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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#include <linux/unaligned.h>
#include "messages.h"
#include "extent_io.h"
#include "fs.h"
#include "accessors.h"
static void __cold report_setget_bounds(const struct extent_buffer *eb,
const void *ptr, unsigned off, int size)
{
unsigned long member_offset = (unsigned long)ptr + off;
btrfs_warn(eb->fs_info,
"bad eb member %s: ptr 0x%lx start %llu member offset %lu size %d",
(member_offset > eb->len ? "start" : "end"),
(unsigned long)ptr, eb->start, member_offset, size);
}
/* Copy bytes from @src1 and @src2 to @dest. */
static __always_inline void memcpy_split_src(char *dest, const char *src1,
const char *src2, const size_t len1,
const size_t total)
{
memcpy(dest, src1, len1);
memcpy(dest + len1, src2, total - len1);
}
/*
* Macro templates that define helpers to read/write extent buffer data of a
* given size, that are also used via ctree.h for access to item members by
* specialized helpers.
*
* Generic helpers:
* - btrfs_set_8 (for 8/16/32/64)
* - btrfs_get_8 (for 8/16/32/64)
*
* The set/get functions handle data spanning two pages transparently, in case
* metadata block size is larger than page. Every pointer to metadata items is
* an offset into the extent buffer page array, cast to a specific type. This
* gives us all the type checking.
*
* The extent buffer pages stored in the array folios may not form a contiguous
* phyusical range, but the API functions assume the linear offset to the range
* from 0 to metadata node size.
*/
#define DEFINE_BTRFS_SETGET_BITS(bits) \
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 idx = get_eb_folio_index(eb, member_offset);\
const unsigned long oif = get_eb_offset_in_folio(eb, \
member_offset);\
char *kaddr = folio_address(eb->folios[idx]) + oif; \
const int part = eb->folio_size - oif; \
u8 lebytes[sizeof(u##bits)]; \
\
if (unlikely(member_offset + sizeof(u##bits) > eb->len)) { \
report_setget_bounds(eb, ptr, off, sizeof(u##bits)); \
return 0; \
} \
if (INLINE_EXTENT_BUFFER_PAGES == 1 || sizeof(u##bits) == 1 || \
likely(sizeof(u##bits) <= part)) \
return get_unaligned_le##bits(kaddr); \
\
if (sizeof(u##bits) == 2) { \
lebytes[0] = *kaddr; \
kaddr = folio_address(eb->folios[idx + 1]); \
lebytes[1] = *kaddr; \
} else { \
memcpy_split_src(lebytes, kaddr, \
folio_address(eb->folios[idx + 1]), \
part, sizeof(u##bits)); \
} \
return get_unaligned_le##bits(lebytes); \
} \
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 idx = get_eb_folio_index(eb, member_offset);\
const unsigned long oif = get_eb_offset_in_folio(eb, \
member_offset);\
char *kaddr = folio_address(eb->folios[idx]) + oif; \
const int part = eb->folio_size - oif; \
u8 lebytes[sizeof(u##bits)]; \
\
if (unlikely(member_offset + sizeof(u##bits) > eb->len)) { \
report_setget_bounds(eb, ptr, off, sizeof(u##bits)); \
return; \
} \
if (INLINE_EXTENT_BUFFER_PAGES == 1 || sizeof(u##bits) == 1 || \
likely(sizeof(u##bits) <= part)) { \
put_unaligned_le##bits(val, kaddr); \
return; \
} \
put_unaligned_le##bits(val, lebytes); \
if (sizeof(u##bits) == 2) { \
*kaddr = lebytes[0]; \
kaddr = folio_address(eb->folios[idx + 1]); \
*kaddr = lebytes[1]; \
} else { \
memcpy(kaddr, lebytes, part); \
kaddr = folio_address(eb->folios[idx + 1]); \
memcpy(kaddr, lebytes + part, sizeof(u##bits) - part); \
} \
}
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(eb, nr);
read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
struct btrfs_key_ptr, key, disk_key);
}
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