/* * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com) * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright *   notice, this list of conditions and the following disclaimer. * - Redistributions in binary form must reproduce the above copyright *   notice, this list of conditions and the following disclaimer in the *   documentation and/or other materials provided with the distribution. * - The name of the author may not be used to endorse or promote products *   derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /** @addtogroup lwext4 * @{ *//** * @file  ext4_bcache.h * @brief Block cache allocator. */ #ifndef EXT4_BCACHE_H_#define EXT4_BCACHE_H_ #ifdef __cplusplusextern "C" {#endif #include <ext4_config.h> #include <stdint.h>#include <stdbool.h>#include <misc/tree.h>#include <misc/queue.h> #define EXT4_BLOCK_ZERO() 	\	{0} /**@brief   Single block descriptor*/struct ext4_buf {	/**@brief   Flags*/	int flags; 	/**@brief   Logical block address*/	uint64_t lba; 	/**@brief   Data buffer.*/	uint8_t *data; 	/**@brief   LRU priority. (unused) */	uint32_t lru_prio; 	/**@brief   LRU id.*/	uint32_t lru_id; 	/**@brief   Reference count table*/	uint32_t refctr; 	/**@brief   The block cache this buffer belongs to. */	struct ext4_bcache *bc; 	/**@brief   Whether or not buffer is on dirty list.*/	bool on_dirty_list; 	/**@brief   LBA tree node*/	RB_ENTRY(ext4_buf) lba_node; 	/**@brief   LRU tree node*/	RB_ENTRY(ext4_buf) lru_node; 	/**@brief   Dirty list node*/	SLIST_ENTRY(ext4_buf) dirty_node; 	/**@brief   Callback routine after a disk-write operation.	 * @param   bc block cache descriptor	 * @param   buf buffer descriptor	 * @param   standard error code returned by bdev->bwrite()	 * @param   arg argument passed to this routine*/	void (*end_write)(struct ext4_bcache *bc,			  struct ext4_buf *buf,			  int res,			  void *arg); 	/**@brief   argument passed to end_write() callback.*/	void *end_write_arg;}; /**@brief   Single block descriptor*/struct ext4_block {	/**@brief   Logical block ID*/	uint64_t lb_id; 	/**@brief   Buffer */	struct ext4_buf *buf; 	/**@brief   Data buffer.*/	uint8_t *data;}; /**@brief   Block cache descriptor*/struct ext4_bcache { 	/**@brief   Item count in block cache*/	uint32_t cnt; 	/**@brief   Item size in block cache*/	uint32_t itemsize; 	/**@brief   Last recently used counter*/	uint32_t lru_ctr; 	/**@brief   Currently referenced datablocks*/	uint32_t ref_blocks; 	/**@brief   Maximum referenced datablocks*/	uint32_t max_ref_blocks; 	/**@brief   The blockdev binded to this block cache*/	struct ext4_blockdev *bdev; 	/**@brief   The cache should not be shaked */	bool dont_shake; 	/**@brief   A tree holding all bufs*/	RB_HEAD(ext4_buf_lba, ext4_buf) lba_root; 	/**@brief   A tree holding unreferenced bufs*/	RB_HEAD(ext4_buf_lru, ext4_buf) lru_root; 	/**@brief   A singly-linked list holding dirty buffers*/	SLIST_HEAD(ext4_buf_dirty, ext4_buf) dirty_list;}; /**@brief buffer state bits * *  - BC_UPTODATE: Buffer contains valid data. *  - BC_DIRTY: Buffer is dirty. *  - BC_FLUSH: Buffer will be immediately flushed, *              when no one references it. *  - BC_TMP: Buffer will be dropped once its refctr *            reaches zero. */enum bcache_state_bits {	BC_UPTODATE,	BC_DIRTY,	BC_FLUSH,	BC_TMP}; #define ext4_bcache_set_flag(buf, b)    \	(buf)->flags |= 1 << (b) #define ext4_bcache_clear_flag(buf, b)    \	(buf)->flags &= ~(1 << (b)) #define ext4_bcache_test_flag(buf, b)    \	(((buf)->flags & (1 << (b))) >> (b)) static inline void ext4_bcache_set_dirty(struct ext4_buf *buf) {	ext4_bcache_set_flag(buf, BC_UPTODATE);	ext4_bcache_set_flag(buf, BC_DIRTY);} static inline void ext4_bcache_clear_dirty(struct ext4_buf *buf) {	ext4_bcache_clear_flag(buf, BC_UPTODATE);	ext4_bcache_clear_flag(buf, BC_DIRTY);} /**@brief   Increment reference counter of buf by 1.