linux/fs/btrfs/accessors.c
Qu Wenruo 8d99361835 btrfs: migrate get_eb_page_index() and get_eb_offset_in_page() to folios
These two functions are still using the old page based code, which is
not going to handle larger folios at all.

The migration itself is going to involve the following changes:

- PAGE_SIZE -> folio_size()
- PAGE_SHIFT -> folio_shift()
- get_eb_page_index() -> get_eb_folio_index()
- get_eb_offset_in_page() -> get_eb_offset_in_folio()

And since we're going to support larger folios, although above straight
conversion is good enough, this patch would add extra comments in the
involved functions to explain why the same single line code can now
cover 3 cases:

- folio_size == PAGE_SIZE, sectorsize == PAGE_SIZE, nodesize >= PAGE_SIZE
  The common, non-subpage case with per-page folio.

- folio_size > PAGE_SIZE, sectorsize == PAGE_SIZE, nodesize >= PAGE_SIZE
  The incoming larger folio, non-subpage case.

- folio_size == PAGE_SIZE, sectorsize < PAGE_SIZE, nodesize < PAGE_SIZE
  The existing subpage case, we won't larger folio anyway.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 23:03:58 +01:00

185 lines
6.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#include <asm/unaligned.h>
#include "messages.h"
#include "ctree.h"
#include "accessors.h"
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 (unlikely(member_offset + size > eb->len)) {
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);
return false;
}
return true;
}
void btrfs_init_map_token(struct btrfs_map_token *token, struct extent_buffer *eb)
{
token->eb = eb;
token->kaddr = folio_address(eb->folios[0]);
token->offset = 0;
}
/*
* 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)
*
* Generic helpers with a token (cached address of the most recently accessed
* page):
* - btrfs_set_token_8 (for 8/16/32/64)
* - btrfs_get_token_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_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 = get_eb_folio_index(token->eb, member_offset); \
const unsigned long oil = get_eb_offset_in_folio(token->eb, \
member_offset);\
const int unit_size = folio_size(token->eb->folios[0]); \
const int unit_shift = folio_shift(token->eb->folios[0]); \
const int size = sizeof(u##bits); \
u8 lebytes[sizeof(u##bits)]; \
const int part = unit_size - oil; \
\
ASSERT(token); \
ASSERT(token->kaddr); \
ASSERT(check_setget_bounds(token->eb, ptr, off, size)); \
if (token->offset <= member_offset && \
member_offset + size <= token->offset + unit_size) { \
return get_unaligned_le##bits(token->kaddr + oil); \
} \
token->kaddr = folio_address(token->eb->folios[idx]); \
token->offset = idx << unit_shift; \
if (INLINE_EXTENT_BUFFER_PAGES == 1 || oil + size <= unit_size) \
return get_unaligned_le##bits(token->kaddr + oil); \
\
memcpy(lebytes, token->kaddr + oil, part); \
token->kaddr = folio_address(token->eb->folios[idx + 1]); \
token->offset = (idx + 1) << unit_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 idx = get_eb_folio_index(eb, member_offset);\
const unsigned long oil = get_eb_offset_in_folio(eb, \
member_offset);\
const int unit_size = folio_size(eb->folios[0]); \
char *kaddr = folio_address(eb->folios[idx]); \
const int size = sizeof(u##bits); \
const int part = unit_size - oil; \
u8 lebytes[sizeof(u##bits)]; \
\
ASSERT(check_setget_bounds(eb, ptr, off, size)); \
if (INLINE_EXTENT_BUFFER_PAGES == 1 || oil + size <= unit_size) \
return get_unaligned_le##bits(kaddr + oil); \
\
memcpy(lebytes, kaddr + oil, part); \
kaddr = folio_address(eb->folios[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 = get_eb_folio_index(token->eb, member_offset); \
const unsigned long oil = get_eb_offset_in_folio(token->eb, \
member_offset);\
const int unit_size = folio_size(token->eb->folios[0]); \
const int unit_shift = folio_shift(token->eb->folios[0]); \
const int size = sizeof(u##bits); \
u8 lebytes[sizeof(u##bits)]; \
const int part = unit_size - oil; \
\
ASSERT(token); \
ASSERT(token->kaddr); \
ASSERT(check_setget_bounds(token->eb, ptr, off, size)); \
if (token->offset <= member_offset && \
member_offset + size <= token->offset + unit_size) { \
put_unaligned_le##bits(val, token->kaddr + oil); \
return; \
} \
token->kaddr = folio_address(token->eb->folios[idx]); \
token->offset = idx << unit_shift; \
if (INLINE_EXTENT_BUFFER_PAGES == 1 || \
oil + size <= unit_size) { \
put_unaligned_le##bits(val, token->kaddr + oil); \
return; \
} \
put_unaligned_le##bits(val, lebytes); \
memcpy(token->kaddr + oil, lebytes, part); \
token->kaddr = folio_address(token->eb->folios[idx + 1]); \
token->offset = (idx + 1) << unit_shift; \
memcpy(token->kaddr, lebytes + part, size - part); \
} \
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 oil = get_eb_offset_in_folio(eb, \
member_offset);\
const int unit_size = folio_size(eb->folios[0]); \
char *kaddr = folio_address(eb->folios[idx]); \
const int size = sizeof(u##bits); \
const int part = unit_size - oil; \
u8 lebytes[sizeof(u##bits)]; \
\
ASSERT(check_setget_bounds(eb, ptr, off, size)); \
if (INLINE_EXTENT_BUFFER_PAGES == 1 || \
oil + size <= unit_size) { \
put_unaligned_le##bits(val, kaddr + oil); \
return; \
} \
\
put_unaligned_le##bits(val, lebytes); \
memcpy(kaddr + oil, lebytes, part); \
kaddr = folio_address(eb->folios[idx + 1]); \
memcpy(kaddr, lebytes + part, size - 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);
}