fs/xfs/xfs_exchmaps_item.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * Copyright (c) 2020-2024 Oracle.  All Rights Reserved.
   4  * Author: Darrick J. Wong <djwong@kernel.org>
   5  */
   6 #ifndef __XFS_EXCHMAPS_ITEM_H__
   7 #define __XFS_EXCHMAPS_ITEM_H__
   8
   9 /*
  10  * The file mapping exchange intent item helps us exchange multiple file
  11  * mappings between two inode forks.  It does this by tracking the range of
  12  * file block offsets that still need to be exchanged, and relogs as progress
  13  * happens.
  14  *
  15  * *I items should be recorded in the *first* of a series of rolled
  16  * transactions, and the *D items should be recorded in the same transaction
  17  * that records the associated bmbt updates.
  18  *
  19  * Should the system crash after the commit of the first transaction but
  20  * before the commit of the final transaction in a series, log recovery will
  21  * use the redo information recorded by the intent items to replay the
  22  * rest of the mapping exchanges.
  23  */
  24
  25 /* kernel only XMI/XMD definitions */
  26
  27 struct xfs_mount;
  28 struct kmem_cache;
  29
  30 /*
  31  * This is the incore file mapping exchange intent log item.  It is used to log
  32  * the fact that we are exchanging mappings between two files.  It is used in
  33  * conjunction with the incore file mapping exchange done log item described
  34  * below.
  35  *
  36  * These log items follow the same rules as struct xfs_efi_log_item; see the
  37  * comments about that structure (in xfs_extfree_item.h) for more details.
  38  */
  39 struct xfs_xmi_log_item {
  40         struct xfs_log_item             xmi_item;
  41         atomic_t                        xmi_refcount;
  42         struct xfs_xmi_log_format       xmi_format;
  43 };
  44
  45 /*
  46  * This is the incore file mapping exchange done log item.  It is used to log
  47  * the fact that an exchange mentioned in an earlier xmi item have been
  48  * performed.
  49  */
  50 struct xfs_xmd_log_item {
  51         struct xfs_log_item             xmd_item;
  52         struct xfs_xmi_log_item         *xmd_intent_log_item;
  53         struct xfs_xmd_log_format       xmd_format;
  54 };
  55
  56 extern struct kmem_cache        *xfs_xmi_cache;
  57 extern struct kmem_cache        *xfs_xmd_cache;
  58
  59 struct xfs_exchmaps_intent;
  60
  61 void xfs_exchmaps_defer_add(struct xfs_trans *tp,
  62                 struct xfs_exchmaps_intent *xmi);
  63
  64 #endif  /* __XFS_EXCHMAPS_ITEM_H__ */