297 lines
8.3 KiB
C
297 lines
8.3 KiB
C
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/*
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* Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* - The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/** @addtogroup lwext4
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* @{
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*/
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/**
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* @file ext4_bcache.h
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* @brief Block cache allocator.
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*/
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#ifndef EXT4_BCACHE_H_
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#define EXT4_BCACHE_H_
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <ext4_config.h>
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#include <stdint.h>
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#include <stdbool.h>
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#include <misc/tree.h>
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#include <misc/queue.h>
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#define EXT4_BLOCK_ZERO() \
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{.lb_id = 0, .data = 0}
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/**@brief Single block descriptor*/
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struct ext4_block {
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/**@brief Logical block ID*/
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uint64_t lb_id;
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/**@brief Buffer */
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struct ext4_buf *buf;
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/**@brief Data buffer.*/
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uint8_t *data;
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};
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struct ext4_bcache;
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/**@brief Single block descriptor*/
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struct ext4_buf {
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/**@brief Flags*/
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int flags;
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/**@brief Logical block address*/
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uint64_t lba;
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/**@brief Data buffer.*/
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uint8_t *data;
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/**@brief LRU priority. (unused) */
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uint32_t lru_prio;
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/**@brief LRU id.*/
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uint32_t lru_id;
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/**@brief Reference count table*/
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uint32_t refctr;
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/**@brief The block cache this buffer belongs to. */
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struct ext4_bcache *bc;
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/**@brief Whether or not buffer is on dirty list.*/
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bool on_dirty_list;
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/**@brief LBA tree node*/
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RB_ENTRY(ext4_buf) lba_node;
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/**@brief LRU tree node*/
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RB_ENTRY(ext4_buf) lru_node;
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/**@brief Dirty list node*/
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SLIST_ENTRY(ext4_buf) dirty_node;
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/**@brief Callback routine after a disk-write operation.
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* @param bc block cache descriptor
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* @param buf buffer descriptor
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* @param standard error code returned by bdev->bwrite()
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* @param arg argument passed to this routine*/
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void (*end_write)(struct ext4_bcache *bc,
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struct ext4_buf *buf,
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int res,
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void *arg);
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/**@brief argument passed to end_write() callback.*/
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void *end_write_arg;
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};
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/**@brief Block cache descriptor*/
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struct ext4_bcache {
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/**@brief Item count in block cache*/
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uint32_t cnt;
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/**@brief Item size in block cache*/
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uint32_t itemsize;
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/**@brief Last recently used counter*/
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uint32_t lru_ctr;
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/**@brief Currently referenced datablocks*/
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uint32_t ref_blocks;
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/**@brief Maximum referenced datablocks*/
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uint32_t max_ref_blocks;
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/**@brief The blockdev binded to this block cache*/
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struct ext4_blockdev *bdev;
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/**@brief The cache should not be shaked */
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bool dont_shake;
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/**@brief A tree holding all bufs*/
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RB_HEAD(ext4_buf_lba, ext4_buf) lba_root;
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/**@brief A tree holding unreferenced bufs*/
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RB_HEAD(ext4_buf_lru, ext4_buf) lru_root;
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/**@brief A singly-linked list holding dirty buffers*/
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SLIST_HEAD(ext4_buf_dirty, ext4_buf) dirty_list;
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};
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/**@brief buffer state bits
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*
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* - BC♡UPTODATE: Buffer contains valid data.
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* - BC_DIRTY: Buffer is dirty.
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* - BC_FLUSH: Buffer will be immediately flushed,
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* when no one references it.
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* - BC_TMP: Buffer will be dropped once its refctr
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* reaches zero.
