// SPDX-License-Identifier: GPL-2.0

  /*

   * Copyright (c) 2000,2005 Silicon Graphics, Inc.
   * All Rights Reserved.

   */
  #ifndef	__XFS_EXTFREE_ITEM_H__
  #define	__XFS_EXTFREE_ITEM_H__

  /* kernel only EFI/EFD definitions */

  struct xfs_mount;
  struct kmem_zone;

  /*
   * Max number of extents in fast allocation path.
   */
  #define	XFS_EFI_MAX_FAST_EXTENTS	16
  
  /*

   * This is the "extent free intention" log item.  It is used to log the fact
   * that some extents need to be free.  It is used in conjunction with the
   * "extent free done" log item described below.
   *
   * The EFI is reference counted so that it is not freed prior to both the EFI

   * and EFD being committed and unpinned. This ensures the EFI is inserted into
   * the AIL even in the event of out of order EFI/EFD processing. In other words,
   * an EFI is born with two references:
   *
   * 	1.) an EFI held reference to track EFI AIL insertion
   * 	2.) an EFD held reference to track EFD commit
   *
   * On allocation, both references are the responsibility of the caller. Once the
   * EFI is added to and dirtied in a transaction, ownership of reference one
   * transfers to the transaction. The reference is dropped once the EFI is
   * inserted to the AIL or in the event of failure along the way (e.g., commit
   * failure, log I/O error, etc.). Note that the caller remains responsible for
   * the EFD reference under all circumstances to this point. The caller has no
   * means to detect failure once the transaction is committed, however.
   * Therefore, an EFD is required after this point, even in the event of
   * unrelated failure.
   *
   * Once an EFD is allocated and dirtied in a transaction, reference two
   * transfers to the transaction. The EFD reference is dropped once it reaches
   * the unpin handler. Similar to the EFI, the reference also drops in the event
   * of commit failure or log I/O errors. Note that the EFD is not inserted in the
   * AIL, so at this point both the EFI and EFD are freed.

   */

  struct xfs_efi_log_item {

  	struct xfs_log_item	efi_item;

  	atomic_t		efi_refcount;

  	atomic_t		efi_next_extent;

  	xfs_efi_log_format_t	efi_format;

  };

  
  /*
   * This is the "extent free done" log item.  It is used to log
   * the fact that some extents earlier mentioned in an efi item
   * have been freed.
   */

  struct xfs_efd_log_item {

  	struct xfs_log_item	efd_item;

  	struct xfs_efi_log_item *efd_efip;

  	uint			efd_next_extent;
  	xfs_efd_log_format_t	efd_format;

  };

  
  /*
   * Max number of extents in fast allocation path.
   */
  #define	XFS_EFD_MAX_FAST_EXTENTS	16
  
  extern struct kmem_zone	*xfs_efi_zone;
  extern struct kmem_zone	*xfs_efd_zone;

  #endif	/* __XFS_EXTFREE_ITEM_H__ */