Allow updates for open file descriptors

even if the calling process itself would not be able to open the file.

Bug: 18688419

Change-Id: I640db19f19c1a677735fd0c14b7e2e38977d0f4d
diff --git a/sdcard/sdcard.c b/sdcard/sdcard.c
index 9ba81ff..d7bccea 100644
--- a/sdcard/sdcard.c
+++ b/sdcard/sdcard.c
@@ -904,7 +904,9 @@
     if (!node) {
         return -ENOENT;
     }
-    if (!check_caller_access_to_node(fuse, hdr, node, W_OK, has_rw)) {
+
+    if (!(req->valid & FATTR_FH) &&
+            !check_caller_access_to_node(fuse, hdr, node, W_OK, has_rw)) {
         return -EACCES;
     }