[LibOS] Fix dentry of open files after rename

Signed-off-by: g2flyer <michael.steiner@intel.com>

libos/src/sys/libos_file.c

@@ -347,8 +347,31 @@ static int do_rename(struct libos_dentry* old_dent, struct libos_dentry* new_den
 
     if (new_dent->inode)
         put_inode(new_dent->inode);
+
     new_dent->inode = old_dent->inode;
     old_dent->inode = NULL;
+
+    /* also update dentry of any potentially open fd pointing to old_dent */
+    struct libos_handle_map* handle_map = get_thread_handle_map(NULL);
+    assert(handle_map != NULL);
+    rwlock_read_lock(&handle_map->lock);
+
+    for (uint32_t i = 0; handle_map->fd_top != FD_NULL && i <= handle_map->fd_top; i++) {
+        struct libos_fd_handle* fd_handle = handle_map->map[i];
+        if (!HANDLE_ALLOCATED(fd_handle))
+            continue;
+        struct libos_handle* handle = fd_handle->handle;
+        /* see comment in libos_handle.h on loocking strategy protecting handle->lock */
+        assert(locked(&g_dcache_lock));
+        lock(&handle->lock);
+        if ((handle->dentry == old_dent) && (handle->inode == new_dent->inode)) {
+            handle->dentry = new_dent;
+            put_dentry(old_dent);
+            get_dentry(new_dent);
+        }
+        unlock(&handle->lock);
+    }
+    rwlock_read_unlock(&handle_map->lock);
     return 0;
 }