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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Oracle. All rights reserved.
4 */
5
6#include <asm/unaligned.h>
7
8#include "ctree.h"
9
10static inline u8 get_unaligned_le8(const void *p)
11{
12 return *(u8 *)p;
13}
14
15static inline void put_unaligned_le8(u8 val, void *p)
16{
17 *(u8 *)p = val;
18}
19
20/*
21 * this is some deeply nasty code.
22 *
23 * The end result is that anyone who #includes ctree.h gets a
24 * declaration for the btrfs_set_foo functions and btrfs_foo functions,
25 * which are wrappers of btrfs_set_token_#bits functions and
26 * btrfs_get_token_#bits functions, which are defined in this file.
27 *
28 * These setget functions do all the extent_buffer related mapping
29 * required to efficiently read and write specific fields in the extent
30 * buffers. Every pointer to metadata items in btrfs is really just
31 * an unsigned long offset into the extent buffer which has been
32 * cast to a specific type. This gives us all the gcc type checking.
33 *
34 * The extent buffer api is used to do the page spanning work required to
35 * have a metadata blocksize different from the page size.
36 *
37 * There are 2 variants defined, one with a token pointer and one without.
38 */
39
40#define DEFINE_BTRFS_SETGET_BITS(bits) \
41u##bits btrfs_get_token_##bits(const struct extent_buffer *eb, \
42 const void *ptr, unsigned long off, \
43 struct btrfs_map_token *token) \
44{ \
45 unsigned long part_offset = (unsigned long)ptr; \
46 unsigned long offset = part_offset + off; \
47 void *p; \
48 int err; \
49 char *kaddr; \
50 unsigned long map_start; \
51 unsigned long map_len; \
52 int size = sizeof(u##bits); \
53 u##bits res; \
54 \
55 ASSERT(token); \
56 ASSERT(token->eb == eb); \
57 \
58 if (token->kaddr && token->offset <= offset && \
59 (token->offset + PAGE_SIZE >= offset + size)) { \
60 kaddr = token->kaddr; \
61 p = kaddr + part_offset - token->offset; \
62 res = get_unaligned_le##bits(p + off); \
63 return res; \
64 } \
65 err = map_private_extent_buffer(eb, offset, size, \
66 &kaddr, &map_start, &map_len); \
67 if (err) { \
68 __le##bits leres; \
69 \
70 read_extent_buffer(eb, &leres, offset, size); \
71 return le##bits##_to_cpu(leres); \
72 } \
73 p = kaddr + part_offset - map_start; \
74 res = get_unaligned_le##bits(p + off); \
75 token->kaddr = kaddr; \
76 token->offset = map_start; \
77 return res; \
78} \
79u##bits btrfs_get_##bits(const struct extent_buffer *eb, \
80 const void *ptr, unsigned long off) \
81{ \
82 unsigned long part_offset = (unsigned long)ptr; \
83 unsigned long offset = part_offset + off; \
84 void *p; \
85 int err; \
86 char *kaddr; \
87 unsigned long map_start; \
88 unsigned long map_len; \
89 int size = sizeof(u##bits); \
90 u##bits res; \
91 \
92 err = map_private_extent_buffer(eb, offset, size, \
93 &kaddr, &map_start, &map_len); \
94 if (err) { \
95 __le##bits leres; \
96 \
97 read_extent_buffer(eb, &leres, offset, size); \
98 return le##bits##_to_cpu(leres); \
99 } \
100 p = kaddr + part_offset - map_start; \
101 res = get_unaligned_le##bits(p + off); \
102 return res; \
103} \
104void btrfs_set_token_##bits(struct extent_buffer *eb, \
105 const void *ptr, unsigned long off, \
106 u##bits val, \
107 struct btrfs_map_token *token) \
108{ \
109 unsigned long part_offset = (unsigned long)ptr; \
110 unsigned long offset = part_offset + off; \
111 void *p; \
112 int err; \
113 char *kaddr; \
114 unsigned long map_start; \
115 unsigned long map_len; \
116 int size = sizeof(u##bits); \
117 \
