ceph: fix statx AT_STATX_DONT_SYNC vs AT_STATX_FORCE_SYNC check

From the posix and the initial statx supporting commit comments,
the AT_STATX_DONT_SYNC is a lightweight stat and the
AT_STATX_FORCE_SYNC is a heaverweight one. And also checked all
the other current usage about these two flags they are all doing
the same, that is only when the AT_STATX_FORCE_SYNC is not set
and the AT_STATX_DONT_SYNC is set will they skip sync retriving
the attributes from storage.
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/inode.c

@@ -2424,7 +2424,7 @@ int ceph_getattr(struct user_namespace *mnt_userns, const struct path *path,
 		return -ESTALE;
 
 	/* Skip the getattr altogether if we're asked not to sync */
-	if (!(flags & AT_STATX_DONT_SYNC)) {
+	if ((flags & AT_STATX_SYNC_TYPE) != AT_STATX_DONT_SYNC) {
 		err = ceph_do_getattr(inode,
 				statx_to_caps(request_mask, inode->i_mode),
 				flags & AT_STATX_FORCE_SYNC);