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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#include <asm/unaligned.h>
#include "ctree.h"
static inline u8 get_unaligned_le8(const void *p)
{
return *(u8 *)p;
}
static inline void put_unaligned_le8(u8 val, void *p)
{
*(u8 *)p = val;
}
static bool check_setget_bounds(const struct extent_buffer *eb,
const void *ptr, unsigned off, int size)
{
const unsigned long member_offset = (unsigned long)ptr + off;
if (member_offset > eb->len) {
btrfs_warn(eb->fs_info,
"bad eb member start: ptr 0x%lx start %llu member offset %lu size %d",
(unsigned long)ptr, eb->start, member_offset, size);
return false;
}
if (member_offset + size > eb->len) {
btrfs_warn(eb->fs_info,
"bad eb member end: ptr 0x%lx start %llu member offset %lu size %d",
(unsigned long)ptr, eb->start, member_offset, size);
return false;
}
return true;
}
/*
* this is some deeply nasty code.
*
* The end result is that anyone who #includes ctree.h gets a
* declaration for the btrfs_set_foo functions and btrfs_foo functions,
* which are wrappers of btrfs_set_token_#bits functions and
* btrfs_get_token_#bits functions, which are defined in this file.
*
* These setget functions do all the extent_buffer related mapping
* required to efficiently read and write specific fields in the extent
* buffers. Every pointer to metadata items in btrfs is really just
* an unsigned long offset into the extent buffer which has been
* cast to a specific type. This gives us all the gcc type checking.
*
* The extent buffer api is used to do the page spanning work required to
* have a metadata blocksize different from the page size.
*
* There are 2 variants defined, one with a token pointer and one without.
*/
#define DEFINE_BTRFS_SETGET_BITS(bits) \
u##bits btrfs_get_token_##bits(struct btrfs_map_token *token, \
const void *ptr, unsigned long off) \
{ \
const unsigned long member_offset = (unsigned long)ptr + off; \
const unsigned long idx = member_offset >> PAGE_SHIFT; \
const unsigned long oip = offset_in_page(member_offset); \
const int size = sizeof(u##bits); \
u8 lebytes[sizeof(u##bits)]; \
const int part = PAGE_SIZE - oip; \
\
ASSERT(token); \
ASSERT(token->kaddr); \
ASSERT(check_setget_bounds(token->eb, ptr, off, size)); \
if (token->offset <= member_offset && \
member_offset + size <= token->offset + PAGE_SIZE) { \
return get_unaligned_le##bits(token->kaddr + oip); \
} \
token->kaddr = page_address(token->eb->pages[idx]); \
token->offset = idx << PAGE_SHIFT; \
if (oip + size <= PAGE_SIZE) \
return get_unaligned_le##bits(token->kaddr + oip); \
\
memcpy(lebytes, token->kaddr + oip, part); \
token->kaddr = page_address(token->eb->pages[idx + 1]); \
token->offset = (idx + 1) << PAGE_SHIFT; \
memcpy(lebytes + part, token->kaddr, size - part); \
return get_unaligned_le##bits(lebytes); \
} \
u##bits btrfs_get_##bits(const struct extent_buffer *eb, \
const void *ptr, unsigned long off) \
{ \
const unsigned long member_offset = (unsigned long)ptr + off; \
const unsigned long oip = offset_in_page(member_offset); \
const unsigned long idx = member_offset >> PAGE_SHIFT; \
char *kaddr = page_address(eb->pages[idx]); \
const int size = sizeof(u##bits); \
const int part = PAGE_SIZE - oip; \
u8 lebytes[sizeof(u##bits)]; \
\
ASSERT(check_setget_bounds(eb, ptr, off, size)); \
if (oip + size <= PAGE_SIZE) \
return get_unaligned_le##bits(kaddr + oip); \
\
memcpy(lebytes, kaddr + oip, part); \
kaddr = page_address(eb->pages[idx + 1]); \
memcpy(lebytes + part, kaddr, size - part); \
return get_unaligned_le##bits(lebytes); \
} \
void btrfs_set_token_##bits(struct btrfs_map_token *token, \
const void *ptr, unsigned long off, \
u##bits val) \
{ \
const unsigned long member_offset = (unsigned long)ptr + off; \
const unsigned long idx = member_offset >> PAGE_SHIFT; \
const unsigned long oip = offset_in_page(member_offset); \
const int size = sizeof(u##bits); \
__le##bits leres; \
\
ASSERT(token); \
ASSERT(token->kaddr); \
ASSERT(check_setget_bounds(token->eb, ptr, off, size)); \
if (token->offset <= member_offset && \
member_offset + size <= token->offset + PAGE_SIZE) { \
put_unaligned_le##bits(val, token->kaddr + oip); \
return; \
} \
if (oip + size <= PAGE_SIZE) { \
token->kaddr = page_address(token->eb->pages[idx]); \
token->offset = idx << PAGE_SHIFT; \
put_unaligned_le##bits(val, token->kaddr + oip); \
return; \
} \
token->kaddr = page_address(token->eb->pages[idx + 1]); \
token->offset = (idx + 1) << PAGE_SHIFT; \
leres = cpu_to_le##bits(val); \
write_extent_buffer(token->eb, &leres, member_offset, size); \
} \
void btrfs_set_##bits(const struct extent_buffer *eb, void *ptr, \
unsigned long off, u##bits val) \
{ \
const unsigned long member_offset = (unsigned long)ptr + off; \
const unsigned long oip = offset_in_page(member_offset); \
const int size = sizeof(u##bits); \
__le##bits leres; \
\
ASSERT(check_setget_bounds(eb, ptr, off, size)); \
if (oip + size <= PAGE_SIZE) { \
const unsigned long idx = member_offset >> PAGE_SHIFT; \
char *kaddr = page_address(eb->pages[idx]); \
put_unaligned_le##bits(val, kaddr + oip); \
return; \
} \
leres = cpu_to_le##bits(val); \
write_extent_buffer(eb, &leres, member_offset, size); \
}
DEFINE_BTRFS_SETGET_BITS(8)
DEFINE_BTRFS_SETGET_BITS(16)
DEFINE_BTRFS_SETGET_BITS(32)
DEFINE_BTRFS_SETGET_BITS(64)
void btrfs_node_key(const struct extent_buffer *eb,
struct btrfs_disk_key *disk_key, int nr)
{
unsigned long ptr = btrfs_node_key_ptr_offset(nr);
read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
struct btrfs_key_ptr, key, disk_key);
}
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