/* * 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 __cplusplus extern "C" { #endif #include #include #include #include #include #define EXT4_BLOCK_ZERO() \ {.lb_id = 0, .data = 0} /**@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; }; struct ext4_bcache; /**@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 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 void ext4_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 void ext4_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*/ 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_ */ /** * @} */