LXR linux/fs/xfs/xfs_extfree

   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_zone;
  13
  14/*
  15 * Max number of extents in fast allocation path.
  16 */
  17#define XFS_EFI_MAX_FAST_EXTENTS        16
  18
  19/*
  20 * Define EFI flag bits. Manipulated by set/clear/test_bit operators.
  21 */
  22#define XFS_EFI_RECOVERED       1
  23
  24/*
  25 * This is the "extent free intention" log item.  It is used to log the fact
  26 * that some extents need to be free.  It is used in conjunction with the
  27 * "extent free done" log item described below.
  28 *
  29 * The EFI is reference counted so that it is not freed prior to both the EFI
  30 * and EFD being committed and unpinned. This ensures the EFI is inserted into
  31 * the AIL even in the event of out of order EFI/EFD processing. In other words,
  32 * an EFI is born with two references:
  33 *
  34 *      1.) an EFI held reference to track EFI AIL insertion
  35 *      2.) an EFD held reference to track EFD commit
  36 *
  37 * On allocation, both references are the responsibility of the caller. Once the
  38 * EFI is added to and dirtied in a transaction, ownership of reference one
  39 * transfers to the transaction. The reference is dropped once the EFI is
  40 * inserted to the AIL or in the event of failure along the way (e.g., commit
  41 * failure, log I/O error, etc.). Note that the caller remains responsible for
  42 * the EFD reference under all circumstances to this point. The caller has no
  43 * means to detect failure once the transaction is committed, however.
  44 * Therefore, an EFD is required after this point, even in the event of
  45 * unrelated failure.
  46 *
  47 * Once an EFD is allocated and dirtied in a transaction, reference two
  48 * transfers to the transaction. The EFD reference is dropped once it reaches
  49 * the unpin handler. Similar to the EFI, the reference also drops in the event
  50 * of commit failure or log I/O errors. Note that the EFD is not inserted in the
  51 * AIL, so at this point both the EFI and EFD are freed.
  52 */
  53typedef struct xfs_efi_log_item {
  54        struct xfs_log_item     efi_item;
  55        atomic_t                efi_refcount;
  56        atomic_t                efi_next_extent;
  57        unsigned long           efi_flags;      /* misc flags */
  58        xfs_efi_log_format_t    efi_format;
  59} xfs_efi_log_item_t;
  60
  61/*
  62 * This is the "extent free done" log item.  It is used to log
  63 * the fact that some extents earlier mentioned in an efi item
  64 * have been freed.
  65 */
  66typedef struct xfs_efd_log_item {
  67        struct xfs_log_item     efd_item;
  68        xfs_efi_log_item_t      *efd_efip;
  69        uint                    efd_next_extent;
  70        xfs_efd_log_format_t    efd_format;
  71} xfs_efd_log_item_t;
  72
  73/*
  74 * Max number of extents in fast allocation path.
  75 */
  76#define XFS_EFD_MAX_FAST_EXTENTS        16
  77
  78extern struct kmem_zone *xfs_efi_zone;
  79extern struct kmem_zone *xfs_efd_zone;
  80
  81xfs_efi_log_item_t      *xfs_efi_init(struct xfs_mount *, uint);
  82int                     xfs_efi_copy_format(xfs_log_iovec_t *buf,
  83                                            xfs_efi_log_format_t *dst_efi_fmt);
  84void                    xfs_efi_item_free(xfs_efi_log_item_t *);
  85void                    xfs_efi_release(struct xfs_efi_log_item *);
  86
  87int                     xfs_efi_recover(struct xfs_mount *mp,
  88                                        struct xfs_efi_log_item *efip);
  89
  90#endif  /* __XFS_EXTFREE_ITEM_H__ */
  91