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cache.h
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cache.h
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#ifndef _CACHE_H_
#define _CACHE_H_
typedef struct hash_ent {
int dev;
fs_off_t bnum;
fs_off_t hash_val;
void *data;
struct hash_ent *next;
} hash_ent;
typedef struct hash_table {
hash_ent **table;
int max;
int mask; /* == max - 1 */
int num_elements;
} hash_table;
#define HT_DEFAULT_MAX 128
typedef struct cache_ent {
int dev;
fs_off_t block_num;
int bsize;
volatile int flags;
void *data;
void *clone; /* copy of data by set_block_info() */
int lock;
void (*func)(fs_off_t bnum, size_t num_blocks, void *arg);
fs_off_t logged_bnum;
void *arg;
struct cache_ent *next, /* points toward mru end of list */
*prev; /* points toward lru end of list */
} cache_ent;
#define CE_NORMAL 0x0000 /* a nice clean pristine page */
#define CE_DIRTY 0x0002 /* needs to be written to disk */
#define CE_BUSY 0x0004 /* this block has i/o happening, don't touch it */
typedef struct cache_ent_list {
cache_ent *lru; /* tail of the list */
cache_ent *mru; /* head of the list */
} cache_ent_list;
typedef struct block_cache {
lock lock;
int flags;
int cur_blocks;
int max_blocks;
hash_table ht;
cache_ent_list normal, /* list of "normal" blocks (clean & dirty) */
locked; /* list of clean and locked blocks */
} block_cache;
#define ALLOW_WRITES 1
#define NO_WRITES 0
extern int init_block_cache(int max_blocks, int flags);
extern void shutdown_block_cache(void);
extern void force_cache_flush(int dev, int prefer_log_blocks);
extern int flush_blocks(int dev, fs_off_t bnum, int nblocks);
extern int flush_device(int dev, int warn_locked);
extern int init_cache_for_device(int fd, fs_off_t max_blocks);
extern int remove_cached_device_blocks(int dev, int allow_write);
extern void *get_block(int dev, fs_off_t bnum, int bsize);
extern void *get_empty_block(int dev, fs_off_t bnum, int bsize);
extern int release_block(int dev, fs_off_t bnum);
extern int mark_blocks_dirty(int dev, fs_off_t bnum, int nblocks);
extern int cached_read(int dev, fs_off_t bnum, void *data,
fs_off_t num_blocks, int bsize);
extern int cached_write(int dev, fs_off_t bnum, const void *data,
fs_off_t num_blocks, int bsize);
extern int cached_write_locked(int dev, fs_off_t bnum, const void *data,
fs_off_t num_blocks, int bsize);
extern int set_blocks_info(int dev, fs_off_t *blocks, int nblocks,
void (*func)(fs_off_t bnum, size_t nblocks, void *arg),
void *arg);
extern size_t read_phys_blocks (int fd, fs_off_t bnum, void *data,
uint num_blocks, int bsize);
extern size_t write_phys_blocks(int fd, fs_off_t bnum, void *data,
uint num_blocks, int bsize);
#endif /* _CACHE_H_ */