3756 want lz4 support for metadata compression

*** 22,31 ****
--- 22,32 ----
  /*
   * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
   * Copyright (c) 2012 by Delphix. All rights reserved.
   * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
   * Copyright (c) 2012, Joyent, Inc. All rights reserved.
+  * Copyright (c) 2013 Martin Matuska. All rights reserved.
   */
  
  /* Portions Copyright 2010 Robert Milkowski */
  
  #ifndef _SYS_DMU_H
*** 397,407 ****
  #define WP_NOFILL       0x1
  #define WP_DMU_SYNC     0x2
  #define WP_SPILL        0x4
  
  void dmu_write_policy(objset_t *os, struct dnode *dn, int level, int wp,
!     struct zio_prop *zp);
  /*
   * The bonus data is accessed more or less like a regular buffer.
   * You must dmu_bonus_hold() to get the buffer, which will give you a
   * dmu_buf_t with db_offset==-1ULL, and db_size = the size of the bonus
   * data.  As with any normal buffer, you must call dmu_buf_read() to
--- 398,408 ----
  #define WP_NOFILL       0x1
  #define WP_DMU_SYNC     0x2
  #define WP_SPILL        0x4
  
  void dmu_write_policy(objset_t *os, struct dnode *dn, int level, int wp,
!     struct zio_prop *zp, uint64_t txg);
  /*
   * The bonus data is accessed more or less like a regular buffer.
   * You must dmu_bonus_hold() to get the buffer, which will give you a
   * dmu_buf_t with db_offset==-1ULL, and db_size = the size of the bonus
   * data.  As with any normal buffer, you must call dmu_buf_read() to