1. 根目录:
2. fs
3. jfs
4. jfs_imap.h

/*
 *   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_IMAP
#define _H_JFS_IMAP

#include "jfs_txnmgr.h"

/*
 *	jfs_imap.h: disk inode manager
 */

#define	EXTSPERIAG	128	/* number of disk inode extent per iag	*/
#define IMAPBLKNO	0	/* lblkno of dinomap within inode map	*/
#define SMAPSZ		4	/* number of words per summary map	*/
#define	EXTSPERSUM	32	/* number of extents per summary map entry */
#define	L2EXTSPERSUM	5	/* l2 number of extents per summary map */
#define	PGSPERIEXT	4	/* number of 4K pages per dinode extent */
#define	MAXIAGS		((1<<20)-1)	/* maximum number of iags	*/
#define	MAXAG		128	/* maximum number of allocation groups	*/

#define AMAPSIZE	512	/* bytes in the IAG allocation maps */
#define SMAPSIZE	16	/* bytes in the IAG summary maps */

/* convert inode number to iag number */
#define	INOTOIAG(ino)	((ino) >> L2INOSPERIAG)

/* convert iag number to logical block number of the iag page */
#define IAGTOLBLK(iagno,l2nbperpg)	(((iagno) + 1) << (l2nbperpg))

/* get the starting block number of the 4K page of an inode extent
 * that contains ino.
 */
#define INOPBLK(pxd,ino,l2nbperpg)	(addressPXD((pxd)) +		\
	((((ino) & (INOSPEREXT-1)) >> L2INOSPERPAGE) << (l2nbperpg)))

/*
 *	inode allocation map:
 *
 * inode allocation map consists of
 * . the inode map control page and
 * . inode allocation group pages (per 4096 inodes)
 * which are addressed by standard JFS xtree.
 */
/*
 *	inode allocation group page (per 4096 inodes of an AG)
 */
struct iag {
	__le64 agstart;		/* 8: starting block of ag		*/
	__le32 iagnum;		/* 4: inode allocation group number	*/
	__le32 inofreefwd;	/* 4: ag inode free list forward	*/
	__le32 inofreeback;	/* 4: ag inode free list back		*/
	__le32 extfreefwd;	/* 4: ag inode extent free list forward	*/
	__le32 extfreeback;	/* 4: ag inode extent free list back	*/
	__le32 iagfree;		/* 4: iag free list			*/

	/* summary map: 1 bit per inode extent */
	__le32 inosmap[SMAPSZ];	/* 16: sum map of mapwords w/ free inodes;
				 *	note: this indicates free and backed
				 *	inodes, if the extent is not backed the
				 *	value will be 1.  if the extent is
				 *	backed but all inodes are being used the
				 *	value will be 1.  if the extent is
				 *	backed but at least one of the inodes is
				 *	free the value will be 0.
				 */
	__le32 extsmap[SMAPSZ];	/* 16: sum map of mapwords w/ free extents */
	__le32 nfreeinos;	/* 4: number of free inodes		*/
	__le32 nfreeexts;	/* 4: number of free extents		*/
	/* (72) */
	u8 pad[1976];		/* 1976: pad to 2048 bytes */
	/* allocation bit map: 1 bit per inode (0 - free, 1 - allocated) */
	__le32 wmap[EXTSPERIAG];	/* 512: working allocation map */
	__le32 pmap[EXTSPERIAG];	/* 512: persistent allocation map */
	pxd_t inoext[EXTSPERIAG];	/* 1024: inode extent addresses */
};				/* (4096) */

/*
 *	per AG control information (in inode map control page)
 */
struct iagctl_disk {
	__le32 inofree;		/* 4: free inode list anchor		*/
	__le32 extfree;		/* 4: free extent list anchor		*/
	__le32 numinos;		/* 4: number of backed inodes		*/
	__le32 numfree;		/* 4: number of free inodes		*/
};				/* (16) */

struct iagctl {
	int inofree;		/* free inode list anchor		*/
	int extfree;		/* free extent list anchor		*/
	int numinos;		/* number of backed inodes		*/
	int numfree;		/* number of free inodes		*/
};

/*
 *	per fileset/aggregate inode map control page
 */
struct dinomap_disk {
	__le32 in_freeiag;	/* 4: free iag list anchor	*/
	__le32 in_nextiag;	/* 4: next free iag number	*/
	__le32 in_numinos;	/* 4: num of backed inodes	*/
	__le32 in_numfree;	/* 4: num of free backed inodes */
	__le32 in_nbperiext;	/* 4: num of blocks per inode extent */
	__le32 in_l2nbperiext;	/* 4: l2 of in_nbperiext	*/
	__le32 in_diskblock;	/* 4: for standalone test driver */
	__le32 in_maxag;	/* 4: for standalone test driver */
	u8 pad[2016];		/* 2016: pad to 2048		*/
	struct iagctl_disk in_agctl[MAXAG]; /* 2048: AG control information */
};				/* (4096) */

struct dinomap {
	int in_freeiag;		/* free iag list anchor		*/
	int in_nextiag;		/* next free iag number		*/
	int in_numinos;		/* num of backed inodes		*/
	int in_numfree;		/* num of free backed inodes	*/
	int in_nbperiext;	/* num of blocks per inode extent */
	int in_l2nbperiext;	/* l2 of in_nbperiext		*/
	int in_diskblock;	/* for standalone test driver	*/
	int in_maxag;		/* for standalone test driver	*/
	struct iagctl in_agctl[MAXAG];	/* AG control information */
};

/*
 *	In-core inode map control page
 */
struct inomap {
	struct dinomap im_imap;		/* 4096: inode allocation control */
	struct inode *im_ipimap;	/* 4: ptr to inode for imap	*/
	struct mutex im_freelock;	/* 4: iag free list lock	*/
	struct mutex im_aglock[MAXAG];	/* 512: per AG locks		*/
	u32 *im_DBGdimap;
	atomic_t im_numinos;	/* num of backed inodes */
	atomic_t im_numfree;	/* num of free backed inodes */
};

#define	im_freeiag	im_imap.in_freeiag
#define	im_nextiag	im_imap.in_nextiag
#define	im_agctl	im_imap.in_agctl
#define	im_nbperiext	im_imap.in_nbperiext
#define	im_l2nbperiext	im_imap.in_l2nbperiext

/* for standalone testdriver
 */
#define	im_diskblock	im_imap.in_diskblock
#define	im_maxag	im_imap.in_maxag

extern int diFree(struct inode *);
extern int diAlloc(struct inode *, bool, struct inode *);
extern int diSync(struct inode *);
/* external references */
extern int diUpdatePMap(struct inode *ipimap, unsigned long inum,
			bool is_free, struct tblock * tblk);
extern int diExtendFS(struct inode *ipimap, struct inode *ipbmap);
extern int diMount(struct inode *);
extern int diUnmount(struct inode *, int);
extern int diRead(struct inode *);
extern struct inode *diReadSpecial(struct super_block *, ino_t, int);
extern void diWriteSpecial(struct inode *, int);
extern void diFreeSpecial(struct inode *);
extern int diWrite(tid_t tid, struct inode *);
#endif				/* _H_JFS_IMAP */