118 ASSERT(token); \
119 ASSERT(token->eb == eb); \
120 \
121 if (token->kaddr && token->offset <= offset && \
122 (token->offset + PAGE_SIZE >= offset + size)) { \
123 kaddr = token->kaddr; \
124 p = kaddr + part_offset - token->offset; \
125 put_unaligned_le##bits(val, p + off); \
126 return; \
127 } \
128 err = map_private_extent_buffer(eb, offset, size, \
129 &kaddr, &map_start, &map_len); \
130 if (err) { \
131 __le##bits val2; \
132 \
133 val2 = cpu_to_le##bits(val); \
134 write_extent_buffer(eb, &val2, offset, size); \
135 return; \
136 } \
137 p = kaddr + part_offset - map_start; \
138 put_unaligned_le##bits(val, p + off); \
139 token->kaddr = kaddr; \
140 token->offset = map_start; \
141} \
142void btrfs_set_##bits(struct extent_buffer *eb, void *ptr, \
143 unsigned long off, u##bits val) \
144{ \
145 unsigned long part_offset = (unsigned long)ptr; \
146 unsigned long offset = part_offset + off; \
147 void *p; \
148 int err; \
149 char *kaddr; \
150 unsigned long map_start; \
151 unsigned long map_len; \
152 int size = sizeof(u##bits); \
153 \
154 err = map_private_extent_buffer(eb, offset, size, \
155 &kaddr, &map_start, &map_len); \
156 if (err) { \
157 __le##bits val2; \
158 \
159 val2 = cpu_to_le##bits(val); \
160 write_extent_buffer(eb, &val2, offset, size); \
161 return; \
162 } \
163 p = kaddr + part_offset - map_start; \
164 put_unaligned_le##bits(val, p + off); \
165}
166
167DEFINE_BTRFS_SETGET_BITS(8)
168DEFINE_BTRFS_SETGET_BITS(16)
169DEFINE_BTRFS_SETGET_BITS(32)
170DEFINE_BTRFS_SETGET_BITS(64)
171
172void btrfs_node_key(const struct extent_buffer *eb,
173 struct btrfs_disk_key *disk_key, int nr)
174{
175 unsigned long ptr = btrfs_node_key_ptr_offset(nr);
176 read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
177 struct btrfs_key_ptr, key, disk_key);
178}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Oracle. All rights reserved.
4 */
5
6#include <asm/unaligned.h>
7
8#include "ctree.h"
9
10static bool check_setget_bounds(const struct extent_buffer *eb,
11 const void *ptr, unsigned off, int size)
12{
13 const unsigned long member_offset = (unsigned long)ptr + off;
14
15 if (member_offset > eb->len) {
16 btrfs_warn(eb->fs_info,
17 "bad eb member start: ptr 0x%lx start %llu member offset %lu size %d",
18 (unsigned long)ptr, eb->start, member_offset, size);
19 return false;
20 }
21 if (member_offset + size > eb->len) {
22 btrfs_warn(eb->fs_info,
23 "bad eb member end: ptr 0x%lx start %llu member offset %lu size %d",
24 (unsigned long)ptr, eb->start, member_offset, size);
25 return false;
26 }
27
28 return true;
29}
30
31/*
32 * Macro templates that define helpers to read/write extent buffer data of a
33 * given size, that are also used via ctree.h for access to item members by
34 * specialized helpers.
35 *
36 * Generic helpers:
37 * - btrfs_set_8 (for 8/16/32/64)
38 * - btrfs_get_8 (for 8/16/32/64)
39 *
40 * Generic helpers with a token (cached address of the most recently accessed
41 * page):
42 * - btrfs_set_token_8 (for 8/16/32/64)
43 * - btrfs_get_token_8 (for 8/16/32/64)
44 *
45 * The set/get functions handle data spanning two pages transparently, in case
46 * metadata block size is larger than page. Every pointer to metadata items is
47 * an offset into the extent buffer page array, cast to a specific type. This
48 * gives us all the type checking.
49 *
50 * The extent buffer pages stored in the array pages do not form a contiguous
51 * phyusical range, but the API functions assume the linear offset to the range
52 * from 0 to metadata node size.
