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