// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2007 Oracle. All rights reserved. */ #include #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; } /* * 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(const struct extent_buffer *eb, \ const void *ptr, unsigned long off, \ struct btrfs_map_token *token) \ { \ unsigned long part_offset = (unsigned long)ptr; \ unsigned long offset = part_offset + off; \ void *p; \ int err; \ char *kaddr; \ unsigned long map_start; \ unsigned long map_len; \ int size = sizeof(u##bits); \ u##bits res; \ \ ASSERT(token); \ \ if (token->kaddr && token->offset <= offset && \ token->eb == eb && \ (token->offset + PAGE_SIZE >= offset + size)) { \ kaddr = token->kaddr; \ p = kaddr + part_offset - token->offset; \ res = get_unaligned_le##bits(p + off); \ return res; \ } \ err = map_private_extent_buffer(eb, offset, size, \ &kaddr, &map_start, &map_len); \ if (err) { \ __le##bits leres; \ \ read_extent_buffer(eb, &leres, offset, size); \ return le##bits##_to_cpu(leres); \ } \ p = kaddr + part_offset - map_start; \ res = get_unaligned_le##bits(p + off); \ token->kaddr = kaddr; \ token->offset = map_start; \ token->eb = eb; \ return res; \ } \ u##bits btrfs_get_##bits(const struct extent_buffer *eb, \ const void *ptr, unsigned long off) \ { \ unsigned long part_offset = (unsigned long)ptr; \ unsigned long offset = part_offset + off; \ void *p; \ int err; \ char *kaddr; \ unsigned long map_start; \ unsigned long map_len; \ int size = sizeof(u##bits); \ u##bits res; \ \ err = map_private_extent_buffer(eb, offset, size, \ &kaddr, &map_start, &map_len); \ if (err) { \ __le##bits leres; \ \ read_extent_buffer(eb, &leres, offset, size); \ return le##bits##_to_cpu(leres); \ } \ p = kaddr + part_offset - map_start; \ res = get_unaligned_le##bits(p + off); \ return res; \ } \ void btrfs_set_token_##bits(struct extent_buffer *eb, \ const void *ptr, unsigned long off, \ u##bits val, \ struct btrfs_map_token *token) \ { \ unsigned long part_offset = (unsigned long)ptr; \ unsigned long offset = part_offset + off; \ void *p; \ int err; \ char *kaddr; \ unsigned long map_start; \ unsigned long map_len; \ int size = sizeof(u##bits); \ \ ASSERT(token); \ \ if (token->kaddr && token->offset <= offset && \ token->eb == eb && \ (token->offset + PAGE_SIZE >= offset + size)) { \ kaddr = token->kaddr; \ p = kaddr + part_offset - token->offset; \ put_unaligned_le##bits(val, p + off); \ return; \ } \ err = map_private_extent_buffer(eb, offset, size, \ &kaddr, &map_start, &map_len); \ if (err) { \ __le##bits val2; \ \ val2 = cpu_to_le##bits(val); \ write_extent_buffer(eb, &val2, offset, size); \ return; \ } \ p = kaddr + part_offset - map_start; \ put_unaligned_le##bits(val, p + off); \ token->kaddr = kaddr; \ token->offset = map_start; \ token->eb = eb; \ } \ void btrfs_set_##bits(struct extent_buffer *eb, void *ptr, \ unsigned long off, u##bits val) \ { \ unsigned long part_offset = (unsigned long)ptr; \ unsigned long offset = part_offset + off; \ void *p; \ int err; \ char *kaddr; \ unsigned long map_start; \ unsigned long map_len; \ int size = sizeof(u##bits); \ \ err = map_private_extent_buffer(eb, offset, size, \ &kaddr, &map_start, &map_len); \ if (err) { \ __le##bits val2; \ \ val2 = cpu_to_le##bits(val); \ write_extent_buffer(eb, &val2, offset, size); \ return; \ } \ p = kaddr + part_offset - map_start; \ put_unaligned_le##bits(val, p + off); \ } 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); }