53 */
54
55#define DEFINE_BTRFS_SETGET_BITS(bits) \
56u##bits btrfs_get_token_##bits(struct btrfs_map_token *token, \
57 const void *ptr, unsigned long off) \
58{ \
59 const unsigned long member_offset = (unsigned long)ptr + off; \
60 const unsigned long idx = get_eb_page_index(member_offset); \
61 const unsigned long oip = get_eb_offset_in_page(token->eb, \
62 member_offset); \
63 const int size = sizeof(u##bits); \
64 u8 lebytes[sizeof(u##bits)]; \
65 const int part = PAGE_SIZE - oip; \
66 \
67 ASSERT(token); \
68 ASSERT(token->kaddr); \
69 ASSERT(check_setget_bounds(token->eb, ptr, off, size)); \
70 if (token->offset <= member_offset && \
71 member_offset + size <= token->offset + PAGE_SIZE) { \
72 return get_unaligned_le##bits(token->kaddr + oip); \
73 } \
74 token->kaddr = page_address(token->eb->pages[idx]); \
75 token->offset = idx << PAGE_SHIFT; \
76 if (oip + size <= PAGE_SIZE) \
77 return get_unaligned_le##bits(token->kaddr + oip); \
78 \
79 memcpy(lebytes, token->kaddr + oip, part); \
80 token->kaddr = page_address(token->eb->pages[idx + 1]); \
81 token->offset = (idx + 1) << PAGE_SHIFT; \
82 memcpy(lebytes + part, token->kaddr, size - part); \
83 return get_unaligned_le##bits(lebytes); \
84} \
85u##bits btrfs_get_##bits(const struct extent_buffer *eb, \
86 const void *ptr, unsigned long off) \
87{ \
88 const unsigned long member_offset = (unsigned long)ptr + off; \
89 const unsigned long oip = get_eb_offset_in_page(eb, member_offset); \
90 const unsigned long idx = get_eb_page_index(member_offset); \
91 char *kaddr = page_address(eb->pages[idx]); \
92 const int size = sizeof(u##bits); \
93 const int part = PAGE_SIZE - oip; \
94 u8 lebytes[sizeof(u##bits)]; \
95 \
96 ASSERT(check_setget_bounds(eb, ptr, off, size)); \
97 if (oip + size <= PAGE_SIZE) \
98 return get_unaligned_le##bits(kaddr + oip); \
99 \
100 memcpy(lebytes, kaddr + oip, part); \
101 kaddr = page_address(eb->pages[idx + 1]); \
102 memcpy(lebytes + part, kaddr, size - part); \
103 return get_unaligned_le##bits(lebytes); \
104} \
105void btrfs_set_token_##bits(struct btrfs_map_token *token, \
106 const void *ptr, unsigned long off, \
107 u##bits val) \
108{ \
109 const unsigned long member_offset = (unsigned long)ptr + off; \
110 const unsigned long idx = get_eb_page_index(member_offset); \
111 const unsigned long oip = get_eb_offset_in_page(token->eb, \
112 member_offset); \
113 const int size = sizeof(u##bits); \
114 u8 lebytes[sizeof(u##bits)]; \
115 const int part = PAGE_SIZE - oip; \
116 \
117 ASSERT(token); \
118 ASSERT(token->kaddr); \
119 ASSERT(check_setget_bounds(token->eb, ptr, off, size)); \
120 if (token->offset <= member_offset && \
121 member_offset + size <= token->offset + PAGE_SIZE) { \
122 put_unaligned_le##bits(val, token->kaddr + oip); \
123 return; \
124 } \
125 token->kaddr = page_address(token->eb->pages[idx]); \
126 token->offset = idx << PAGE_SHIFT; \
127 if (oip + size <= PAGE_SIZE) { \
128 put_unaligned_le##bits(val, token->kaddr + oip); \
129 return; \
130 } \
131 put_unaligned_le##bits(val, lebytes); \
132 memcpy(token->kaddr + oip, lebytes, part); \
133 token->kaddr = page_address(token->eb->pages[idx + 1]); \
134 token->offset = (idx + 1) << PAGE_SHIFT; \
135 memcpy(token->kaddr, lebytes + part, size - part); \
136} \
137void btrfs_set_##bits(const struct extent_buffer *eb, void *ptr, \
138 unsigned long off, u##bits val) \
139{ \
140 const unsigned long member_offset = (unsigned long)ptr + off; \
141 const unsigned long oip = get_eb_offset_in_page(eb, member_offset); \
142 const unsigned long idx = get_eb_page_index(member_offset); \
143 char *kaddr = page_address(eb->pages[idx]); \
144 const int size = sizeof(u##bits); \
145 const int part = PAGE_SIZE - oip; \
146 u8 lebytes[sizeof(u##bits)]; \
147 \
148 ASSERT(check_setget_bounds(eb, ptr, off, size)); \
149 if (oip + size <= PAGE_SIZE) { \
150 put_unaligned_le##bits(val, kaddr + oip); \
151 return; \
152 } \
153 \
154 put_unaligned_le##bits(val, lebytes); \
155 memcpy(kaddr + oip, lebytes, part); \
156 kaddr = page_address(eb->pages[idx + 1]); \
157 memcpy(kaddr, lebytes + part, size - part); \
158}
159
160DEFINE_BTRFS_SETGET_BITS(8)
161DEFINE_BTRFS_SETGET_BITS(16)
162DEFINE_BTRFS_SETGET_BITS(32)
163DEFINE_BTRFS_SETGET_BITS(64)
164
165void btrfs_node_key(const struct extent_buffer *eb,
166 struct btrfs_disk_key *disk_key, int nr)
167{
168 unsigned long ptr = btrfs_node_key_ptr_offset(nr);
169 read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
170 struct btrfs_key_ptr, key, disk_key);
171}