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*/
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enum bcache_state_bits {
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BC_UPTODATE,
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BC_DIRTY,
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BC_FLUSH,
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BC_TMP
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};
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#define ext4_bcache_set_flag(buf, b) \
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(buf)->flags |= 1 << (b)
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#define ext4_bcache_clear_flag(buf, b) \
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(buf)->flags &= ~(1 << (b))
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#define ext4_bcache_test_flag(buf, b) \
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(((buf)->flags & (1 << (b))) >> (b))
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static inline void ext4_bcache_set_dirty(struct ext4_buf *buf) {
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ext4_bcache_set_flag(buf, BC_UPTODATE);
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ext4_bcache_set_flag(buf, BC_DIRTY);
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}
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static inline void ext4_bcache_clear_dirty(struct ext4_buf *buf) {
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ext4_bcache_clear_flag(buf, BC_UPTODATE);
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ext4_bcache_clear_flag(buf, BC_DIRTY);
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}
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/**@brief Increment reference counter of buf by 1.*/
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#define ext4_bcache_inc_ref(buf) ((buf)->refctr++)
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/**@brief Decrement reference counter of buf by 1.*/
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#define ext4_bcache_dec_ref(buf) ((buf)->refctr--)
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/**@brief Insert buffer to dirty cache list
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* @param bc block cache descriptor
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* @param buf buffer descriptor */
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static inline void
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ext4_bcache_insert_dirty_node(struct ext4_bcache *bc, struct ext4_buf *buf) {
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if (!buf->on_dirty_list) {
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SLIST_INSERT_HEAD(&bc->dirty_list, buf, dirty_node);
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buf->on_dirty_list = true;
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}
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}
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/**@brief Remove buffer to dirty cache list
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* @param bc block cache descriptor
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* @param buf buffer descriptor */
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static inline void
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ext4_bcache_remove_dirty_node(struct ext4_bcache *bc, struct ext4_buf *buf) {
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if (buf->on_dirty_list) {
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SLIST_REMOVE(&bc->dirty_list, buf, ext4_buf, dirty_node);
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buf->on_dirty_list = false;
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}
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}
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/**@brief Dynamic initialization of block cache.
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* @param bc block cache descriptor
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* @param cnt items count in block cache
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* @param itemsize single item size (in bytes)
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* @return standard error code*/
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int ext4_bcache_init_dynamic(struct ext4_bcache *bc, uint32_t cnt,
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uint32_t itemsize);
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/**@brief Do cleanup works on block cache.
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* @param bc block cache descriptor.*/
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void ext4_bcache_cleanup(struct ext4_bcache *bc);
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/**@brief Dynamic de-initialization of block cache.
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* @param bc block cache descriptor
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* @return standard error code*/
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int ext4_bcache_fini_dynamic(struct ext4_bcache *bc);
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/**@brief Get a buffer with the lowest LRU counter in bcache.
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* @param bc block cache descriptor
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* @return buffer with the lowest LRU counter*/
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struct ext4_buf *ext4_buf_lowest_lru(struct ext4_bcache *bc);
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/**@brief Drop unreferenced buffer from bcache.
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* @param bc block cache descriptor
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* @param buf buffer*/
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void ext4_bcache_drop_buf(struct ext4_bcache *bc, struct ext4_buf *buf);
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/**@brief Invalidate a buffer.
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* @param bc block cache descriptor
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* @param buf buffer*/
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void ext4_bcache_invalidate_buf(struct ext4_bcache *bc,
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struct ext4_buf *buf);
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/**@brief Invalidate a range of buffers.
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* @param bc block cache descriptor
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* @param from starting lba
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* @param cnt block counts*/
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void ext4_bcache_invalidate_lba(struct ext4_bcache *bc,
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uint64_t from,
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uint32_t cnt);
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/**@brief Find existing buffer from block cache memory.
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* Unreferenced block allocation is based on LRU
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* (Last Recently Used) algorithm.
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* @param bc block cache descriptor
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* @param b block to alloc
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* @param lba logical block address
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* @return block cache buffer */
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struct ext4_buf *
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ext4_bcache_find_get(struct ext4_bcache *bc, struct ext4_block *b,
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uint64_t lba);
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/**@brief Allocate block from block cache memory.
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* Unreferenced block allocation is based on LRU
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* (Last Recently Used) algorithm.
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* @param bc block cache descriptor
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* @param b block to alloc
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* @param is_new block is new (needs to be read)
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* @return standard error code*/
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int ext4_bcache_alloc(struct ext4_bcache *bc, struct ext4_block *b,
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bool *is_new);
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/**@brief Free block from cache memory (decrement reference counter).
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* @param bc block cache descriptor
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* @param b block to free
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* @return standard error code*/
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int ext4_bcache_free(struct ext4_bcache *bc, struct ext4_block *b);
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/**@brief Return a full status of block cache.
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* @param bc block cache descriptor
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* @return full status*/
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bool ext4_bcache_is_full(struct ext4_bcache *bc);
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#ifdef __cplusplus
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}
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#endif
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#endif /* EXT4_BCACHE_H_ */
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/**
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* @}
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*/
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