Fix sdcard's FUSE_FSYNCDIR handling.

For a file the FUSE fh is a struct handle containing an int fd;
for a directory it's a struct dirhandle containing a DIR*. Fix
handle_fsync to extract the file descriptor appropriately in
both cases.

Bug: 14613980
Change-Id: I45515cff6638e27a99b849e6fc639d355dbb4d27
diff --git a/sdcard/sdcard.c b/sdcard/sdcard.c
index 566a66c..844ca65 100644
--- a/sdcard/sdcard.c
+++ b/sdcard/sdcard.c
@@ -1309,14 +1309,23 @@
 static int handle_fsync(struct fuse* fuse, struct fuse_handler* handler,
         const struct fuse_in_header* hdr, const struct fuse_fsync_in* req)
 {
-    int is_data_sync = req->fsync_flags & 1;
-    struct handle *h = id_to_ptr(req->fh);
-    int res;
+    bool is_dir = (hdr->opcode == FUSE_FSYNCDIR);
+    bool is_data_sync = req->fsync_flags & 1;
 
-    TRACE("[%d] FSYNC %p(%d) is_data_sync=%d\n", handler->token,
-            h, h->fd, is_data_sync);
-    res = is_data_sync ? fdatasync(h->fd) : fsync(h->fd);
-    if (res < 0) {
+    int fd = -1;
+    if (is_dir) {
+      struct dirhandle *dh = id_to_ptr(req->fh);
+      fd = dirfd(dh->d);
+    } else {
+      struct handle *h = id_to_ptr(req->fh);
+      fd = h->fd;
+    }
+
+    TRACE("[%d] %s %p(%d) is_data_sync=%d\n", handler->token,
+            is_dir ? "FSYNCDIR" : "FSYNC",
+            id_to_ptr(req->fh), fd, is_data_sync);
+    int res = is_data_sync ? fdatasync(fd) : fsync(fd);
+    if (res == -1) {
         return -errno;
     }
     return 0;