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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 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}