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jfs_dmap.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_DMAP
#define _H_JFS_DMAP

#include "jfs_types.h"

#define BMAPVERSION     1     /* version number */
#define     TREESIZE    (256+64+16+4+1)   /* size of a dmap tree */
#define     LEAFIND           (64+16+4+1) /* index of 1st leaf of a dmap tree */
#define LPERDMAP  256   /* num leaves per dmap tree */
#define L2LPERDMAP      8     /* l2 number of leaves per dmap tree */
#define     DBWORD            32    /* # of blks covered by a map word */
#define     L2DBWORD    5     /* l2 # of blks covered by a mword */
#define BUDMIN    L2DBWORD    /* max free string in a map word */
#define BPERDMAP  (LPERDMAP * DBWORD)     /* num of blks per dmap */
#define L2BPERDMAP      13    /* l2 num of blks per dmap */
#define CTLTREESIZE     (1024+256+64+16+4+1)    /* size of a dmapctl tree */
#define CTLLEAFIND      (256+64+16+4+1)   /* idx of 1st leaf of a dmapctl tree */
#define LPERCTL         1024  /* num of leaves per dmapctl tree */
#define L2LPERCTL 10    /* l2 num of leaves per dmapctl tree */
#define     ROOT        0     /* index of the root of a tree */
#define     NOFREE            ((int8_t) -1)     /* no blocks free */
#define     MAXAG       128   /* max number of allocation groups */
#define L2MAXAG         7     /* l2 max num of AG */
#define L2MINAGSZ 25    /* l2 of minimum AG size in bytes */
#define     BMAPBLKNO   0     /* lblkno of bmap within the map */

/*
 * maximum l2 number of disk blocks at the various dmapctl levels.
 */
#define     L2MAXL0SIZE (L2BPERDMAP + 1 * L2LPERCTL)
#define     L2MAXL1SIZE (L2BPERDMAP + 2 * L2LPERCTL)
#define     L2MAXL2SIZE (L2BPERDMAP + 3 * L2LPERCTL)

/*
 * maximum number of disk blocks at the various dmapctl levels.
 */
#define     MAXL0SIZE   ((int64_t)1 << L2MAXL0SIZE)
#define     MAXL1SIZE   ((int64_t)1 << L2MAXL1SIZE)
#define     MAXL2SIZE   ((int64_t)1 << L2MAXL2SIZE)

#define     MAXMAPSIZE  MAXL2SIZE   /* maximum aggregate map size */

/*
 * determine the maximum free string for four (lower level) nodes
 * of the tree.
 */
#define     TREEMAX(cp)                         \
      ((signed char)(MAX(MAX(*(cp),*((cp)+1)),  \
                         MAX(*((cp)+2),*((cp)+3)))))

/*
 * convert disk block number to the logical block number of the dmap
 * describing the disk block.  s is the log2(number of logical blocks per page)
 *
 * The calculation figures out how many logical pages are in front of the dmap.
 *    - the number of dmaps preceding it
 *    - the number of L0 pages preceding its L0 page
 *    - the number of L1 pages preceding its L1 page
 *    - 3 is added to account for the L2, L1, and L0 page for this dmap
 *    - 1 is added to account for the control page of the map.
 */
#define BLKTODMAP(b,s)    \
        ((((b) >> 13) + ((b) >> 23) + ((b) >> 33) + 3 + 1) << (s))

/*
 * convert disk block number to the logical block number of the LEVEL 0
 * dmapctl describing the disk block.  s is the log2(number of logical blocks
 * per page)
 *
 * The calculation figures out how many logical pages are in front of the L0.
 *    - the number of dmap pages preceding it
 *    - the number of L0 pages preceding it
 *    - the number of L1 pages preceding its L1 page
 *    - 2 is added to account for the L2, and L1 page for this L0
 *    - 1 is added to account for the control page of the map.
 */
#define BLKTOL0(b,s)      \
        (((((b) >> 23) << 10) + ((b) >> 23) + ((b) >> 33) + 2 + 1) << (s))

/*
 * convert disk block number to the logical block number of the LEVEL 1
 * dmapctl describing the disk block.  s is the log2(number of logical blocks
 * per page)
 *
 * The calculation figures out how many logical pages are in front of the L1.
 *    - the number of dmap pages preceding it
 *    - the number of L0 pages preceding it
 *    - the number of L1 pages preceding it
 *    - 1 is added to account for the L2 page
 *    - 1 is added to account for the control page of the map.
 */
#define BLKTOL1(b,s)      \
     (((((b) >> 33) << 20) + (((b) >> 33) << 10) + ((b) >> 33) + 1 + 1) << (s))

/*
 * convert disk block number to the logical block number of the dmapctl
 * at the specified level which describes the disk block.
 */
#define BLKTOCTL(b,s,l)   \
        (((l) == 2) ? 1 : ((l) == 1) ? BLKTOL1((b),(s)) : BLKTOL0((b),(s)))

