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
12 static 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
28 void 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) \
60 u##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 } \
91 u##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 } \
113 void 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 } \
148 void 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
174 DEFINE_BTRFS_SETGET_BITS(8)
175 DEFINE_BTRFS_SETGET_BITS(16)
176 DEFINE_BTRFS_SETGET_BITS(32)
177 DEFINE_BTRFS_SETGET_BITS(64)
178
179 void 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
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