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1.  Add another buffer to log, used for the case where a log record
	gets split in two when wrapping the physical log.
2.  Put iclog into bp->b_fsprivate field.  The original hack no
	longer works when a log record gets split in two.
3.  Add lots of ASSERT statements
4.  Re-use ic_refcnt field, so split writes will only kick off one
	iodone() for the pair of writes.
5.  Add original reservation length field in ticket for correct
	accounting of reservations.

#ifndef	_XFS_LOG_PRIV_H
#define _XFS_LOG_PRIV_H
/*
 * Macros, structures, prototypes for internal log manager use.
 */



#define LOG_NUM_ICLOGS		2
#define LOG_CALLBACK_SIZE	10
#define LOG_HEADER_MAGIC_NUM	0xFEEDbabe	/* need to outlaw as cycle XXX*/
#define LOG_RECORD_BSIZE	(4*1024)	/* eventually 32k */
#define LOG_RECORD_BSHIFT	12		/* 4096 == 1 << 12 */
#define LOG_HEADER_SIZE		512
#define LOG_BBSHIFT		12
#define LOG_BBSIZE		(1<<LOG_BBSHIFT)	/* 4096 */
#define LOG_BBMASK		(LOG_BBSIZE-1)
#define XLOGBB_TO_BB(x)		(((x) << LOG_BBSHIFT) >> BBSHIFT)

#define NBLOCKS(size)		((size)+LOG_BBSIZE-1 >> LOG_BBSHIFT)

#define ASSIGN_LSN(lsn,log)	{ ((uint *)&(lsn))[0] = (log)->l_curr_cycle; \
				  ((uint *)&(lsn))[1] = (log)->l_curr_block; }
#define CYCLE_LSN(lsn)		(((uint *)&(lsn))[0])
#define BLOCK_LSN(lsn)		(((uint *)&(lsn))[1])
#define log_panic(s)		{printf("%s\n", s); abort();}


/*
 * In core log state
 */
#define LOG_STATE_ACTIVE    1 /* Current IC log being written to */
#define LOG_STATE_WANT_SYNC 2 /* Want to sync this iclog; no more writes */
#define LOG_STATE_SYNCING   3 /* This IC log is syncing */
#define LOG_STATE_CALLBACK  4 /* Callback functions now */
#define LOG_STATE_DIRTY	    5 /* Dirty IC log, not ready for ACTIVE status */
#define LOG_STATE_NOTUSED   6 /* This IC log not being used */

/*
 * Flags to log operation header
 *
 * The first write of a new transaction will be preceded with a start
 * record, LOG_START_TRANS.  Once a transaction is committed, a commit
 * record is written, LOG_COMMIT_TRANS.  If a single region can not fit into
 * the remainder of the current active in-core log, it is split up into
 * multiple regions.  Each partial region will be marked with a
 * LOG_CONTINUE_TRANS until the last one, which gets marked with LOG_END_TRANS.
 *
 */
#define LOG_START_TRANS		0x1	/* Start a new transaction */
#define LOG_COMMIT_TRANS	0x2	/* Commit this transaction */
#define LOG_CONTINUE_TRANS	0x4	/* Cont this trans into new region */
#define LOG_END_TRANS		0x8	/* End a continued transaction */

/*
 * Flags to log ticket
 */
#define LOG_TIC_INITED		0x1	/* has been initialized */
#define LOG_TIC_PERM_RESERV	0x2	/* permanent reservation */

typedef void * log_tid_t;

typedef struct log_ticket {
	struct log_ticket *t_next;	/*			        : 4 */
	log_tid_t	  t_tid;	/* transaction identifier	: 4 */
	uint		  t_curr_reserv;/* current reservation in bytes : 4 */
	uint		  t_orig_reserv;/* original reservation in bytes: 4 */
	char		  t_clientid;	/* who does this belong to;	: 1 */
	char		  t_flags;	/* 				: 1 */
} log_ticket_t;