/*
 * convert aggregate map size to the zero origin dmapctl level of the
 * top dmapctl.
 */
#define     BMAPSZTOLEV(size) \
      (((size) <= MAXL0SIZE) ? 0 : ((size) <= MAXL1SIZE) ? 1 : 2)

/* convert disk block number to allocation group number.
 */
#define BLKTOAG(b,sb)   ((b) >> ((sb)->s_jfs_bmap->db_agl2size))

/* convert allocation group number to starting disk block
 * number.
 */
#define AGTOBLK(a,ip)   \
      ((int64_t)(a) << ((ip)->i_sb->s_jfs_bmap->db_agl2size))

/*
 *    dmap summary tree
 *
 * struct dmaptree must be consistent with struct dmapctl.
 */
struct dmaptree {
      int32_t  nleafs;        /* 4: number of tree leafs      */
      int32_t  l2nleafs;            /* 4: l2 number of tree leafs   */
      int32_t  leafidx;       /* 4: index of first tree leaf  */
      int32_t  height;        /* 4: height of the tree        */
      int8_t   budmin;        /* 1: min l2 tree leaf value to combine */
      int8_t   stree[TREESIZE];     /* TREESIZE: tree               */
      uint8_t  pad[2];        /* 2: pad to word boundary      */
};                    /* - 360 -                      */

/*
 *    dmap page per 8K blocks bitmap
 */
struct dmap {
      int32_t     nblocks;          /* 4: num blks covered by this dmap     */
      int32_t     nfree;                /* 4: num of free blks in this dmap     */
      int64_t     start;                /* 8: starting blkno for this dmap      */
      struct dmaptree tree;           /* 360: dmap tree                       */
      uint8_t     pad[1672];        /* 1672: pad to 2048 bytes              */
      uint32_t    wmap[LPERDMAP];   /* 1024: bits of the working map        */
      uint32_t    pmap[LPERDMAP];   /* 1024: bits of the persistent map     */
};                                  /* - 4096 -                             */

/*
 *    disk map control page per level.
 *
 * struct dmapctl must be consistent with struct dmaptree.
 */
struct dmapctl {
      int32_t  nleafs;        /* 4: number of tree leafs         */
      int32_t  l2nleafs;            /* 4: l2 number of tree leafs      */
      int32_t  leafidx;       /* 4: index of the first tree leaf */
      int32_t  height;        /* 4: height of tree               */
      int8_t   budmin;        /* 1: minimum l2 tree leaf value   */
      int8_t   stree[CTLTREESIZE];/* CTLTREESIZE: dmapctl tree   */
      uint8_t  pad[2714];           /* 2714: pad to 4096               */
};                      /* - 4096 -                        */

/*
 *    common definition for dmaptree within dmap and dmapctl
 */
typedef union {
      struct dmaptree t1;
      struct dmapctl t2;
} dmtree_t;

/* macros for accessing fields within dmtree_t */
#define     dmt_nleafs    t1.nleafs
#define     dmt_l2nleafs  t1.l2nleafs
#define     dmt_leafidx   t1.leafidx
#define     dmt_height    t1.height
#define     dmt_budmin    t1.budmin
#define     dmt_stree     t1.stree

/*
 *    on-disk aggregate disk allocation map descriptor.
 */
struct dbmap {
      int64_t  dn_mapsize;          /* 8: number of blocks in aggregate     */
      int64_t  dn_nfree;                /* 8: num free blks in aggregate map    */
      int32_t  dn_l2nbperpage;      /* 4: number of blks per page           */
      int32_t  dn_numag;                /* 4: total number of ags               */
      int32_t  dn_maxlevel;       /* 4: number of active ags              */
      int32_t  dn_maxag;                /* 4: max active alloc group number     */
      int32_t  dn_agpref;           /* 4: preferred alloc group (hint)      */
      int32_t  dn_aglevel;          /* 4: dmapctl level holding the AG      */
      int32_t  dn_agheigth;       /* 4: height in dmapctl of the AG       */
      int32_t  dn_agwidth;          /* 4: width in dmapctl of the AG        */
      int32_t  dn_agstart;          /* 4: start tree index at AG height     */
      int32_t  dn_agl2size;       /* 4: l2 num of blks per alloc group    */
      int64_t  dn_agfree[MAXAG];  /* 8*MAXAG: per AG free count           */
      int64_t  dn_agsize;               /* 8: num of blks per alloc group       */
      int8_t   dn_maxfreebud;     /* 1: max free buddy system             */
      uint8_t  pad[3007];               /* 3007: pad to 4096                    */
};                            /* - 4096 -                             */

#endif                        /* _H_JFS_DMAP */

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