from, const char* to, bool update_ct
         }
 
         // upload
-        if(0 != (result = ent->RowFlush(autoent.GetPseudoFd(), to, true))){
+        if(0 != (result = ent->RowFlush(autoent.GetPseudoFd(), to, AutoLock::NONE, true))){
             S3FS_PRN_ERR("could not upload file(%s): result=%d", to, result);
             return result;
         }
@@ -1526,7 +1526,7 @@ static int s3fs_rename(const char* _from, const char* _to)
         AutoFdEntity autoent;
         FdEntity*    ent;
         if(NULL != (ent = autoent.OpenExistFdEntity(from, O_RDWR))){
-            if(0 != (result = ent->Flush(autoent.GetPseudoFd(), true))){
+            if(0 != (result = ent->Flush(autoent.GetPseudoFd(), AutoLock::NONE, true))){
                 S3FS_PRN_ERR("could not upload file(%s): result=%d", to, result);
                 return result;
             }
@@ -1719,7 +1719,7 @@ static int s3fs_chmod_nocopy(const char* _path, mode_t mode)
         ent->SetMode(mode);
 
         // upload
-        if(0 != (result = ent->Flush(autoent.GetPseudoFd(), true))){
+        if(0 != (result = ent->Flush(autoent.GetPseudoFd(), AutoLock::NONE, true))){
             S3FS_PRN_ERR("could not upload file(%s): result=%d", strpath.c_str(), result);
             return result;
         }
@@ -1904,7 +1904,7 @@ static int s3fs_chown_nocopy(const char* _path, uid_t uid, gid_t gid)
         ent->SetGId(gid);
   
         // upload
-        if(0 != (result = ent->Flush(autoent.GetPseudoFd(), true))){
+        if(0 != (result = ent->Flush(autoent.GetPseudoFd(), AutoLock::NONE, true))){
             S3FS_PRN_ERR("could not upload file(%s): result=%d", strpath.c_str(), result);
             return result;
         }
@@ -2136,7 +2136,7 @@ static int s3fs_utimens_nocopy(const char* _path, const struct timespec ts[2])
         }
 
         // upload
-        if(0 != (result = ent->Flush(autoent.GetPseudoFd(), true))){
+        if(0 != (result = ent->Flush(autoent.GetPseudoFd(), AutoLock::NONE, true))){
             S3FS_PRN_ERR("could not upload file(%s): result=%d", strpath.c_str(), result);
             return result;
         }
@@ -2210,7 +2210,7 @@ static int s3fs_truncate(const char* _path, off_t size)
         // The cause is unknown now, but it can be avoided by flushing the file.
         //
         if(0 == size){
-            if(0 != (result = ent->Flush(autoent.GetPseudoFd(), true))){
+            if(0 != (result = ent->Flush(autoent.GetPseudoFd(), AutoLock::NONE, true))){
                 S3FS_PRN_ERR("could not upload file(%s): result=%d", path, result);
                 return result;
             }
@@ -2236,7 +2236,7 @@ static int s3fs_truncate(const char* _path, off_t size)
             S3FS_PRN_ERR("could not open file(%s): errno=%d", path, errno);
             return -EIO;
         }
-        if(0 != (result = ent->Flush(autoent.GetPseudoFd(), true))){
+        if(0 != (result = ent->Flush(autoent.GetPseudoFd(), AutoLock::NONE, true))){
             S3FS_PRN_ERR("could not upload file(%s): result=%d", path, result);
             return result;
         }
@@ -2311,7 +2311,7 @@ static int s3fs_open(const char* _path, struct fuse_file_info* fi)
         time_t now = time(NULL);
         struct timespec ts = {now, 0};
         ent->SetMCtime(ts, ts);
-        if(0 != (result = ent->RowFlush(autoent.GetPseudoFd(), path, true))){
+        if(0 != (result = ent->RowFlush(autoent.GetPseudoFd(), path, AutoLock::NONE, true))){
             S3FS_PRN_ERR("could not upload file(%s): result=%d", path, result);
             StatCache::getStatCacheData()->DelStat(path);
             return result;
@@ -2372,7 +2372,7 @@ static int s3fs_write(const char* _path, const char* buf, size_t size, off_t off
 
     if(max_dirty_data != -1 && ent->BytesModified() >= max_dirty_data){
         int flushres;
-        if(0 != (flushres = ent->RowFlush(static_cast<int>(fi->fh), path, true))){
+        if(0 != (flushres = ent->RowFlush(static_cast<int>(fi->fh), path, AutoLock::NONE, true))){
             S3FS_PRN_ERR("could not upload file(%s): result=%d", path, flushres);
             StatCache::getStatCacheData()->DelStat(path);
             return flushres;
@@ -2430,7 +2430,7 @@ static int s3fs_flush(const char* _path, struct fuse_file_info* fi)
     if(NULL != (ent = autoent.GetExistFdEntity(path, static_cast<int>(fi->fh)))){
         ent->UpdateMtime(true);         // clear the flag not to update mtime.
         ent->UpdateCtime();
-        result = ent->Flush(static_cast<int>(fi->fh), false);
+        result = ent->Flush(static_cast<int>(fi->fh), AutoLock::NONE, false);
         StatCache::getStatCacheData()->DelStat(path);
     }
     S3FS_MALLOCTRIM(0);
@@ -2455,7 +2455,7 @@ static int s3fs_fsync(const char* _path, int datasync, struct fuse_file_info* fi
             ent->UpdateMtime();
             ent->UpdateCtime();
         }
-        result = ent->Flush(static_cast<int>(fi->fh), false);
+        result = ent->Flush(static_cast<int>(fi->fh), AutoLock::NONE, false);
     }
     S3FS_MALLOCTRIM(0);
 
@@ -2498,7 +2498,8 @@ static int s3fs_release(const char* _path, struct fuse_file_info* fi)
             return -EIO;
         }
 
-        int result = ent->UploadPending(static_cast<int>(fi->fh));
+        // TODO: correct locks held?
+        int result = ent->UploadPending(static_cast<int>(fi->fh), AutoLock::NONE);
         if(0 != result){
             S3FS_PRN_ERR("could not upload pending data(meta, etc) for pseudo_fd(%llu) / path(%s)", (unsigned long long)(fi->fh), path);
             return result;