3741 zfs needs better comments
Submitted by:   Will Andrews <willa@spectralogic.com>
Submitted by:   Justin Gibbs <justing@spectralogic.com>
Submitted by:   Alan Somers <alans@spectralogic.com>
Reviewed by:    Matthew Ahrens <mahrens@delphix.com>
Reviewed by:    Eric Schrock <eric.schrock@delphix.com>

*** 503,512 ****
--- 503,517 ----
          { VOPNAME_PATHCONF,     { .vop_pathconf = zfsctl_pathconf }     },
          { VOPNAME_FID,          { .vop_fid = zfsctl_common_fid  }       },
          { NULL }
  };
  
+ /*
+  * Gets the full dataset name that corresponds to the given snapshot name
+  * Example:
+  *      zfsctl_snapshot_zname("snap1") -> "mypool/myfs@snap1"
+  */
  static int
  zfsctl_snapshot_zname(vnode_t *vp, const char *name, int len, char *zname)
  {
          objset_t *os = ((zfsvfs_t *)((vp)->v_vfsp->vfs_data))->z_os;