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// SPDX-License-Identifier: GPL-2.0+
* Copyright (C) 2016 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <>
#ifndef __XFS_BMAP_ITEM_H__
#define __XFS_BMAP_ITEM_H__
* There are (currently) two pairs of bmap btree redo item types: map & unmap.
* The common abbreviations for these are BUI (bmap update intent) and BUD
* (bmap update done). The redo item type is encoded in the flags field of
* each xfs_map_extent.
* *I items should be recorded in the *first* of a series of rolled
* transactions, and the *D items should be recorded in the same transaction
* that records the associated bmbt updates.
* Should the system crash after the commit of the first transaction but
* before the commit of the final transaction in a series, log recovery will
* use the redo information recorded by the intent items to replay the
* bmbt metadata updates in the non-first transaction.
/* kernel only BUI/BUD definitions */
struct xfs_mount;
struct kmem_zone;
* Max number of extents in fast allocation path.
* This is the "bmap update intent" log item. It is used to log the fact that
* some reverse mappings need to change. It is used in conjunction with the
* "bmap update done" log item described below.
* These log items follow the same rules as struct xfs_efi_log_item; see the
* comments about that structure (in xfs_extfree_item.h) for more details.
struct xfs_bui_log_item {
struct xfs_log_item bui_item;
atomic_t bui_refcount;
atomic_t bui_next_extent;
struct xfs_bui_log_format bui_format;
static inline size_t
unsigned int nr)
return offsetof(struct xfs_bui_log_item, bui_format) +
* This is the "bmap update done" log item. It is used to log the fact that
* some bmbt updates mentioned in an earlier bui item have been performed.
struct xfs_bud_log_item {
struct xfs_log_item bud_item;
struct xfs_bui_log_item *bud_buip;
struct xfs_bud_log_format bud_format;
extern struct kmem_zone *xfs_bui_zone;
extern struct kmem_zone *xfs_bud_zone;
#endif /* __XFS_BMAP_ITEM_H__ */