[fix] copyfile dest file empty first (#8012)

components/dfs/dfs_v1/src/dfs_file.c

@@ -879,7 +879,7 @@ static void copyfile(const char *src, const char *dst)
         return;
     }
     fd_init(&fd);
-    if (dfs_file_open(&fd, dst, O_WRONLY | O_CREAT) < 0)
+    if (dfs_file_open(&fd, dst, O_WRONLY | O_CREAT | O_TRUNC) < 0)
     {
         rt_free(block_ptr);
         dfs_file_close(&src_fd);

components/dfs/dfs_v2/src/dfs_file.c

@@ -1939,7 +1939,7 @@ static void copyfile(const char *src, const char *dst)
 
     dfs_file_init(&dst_file);
 
-    ret = dfs_file_open(&dst_file, dst, O_WRONLY | O_CREAT, 0);
+    ret = dfs_file_open(&dst_file, dst, O_WRONLY | O_CREAT | O_TRUNC, 0);
     if (ret < 0)
     {
         dfs_file_deinit(&dst_file);