1 files changed, 74 insertions, 0 deletions
diff --git a/fs/xfs/xfs_rmap_item.h b/fs/xfs/xfs_rmap_item.h
new file mode 100644
index 000000000..802e5119e
--- /dev/null
+++ b/fs/xfs/xfs_rmap_item.h
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2016 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ */
+#ifndef	__XFS_RMAP_ITEM_H__
+#define	__XFS_RMAP_ITEM_H__
+
+/*
+ * There are (currently) three pairs of rmap btree redo item types: map, unmap,
+ * and convert.  The common abbreviations for these are RUI (rmap update
+ * intent) and RUD (rmap 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 rmapbt updates.  Typically, the first
+ * transaction will record a bmbt update, followed by some number of
+ * transactions containing rmapbt updates, and finally transactions with any
+ * bnobt/cntbt 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
+ * (rmapbt/bnobt/cntbt) metadata updates in the non-first transaction.
+ */
+
+/* kernel only RUI/RUD definitions */
+
+struct xfs_mount;
+struct kmem_cache;
+
+/*
+ * Max number of extents in fast allocation path.
+ */
+#define	XFS_RUI_MAX_FAST_EXTENTS	16
+
+/*
+ * This is the "rmap 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
+ * "rmap 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_rui_log_item {
+	struct xfs_log_item		rui_item;
+	atomic_t			rui_refcount;
+	atomic_t			rui_next_extent;
+	struct xfs_rui_log_format	rui_format;
+};
+
+static inline size_t
+xfs_rui_log_item_sizeof(
+	unsigned int		nr)
+{
+	return offsetof(struct xfs_rui_log_item, rui_format) +
+			xfs_rui_log_format_sizeof(nr);
+}
+
+/*
+ * This is the "rmap update done" log item.  It is used to log the fact that
+ * some rmapbt updates mentioned in an earlier rui item have been performed.
+ */
+struct xfs_rud_log_item {
+	struct xfs_log_item		rud_item;
+	struct xfs_rui_log_item		*rud_ruip;
+	struct xfs_rud_log_format	rud_format;
+};
+
+extern struct kmem_cache	*xfs_rui_cache;
+extern struct kmem_cache	*xfs_rud_cache;
+
+#endif	/* __XFS_RMAP_ITEM_H__ */