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 "ctree.h" 9 #include "accessors.h" 10 11 static bool check_setget_bounds(const struct extent_buffer *eb, 12 const void *ptr, unsigned off, int size) 13 { 14 const unsigned long member_offset = (unsigned long)ptr + off; 15 16 if (unlikely(member_offset + size > eb->len)) { 17 btrfs_warn(eb->fs_info, 18 "bad eb member %s: ptr 0x%lx start %llu member offset %lu size %d", 19 (member_offset > eb->len ? "start" : "end"), 20 (unsigned long)ptr, eb->start, member_offset, size); 21 return false; 22 } 23 24 return true; 25 } 26 27 void btrfs_init_map_token(struct btrfs_map_token *token, struct extent_buffer *eb) 28 { 29 token->eb = eb; 30 token->kaddr = folio_address(eb->folios[0]); 31 token->offset = 0; 32 } 33 34 /* 35 * Macro templates that define helpers to read/write extent buffer data of a 36 * given size, that are also used via ctree.h for access to item members by 37 * specialized helpers. 38 * 39 * Generic helpers: 40 * - btrfs_set_8 (for 8/16/32/64) 41 * - btrfs_get_8 (for 8/16/32/64) 42 * 43 * Generic helpers with a token (cached address of the most recently accessed 44 * page): 45 * - btrfs_set_token_8 (for 8/16/32/64) 46 * - btrfs_get_token_8 (for 8/16/32/64) 47 * 48 * The set/get functions handle data spanning two pages transparently, in case 49 * metadata block size is larger than page. Every pointer to metadata items is 50 * an offset into the extent buffer page array, cast to a specific type. This 51 * gives us all the type checking. 52 * 53 * The extent buffer pages stored in the array folios may not form a contiguous 54 * phyusical range, but the API functions assume the linear offset to the range 55 * from 0 to metadata node size. 56 */ 57 58 #define DEFINE_BTRFS_SETGET_BITS(bits) \ 59 u##bits btrfs_get_token_##bits(struct btrfs_map_token *token, \ 60 const void *ptr, unsigned long off) \ 61 { \ 62 const unsigned long member_offset = (unsigned long)ptr + off; \ 63 const unsigned long idx = get_eb_folio_index(token->eb, member_offset); \ 64 const unsigned long oil = get_eb_offset_in_folio(token->eb, \ 65 member_offset);\ 66 const int unit_size = folio_size(token->eb->folios[0]); \ 67 const int unit_shift = folio_shift(token->eb->folios[0]); \ 68 const int size = sizeof(u##bits); \ 69 u8 lebytes[sizeof(u##bits)]; \ 70 const int part = unit_size - oil; \ 71 \ 72 ASSERT(token); \ 73 ASSERT(token->kaddr); \ 74 ASSERT(check_setget_bounds(token->eb, ptr, off, size)); \ 75 if (token->offset <= member_offset && \ 76 member_offset + size <= token->offset + unit_size) { \ 77 return get_unaligned_le##bits(token->kaddr + oil); \ 78 } \ 79 token->kaddr = folio_address(token->eb->folios[idx]); \ 80 token->offset = idx << unit_shift; \ 81 if (INLINE_EXTENT_BUFFER_PAGES == 1 || oil + size <= unit_size) \ 82 return get_unaligned_le##bits(token->kaddr + oil); \ 83 \ 84 memcpy(lebytes, token->kaddr + oil, part); \ 85 token->kaddr = folio_address(token->eb->folios[idx + 1]); \ 86 token->offset = (idx + 1) << unit_shift; \ 87 memcpy(lebytes + part, token->kaddr, size - part); \ 88 return get_unaligned_le##bits(lebytes); \ 89 } \ 90 u##bits btrfs_get_##bits(const struct extent_buffer *eb, \ 91 const void *ptr, unsigned long off) \ 92 { \ 93 const unsigned long member_offset = (unsigned long)ptr + off; \ 94 const unsigned long idx = get_eb_folio_index(eb, member_offset);\ 95 const unsigned long oil = get_eb_offset_in_folio(eb, \ 