jfs_logmgr.h

在Linux内核从2.4升级到2.6时需要升级的软件包

/*
 *   Copyright (c) International Business Machines Corp., 2000-2002
 *
 *   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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
#ifndef	_H_JFS_LOGMGR
#define _H_JFS_LOGMGR

#ifndef	_H_JFS_SUPERBLOCK
#include <uuid/uuid.h>
#endif

#include "jfs_types.h"
#include "jfs_filsys.h"

/*
 *	log manager configuration parameters
 */

/* log page size */
#define	LOGPSIZE	4096
#define	L2LOGPSIZE	  12

#define LOGPAGES	  16	/* Log pages per mounted file system */

/*
 *	log logical volume
 *
 * a log is used to make the commit operation on journalled
 * files within the same logical volume group atomic.
 * a log is implemented with a logical volume.
 * there is one log per logical volume group.
 *
 * block 0 of the log logical volume is not used (ipl etc).
 * block 1 contains a log "superblock" and is used by logFormat(),
 * lmLogInit(), lmLogShutdown(), and logRedo() to record status
 * of the log but is not otherwise used during normal processing.
 * blocks 2 - (N-1) are used to contain log records.
 *
 * when a volume group is varied-on-line, logRedo() must have
 * been executed before the file systems (logical volumes) in
 * the volume group can be mounted.
 */
/*
 *	log superblock (block 1 of logical volume)
 */
#define	LOGSUPER_B	1
#define	LOGSTART_B	2

#define	LOGMAGIC	0x87654321
#define	LOGVERSION	1

#define MAX_ACTIVE	128	/* Max active file systems sharing log */

struct logsuper {
	uint32_t magic;		/* 4: log lv identifier */
	int32_t version;	/* 4: version number */
	int32_t serial;		/* 4: log open/mount counter */
	int32_t size;		/* 4: size in number of LOGPSIZE blocks */
	int32_t bsize;		/* 4: logical block size in byte */
	int32_t l2bsize;	/* 4: log2 of bsize */

	uint32_t flag;		/* 4: option */
	uint32_t state;		/* 4: state - see below */

	int32_t end;		/* 4: addr of last log record set by logredo */
	uuid_t uuid;		/* 16: 128-bit journal uuid */
	char label[16];		/* 16: journal label */
	uuid_t active[MAX_ACTIVE];	/* 2048: active file systems list */
};

/* log flag: commit option (see jfs_filsys.h) */

/* log state */
#define	LOGMOUNT	0	/* log mounted by lmLogInit() */
#define LOGREDONE	1	/* log shutdown by lmLogShutdown().
				 * log redo completed by logredo().
				 */
#define LOGWRAP		2	/* log wrapped */
#define LOGREADERR	3	/* log read error detected in logredo() */

/*
 *	log logical page
 *
 * (this comment should be rewritten !)
 * the header and trailer structures (h,t) will normally have
 * the same page and eor value.
 * An exception to this occurs when a complete page write is not
 * accomplished on a power failure. Since the hardware may "split write"
 * sectors in the page, any out of order sequence may occur during powerfail
 * and needs to be recognized during log replay.  The xor value is
 * an "exclusive or" of all log words in the page up to eor.  This
 * 32 bit eor is stored with the top 16 bits in the header and the
 * bottom 16 bits in the trailer.  logredo can easily recognize pages
 * that were not completed by reconstructing this eor and checking
 * the log page.
 *
 * Previous versions of the operating system did not allow split
 * writes and detected partially written records in logredo by
 * ordering the updates to the header, trailer, and the move of data
 * into the logdata area.  The order: (1) data is moved (2) header
 * is updated (3) trailer is updated.  In logredo, when the header
 * differed from the trailer, the header and trailer were reconciled
 * as follows: if h.page != t.page they were set to the smaller of
 * the two and h.eor and t.eor set to 8 (i.e. empty page). if (only)
 * h.eor != t.eor they were set to the smaller of their two values.
 */
struct logpage {
	struct {		/* header */
		int32_t page;	/* 4: log sequence page number */
		int16_t rsrvd;	/* 2: */
		int16_t eor;	/* 2: end-of-log offset of lasrt record write */
	} h;

	int32_t data[LOGPSIZE / 4 - 4];	/* log record area */

	struct {		/* trailer */
		int32_t page;	/* 4: normally the same as h.page */
		int16_t rsrvd;	/* 2: */
		int16_t eor;	/* 2: normally the same as h.eor */
	} t;
};

