// SPDX-License-Identifier: GPL-2.0+

  /*
   * Copyright (C) 2016 Oracle.  All Rights Reserved.

   * Author: Darrick J. Wong <darrick.wong@oracle.com>

   */
  #ifndef	__XFS_RMAP_ITEM_H__
  #define	__XFS_RMAP_ITEM_H__
  
  /*
   * There are (currently) three pairs of rmap btree redo item types: map, unmap,
   * and convert.  The common abbreviations for these are RUI (rmap update
   * intent) and RUD (rmap 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 rmapbt updates.  Typically, the first
   * transaction will record a bmbt update, followed by some number of
   * transactions containing rmapbt updates, and finally transactions with any
   * bnobt/cntbt 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
   * (rmapbt/bnobt/cntbt) metadata updates in the non-first transaction.
   */
  
  /* kernel only RUI/RUD definitions */
  
  struct xfs_mount;
  struct kmem_zone;
  
  /*
   * Max number of extents in fast allocation path.
   */
  #define	XFS_RUI_MAX_FAST_EXTENTS	16
  
  /*
   * Define RUI flag bits. Manipulated by set/clear/test_bit operators.
   */
  #define	XFS_RUI_RECOVERED		1
  
  /*
   * This is the "rmap 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
   * "rmap 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_rui_log_item {
  	struct xfs_log_item		rui_item;
  	atomic_t			rui_refcount;
  	atomic_t			rui_next_extent;
  	unsigned long			rui_flags;	/* misc flags */
  	struct xfs_rui_log_format	rui_format;
  };

  static inline size_t
  xfs_rui_log_item_sizeof(
  	unsigned int		nr)
  {
  	return offsetof(struct xfs_rui_log_item, rui_format) +
  			xfs_rui_log_format_sizeof(nr);
  }

  /*
   * This is the "rmap update done" log item.  It is used to log the fact that
   * some rmapbt updates mentioned in an earlier rui item have been performed.
   */
  struct xfs_rud_log_item {
  	struct xfs_log_item		rud_item;
  	struct xfs_rui_log_item		*rud_ruip;

  	struct xfs_rud_log_format	rud_format;
  };

  extern struct kmem_zone	*xfs_rui_zone;
  extern struct kmem_zone	*xfs_rud_zone;
  
  struct xfs_rui_log_item *xfs_rui_init(struct xfs_mount *, uint);

  int xfs_rui_copy_format(struct xfs_log_iovec *buf,
  		struct xfs_rui_log_format *dst_rui_fmt);
  void xfs_rui_item_free(struct xfs_rui_log_item *);
  void xfs_rui_release(struct xfs_rui_log_item *);

  int xfs_rui_recover(struct xfs_mount *mp, struct xfs_rui_log_item *ruip);

  
  #endif	/* __XFS_RMAP_ITEM_H__ */