fs/xfs/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
  11 struct xfs_mount;
  12 struct 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  */
  53 typedef struct xfs_efi_log_item {
  54         xfs_log_item_t          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  */
  66 typedef struct xfs_efd_log_item {
  67         xfs_log_item_t          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
  78 extern struct kmem_zone *xfs_efi_zone;
  79 extern struct kmem_zone *xfs_efd_zone;
  80
  81 xfs_efi_log_item_t      *xfs_efi_init(struct xfs_mount *, uint);
  82 xfs_efd_log_item_t      *xfs_efd_init(struct xfs_mount *, xfs_efi_log_item_t *,
  83                                       uint);
  84 int                     xfs_efi_copy_format(xfs_log_iovec_t *buf,
  85                                             xfs_efi_log_format_t *dst_efi_fmt);
  86 void                    xfs_efi_item_free(xfs_efi_log_item_t *);
  87 void                    xfs_efi_release(struct xfs_efi_log_item *);
  88
  89 int                     xfs_efi_recover(struct xfs_mount *mp,
  90                                         struct xfs_efi_log_item *efip);
  91
  92 #endif  /* __XFS_EXTFREE_ITEM_H__ */