typedef struct log_op_header {
	log_tid_t  oh_tid;	/* transaction id of operation	:  4 b */
	int	   oh_len;	/* bytes in data region		:  4 b */
	char	   oh_clientid;	/* who sent me this		:  1 b */
	char	   oh_flags;	/* 				:  1 b */
	ushort	   oh_res2;	/* 32 bit align			:  2 b */
} log_op_header_t;


typedef struct log_rec_header {
	uint	  h_magicno;	/* log record (LR) identifier		:  4 */
	uint	  h_cycle;	/* write cycle of log			:  4 */
	int	  h_version;	/* LR version				:  4 */
	xfs_lsn_t h_lsn;	/* lsn of this LR			:  8 */
	xfs_lsn_t h_sync_lsn;	/* lsn of last LR with buffers committed:  8 */
	int	  h_len;	/* len in bytes; should be 64-bit aligned: 4 */
	uint	  h_chksum;	/* may not be used; non-zero if used	:  4 */
	int	  h_prev_offset;/* block offset to previous LR		:  4 */
	int	  h_num_logops;	/* number of log operations in this LR	:  4 */
	uint	  h_cycle_data[LOG_RECORD_BSIZE / BBSIZE];
} log_rec_header_t;


/*
 * - A log record header is 512 bytes.  There is plenty of room to grow the
 *	log_rec_header_t into the reserved space.
 * - ic_data follows, so a write to disk can start at the beginning of
 *	the iclog.
 * - ic_forcesema is used to implement synchronous forcing of the iclog to disk.
 * - ic_next is the pointer to the next iclog in the ring.
 * - ic_bp is a pointer to the buffer used to write this incore log to disk.
 * - ic_log is a pointer back to the global log structure.
 * - ic_callback is a linked list of callback function/argument pairs to be
 *	called after an iclog finishes writing.
 * - ic_size is the full size of the header plus data.
 * - ic_offset is the current number of bytes written to in this iclog.
 * - ic_refcnt is bumped when someone is writing to the log.
 * - ic_state is the state of the iclog.
 */
typedef struct log_in_core {
	union {
		log_rec_header_t hic_header;
		char		 hic_sector[LOG_HEADER_SIZE];
	} ic_h;
	char			ic_data[LOG_RECORD_BSIZE-LOG_HEADER_SIZE];
	sema_t			ic_forcesema;
	struct log_in_core	*ic_next;
	buf_t	  		*ic_bp;
	struct log		*ic_log;
	xfs_log_callback_t	*ic_callback;
	int	  		ic_size;
	int	  		ic_offset;
	int	  		ic_refcnt;
	char	  		ic_state;
} log_in_core_t;


#define ic_header	ic_h.hic_header

/*
 * 
 */
typedef struct log {
	log_ticket_t	*l_freelist;  /* free list of tickets		  :  4*/
	log_in_core_t	*l_iclog;     /* head log queue			  :  4*/
	sema_t		l_flushsema;  /* iclog flushing semaphore	  : 20*/
	lock_t		l_icloglock;  /* grab to change iclog state	  :  4*/
	xfs_lsn_t	l_sync_lsn;   /* lsn of 1st LR w/ unflushed buffers: 8*/
	xfs_mount_t	*l_mp;	      /* mount point			   : 4*/
    buf_t		*l_xbuf;      /* extra buffer for log wrapping	   : 4*/
	dev_t		l_dev;	      /* dev_t of log			   : 4*/
	int		l_logstart;   /* start block of log		   : 4*/
	int		l_logsize;    /* size of log in bytes 		   : 4*/
	int		l_logBBsize;  /* size of log in 512 byte chunks    : 4*/
	int		l_curr_cycle; /* Cycle number of log writes	   : 4*/
	int		l_prev_cycle; /* Cycle # b4 last block increment   : 4*/
	int		l_curr_block; /* current logical block of log	   : 4*/
	int		l_prev_block; /* previous logical block of log	   : 4*/
	int		l_logreserved;/* log space reserved		   : 4*/
} log_t;



#endif	/* _XFS_LOG_PRIV_H */