NEX-8972 Async-delete side-effect that may cause unmount EBUSY
Reviewed by: Alek Pinchuk <alek@nexenta.com>
Reviewed by: Sanjay Nadkarni <sanjay.nadkarni@nexenta.com>
NEX-3762 Appliance crashes with a NULL pointer dereference during a zpool export when a zfs_vn_rele_taskq thread attempts to check a bogus rwlock from rw_write_held
Reviewed by: Josef 'Jeff' Sipek <josef.sipek@nexenta.com>

*** 19,28 ****
--- 19,29 ----
   * CDDL HEADER END
   */
  /*
   * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
+  * Copyright 2016 Nexenta Systems Inc. All rights reserved.
   */
  
  #ifndef _SYS_FS_ZFS_DIR_H
  #define _SYS_FS_ZFS_DIR_H
  
*** 61,70 ****
--- 62,72 ----
  extern void zfs_rmnode(znode_t *);
  extern void zfs_dl_name_switch(zfs_dirlock_t *dl, char *new, char **old);
  extern boolean_t zfs_dirempty(znode_t *);
  extern void zfs_unlinked_add(znode_t *, dmu_tx_t *);
  extern void zfs_unlinked_drain(zfsvfs_t *zfsvfs);
+ extern void zfs_unlinked_drain_stop_wait(zfsvfs_t *zfsvfs);
  extern int zfs_sticky_remove_access(znode_t *, znode_t *, cred_t *cr);
  extern int zfs_get_xattrdir(znode_t *, vnode_t **, cred_t *, int);
  extern int zfs_make_xattrdir(znode_t *, vattr_t *, vnode_t **, cred_t *);
  
  #ifdef  __cplusplus