/*
   * Copyright (C) 2016 Oracle.  All Rights Reserved.
   *
   * Author: Darrick J. Wong <darrick.wong@oracle.com>
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version 2
   * of the License, or (at your option) any later version.
   *
   * This program is distributed in the hope that it would be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write the Free Software Foundation,
   * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
   */
  #ifndef	__XFS_REFCOUNT_ITEM_H__
  #define	__XFS_REFCOUNT_ITEM_H__
  
  /*
   * There are (currently) two pairs of refcount btree redo item types:
   * increase and decrease.  The log items for these are CUI (refcount
   * update intent) and CUD (refcount update done).  The redo item type
   * is encoded in the flags field of each xfs_map_extent.
   *
   * *I items should be recorded in the *first* of a series of rolled
   * transactions, and the *D items should be recorded in the same
   * transaction that records the associated refcountbt updates.
   *
   * Should the system crash after the commit of the first transaction
   * but before the commit of the final transaction in a series, log
   * recovery will use the redo information recorded by the intent items
   * to replay the refcountbt metadata updates.
   */
  
  /* kernel only CUI/CUD definitions */
  
  struct xfs_mount;
  struct kmem_zone;
  
  /*
   * Max number of extents in fast allocation path.
   */
  #define	XFS_CUI_MAX_FAST_EXTENTS	16
  
  /*
   * Define CUI flag bits. Manipulated by set/clear/test_bit operators.
   */
  #define	XFS_CUI_RECOVERED		1
  
  /*
   * This is the "refcount update intent" log item.  It is used to log
   * the fact that some reverse mappings need to change.  It is used in
   * conjunction with the "refcount update done" log item described
   * below.
   *
   * These log items follow the same rules as struct xfs_efi_log_item;
   * see the comments about that structure (in xfs_extfree_item.h) for
   * more details.
   */
  struct xfs_cui_log_item {
  	struct xfs_log_item		cui_item;
  	atomic_t			cui_refcount;
  	atomic_t			cui_next_extent;
  	unsigned long			cui_flags;	/* misc flags */
  	struct xfs_cui_log_format	cui_format;
  };
  
  static inline size_t
  xfs_cui_log_item_sizeof(
  	unsigned int		nr)
  {
  	return offsetof(struct xfs_cui_log_item, cui_format) +
  			xfs_cui_log_format_sizeof(nr);
  }
  
  /*
   * This is the "refcount update done" log item.  It is used to log the
   * fact that some refcountbt updates mentioned in an earlier cui item
   * have been performed.
   */
  struct xfs_cud_log_item {
  	struct xfs_log_item		cud_item;
  	struct xfs_cui_log_item		*cud_cuip;
  	struct xfs_cud_log_format	cud_format;
  };
  
  extern struct kmem_zone	*xfs_cui_zone;
  extern struct kmem_zone	*xfs_cud_zone;
  
  struct xfs_cui_log_item *xfs_cui_init(struct xfs_mount *, uint);
  struct xfs_cud_log_item *xfs_cud_init(struct xfs_mount *,
  		struct xfs_cui_log_item *);
  void xfs_cui_item_free(struct xfs_cui_log_item *);
  void xfs_cui_release(struct xfs_cui_log_item *);

  int xfs_cui_recover(struct xfs_mount *mp, struct xfs_cui_log_item *cuip,
  		struct xfs_defer_ops *dfops);

  
  #endif	/* __XFS_REFCOUNT_ITEM_H__ */