xfs_rmap_item.h 2.4 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Copyright (C) 2016 Oracle. All Rights Reserved.
  4. * Author: Darrick J. Wong <darrick.wong@oracle.com>
  5. */
  6. #ifndef __XFS_RMAP_ITEM_H__
  7. #define __XFS_RMAP_ITEM_H__
  8. /*
  9. * There are (currently) three pairs of rmap btree redo item types: map, unmap,
  10. * and convert. The common abbreviations for these are RUI (rmap update
  11. * intent) and RUD (rmap update done). The redo item type is encoded in the
  12. * flags field of each xfs_map_extent.
  13. *
  14. * *I items should be recorded in the *first* of a series of rolled
  15. * transactions, and the *D items should be recorded in the same transaction
  16. * that records the associated rmapbt updates. Typically, the first
  17. * transaction will record a bmbt update, followed by some number of
  18. * transactions containing rmapbt updates, and finally transactions with any
  19. * bnobt/cntbt updates.
  20. *
  21. * Should the system crash after the commit of the first transaction but
  22. * before the commit of the final transaction in a series, log recovery will
  23. * use the redo information recorded by the intent items to replay the
  24. * (rmapbt/bnobt/cntbt) metadata updates in the non-first transaction.
  25. */
  26. /* kernel only RUI/RUD definitions */
  27. struct xfs_mount;
  28. struct kmem_zone;
  29. /*
  30. * Max number of extents in fast allocation path.
  31. */
  32. #define XFS_RUI_MAX_FAST_EXTENTS 16
  33. /*
  34. * This is the "rmap update intent" log item. It is used to log the fact that
  35. * some reverse mappings need to change. It is used in conjunction with the
  36. * "rmap update done" log item described below.
  37. *
  38. * These log items follow the same rules as struct xfs_efi_log_item; see the
  39. * comments about that structure (in xfs_extfree_item.h) for more details.
  40. */
  41. struct xfs_rui_log_item {
  42. struct xfs_log_item rui_item;
  43. atomic_t rui_refcount;
  44. atomic_t rui_next_extent;
  45. struct xfs_rui_log_format rui_format;
  46. };
  47. static inline size_t
  48. xfs_rui_log_item_sizeof(
  49. unsigned int nr)
  50. {
  51. return offsetof(struct xfs_rui_log_item, rui_format) +
  52. xfs_rui_log_format_sizeof(nr);
  53. }
  54. /*
  55. * This is the "rmap update done" log item. It is used to log the fact that
  56. * some rmapbt updates mentioned in an earlier rui item have been performed.
  57. */
  58. struct xfs_rud_log_item {
  59. struct xfs_log_item rud_item;
  60. struct xfs_rui_log_item *rud_ruip;
  61. struct xfs_rud_log_format rud_format;
  62. };
  63. extern struct kmem_zone *xfs_rui_zone;
  64. extern struct kmem_zone *xfs_rud_zone;
  65. #endif /* __XFS_RMAP_ITEM_H__ */