mirror of
https://github.com/kdave/btrfs-progs
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120 lines
3.8 KiB
C
120 lines
3.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*/
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#include "kerncompat.h"
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#include <stdbool.h>
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#include "kernel-shared/extent_io.h"
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#include "kernel-shared/uapi/btrfs_tree.h"
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#include "kernel-shared/messages.h"
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#include "kernel-shared/accessors.h"
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static bool check_setget_bounds(const struct extent_buffer *eb,
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const void *ptr, unsigned off, int size)
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{
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const unsigned long member_offset = (unsigned long)ptr + off;
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if (unlikely(member_offset + size > eb->len)) {
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btrfs_warn(eb->fs_info,
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"bad eb member %s: ptr 0x%lx start %llu member offset %lu size %d",
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(member_offset > eb->len ? "start" : "end"),
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(unsigned long)ptr, eb->start, member_offset, size);
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return false;
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}
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return true;
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}
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/*
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* MODIFIED:
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* - We don't have eb->pages.
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*/
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void btrfs_init_map_token(struct btrfs_map_token *token, struct extent_buffer *eb)
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{
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token->eb = eb;
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token->kaddr = eb->data;
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token->offset = 0;
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}
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/*
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* MODIFIED:
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* - We don't have eb->pages, simply wrap the set/get helpers.
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*/
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/*
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* Macro templates that define helpers to read/write extent buffer data of a
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* given size, that are also used via ctree.h for access to item members by
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* specialized helpers.
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*
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* Generic helpers:
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* - btrfs_set_8 (for 8/16/32/64)
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* - btrfs_get_8 (for 8/16/32/64)
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*
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* Generic helpers with a token (cached address of the most recently accessed
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* page):
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* - btrfs_set_token_8 (for 8/16/32/64)
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* - btrfs_get_token_8 (for 8/16/32/64)
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*
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* The set/get functions handle data spanning two pages transparently, in case
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* metadata block size is larger than page. Every pointer to metadata items is
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* an offset into the extent buffer page array, cast to a specific type. This
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* gives us all the type checking.
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*
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* The extent buffer pages stored in the array pages do not form a contiguous
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* phyusical range, but the API functions assume the linear offset to the range
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* from 0 to metadata node size.
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*/
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#define DEFINE_BTRFS_SETGET_BITS(bits) \
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u##bits btrfs_get_token_##bits(struct btrfs_map_token *token, \
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const void *ptr, unsigned long off) \
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{ \
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const unsigned long member_offset = (unsigned long)ptr + off; \
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const int size = sizeof(u##bits); \
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ASSERT(token); \
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ASSERT(token->kaddr); \
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ASSERT(check_setget_bounds(token->eb, ptr, off, size)); \
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return get_unaligned_le##bits(token->kaddr + member_offset); \
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} \
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u##bits btrfs_get_##bits(const struct extent_buffer *eb, \
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const void *ptr, unsigned long off) \
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{ \
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const unsigned long member_offset = (unsigned long)ptr + off; \
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const int size = sizeof(u##bits); \
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ASSERT(check_setget_bounds(eb, ptr, off, size)); \
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return get_unaligned_le##bits(eb->data + member_offset); \
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} \
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void btrfs_set_token_##bits(struct btrfs_map_token *token, \
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const void *ptr, unsigned long off, \
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u##bits val) \
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{ \
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unsigned long member_offset = (unsigned long)ptr + off; \
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const int size = sizeof(u##bits); \
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ASSERT(token); \
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ASSERT(token->kaddr); \
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ASSERT(check_setget_bounds(token->eb, ptr, off, size)); \
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put_unaligned_le##bits(val, token->kaddr + member_offset); \
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} \
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void btrfs_set_##bits(const struct extent_buffer *eb, void *ptr, \
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unsigned long off, u##bits val) \
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{ \
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unsigned long member_offset = (unsigned long)ptr + off; \
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const int size = sizeof(u##bits); \
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ASSERT(check_setget_bounds(eb, ptr, off, size)); \
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put_unaligned_le##bits(val, (void *)eb->data + member_offset); \
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}
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DEFINE_BTRFS_SETGET_BITS(8)
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DEFINE_BTRFS_SETGET_BITS(16)
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DEFINE_BTRFS_SETGET_BITS(32)
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DEFINE_BTRFS_SETGET_BITS(64)
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void btrfs_node_key(const struct extent_buffer *eb,
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struct btrfs_disk_key *disk_key, int nr)
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{
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unsigned long ptr = btrfs_node_key_ptr_offset(eb, nr);
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read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
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struct btrfs_key_ptr, key, disk_key);
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}
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