1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (C) 2007 Oracle.  All rights reserved.
  4 */
  5
  6#include <asm/unaligned.h>
  7#include "messages.h"
  8#include "ctree.h"
  9#include "accessors.h"
 10
 11static bool check_setget_bounds(const struct extent_buffer *eb,
 12				const void *ptr, unsigned off, int size)
 13{
 14	const unsigned long member_offset = (unsigned long)ptr + off;
 15
 16	if (unlikely(member_offset + size > eb->len)) {
 17		btrfs_warn(eb->fs_info,
 18		"bad eb member %s: ptr 0x%lx start %llu member offset %lu size %d",
 19			(member_offset > eb->len ? "start" : "end"),
 20			(unsigned long)ptr, eb->start, member_offset, size);
 21		return false;
 22	}
 23
 24	return true;
 25}
 26
 27void btrfs_init_map_token(struct btrfs_map_token *token, struct extent_buffer *eb)
 28{
 29	token->eb = eb;
 30	token->kaddr = folio_address(eb->folios[0]);
 31	token->offset = 0;
 32}
 33
 34/*
 35 * Macro templates that define helpers to read/write extent buffer data of a
 36 * given size, that are also used via ctree.h for access to item members by
 37 * specialized helpers.
 38 *
 39 * Generic helpers:
 40 * - btrfs_set_8 (for 8/16/32/64)
 41 * - btrfs_get_8 (for 8/16/32/64)
 42 *
 43 * Generic helpers with a token (cached address of the most recently accessed
 44 * page):
 45 * - btrfs_set_token_8 (for 8/16/32/64)
 46 * - btrfs_get_token_8 (for 8/16/32/64)
 47 *
 48 * The set/get functions handle data spanning two pages transparently, in case
 49 * metadata block size is larger than page.  Every pointer to metadata items is
 50 * an offset into the extent buffer page array, cast to a specific type.  This
 51 * gives us all the type checking.
 52 *
 53 * The extent buffer pages stored in the array folios may not form a contiguous
 54 * phyusical range, but the API functions assume the linear offset to the range
 55 * from 0 to metadata node size.
 56 */
 57
 58#define DEFINE_BTRFS_SETGET_BITS(bits)					\
 59u##bits btrfs_get_token_##bits(struct btrfs_map_token *token,		\
 60			       const void *ptr, unsigned long off)	\
 61{									\
 62	const unsigned long member_offset = (unsigned long)ptr + off;	\
 63	const unsigned long idx = get_eb_folio_index(token->eb, member_offset); \
 64	const unsigned long oil = get_eb_offset_in_folio(token->eb,	\
 65							 member_offset);\
 66	const int unit_size = folio_size(token->eb->folios[0]);		\
 67	const int unit_shift = folio_shift(token->eb->folios[0]);	\
 68	const int size = sizeof(u##bits);				\
 69	u8 lebytes[sizeof(u##bits)];					\
 70	const int part = unit_size - oil;				\
 71									\
 72	ASSERT(token);							\
 73	ASSERT(token->kaddr);						\
 74	ASSERT(check_setget_bounds(token->eb, ptr, off, size));		\
 75	if (token->offset <= member_offset &&				\
 76	    member_offset + size <= token->offset + unit_size) {	\
 77		return get_unaligned_le##bits(token->kaddr + oil);	\
 78	}								\
 79	token->kaddr = folio_address(token->eb->folios[idx]);		\
 80	token->offset = idx << unit_shift;				\
 81	if (INLINE_EXTENT_BUFFER_PAGES == 1 || oil + size <= unit_size) \
 82		return get_unaligned_le##bits(token->kaddr + oil);	\
 83									\
 84	memcpy(lebytes, token->kaddr + oil, part);			\
 85	token->kaddr = folio_address(token->eb->folios[idx + 1]);	\
 86	token->offset = (idx + 1) << unit_shift;			\
 87	memcpy(lebytes + part, token->kaddr, size - part);		\
 88	return get_unaligned_le##bits(lebytes);				\
 89}									\
 90u##bits btrfs_get_##bits(const struct extent_buffer *eb,		\
 91			 const void *ptr, unsigned long off)		\
 92{									\
 93	const unsigned long member_offset = (unsigned long)ptr + off;	\
 94	const unsigned long idx = get_eb_folio_index(eb, member_offset);\
 95	const unsigned long oil = get_eb_offset_in_folio(eb,		\
