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 "extent_io.h"
9#include "fs.h"
10#include "accessors.h"
11
12static bool check_setget_bounds(const struct extent_buffer *eb,
13				const void *ptr, unsigned off, int size)
14{
15	const unsigned long member_offset = (unsigned long)ptr + off;
16
17	if (unlikely(member_offset + size > eb->len)) {
18		btrfs_warn(eb->fs_info,
19		"bad eb member %s: ptr 0x%lx start %llu member offset %lu size %d",
20			(member_offset > eb->len ? "start" : "end"),
21			(unsigned long)ptr, eb->start, member_offset, size);
22		return false;
23	}
24
25	return true;
26}
27
28void btrfs_init_map_token(struct btrfs_map_token *token, struct extent_buffer *eb)
29{
30	token->eb = eb;
31	token->kaddr = folio_address(eb->folios[0]);
32	token->offset = 0;
33}
34
35/*
36 * Macro templates that define helpers to read/write extent buffer data of a
37 * given size, that are also used via ctree.h for access to item members by
38 * specialized helpers.
39 *
40 * Generic helpers:
41 * - btrfs_set_8 (for 8/16/32/64)
42 * - btrfs_get_8 (for 8/16/32/64)
43 *
44 * Generic helpers with a token (cached address of the most recently accessed
45 * page):
46 * - btrfs_set_token_8 (for 8/16/32/64)
47 * - btrfs_get_token_8 (for 8/16/32/64)
48 *
49 * The set/get functions handle data spanning two pages transparently, in case
50 * metadata block size is larger than page.  Every pointer to metadata items is
51 * an offset into the extent buffer page array, cast to a specific type.  This
52 * gives us all the type checking.
53 *
54 * The extent buffer pages stored in the array folios may not form a contiguous
55 * phyusical range, but the API functions assume the linear offset to the range
56 * from 0 to metadata node size.
57 */
58
59#define DEFINE_BTRFS_SETGET_BITS(bits)					\
60u##bits btrfs_get_token_##bits(struct btrfs_map_token *token,		\
61			       const void *ptr, unsigned long off)	\
62{									\
63	const unsigned long member_offset = (unsigned long)ptr + off;	\
64	const unsigned long idx = get_eb_folio_index(token->eb, member_offset); \
65	const unsigned long oil = get_eb_offset_in_folio(token->eb,	\
66							 member_offset);\
67	const int unit_size = token->eb->folio_size;			\
68	const int unit_shift = token->eb->folio_shift;			\
69	const int size = sizeof(u##bits);				\
70	u8 lebytes[sizeof(u##bits)];					\
71	const int part = unit_size - oil;				\
72									\
73	ASSERT(token);							\
74	ASSERT(token->kaddr);						\
75	ASSERT(check_setget_bounds(token->eb, ptr, off, size));		\
76	if (token->offset <= member_offset &&				\
77	    member_offset + size <= token->offset + unit_size) {	\
78		return get_unaligned_le##bits(token->kaddr + oil);	\
79	}								\
80	token->kaddr = folio_address(token->eb->folios[idx]);		\
81	token->offset = idx << unit_shift;				\
82	if (INLINE_EXTENT_BUFFER_PAGES == 1 || oil + size <= unit_size) \
83		return get_unaligned_le##bits(token->kaddr + oil);	\
84									\
85	memcpy(lebytes, token->kaddr + oil, part);			\
86	token->kaddr = folio_address(token->eb->folios[idx + 1]);	\
87	token->offset = (idx + 1) << unit_shift;			\
88	memcpy(lebytes + part, token->kaddr, size - part);		\
89	return get_unaligned_le##bits(lebytes);				\
90}									\
91u##bits btrfs_get_##bits(const struct extent_buffer *eb,		\
92			 const void *ptr, unsigned long off)		\
93{									\
94	const unsigned long member_offset = (unsigned long)ptr + off;	\
95	const unsigned long idx = get_eb_folio_index(eb, member_offset);\
96	const unsigned long oil = get_eb_offset_in_folio(eb,		\
97							 member_offset);\
98	const int unit_size = eb->folio_size;				\
