rofiles: Fix --copyup when creating a new file

This tripped up the `docbook-dtds` `%post` in my experiments
with doing rpm-ostree for buildroots.

I cloned and built [xfstests](https://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git)
but haven't yet investigated actually running it.

In the meantime let's do the obvious fix here; we need to distinguish
between "copyup enabled" and "actually did a copyup" in the open path
at least, since if we didn't do a copyup we don't need to re-open.

Closes: #1396
Approved by: jlebon

src/rofiles-fuse/main.c

@@ -247,10 +247,14 @@ gioerror_to_errno (GIOErrorEnum e)
 }
 
 static int
-verify_write_or_copyup (const char *path, const struct stat *stbuf)
+verify_write_or_copyup (const char *path, const struct stat *stbuf,
+                        gboolean *out_did_copyup)
 {
   struct stat stbuf_local;
 
+  if (out_did_copyup)
+    *out_did_copyup = FALSE;
+
   /* If a stbuf wasn't provided, gather it now */
   if (!stbuf)
     {
@@ -272,6 +276,8 @@ verify_write_or_copyup (const char *path, const struct stat *stbuf)
           g_autoptr(GError) tmp_error = NULL;
           if (!ostree_break_hardlink (basefd, path, FALSE, NULL, &tmp_error))
             return -gioerror_to_errno ((GIOErrorEnum)tmp_error->code);
+          if (out_did_copyup)
+            *out_did_copyup = TRUE;
         }
       else
         return -EROFS;
@@ -286,7 +292,7 @@ verify_write_or_copyup (const char *path, const struct stat *stbuf)
  */
 #define PATH_WRITE_ENTRYPOINT(path) do {                     \
     path = ENSURE_RELPATH (path);                            \
-    int r = verify_write_or_copyup (path, NULL);             \
+    int r = verify_write_or_copyup (path, NULL, NULL);       \
     if (r != 0)                                              \
       return r;                                              \
   } while (0)
@@ -374,7 +380,8 @@ do_open (const char *path, mode_t mode, struct fuse_file_info *finfo)
           return -errno;
         }
 
-      int r = verify_write_or_copyup (path, &stbuf);
+      gboolean did_copyup;
+      int r = verify_write_or_copyup (path, &stbuf, &did_copyup);
       if (r != 0)
         {
           (void) close (fd);
@@ -382,7 +389,7 @@ do_open (const char *path, mode_t mode, struct fuse_file_info *finfo)
         }
 
       /* In the copyup case, we need to re-open */
-      if (opt_copyup)
+      if (did_copyup)
         {
           (void) close (fd);
           /* Note that unlike the initial open, we will pass through