an unclean server restart (i.e. a crash) can cause data to be lost or
corrupted.
+.TP
+.IR sync
+Reply to requests only after the changes have been committed to stable
+storage (see
+.IR async
+above).
+
In releases of nfs-utils upto and including 1.0.0, this option was the
default. In this and future releases,
.I sync
The option can be explicitly disabled with
.IR hide .
.TP
+.IR crossmnt
+This option is similar to
+.I nohide
+but it makes it possible for clients to move from the filesystem marked
+with crossmnt to exported filesystems mounted on it. Thus when a child
+filesystem "B" is mounted on a parent "A", setting crossmnt on "A" has
+the same effect as setting "nohide" on B.
+.TP
.IR no_subtree_check
This option disables subtree checking, which has mild security
implications, but can improve reliability in some circumstances.