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//
// buf.h
//
// I/O buffer cache
//
// Copyright (C) 2002 Michael Ringgaard. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// 2. 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.
// 3. Neither the name of the project nor the names of its contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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.
//
#ifndef BUF_H
#define BUF_H
#define BUFPOOL_HASHSIZE 512
#define BUF_STATE_FREE 0
#define BUF_STATE_CLEAN 1
#define BUF_STATE_DIRTY 2
#define BUF_STATE_READING 3
#define BUF_STATE_WRITING 4
#define BUF_STATE_LOCKED 5
#define BUF_STATE_UPDATED 6
#define BUF_STATE_INVALID 7
#define BUF_STATE_ERROR 8
#define BUF_STATES 9
struct thread;
struct buf;
struct buflist {
struct buf *head;
struct buf *tail;
};
struct buflink {
struct buf *next;
struct buf *prev;
};
struct buf {
struct buflink bucket;
struct buflink chain;
unsigned short state;
unsigned short locks;
struct thread *waiters;
blkno_t blkno;
char *data;
};
struct bufpool {
dev_t devno;
int poolsize;
int bufsize;
int blks_per_buffer;
int ioactive;
void (*sync)(void *arg);
void *syncarg;
time_t last_sync;
int nosync;
int blocks_read;
int cache_hits;
int cache_misses;
int blocks_allocated;
int blocks_freed;
int blocks_updated;
int blocks_written;
int blocks_lazywrite;
int blocks_synched;
struct bufpool *next;
struct bufpool *prev;
struct buf *bufbase;
char *database;
struct buflist dirty; // List of dirty buffers (head is least recently changed)
struct buflist clean; // List of clean buffers (head is least recently used)
struct buf *freelist; // List of free buffers
int bufcount[BUF_STATES];
struct buf *hashtable[BUFPOOL_HASHSIZE];
};
krnlapi struct bufpool *init_buffer_pool(dev_t devno, int poolsize, int bufsize, void (*sync)(void *arg), void *syncarg);
krnlapi void free_buffer_pool(struct bufpool *pool);
krnlapi struct buf *get_buffer(struct bufpool *pool, blkno_t blkno);
krnlapi struct buf *alloc_buffer(struct bufpool *pool, blkno_t blkno);
krnlapi void mark_buffer_updated(struct bufpool *pool, struct buf *buf);
krnlapi void mark_buffer_invalid(struct bufpool *pool, struct buf *buf);
krnlapi void release_buffer(struct bufpool *pool, struct buf *buf);
krnlapi void invalidate_buffer(struct bufpool *pool, blkno_t blkno);
krnlapi int flush_buffers(struct bufpool *pool, int interruptable);
krnlapi int sync_buffers(struct bufpool *pool, int interruptable);
#endif