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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

/*
 *    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 {
      int64_t   agstart;                   /* 8: starting block of ag              */
      int32_t   iagnum;              /* 4: inode allocation group number     */
      int32_t   inofreefwd;            /* 4: ag inode free list forward        */
      int32_t   inofreeback;         /* 4: ag inode free list back           */
      int32_t   extfreefwd;            /* 4: ag inode extent free list forward */
      int32_t   extfreeback;         /* 4: ag inode extent free list back    */
      int32_t   iagfree;                   /* 4: iag free list                     */

      /* summary map: 1 bit per inode extent */
      int32_t   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.
                                            */
      int32_t   extsmap[SMAPSZ];       /* 16: sum map of mapwords w/ free extents */
      int32_t   nfreeinos;             /* 4: number of free inodes             */
      int32_t   nfreeexts;             /* 4: number of free extents            */
      /* (72) */
      uint8_t   pad[1976];             /* 1976: pad to 2048 bytes */
      /* allocation bit map: 1 bit per inode (0 - free, 1 - allocated) */
      uint32_t  wmap[EXTSPERIAG];      /* 512: working allocation map  */
      uint32_t  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 {
      int32_t  inofree;       /* 4: free inode list anchor            */
      int32_t  extfree;       /* 4: free extent list anchor           */
      int32_t  numinos;       /* 4: number of backed inodes           */
      int32_t  numfree;       /* 4: number of free inodes             */
};                /* (16) */

/*
 *    per fileset/aggregate inode map control page
 */
struct dinomap {
      int32_t   in_freeiag;         /* 4: free iag list anchor     */
      int32_t   in_nextiag;         /* 4: next free iag number     */
      int32_t   in_numinos;         /* 4: num of backed inodes */
      int32_t   in_numfree;         /* 4: num of free backed inodes */
      int32_t   in_nbperiext;     /* 4: num of blocks per inode extent */
      int32_t   in_l2nbperiext;     /* 4: l2 of in_nbperiext */
      int32_t   in_diskblock;     /* 4: for standalone test driver  */
      int32_t   in_maxag;               /* 4: for standalone test driver  */
      uint8_t   pad[2016];          /* 2016: pad to 2048 */
      struct iagctl  in_agctl[MAXAG];     /* 2048: AG control information */
};                /* (4096) */

#endif                        /* _H_JFS_IMAP */

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