jfs_btree.h

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/*
 *   Copyright (C) International Business Machines Corp., 2000-2004
 *
 *   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_BTREE
#define _H_JFS_BTREE

/*
 *  jfs_btree.h: B+-tree
 *
 * JFS B+-tree (dtree and xtree) common definitions
 */

/*
 *  basic btree page - btpage
 *
struct btpage {
    s64 next;       right sibling bn
    s64 prev;       left sibling bn

    u8 flag;
    u8 rsrvd[7];        type specific
    s64 self;       self address

    u8 entry[4064];
};                      */

/* btpaget_t flag */
#define BT_TYPE     0x07    /* B+-tree index */
#define BT_ROOT     0x01    /* root page */
#define BT_LEAF     0x02    /* leaf page */
#define BT_INTERNAL 0x04    /* internal page */
#define BT_RIGHTMOST    0x10    /* rightmost page */
#define BT_LEFTMOST 0x20    /* leftmost page */
#define BT_SWAPPED  0x80    /* used by fsck for endian swapping */

/* btorder (in inode) */
#define BT_RANDOM       0x0000
#define BT_SEQUENTIAL       0x0001
#define BT_LOOKUP       0x0010
#define BT_INSERT       0x0020
#define BT_DELETE       0x0040

/*
 *  btree page buffer cache access
 */
#define BT_IS_ROOT(MP) (((MP)->xflag & COMMIT_PAGE) == 0)

/* get page from buffer page */
#define BT_PAGE(IP, MP, TYPE, ROOT)\
    (BT_IS_ROOT(MP) ? (TYPE *)&JFS_IP(IP)->ROOT : (TYPE *)(MP)->data)

/* get the page buffer and the page for specified block address */
#define BT_GETPAGE(IP, BN, MP, TYPE, SIZE, P, RC, ROOT)\
{\
    if ((BN) == 0)\
    {\
        MP = (struct metapage *)&JFS_IP(IP)->bxflag;\
        P = (TYPE *)&JFS_IP(IP)->ROOT;\
        RC = 0;\
    }\
    else\
    {\
        MP = read_metapage((IP), BN, SIZE, 1);\
        if (MP) {\
            RC = 0;\
            P = (MP)->data;\
        } else {\
            P = NULL;\
            jfs_err("bread failed!");\
            RC = -EIO;\
        }\
    }\
}

#define BT_MARK_DIRTY(MP, IP)\
{\
    if (BT_IS_ROOT(MP))\
        mark_inode_dirty(IP);\
    else\
        mark_metapage_dirty(MP);\
}

/* put the page buffer */
#define BT_PUTPAGE(MP)\
{\
    if (! BT_IS_ROOT(MP)) \
        release_metapage(MP); \
}


/*
 *  btree traversal stack
 *
 * record the path traversed during the search;
 * top frame record the leaf page/entry selected.
 */
struct btframe {    /* stack frame */
    s64 bn;         /* 8: */
    s16 index;      /* 2: */
    s16 lastindex;      /* 2: unused */
    struct metapage *mp;    /* 4/8: */
};              /* (16/24) */

struct btstack {
    struct btframe *top;
    int nsplit;
    struct btframe stack[MAXTREEHEIGHT];
};

#define BT_CLR(btstack)\
    (btstack)->top = (btstack)->stack

#define BT_STACK_FULL(btstack)\
    ( (btstack)->top == &((btstack)->stack[MAXTREEHEIGHT-1]))

#define BT_PUSH(BTSTACK, BN, INDEX)\
{\
    assert(!BT_STACK_FULL(BTSTACK));\
    (BTSTACK)->top->bn = BN;\
    (BTSTACK)->top->index = INDEX;\
    ++(BTSTACK)->top;\
}

#define BT_POP(btstack)\
    ( (btstack)->top == (btstack)->stack ? NULL : --(btstack)->top )

#define BT_STACK(btstack)\
    ( (btstack)->top == (btstack)->stack ? NULL : (btstack)->top )

static inline void BT_STACK_DUMP(struct btstack *btstack)
{
    int i;
    printk("btstack dump:\n");
    for (i = 0; i < MAXTREEHEIGHT; i++)
        printk(KERN_ERR "bn = %Lx, index = %d\n",
               (long long)btstack->stack[i].bn,
               btstack->stack[i].index);
}

/* retrieve search results */
#define BT_GETSEARCH(IP, LEAF, BN, MP, TYPE, P, INDEX, ROOT)\
{\
    BN = (LEAF)->bn;\
    MP = (LEAF)->mp;\
    if (BN)\
        P = (TYPE *)MP->data;\
    else\
        P = (TYPE *)&JFS_IP(IP)->ROOT;\
    INDEX = (LEAF)->index;\
}

/* put the page buffer of search */
#define BT_PUTSEARCH(BTSTACK)\
{\
    if (! BT_IS_ROOT((BTSTACK)->top->mp))\
        release_metapage((BTSTACK)->top->mp);\
}
#endif              /* _H_JFS_BTREE */