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-rw-r--r--fs/xfs/xfs_rmap_item.h74
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diff --git a/fs/xfs/xfs_rmap_item.h b/fs/xfs/xfs_rmap_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_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__ */