fs/btrfs/struct-funcs.c

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