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diff --git a/fs/xfs/xfs_bmap_item.h b/fs/xfs/xfs_bmap_item.h
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+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2016 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ */
+#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_cache;
+
+/*
+ * Max number of extents in fast allocation path.
+ */
+#define XFS_BUI_MAX_FAST_EXTENTS 1
+
+/*
+ * 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
+xfs_bui_log_item_sizeof(
+ unsigned int nr)
+{
+ return offsetof(struct xfs_bui_log_item, bui_format) +
+ xfs_bui_log_format_sizeof(nr);
+}
+
+/*
+ * 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_cache *xfs_bui_cache;
+extern struct kmem_cache *xfs_bud_cache;
+
+#endif /* __XFS_BMAP_ITEM_H__ */