*/#define ext4_bcache_inc_ref(buf) ((buf)->refctr++) /**@brief   Decrement reference counter of buf by 1.*/#define ext4_bcache_dec_ref(buf) ((buf)->refctr--) /**@brief   Insert buffer to dirty cache list * @param   bc block cache descriptor * @param   buf buffer descriptor */static inline voidext4_bcache_insert_dirty_node(struct ext4_bcache *bc, struct ext4_buf *buf) {	if (!buf->on_dirty_list) {		SLIST_INSERT_HEAD(&bc->dirty_list, buf, dirty_node);		buf->on_dirty_list = true;	}} /**@brief   Remove buffer to dirty cache list * @param   bc block cache descriptor * @param   buf buffer descriptor */static inline voidext4_bcache_remove_dirty_node(struct ext4_bcache *bc, struct ext4_buf *buf) {	if (buf->on_dirty_list) {		SLIST_REMOVE(&bc->dirty_list, buf, ext4_buf, dirty_node);		buf->on_dirty_list = false;	}}  /**@brief   Dynamic initialization of block cache. * @param   bc block cache descriptor * @param   cnt items count in block cache * @param   itemsize single item size (in bytes) * @return  standard error code*/int ext4_bcache_init_dynamic(struct ext4_bcache *bc, uint32_t cnt,			     uint32_t itemsize); /**@brief   Do cleanup works on block cache. * @param   bc block cache descriptor.*/void ext4_bcache_cleanup(struct ext4_bcache *bc); /**@brief   Dynamic de-initialization of block cache. * @param   bc block cache descriptor * @return  standard error code*/int ext4_bcache_fini_dynamic(struct ext4_bcache *bc); /**@brief   Get a buffer with the lowest LRU counter in bcache. * @param   bc block cache descriptor * @return  buffer with the lowest LRU counter*/struct ext4_buf *ext4_buf_lowest_lru(struct ext4_bcache *bc); /**@brief   Drop unreferenced buffer from bcache. * @param   bc block cache descriptor * @param   buf buffer*/void ext4_bcache_drop_buf(struct ext4_bcache *bc, struct ext4_buf *buf); /**@brief   Invalidate a buffer. * @param   bc block cache descriptor * @param   buf buffer*/void ext4_bcache_invalidate_buf(struct ext4_bcache *bc,				struct ext4_buf *buf); /**@brief   Invalidate a range of buffers. * @param   bc block cache descriptor * @param   from starting lba * @param   cnt block counts * @param   buf buffer*/void ext4_bcache_invalidate_lba(struct ext4_bcache *bc,				uint64_t from,				uint32_t cnt); /**@brief   Find existing buffer from block cache memory. *          Unreferenced block allocation is based on LRU *          (Last Recently Used) algorithm. * @param   bc block cache descriptor * @param   b block to alloc * @param   lba logical block address * @return  block cache buffer */struct ext4_buf *ext4_bcache_find_get(struct ext4_bcache *bc, struct ext4_block *b,		     uint64_t lba); /**@brief   Allocate block from block cache memory. *          Unreferenced block allocation is based on LRU *          (Last Recently Used) algorithm. * @param   bc block cache descriptor * @param   b block to alloc * @param   is_new block is new (needs to be read) * @return  standard error code*/int ext4_bcache_alloc(struct ext4_bcache *bc, struct ext4_block *b,		      bool *is_new); /**@brief   Free block from cache memory (decrement reference counter). * @param   bc block cache descriptor * @param   b block to free * @return  standard error code*/int ext4_bcache_free(struct ext4_bcache *bc, struct ext4_block *b); /**@brief   Return a full status of block cache. * @param   bc block cache descriptor * @return  full status*/bool ext4_bcache_is_full(struct ext4_bcache *bc); #ifdef __cplusplus}#endif #endif /* EXT4_BCACHE_H_ */ /** * @} */