#define LOGPHDRSIZE	8	/* log page header size */
#define LOGPTLRSIZE	8	/* log page trailer size */

/*
 *	log record
 *
 * (this comment should be rewritten !)
 * jfs uses only "after" log records (only a single writer is allowed
 * in a  page, pages are written to temporary paging space if
 * if they must be written to disk before commit, and i/o is
 * scheduled for modified pages to their home location after
 * the log records containing the after values and the commit
 * record is written to the log on disk, undo discards the copy
 * in main-memory.)
 *
 * a log record consists of a data area of variable length followed by
 * a descriptor of fixed size LOGRDSIZE bytes.
 * the  data area is rounded up to an integral number of 4-bytes and
 * must be no longer than LOGPSIZE.
 * the descriptor is of size of multiple of 4-bytes and aligned on a
 * 4-byte boundary.
 * records are packed one after the other in the data area of log pages.
 * (sometimes a DUMMY record is inserted so that at least one record ends
 * on every page or the longest record is placed on at most two pages).
 * the field eor in page header/trailer points to the byte following
 * the last record on a page.
 */

/* log record types */
#define LOG_COMMIT		0x8000
#define LOG_SYNCPT		0x4000
#define LOG_MOUNT		0x2000
#define LOG_REDOPAGE		0x0800
#define LOG_NOREDOPAGE		0x0080
#define LOG_NOREDOINOEXT	0x0040
#define LOG_UPDATEMAP		0x0008
#define LOG_NOREDOFILE		0x0001

/* REDOPAGE/NOREDOPAGE log record data type */
#define	LOG_INODE		0x0001
#define	LOG_XTREE		0x0002
#define	LOG_DTREE		0x0004
#define	LOG_BTROOT		0x0010
#define	LOG_EA			0x0020
#define	LOG_ACL			0x0040
#define	LOG_DATA		0x0080
#define	LOG_NEW			0x0100
#define	LOG_EXTEND		0x0200
#define LOG_RELOCATE		0x0400
#define LOG_DIR_XTREE		0x0800	/* Xtree is in directory inode */

/* UPDATEMAP log record descriptor type */
#define	LOG_ALLOCXADLIST	0x0080
#define	LOG_ALLOCPXDLIST	0x0040
#define	LOG_ALLOCXAD		0x0020
#define	LOG_ALLOCPXD		0x0010
#define	LOG_FREEXADLIST		0x0008
#define	LOG_FREEPXDLIST		0x0004
#define	LOG_FREEXAD		0x0002
#define	LOG_FREEPXD		0x0001

struct lrd {
	/*
	 * type independent area
	 */
	int32_t logtid;		/* 4: log transaction identifier */
	int32_t backchain;	/* 4: ptr to prev record of same transaction */
	uint16_t type;		/* 2: record type */
	int16_t length;		/* 2: length of data in record (in byte) */
	uint32_t aggregate;	/* 4: file system lv/aggregate */
				/* (16) */

	/*
	 * type dependent area (20)
	 */
	union {

		/*
		 *      COMMIT: commit
		 *
		 * transaction commit: no type-dependent information;
		 */

		/*
		 *      REDOPAGE: after-image
		 *
		 * apply after-image;
		 *
		 * N.B. REDOPAGE, NOREDOPAGE, and UPDATEMAP must be same format;
		 */
		struct {
			uint32_t fileset;	/* 4: fileset number */
			uint32_t inode;		/* 4: inode number */
			uint16_t type;		/* 2: REDOPAGE record type */
			int16_t l2linesize;	/* 2: log2 of line size */
			pxd_t pxd;		/* 8: on-disk page pxd */
		} redopage;			/* (20) */