96 member_offset);\ 97 const int unit_size = folio_size(eb->folios[0]); \ 98 char *kaddr = folio_address(eb->folios[idx]); \ 99 const int size = sizeof(u##bits); \ 100 const int part = unit_size - oil; \ 101 u8 lebytes[sizeof(u##bits)]; \ 102 \ 103 ASSERT(check_setget_bounds(eb, ptr, off, size)); \ 104 if (INLINE_EXTENT_BUFFER_PAGES == 1 || oil + size <= unit_size) \ 105 return get_unaligned_le##bits(kaddr + oil); \ 106 \ 107 memcpy(lebytes, kaddr + oil, part); \ 108 kaddr = folio_address(eb->folios[idx + 1]); \ 109 memcpy(lebytes + part, kaddr, size - part); \ 110 return get_unaligned_le##bits(lebytes); \ 111 } \ 112 void btrfs_set_token_##bits(struct btrfs_map_token *token, \ 113 const void *ptr, unsigned long off, \ 114 u##bits val) \ 115 { \ 116 const unsigned long member_offset = (unsigned long)ptr + off; \ 117 const unsigned long idx = get_eb_folio_index(token->eb, member_offset); \ 118 const unsigned long oil = get_eb_offset_in_folio(token->eb, \ 119 member_offset);\ 120 const int unit_size = folio_size(token->eb->folios[0]); \ 121 const int unit_shift = folio_shift(token->eb->folios[0]); \ 122 const int size = sizeof(u##bits); \ 123 u8 lebytes[sizeof(u##bits)]; \ 124 const int part = unit_size - oil; \ 125 \ 126 ASSERT(token); \ 127 ASSERT(token->kaddr); \ 128 ASSERT(check_setget_bounds(token->eb, ptr, off, size)); \ 129 if (token->offset <= member_offset && \ 130 member_offset + size <= token->offset + unit_size) { \ 131 put_unaligned_le##bits(val, token->kaddr + oil); \ 132 return; \ 133 } \ 134 token->kaddr = folio_address(token->eb->folios[idx]); \ 135 token->offset = idx << unit_shift; \ 136 if (INLINE_EXTENT_BUFFER_PAGES == 1 || \ 137 oil + size <= unit_size) { \ 138 put_unaligned_le##bits(val, token->kaddr + oil); \ 139 return; \ 140 } \ 141 put_unaligned_le##bits(val, lebytes); \ 142 memcpy(token->kaddr + oil, lebytes, part); \ 143 token->kaddr = folio_address(token->eb->folios[idx + 1]); \ 144 token->offset = (idx + 1) << unit_shift; \ 145 memcpy(token->kaddr, lebytes + part, size - part); \ 146 } \ 147 void btrfs_set_##bits(const struct extent_buffer *eb, void *ptr, \ 148 unsigned long off, u##bits val) \ 149 { \ 150 const unsigned long member_offset = (unsigned long)ptr + off; \ 151 const unsigned long idx = get_eb_folio_index(eb, member_offset);\ 152 const unsigned long oil = get_eb_offset_in_folio(eb, \ 153 member_offset);\ 154 const int unit_size = folio_size(eb->folios[0]); \ 155 char *kaddr = folio_address(eb->folios[idx]); \ 156 const int size = sizeof(u##bits); \ 157 const int part = unit_size - oil; \ 158 u8 lebytes[sizeof(u##bits)]; \ 159 \ 160 ASSERT(check_setget_bounds(eb, ptr, off, size)); \ 161 if (INLINE_EXTENT_BUFFER_PAGES == 1 || \ 162 oil + size <= unit_size) { \ 163 put_unaligned_le##bits(val, kaddr + oil); \ 164 return; \ 165 } \ 166 \ 167 put_unaligned_le##bits(val, lebytes); \ 168 memcpy(kaddr + oil, lebytes, part); \ 169 kaddr = folio_address(eb->folios[idx + 1]); \ 170 memcpy(kaddr, lebytes + part, size - part); \ 171 } 172 173 DEFINE_BTRFS_SETGET_BITS(8) 174 DEFINE_BTRFS_SETGET_BITS(16) 175 DEFINE_BTRFS_SETGET_BITS(32) 176 DEFINE_BTRFS_SETGET_BITS(64) 177 178 void btrfs_node_key(const struct extent_buffer *eb, 179 struct btrfs_disk_key *disk_key, int nr) 180 { 181 unsigned long ptr = btrfs_node_key_ptr_offset(eb, nr); 182 read_eb_member(eb, (struct btrfs_key_ptr *)ptr, 183 struct btrfs_key_ptr, key, disk_key); 184 } 185