diff options
Diffstat (limited to 'fs/btrfs/struct-funcs.c')
| -rw-r--r-- | fs/btrfs/struct-funcs.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/fs/btrfs/struct-funcs.c b/fs/btrfs/struct-funcs.c new file mode 100644 index 000000000..12455b2b4 --- /dev/null +++ b/fs/btrfs/struct-funcs.c @@ -0,0 +1,166 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2007 Oracle. All rights reserved. + */ + +#include <asm/unaligned.h> + +#include "ctree.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; +} + +/* + * 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 pages do 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_page_index(member_offset); \ + const unsigned long oip = get_eb_offset_in_page(token->eb, \ + 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 (INLINE_EXTENT_BUFFER_PAGES == 1 || 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 = get_eb_offset_in_page(eb, member_offset); \ + const unsigned long idx = get_eb_page_index(member_offset); \ + 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 (INLINE_EXTENT_BUFFER_PAGES == 1 || 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 = get_eb_page_index(member_offset); \ + const unsigned long oip = get_eb_offset_in_page(token->eb, \ + 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) { \ + put_unaligned_le##bits(val, token->kaddr + oip); \ + return; \ + } \ + token->kaddr = page_address(token->eb->pages[idx]); \ + token->offset = idx << PAGE_SHIFT; \ + if (INLINE_EXTENT_BUFFER_PAGES == 1 || oip + size <= PAGE_SIZE) { \ + put_unaligned_le##bits(val, token->kaddr + oip); \ + return; \ + } \ + put_unaligned_le##bits(val, lebytes); \ + memcpy(token->kaddr + oip, lebytes, part); \ + token->kaddr = page_address(token->eb->pages[idx + 1]); \ + token->offset = (idx + 1) << PAGE_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 oip = get_eb_offset_in_page(eb, member_offset); \ + const unsigned long idx = get_eb_page_index(member_offset); \ + 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 (INLINE_EXTENT_BUFFER_PAGES == 1 || oip + size <= PAGE_SIZE) { \ + put_unaligned_le##bits(val, kaddr + oip); \ + return; \ + } \ + \ + put_unaligned_le##bits(val, lebytes); \ + memcpy(kaddr + oip, lebytes, part); \ + kaddr = page_address(eb->pages[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(nr); + read_eb_member(eb, (struct btrfs_key_ptr *)ptr, + struct btrfs_key_ptr, key, disk_key); +} |