		/*
		 *      NOREDOPAGE: the page is freed
		 *
		 * do not apply after-image records which precede this record
		 * in the log with the same page block number to this page.
		 *
		 * N.B. REDOPAGE, NOREDOPAGE, and UPDATEMAP must be same format;
		 */
		struct {
			int32_t fileset;	/* 4: fileset number */
			uint32_t inode;		/* 4: inode number */
			uint16_t type;		/* 2: NOREDOPAGE record type */
			int16_t rsrvd;		/* 2: reserved */
			pxd_t pxd;		/* 8: on-disk page pxd */
		} noredopage;			/* (20) */

		/*
		 *      UPDATEMAP: update block allocation map
		 *
		 * either in-line PXD,
		 * or     out-of-line  XADLIST;
		 *
		 * N.B. REDOPAGE, NOREDOPAGE, and UPDATEMAP must be same format;
		 */
		struct {
			uint32_t fileset;	/* 4: fileset number */
			uint32_t inode;		/* 4: inode number */
			uint16_t type;		/* 2: UPDATEMAP record type */
			int16_t nxd;		/* 2: number of extents */
			pxd_t pxd;		/* 8: pxd */
		} updatemap;			/* (20) */

		/*
		 *      NOREDOINOEXT: the inode extent is freed
		 *
		 * do not apply after-image records which precede this
		 * record in the log with the any of the 4 page block
		 * numbers in this inode extent.
		 *
		 * NOTE: The fileset and pxd fields MUST remain in
		 *       the same fields in the REDOPAGE record format.
		 *
		 */
		struct {
			int32_t fileset;	/* 4: fileset number */
			int32_t iagnum;		/* 4: IAG number     */
			int32_t inoext_idx;	/* 4: inode extent index */
			pxd_t pxd;		/* 8: on-disk page pxd */
		} noredoinoext;			/* (20) */

		/*
		 *      SYNCPT: log sync point
		 *
		 * replay log upto syncpt address specified;
		 */
		struct {
			int32_t sync;	/* 4: syncpt address (0 = here) */
		} syncpt;

		/*
		 *      MOUNT: file system mount
		 *
		 * file system mount: no type-dependent information;
		 */

		/*
		 *      ? FREEXTENT: free specified extent(s)
		 *
		 * free specified extent(s) from block allocation map
		 * N.B.: nextents should be length of data/sizeof(xad_t)
		 */
		struct {
			int32_t type;		/* 4: FREEXTENT record type */
			int32_t nextent;	/* 4: number of extents */

			/* data: PXD or XAD list */
		} freextent;

		/*
		 *      ? NOREDOFILE: this file is freed
		 *
		 * do not apply records which precede this record in the log
		 * with the same inode number.
		 *
		 * NOREDILE must be the first to be written at commit
		 * (last to be read in logredo()) - it prevents
		 * replay of preceding updates of all preceding generations
		 * of the inumber esp. the on-disk inode itself,
		 * but does NOT prevent
		 * replay of the
		 */
		struct {
			int32_t fileset;	/* 4: fileset number */
			uint32_t inode;		/* 4: inode number */
		} noredofile;

		/*
		 *      ? NEWPAGE:
		 *
		 * metadata type dependent
		 */
		struct {
			int32_t fileset;	/* 4: fileset number */
			uint32_t inode;		/* 4: inode number */
			int32_t type;		/* 4: NEWPAGE record type */
			pxd_t pxd;		/* 8: on-disk page pxd */
		} newpage;

		/*
		 *      ? DUMMY: filler
		 *
		 * no type-dependent information
		 */
	} log;
};					/* (36) */

#define	LOGRDSIZE	(sizeof(struct lrd))

#endif				/* _H_JFS_LOGMGR */