FreeBSD/Linux Kernel Cross Reference
sys/fs/jfs/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 {
            s64 agstart;            /* 8: starting block of ag              */
            s32 iagnum;             /* 4: inode allocation group number     */
            s32 inofreefwd;         /* 4: ag inode free list forward        */
            s32 inofreeback;        /* 4: ag inode free list back           */
            s32 extfreefwd;         /* 4: ag inode extent free list forward */
            s32 extfreeback;        /* 4: ag inode extent free list back    */
            s32 iagfree;            /* 4: iag free list                     */
    
            /* summary map: 1 bit per inode extent */
            s32 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.
                                     */
            s32 extsmap[SMAPSZ];    /* 16: sum map of mapwords w/ free extents */
            s32 nfreeinos;          /* 4: number of free inodes             */
            s32 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) */
            u32 wmap[EXTSPERIAG];   /* 512: working allocation map  */
            u32 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 {
            s32 inofree;            /* 4: free inode list anchor            */
            s32 extfree;            /* 4: free extent list anchor           */
            s32 numinos;            /* 4: number of backed inodes           */
            s32 numfree;            /* 4: number of free inodes             */
   };                              /* (16) */
   
   /*
    *      per fileset/aggregate inode map control page
    */
   struct dinomap {
           s32 in_freeiag;         /* 4: free iag list anchor     */
           s32 in_nextiag;         /* 4: next free iag number     */
           s32 in_numinos;         /* 4: num of backed inodes */
           s32 in_numfree;         /* 4: num of free backed inodes */
           s32 in_nbperiext;       /* 4: num of blocks per inode extent */
           s32 in_l2nbperiext;     /* 4: l2 of in_nbperiext */
           s32 in_diskblock;       /* 4: for standalone test driver  */
           s32 in_maxag;           /* 4: for standalone test driver  */
           u8 pad[2016];           /* 2016: pad to 2048 */
           struct iagctl in_agctl[MAXAG];  /* 2048: AG control information */
   };                              /* (4096) */
   
   
   /*
    *      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 semaphore im_freelock;   /* 4: iag free list lock      */
           struct semaphore 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 *, boolean_t, struct inode *);
   extern int diSync(struct inode *);
   /* external references */
   extern int diUpdatePMap(struct inode *ipimap, unsigned long inum,
                           boolean_t 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 */

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