xfs_extfree_item.h

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (c) 2000,2005 Silicon Graphics, Inc.
  4 * All Rights Reserved.
  5 */
  6#ifndef	__XFS_EXTFREE_ITEM_H__
  7#define	__XFS_EXTFREE_ITEM_H__
  8
  9/* kernel only EFI/EFD definitions */
 10
 11struct xfs_mount;
 12struct kmem_cache;
 13
 14/*
 15 * Max number of extents in fast allocation path.
 16 */
 17#define	XFS_EFI_MAX_FAST_EXTENTS	16
 18
 19/*
 20 * This is the "extent free intention" log item.  It is used to log the fact
 21 * that some extents need to be free.  It is used in conjunction with the
 22 * "extent free done" log item described below.
 23 *
 24 * The EFI is reference counted so that it is not freed prior to both the EFI
 25 * and EFD being committed and unpinned. This ensures the EFI is inserted into
 26 * the AIL even in the event of out of order EFI/EFD processing. In other words,
 27 * an EFI is born with two references:
 28 *
 29 * 	1.) an EFI held reference to track EFI AIL insertion
 30 * 	2.) an EFD held reference to track EFD commit
 31 *
 32 * On allocation, both references are the responsibility of the caller. Once the
 33 * EFI is added to and dirtied in a transaction, ownership of reference one
 34 * transfers to the transaction. The reference is dropped once the EFI is
 35 * inserted to the AIL or in the event of failure along the way (e.g., commit
 36 * failure, log I/O error, etc.). Note that the caller remains responsible for
 37 * the EFD reference under all circumstances to this point. The caller has no
 38 * means to detect failure once the transaction is committed, however.
 39 * Therefore, an EFD is required after this point, even in the event of
 40 * unrelated failure.
 41 *
 42 * Once an EFD is allocated and dirtied in a transaction, reference two
 43 * transfers to the transaction. The EFD reference is dropped once it reaches
 44 * the unpin handler. Similar to the EFI, the reference also drops in the event
 45 * of commit failure or log I/O errors. Note that the EFD is not inserted in the
 46 * AIL, so at this point both the EFI and EFD are freed.
 47 */
 48struct xfs_efi_log_item {
 49	struct xfs_log_item	efi_item;
 50	atomic_t		efi_refcount;
 51	atomic_t		efi_next_extent;
 52	struct xfs_efi_log_format efi_format;
 53};
 54
 55static inline size_t
 56xfs_efi_log_item_sizeof(
 57	unsigned int		nr)
 58{
 59	return offsetof(struct xfs_efi_log_item, efi_format) +
 60			xfs_efi_log_format_sizeof(nr);
 61}
 62
 63/*
 64 * This is the "extent free done" log item.  It is used to log
 65 * the fact that some extents earlier mentioned in an efi item
 66 * have been freed.
 67 */
 68struct xfs_efd_log_item {
 69	struct xfs_log_item	efd_item;
 70	struct xfs_efi_log_item *efd_efip;
 71	uint			efd_next_extent;
 72	struct xfs_efd_log_format efd_format;
 73};
 74
 75static inline size_t
 76xfs_efd_log_item_sizeof(
 77	unsigned int		nr)
 78{
 79	return offsetof(struct xfs_efd_log_item, efd_format) +
 80			xfs_efd_log_format_sizeof(nr);
 81}
 82
 83/*
 84 * Max number of extents in fast allocation path.
 85 */
 86#define	XFS_EFD_MAX_FAST_EXTENTS	16
 87
 88extern struct kmem_cache	*xfs_efi_cache;
 89extern struct kmem_cache	*xfs_efd_cache;
 90
 91struct xfs_extent_free_item;
 92
 93void xfs_extent_free_defer_add(struct xfs_trans *tp,
 94		struct xfs_extent_free_item *xefi,
 95		struct xfs_defer_pending **dfpp);
 96
 97unsigned int xfs_efi_log_space(unsigned int nr);
 98unsigned int xfs_efd_log_space(unsigned int nr);
 99
100#endif	/* __XFS_EXTFREE_ITEM_H__ */