FreeBSD/Linux Kernel Cross Reference
sys/fs/jfs/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_txnmgr.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          ((s8) -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       ((s64)1 << L2MAXL0SIZE)
    #define MAXL1SIZE       ((s64)1 << L2MAXL1SIZE)
    #define MAXL2SIZE       ((s64)1 << L2MAXL2SIZE)
    
    #define MAXMAPSIZE      MAXL2SIZE       /* maximum aggregate map size */
    
    /* 
     * determine the maximum free string for four (lower level) nodes
     * of the tree.
     */
    static __inline signed char TREEMAX(signed char *cp)
    {
            signed char tmp1, tmp2;
    
            tmp1 = max(*(cp+2), *(cp+3));
            tmp2 = max(*(cp), *(cp+1));
    
            return max(tmp1, tmp2);
    }
    
    /*
     * 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,sbi)  ((b) >> ((sbi)->bmap->db_agl2size))
   
   /* convert allocation group number to starting disk block
    * number.
    */
   #define AGTOBLK(a,ip)   \
           ((s64)(a) << (JFS_SBI((ip)->i_sb)->bmap->db_agl2size))
   
   /*
    *      dmap summary tree
    *
    * dmaptree must be consistent with dmapctl.
    */
   struct dmaptree {
           s32 nleafs;             /* 4: number of tree leafs      */
           s32 l2nleafs;           /* 4: l2 number of tree leafs   */
           s32 leafidx;            /* 4: index of first tree leaf  */
           s32 height;             /* 4: height of the tree        */
           s8 budmin;              /* 1: min l2 tree leaf value to combine */
           s8 stree[TREESIZE];     /* TREESIZE: tree               */
           u8 pad[2];              /* 2: pad to word boundary      */
   };                              /* - 360 -                      */
   
   /*
    *      dmap page per 8K blocks bitmap
    */
   struct dmap {
           s32 nblocks;            /* 4: num blks covered by this dmap     */
           s32 nfree;              /* 4: num of free blks in this dmap     */
           s64 start;              /* 8: starting blkno for this dmap      */
           struct dmaptree tree;   /* 360: dmap tree                       */
           u8 pad[1672];           /* 1672: pad to 2048 bytes              */
           u32 wmap[LPERDMAP];     /* 1024: bits of the working map        */
           u32 pmap[LPERDMAP];     /* 1024: bits of the persistent map     */
   };                              /* - 4096 -                             */
   
   /*
    *      disk map control page per level.
    *
    * dmapctl must be consistent with dmaptree.
    */
   struct dmapctl {
           s32 nleafs;             /* 4: number of tree leafs      */
           s32 l2nleafs;           /* 4: l2 number of tree leafs   */
           s32 leafidx;            /* 4: index of the first tree leaf      */
           s32 height;             /* 4: height of tree            */
           s8 budmin;              /* 1: minimum l2 tree leaf value        */
           s8 stree[CTLTREESIZE];  /* CTLTREESIZE: dmapctl tree    */
           u8 pad[2714];           /* 2714: pad to 4096            */
   };                              /* - 4096 -                     */
   
   /*
    *      common definition for dmaptree within dmap and dmapctl
    */
   typedef union dmtree {
           struct dmaptree t1;
           struct dmapctl t2;
   } dmtree_t;
   
   /* macros for accessing fields within dmtree */
   #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 {
           s64 dn_mapsize;         /* 8: number of blocks in aggregate     */
           s64 dn_nfree;           /* 8: num free blks in aggregate map    */
           s32 dn_l2nbperpage;     /* 4: number of blks per page           */
           s32 dn_numag;           /* 4: total number of ags               */
           s32 dn_maxlevel;        /* 4: number of active ags              */
           s32 dn_maxag;           /* 4: max active alloc group number     */
           s32 dn_agpref;          /* 4: preferred alloc group (hint)      */
           s32 dn_aglevel;         /* 4: dmapctl level holding the AG      */
           s32 dn_agheigth;        /* 4: height in dmapctl of the AG       */
           s32 dn_agwidth;         /* 4: width in dmapctl of the AG        */
           s32 dn_agstart;         /* 4: start tree index at AG height     */
           s32 dn_agl2size;        /* 4: l2 num of blks per alloc group    */
           s64 dn_agfree[MAXAG];   /* 8*MAXAG: per AG free count           */
           s64 dn_agsize;          /* 8: num of blks per alloc group       */
           s8 dn_maxfreebud;       /* 1: max free buddy system             */
           u8 pad[3007];           /* 3007: pad to 4096                    */
   };                              /* - 4096 -                             */
   
