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
check_setget_bounds(const struct extent_buffer * eb,const void * ptr,unsigned off,int size)10 static 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) \
56 u##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 (INLINE_EXTENT_BUFFER_PAGES == 1 || 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 } \
85 u##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 (INLINE_EXTENT_BUFFER_PAGES == 1 || 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 } \
105 void 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 (INLINE_EXTENT_BUFFER_PAGES == 1 || 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 } \
137 void 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 (INLINE_EXTENT_BUFFER_PAGES == 1 || 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
160 DEFINE_BTRFS_SETGET_BITS(8)
161 DEFINE_BTRFS_SETGET_BITS(16)
162 DEFINE_BTRFS_SETGET_BITS(32)
163 DEFINE_BTRFS_SETGET_BITS(64)
164
btrfs_node_key(const struct extent_buffer * eb,struct btrfs_disk_key * disk_key,int nr)165 void 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 }
172