 96							 member_offset);\
 97	const int unit_size = folio_size(eb->folios[0]);		\
 98	char *kaddr = folio_address(eb->folios[idx]);			\
 99	const int size = sizeof(u##bits);				\
100	const int part = unit_size - oil;				\
101	u8 lebytes[sizeof(u##bits)];					\
102									\
103	ASSERT(check_setget_bounds(eb, ptr, off, size));		\
104	if (INLINE_EXTENT_BUFFER_PAGES == 1 || oil + size <= unit_size)	\
105		return get_unaligned_le##bits(kaddr + oil);		\
106									\
107	memcpy(lebytes, kaddr + oil, part);				\
108	kaddr = folio_address(eb->folios[idx + 1]);			\
109	memcpy(lebytes + part, kaddr, size - part);			\
110	return get_unaligned_le##bits(lebytes);				\
111}									\
112void btrfs_set_token_##bits(struct btrfs_map_token *token,		\
113			    const void *ptr, unsigned long off,		\
114			    u##bits val)				\
115{									\
116	const unsigned long member_offset = (unsigned long)ptr + off;	\
117	const unsigned long idx = get_eb_folio_index(token->eb, member_offset); \
118	const unsigned long oil = get_eb_offset_in_folio(token->eb,	\
119							 member_offset);\
120	const int unit_size = folio_size(token->eb->folios[0]);		\
121	const int unit_shift = folio_shift(token->eb->folios[0]);	\
122	const int size = sizeof(u##bits);				\
123	u8 lebytes[sizeof(u##bits)];					\
124	const int part = unit_size - oil;				\
125									\
126	ASSERT(token);							\
127	ASSERT(token->kaddr);						\
128	ASSERT(check_setget_bounds(token->eb, ptr, off, size));		\
129	if (token->offset <= member_offset &&				\
130	    member_offset + size <= token->offset + unit_size) {	\
131		put_unaligned_le##bits(val, token->kaddr + oil);	\
132		return;							\
133	}								\
134	token->kaddr = folio_address(token->eb->folios[idx]);		\
135	token->offset = idx << unit_shift;				\
136	if (INLINE_EXTENT_BUFFER_PAGES == 1 ||				\
137	    oil + size <= unit_size) {					\
138		put_unaligned_le##bits(val, token->kaddr + oil);	\
139		return;							\
140	}								\
141	put_unaligned_le##bits(val, lebytes);				\
142	memcpy(token->kaddr + oil, lebytes, part);			\
143	token->kaddr = folio_address(token->eb->folios[idx + 1]);	\
144	token->offset = (idx + 1) << unit_shift;			\
145	memcpy(token->kaddr, lebytes + part, size - part);		\
146}									\
147void btrfs_set_##bits(const struct extent_buffer *eb, void *ptr,	\
148		      unsigned long off, u##bits val)			\
149{									\
150	const unsigned long member_offset = (unsigned long)ptr + off;	\
151	const unsigned long idx = get_eb_folio_index(eb, member_offset);\
152	const unsigned long oil = get_eb_offset_in_folio(eb,		\
153							 member_offset);\
154	const int unit_size = folio_size(eb->folios[0]);		\
155	char *kaddr = folio_address(eb->folios[idx]);			\
156	const int size = sizeof(u##bits);				\
157	const int part = unit_size - oil;				\
158	u8 lebytes[sizeof(u##bits)];					\
159									\
160	ASSERT(check_setget_bounds(eb, ptr, off, size));		\
161	if (INLINE_EXTENT_BUFFER_PAGES == 1 ||				\
162	    oil + size <= unit_size) {					\
163		put_unaligned_le##bits(val, kaddr + oil);		\
164		return;							\
165	}								\
166									\
167	put_unaligned_le##bits(val, lebytes);				\
168	memcpy(kaddr + oil, lebytes, part);				\
169	kaddr = folio_address(eb->folios[idx + 1]);			\
170	memcpy(kaddr, lebytes + part, size - part);			\
171}
172
173DEFINE_BTRFS_SETGET_BITS(8)
174DEFINE_BTRFS_SETGET_BITS(16)
175DEFINE_BTRFS_SETGET_BITS(32)
176DEFINE_BTRFS_SETGET_BITS(64)
177
178void btrfs_node_key(const struct extent_buffer *eb,
179		    struct btrfs_disk_key *disk_key, int nr)
180{
181	unsigned long ptr = btrfs_node_key_ptr_offset(eb, nr);
182	read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
183		       struct btrfs_key_ptr, key, disk_key);
184}