ocfs2_nfs_sync_lock
int ocfs2_nfs_sync_lock(struct ocfs2_super *osb, int ex);
status = ocfs2_nfs_sync_lock(OCFS2_SB(dir->i_sb), 1);
status = ocfs2_nfs_sync_lock(osb, 1);
status = ocfs2_nfs_sync_lock(OCFS2_SB(inode->i_sb), 0);