   /* 
    *      in-memory aggregate disk allocation map descriptor.
    */
   struct bmap {
           struct dbmap db_bmap;   /* on-disk aggregate map descriptor */
           struct inode *db_ipbmap;        /* ptr to aggregate map incore inode */
           struct semaphore db_bmaplock;   /* aggregate map lock */
           atomic_t db_active[MAXAG];      /* count of active, open files in AG */
           u32 *db_DBmap;
   };
   
   /* macros for accessing fields within in-memory aggregate map descriptor */
   #define db_mapsize      db_bmap.dn_mapsize
   #define db_nfree        db_bmap.dn_nfree
   #define db_agfree       db_bmap.dn_agfree
   #define db_agsize       db_bmap.dn_agsize
   #define db_agl2size     db_bmap.dn_agl2size
   #define db_agwidth      db_bmap.dn_agwidth
   #define db_agheigth     db_bmap.dn_agheigth
   #define db_agstart      db_bmap.dn_agstart
   #define db_numag        db_bmap.dn_numag
   #define db_maxlevel     db_bmap.dn_maxlevel
   #define db_aglevel      db_bmap.dn_aglevel
   #define db_agpref       db_bmap.dn_agpref
   #define db_maxag        db_bmap.dn_maxag
   #define db_maxfreebud   db_bmap.dn_maxfreebud
   #define db_l2nbperpage  db_bmap.dn_l2nbperpage
   
   /*
    * macros for various conversions needed by the allocators.
    * blkstol2(), cntlz(), and cnttz() are operating system dependent functions.
    */
   /* convert number of blocks to log2 number of blocks, rounding up to
    * the next log2 value if blocks is not a l2 multiple.
    */
   #define BLKSTOL2(d)             (blkstol2(d))
   
   /* convert number of leafs to log2 leaf value */
   #define NLSTOL2BSZ(n)           (31 - cntlz((n)) + BUDMIN)
   
   /* convert leaf index to log2 leaf value */
   #define LITOL2BSZ(n,m,b)        ((((n) == 0) ? (m) : cnttz((n))) + (b))
   
   /* convert a block number to a dmap control leaf index */
   #define BLKTOCTLLEAF(b,m)       \
           (((b) & (((s64)1 << ((m) + L2LPERCTL)) - 1)) >> (m))
   
   /* convert log2 leaf value to buddy size */
   #define BUDSIZE(s,m)            (1 << ((s) - (m)))
   
   /*
    *      external references.
    */
   extern int dbMount(struct inode *ipbmap);
   
   extern int dbUnmount(struct inode *ipbmap, int mounterror);
   
   extern int dbFree(struct inode *ipbmap, s64 blkno, s64 nblocks);
   
   extern int dbUpdatePMap(struct inode *ipbmap,
                           int free, s64 blkno, s64 nblocks, struct tblock * tblk);
   
   extern int dbNextAG(struct inode *ipbmap);
   
   extern int dbAlloc(struct inode *ipbmap, s64 hint, s64 nblocks, s64 * results);
   
   extern int dbAllocExact(struct inode *ip, s64 blkno, int nblocks);
   
   extern int dbReAlloc(struct inode *ipbmap,
                        s64 blkno, s64 nblocks, s64 addnblocks, s64 * results);
   
   extern int dbSync(struct inode *ipbmap);
   extern int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks);
   extern int dbExtendFS(struct inode *ipbmap, s64 blkno, s64 nblocks);
   extern void dbFinalizeBmap(struct inode *ipbmap);
   extern s64 dbMapFileSizeToMapSize(struct inode *ipbmap);
   #endif                          /* _H_JFS_DMAP */

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