linux/fs/btrfs/accessors.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 */

#include <asm/unaligned.h>
#include "messages.h"
#include "extent_io.h"
#include "fs.h"
#include "accessors.h"

static bool check_setget_bounds(const struct extent_buffer *eb,
				const void *ptr, unsigned off, int size)
{ … }

void btrfs_init_map_token(struct btrfs_map_token *token, struct extent_buffer *eb)
{ … }

/*
 * Macro templates that define helpers to read/write extent buffer data of a
 * given size, that are also used via ctree.h for access to item members by
 * specialized helpers.
 *
 * Generic helpers:
 * - btrfs_set_8 (for 8/16/32/64)
 * - btrfs_get_8 (for 8/16/32/64)
 *
 * Generic helpers with a token (cached address of the most recently accessed
 * page):
 * - btrfs_set_token_8 (for 8/16/32/64)
 * - btrfs_get_token_8 (for 8/16/32/64)
 *
 * The set/get functions handle data spanning two pages transparently, in case
 * metadata block size is larger than page.  Every pointer to metadata items is
 * an offset into the extent buffer page array, cast to a specific type.  This
 * gives us all the type checking.
 *
 * The extent buffer pages stored in the array folios may not form a contiguous
 * phyusical range, but the API functions assume the linear offset to the range
 * from 0 to metadata node size.
 */

#define DEFINE_BTRFS_SETGET_BITS(bits) …

DEFINE_BTRFS_SETGET_BITS(…)
DEFINE_BTRFS_SETGET_BITS(…)
DEFINE_BTRFS_SETGET_BITS(…)
DEFINE_BTRFS_SETGET_BITS(…)

void btrfs_node_key(const struct extent_buffer *eb,
		    struct btrfs_disk_key *disk_key, int nr)
{ … }