mars/lib_log.h

141 lines
3.4 KiB
C

// (c) 2010 Thomas Schoebel-Theuer / 1&1 Internet AG
/* Definitions for logfile format.
*
* This is meant for sharing between different transaction logger variants,
* and/or for sharing with userspace tools (e.g. logfile analyzers).
* TODO: factor out some remaining kernelspace issues.
*/
#ifndef LIB_LOG_H
#define LIB_LOG_H
#include "mars.h"
/* The following structure is memory-only.
* Transfers to disk are indirectly via the
* format conversion functions below.
* The advantage is that even newer disk formats can be parsed
* by old code (of course, not all information / features will be
* available then).
*/
#define log_header log_header_v1
struct log_header_v1 {
struct timespec l_stamp;
struct timespec l_written;
loff_t l_pos;
int l_len;
int l_extra_len;
short l_code;
short l_extra;
int l_crc; // NYI
};
#define FORMAT_VERSION 1 // version of disk format, currently there is no other one
#define CODE_UNKNOWN 0
#define CODE_WRITE_NEW 1
#define CODE_WRITE_OLD 2
#define START_MAGIC 0xa8f7e908d9177957ll
#define END_MAGIC 0x74941fb74ab5726dll
#define START_OVERHEAD \
( \
sizeof(START_MAGIC) + \
sizeof(char) + \
sizeof(char) + \
sizeof(short) + \
sizeof(struct timespec) + \
sizeof(loff_t) + \
sizeof(int) + \
sizeof(int) + \
sizeof(short) + \
sizeof(short) + \
0 \
)
#define END_OVERHEAD \
( \
sizeof(END_MAGIC) + \
sizeof(int) + \
sizeof(char) + \
3 + 4 /*spare*/ + \
sizeof(struct timespec) + \
0 \
)
#define OVERHEAD (START_OVERHEAD + END_OVERHEAD)
// TODO: make this bytesex-aware.
#define DATA_PUT(data,offset,val) \
do { \
*((typeof(val)*)((data)+offset)) = val; \
offset += sizeof(val); \
} while (0)
#define DATA_GET(data,offset,val) \
do { \
val = *((typeof(val)*)((data)+offset)); \
offset += sizeof(val); \
} while (0)
////////////////////////////////////////////////////////////////////////////
#ifdef __KERNEL__
/* Bookkeeping status between calls
*/
struct log_status {
// tunables
int align_size; // alignment between requests
int chunk_size; // must be at least 8K (better 64k)
int max_flying; // limit allocation of buffers
int io_prio;
// informational
atomic_t mref_flying;
int count;
loff_t log_pos;
// internal
struct mars_input *input;
struct mars_brick *brick;
struct generic_object_layout ref_object_layout;
struct mars_info info;
int offset;
int validflag_offset;
int reallen_offset;
int payload_offset;
int payload_len;
struct mref_object *log_mref;
struct mref_object *read_mref;
wait_queue_head_t event;
int error_code;
bool got;
bool do_free;
void *private;
};
void init_logst(struct log_status *logst, struct mars_input *input, loff_t start_pos);
void exit_logst(struct log_status *logst);
bool is_log_ready(struct log_status *logst);
void log_flush(struct log_status *logst);
void *log_reserve(struct log_status *logst, struct log_header *lh);
bool log_finalize(struct log_status *logst, int len, void (*preio)(void *private), void (*endio)(void *private, int error), void *private);
int log_read(struct log_status *logst, struct log_header *lh, void **payload, int *payload_len);
/////////////////////////////////////////////////////////////////////////
// init
extern int init_log_format(void);
extern void exit_log_format(void);
#endif
#endif