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1/*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/highmem.h>
20
21/* this is some deeply nasty code. ctree.h has a different
22 * definition for this BTRFS_SETGET_FUNCS macro, behind a #ifndef
23 *
24 * The end result is that anyone who #includes ctree.h gets a
25 * declaration for the btrfs_set_foo functions and btrfs_foo functions
26 *
27 * This file declares the macros and then #includes ctree.h, which results
28 * in cpp creating the function here based on the template below.
29 *
30 * These setget functions do all the extent_buffer related mapping
31 * required to efficiently read and write specific fields in the extent
32 * buffers. Every pointer to metadata items in btrfs is really just
33 * an unsigned long offset into the extent buffer which has been
34 * cast to a specific type. This gives us all the gcc type checking.
35 *
36 * The extent buffer api is used to do all the kmapping and page
37 * spanning work required to get extent buffers in highmem and have
38 * a metadata blocksize different from the page size.
39 *
40 * The macro starts with a simple function prototype declaration so that
41 * sparse won't complain about it being static.
42 */
43
44#define BTRFS_SETGET_FUNCS(name, type, member, bits) \
45u##bits btrfs_##name(struct extent_buffer *eb, type *s); \
46void btrfs_set_##name(struct extent_buffer *eb, type *s, u##bits val); \
47u##bits btrfs_##name(struct extent_buffer *eb, \
48 type *s) \
49{ \
50 unsigned long part_offset = (unsigned long)s; \
51 unsigned long offset = part_offset + offsetof(type, member); \
52 type *p; \
53 int err; \
54 char *kaddr; \
55 unsigned long map_start; \
56 unsigned long map_len; \
57 u##bits res; \
58 err = map_private_extent_buffer(eb, offset, \
59 sizeof(((type *)0)->member), \
60 &kaddr, &map_start, &map_len); \
61 if (err) { \
62 __le##bits leres; \
63 read_eb_member(eb, s, type, member, &leres); \
64 return le##bits##_to_cpu(leres); \
65 } \
66 p = (type *)(kaddr + part_offset - map_start); \
67 res = le##bits##_to_cpu(p->member); \
68 return res; \
69} \
70void btrfs_set_##name(struct extent_buffer *eb, \
71 type *s, u##bits val) \
72{ \
73 unsigned long part_offset = (unsigned long)s; \
74 unsigned long offset = part_offset + offsetof(type, member); \
75 type *p; \
76 int err; \
77 char *kaddr; \
78 unsigned long map_start; \
79 unsigned long map_len; \
80 err = map_private_extent_buffer(eb, offset, \
81 sizeof(((type *)0)->member), \
82 &kaddr, &map_start, &map_len); \
83 if (err) { \
84 __le##bits val2; \
85 val2 = cpu_to_le##bits(val); \
86 write_eb_member(eb, s, type, member, &val2); \
87 return; \
88 } \
89 p = (type *)(kaddr + part_offset - map_start); \
90 p->member = cpu_to_le##bits(val); \
91}
92
93#include "ctree.h"
94
95void btrfs_node_key(struct extent_buffer *eb,
96 struct btrfs_disk_key *disk_key, int nr)
97{
98 unsigned long ptr = btrfs_node_key_ptr_offset(nr);
99 read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
100 struct btrfs_key_ptr, key, disk_key);
101}
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}