+static int fuse_sync_fs(struct super_block *sb, int wait)
+{
+ struct fuse_mount *fm = get_fuse_mount_super(sb);
+ struct fuse_conn *fc = fm->fc;
+ struct fuse_syncfs_in inarg;
+ FUSE_ARGS(args);
+ int err;
+
+ /*
+ * Userspace cannot handle the wait == 0 case. Avoid a
+ * gratuitous roundtrip.
+ */
+ if (!wait)
+ return 0;
+
+ /* The filesystem is being unmounted. Nothing to do. */
+ if (!sb->s_root)
+ return 0;
+
+ if (!fc->sync_fs)
+ return 0;
+
+ memset(&inarg, 0, sizeof(inarg));
+ args.in_numargs = 1;
+ args.in_args[0].size = sizeof(inarg);
+ args.in_args[0].value = &inarg;
+ args.opcode = FUSE_SYNCFS;
+ args.nodeid = get_node_id(sb->s_root->d_inode);
+ args.out_numargs = 0;
+
+ err = fuse_simple_request(fm, &args);
+ if (err == -ENOSYS) {
+ fc->sync_fs = 0;
+ err = 0;
+ }
+
+ return err;
+}
+