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/*-------------------------------------------------------------------------
*
* Shared Disk File EXclusiveness Control Program(SF-EX)
*
* sfex.h --- Primary include file for SF-EX *.c files.
*
* Copyright (c) 2007 NIPPON TELEGRAPH AND TELEPHONE CORPORATION
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* $Id$
*
*-------------------------------------------------------------------------*/
#ifndef SFEX_H
#define SFEX_H
#include <clplumbing/cl_log.h>
#include <clplumbing/coredumps.h>
#include <clplumbing/realtime.h>
#include <stdint.h>
/* version, revision */
/* These numbers are integer and, max number is 999.
If these numbers change, version numbers in the configure.ac
(AC_INIT, AM_INIT_AUTOMAKE) must change together.
*/
#define SFEX_VERSION 1
#define SFEX_REVISION 3
#if 0
#ifndef TRUE
# define TRUE 1
#endif
#ifndef FALSE
# define FALSE 0
#endif
#ifndef MIN
# define MIN(a, b) ((a) < (b) ? (a) : (b))
#endif
#ifndef MAX
# define MAX(a, b) ((a) > (b) ? (a) : (b))
#endif
#endif
/* for Linux >= 2.6, the alignment should be 512
for Linux < 2.6, the alignment should be sysconf(_SC_PAGESIZE)
we default to _SC_PAGESIZE
*/
#define SFEX_ODIRECT_ALIGNMENT sysconf(_SC_PAGESIZE)
/*
* sfex_controldata --- control data
*
* This is allocated the head of sfex mata-data area.
*
* magic number --- 4 bytes. This is fixed in {0x01, 0x1f, 0x71, 0x7f}.
*
* version number --- 4 bytes. This is printable integer number and
* range is from 0 to 999. This must be left-justify, null(0x00) padding, and
* make a last byte null.
*
* revision number --- 4 bytes. This is printable integer number and
* range is from 0 to 999. This must be left-justify, null(0x00) padding, and
* make a last byte null.
*
* blocksize --- 8bytes. This is printable integer number and range is from
* 512 to 9999999. This must be left-justify, null(0x00) padding, and make a
* last byte null. This is a size of control data and lock data(one lock data
* size when there are plural), and it is shown by number of bytes.
* For avoiding partial writing, usually block size is set 512 byte etc.
* If you use direct I/O(if you spacificate --enable-directio for configure
* script), note that this value is used for input and output buffer alignment.
* (In the Linux kernel 2.6, if this value is not 512 multibles, direct I/O
* does not work)
* number of locks --- 4 bytes. This is printable integer number and range
* is from 1 to 999. This must be left-justify, null(0x00) padding, and make
* a last byte null. This is the number of locks following this control data.
*
* padding --- The size of this member depend on blocksize. It is adjusted so
* that the whole of the control data including this padding area becomes
* blocksize. The contents of padding area are all 0x00.
*/
typedef struct sfex_controldata {
char magic[4]; /* magic number */
int version; /* version number */
int revision; /* revision number */
size_t blocksize; /* block size */
int numlocks; /* number of locks */
} sfex_controldata;
typedef struct sfex_controldata_ondisk {
uint8_t magic[4];
uint8_t version[4];
uint8_t revision[4];
uint8_t blocksize[8];
uint8_t numlocks[4];
} sfex_controldata_ondisk;
/*
* sfex_lockdata --- lock data
*
* This data(number is sfex_controldata.numlocks) are allocated behind of
* sfex_controldata in the sfex meta-data area. The meaning of each member
* and the storage method to mata data area are following;
*
* lock status --- 1 byte. printable character. Content is either one of
* following;
* SFEX_STATUS_UNLOCK: It show the status that no node locks.
* SFEX_STATUS_LOCK: It show the status that nodename node is holding lock.
* (But there is an exception. Refer to explanation of "count" member.)
*
* increment counter --- 4 bytes. This is printable integer number and range
* is from 1 to 999. This must be left-justify, null(0x00) padding, and make
* a last byte null. The node holding a lock increments this counter
* periodically. If this counter does not increment for a certain period of
* time, we consider that the lock is invalid. If it overflow, return to 0.
* Initial value is 0.
*
* node name --- 256bytes. This is printable string. This must be left-justify,
* null(0x00) padding, and make a last byte null. This is node name that update
* lock data last. The node name must be same to get uname(2). Initial values
* are white spaces.
*
* padding --- The size of this member depend on blocksize. It is adjusted so
* that the whole of the control data including this padding area becomes
* blocksize. The contents of padding area are all 0x00.
*/
typedef struct sfex_lockdata {
char status; /* status of lock */
int count; /* increment counter */
char nodename[256]; /* node name */
} sfex_lockdata;
typedef struct sfex_lockdata_ondisk {
uint8_t status;
uint8_t count[4];
uint8_t nodename[256];
} sfex_lockdata_ondisk;
/* character for lock status. This is used in sfex_lockdata.status */
#define SFEX_STATUS_UNLOCK 'u' /* unlock */
#define SFEX_STATUS_LOCK 'l' /* lock */
/* features of each member of control data and lock data */
#define SFEX_MAGIC "SFEX"
#define SFEX_MIN_NUMLOCKS 1
#define SFEX_MAX_NUMLOCKS 999
#define SFEX_MIN_COUNT 0
#define SFEX_MAX_COUNT 999
#define SFEX_MAX_NODENAME (sizeof(((sfex_lockdata *)0)->nodename) - 1)
/* update macro for increment counter */
#define SFEX_NEXT_COUNT(c) (c >= SFEX_MAX_COUNT ? c - SFEX_MAX_COUNT : c + 1)
/* extern variables */
extern const char *progname;
extern char *nodename;
extern unsigned long sector_size;
#endif /* SFEX_H */

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