99	char *kaddr = folio_address(eb->folios[idx]);			\
100	const int size = sizeof(u##bits);				\
101	const int part = unit_size - oil;				\
102	u8 lebytes[sizeof(u##bits)];					\
103									\
104	ASSERT(check_setget_bounds(eb, ptr, off, size));		\
105	if (INLINE_EXTENT_BUFFER_PAGES == 1 || oil + size <= unit_size)	\
106		return get_unaligned_le##bits(kaddr + oil);		\
107									\
108	memcpy(lebytes, kaddr + oil, part);				\
109	kaddr = folio_address(eb->folios[idx + 1]);			\
110	memcpy(lebytes + part, kaddr, size - part);			\
111	return get_unaligned_le##bits(lebytes);				\
112}									\
113void btrfs_set_token_##bits(struct btrfs_map_token *token,		\
114			    const void *ptr, unsigned long off,		\
115			    u##bits val)				\
116{									\
117	const unsigned long member_offset = (unsigned long)ptr + off;	\
118	const unsigned long idx = get_eb_folio_index(token->eb, member_offset); \
119	const unsigned long oil = get_eb_offset_in_folio(token->eb,	\
120							 member_offset);\
121	const int unit_size = token->eb->folio_size;			\
122	const int unit_shift = token->eb->folio_shift;			\
123	const int size = sizeof(u##bits);				\
124	u8 lebytes[sizeof(u##bits)];					\
125	const int part = unit_size - oil;				\
126									\
127	ASSERT(token);							\
128	ASSERT(token->kaddr);						\
129	ASSERT(check_setget_bounds(token->eb, ptr, off, size));		\
130	if (token->offset <= member_offset &&				\
131	    member_offset + size <= token->offset + unit_size) {	\
132		put_unaligned_le##bits(val, token->kaddr + oil);	\
133		return;							\
134	}								\
135	token->kaddr = folio_address(token->eb->folios[idx]);		\
136	token->offset = idx << unit_shift;				\
137	if (INLINE_EXTENT_BUFFER_PAGES == 1 ||				\
138	    oil + size <= unit_size) {					\
139		put_unaligned_le##bits(val, token->kaddr + oil);	\
140		return;							\
141	}								\
142	put_unaligned_le##bits(val, lebytes);				\
143	memcpy(token->kaddr + oil, lebytes, part);			\
144	token->kaddr = folio_address(token->eb->folios[idx + 1]);	\
145	token->offset = (idx + 1) << unit_shift;			\
146	memcpy(token->kaddr, lebytes + part, size - part);		\
147}									\
148void btrfs_set_##bits(const struct extent_buffer *eb, void *ptr,	\
149		      unsigned long off, u##bits val)			\
150{									\
151	const unsigned long member_offset = (unsigned long)ptr + off;	\
152	const unsigned long idx = get_eb_folio_index(eb, member_offset);\
153	const unsigned long oil = get_eb_offset_in_folio(eb,		\
154							 member_offset);\
155	const int unit_size = eb->folio_size;				\
156	char *kaddr = folio_address(eb->folios[idx]);			\
157	const int size = sizeof(u##bits);				\
158	const int part = unit_size - oil;				\
159	u8 lebytes[sizeof(u##bits)];					\
160									\
161	ASSERT(check_setget_bounds(eb, ptr, off, size));		\
162	if (INLINE_EXTENT_BUFFER_PAGES == 1 ||				\
163	    oil + size <= unit_size) {					\
164		put_unaligned_le##bits(val, kaddr + oil);		\
165		return;							\
166	}								\
167									\
168	put_unaligned_le##bits(val, lebytes);				\
169	memcpy(kaddr + oil, lebytes, part);				\
170	kaddr = folio_address(eb->folios[idx + 1]);			\
171	memcpy(kaddr, lebytes + part, size - part);			\
172}
173
174DEFINE_BTRFS_SETGET_BITS(8)
175DEFINE_BTRFS_SETGET_BITS(16)
176DEFINE_BTRFS_SETGET_BITS(32)
177DEFINE_BTRFS_SETGET_BITS(64)
178
179void btrfs_node_key(const struct extent_buffer *eb,
180		    struct btrfs_disk_key *disk_key, int nr)
181{
182	unsigned long ptr = btrfs_node_key_ptr_offset(eb, nr);
183	read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
184		       struct btrfs_key_ptr, key, disk_key);
185}
186