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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <lk/reflist.h>
#include <stdbool.h>
#include <stdint.h>
#include "block_device.h"
#include "crypt.h"
#ifdef APP_STORAGE_BLOCK_CACHE_SIZE
#define BLOCK_CACHE_SIZE (APP_STORAGE_BLOCK_CACHE_SIZE)
#else
#define BLOCK_CACHE_SIZE (64)
#endif
#ifdef APP_STORAGE_MAIN_BLOCK_SIZE
#define MAX_BLOCK_SIZE (APP_STORAGE_MAIN_BLOCK_SIZE)
#else
#define MAX_BLOCK_SIZE (2048)
#endif
/**
* enum block_cache_entry_data_state - State of a block cache entry's data
* @BLOCK_ENTRY_DATA_INVALID: Block entry does not contain valid data.
* @BLOCK_ENTRY_DATA_LOADING: Block entry data load is pending. State will
* be updated when the load operation completes.
* @BLOCK_ENTRY_DATA_LOAD_FAILED: Block data could not be loaded from the disk.
* This may be caused by a transient I/O error.
* @BLOCK_ENTRY_DATA_NOT_FOUND: Block does not exist on disk.
* @BLOCK_ENTRY_DATA_CLEAN_DECRYPTED: Block entry contains valid plaintext data
* that is either on disk or queued to be
* written to disk
* @BLOCK_ENTRY_DATA_CLEAN_ENCRYPTED: Block entry contains valid ciphertext data
* that is either on disk or queued to be
* written to disk.
* @BLOCK_ENTRY_DATA_DIRTY_DECRYPTED: Block entry contains valid plaintext data
* that has not yet been queued for write
* back to disk. Data must be encrypted and
* written back or discarded before the cache
* entry can be reused.
* @BLOCK_ENTRY_DATA_DIRTY_ENCRYPTED: Block entry contains valid ciphertext data
* that has not yet been queued for write
* back to disk. Data must be written back or
* discarded before the cache entry can be
* reused.
*/
enum block_cache_entry_data_state {
BLOCK_ENTRY_DATA_INVALID = 0,
BLOCK_ENTRY_DATA_LOADING,
BLOCK_ENTRY_DATA_LOAD_FAILED,
BLOCK_ENTRY_DATA_NOT_FOUND,
BLOCK_ENTRY_DATA_CLEAN_DECRYPTED,
BLOCK_ENTRY_DATA_CLEAN_ENCRYPTED,
BLOCK_ENTRY_DATA_DIRTY_DECRYPTED,
BLOCK_ENTRY_DATA_DIRTY_ENCRYPTED,
};
/**
* struct block_cache_entry - block cache entry
* @guard1: Set to BLOCK_CACHE_GUARD_1 to detect out of bound
* writes to data.
* @data: Decrypted block data.
* @guard2: Set to BLOCK_CACHE_GUARD_2 to detect out of bound
* writes to data.
* @key: Key to use for encrypt, decrypt and calculate_mac.
* @dev: Device that block was read from and will be written
* to.
* @block: Block number in dev.
* @block_size: Size of block, but match dev->block_size.
* @mac: Last calculated mac of encrypted block data.
* @state: Current state of @data, indicating if data has been
* loaded from disk or written into this cache entry.
* This state is reset to %BLOCK_ENTRY_INVALID when a
* cache entry previously containing a different block
* is selected for reuse. See &enum
* block_cache_entry_state for details.
* @encrypted: %true if @data is currently encrypted.
* @dirty_ref: Data is currently being modified. Only a single
* reference should be allowed.
* @dirty_mac: Data has been modified. Mac needs to be updated
* after encrypting block.
* @dirty_tmp: Data can be discarded by
* block_cache_discard_transaction.
* @pinned: Block cannot be reused if it fails to write.
* @is_superblock: Block is used as a superblock and files should be
* synced before it is written.
* @dirty_tr: Transaction that modified block.
* @obj: Reference tracking struct.
* @lru_node: List node for tracking least recently used cache
* entries.
* @io_op_node: List node for tracking active read and write
* operations.
* @io_op: Currently active io operation.
*
* @dirty_ref, @dirty_mac, @dirty_tmp, and @dirty_tr are only relevant if @state
* is %BLOCK_ENTRY_DATA_DIRTY, i.e. @data has been modified and not yet queued
* for write or discarded.
*/
struct block_cache_entry {
uint64_t guard1;
uint8_t data[MAX_BLOCK_SIZE];
uint64_t guard2;
const struct key* key;
struct block_device* dev;
data_block_t block;
size_t block_size;
struct mac mac;
enum block_cache_entry_data_state state;
bool dirty_ref;
bool dirty_mac;
bool dirty_tmp;
bool pinned;
bool is_superblock;
struct transaction* dirty_tr;
struct obj obj;
struct list_node lru_node;
struct list_node io_op_node;
enum {
BLOCK_CACHE_IO_OP_NONE,
BLOCK_CACHE_IO_OP_READ,
BLOCK_CACHE_IO_OP_WRITE,
} io_op;
};
#define BLOCK_CACHE_SIZE_BYTES \
(sizeof(struct block_cache_entry[BLOCK_CACHE_SIZE]))