xfs_btree.h

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/*
 * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * 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.
 *
 * This program is distributed in the hope that it would 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 the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#ifndef __XFS_BTREE_H__
#define __XFS_BTREE_H__

struct xfs_buf;
struct xfs_bmap_free;
struct xfs_inode;
struct xfs_mount;
struct xfs_trans;

extern kmem_zone_t  *xfs_btree_cur_zone;

/*
 * This nonsense is to make -wlint happy.
 */
#define XFS_LOOKUP_EQ   ((xfs_lookup_t)XFS_LOOKUP_EQi)
#define XFS_LOOKUP_LE   ((xfs_lookup_t)XFS_LOOKUP_LEi)
#define XFS_LOOKUP_GE   ((xfs_lookup_t)XFS_LOOKUP_GEi)

#define XFS_BTNUM_BNO   ((xfs_btnum_t)XFS_BTNUM_BNOi)
#define XFS_BTNUM_CNT   ((xfs_btnum_t)XFS_BTNUM_CNTi)
#define XFS_BTNUM_BMAP  ((xfs_btnum_t)XFS_BTNUM_BMAPi)
#define XFS_BTNUM_INO   ((xfs_btnum_t)XFS_BTNUM_INOi)

/*
 * Generic btree header.
 *
 * This is a combination of the actual format used on disk for short and long
 * format btrees.  The first three fields are shared by both format, but
 * the pointers are different and should be used with care.
 *
 * To get the size of the actual short or long form headers please use
 * the size macros below.  Never use sizeof(xfs_btree_block).
 */
struct xfs_btree_block {
    __be32      bb_magic;   /* magic number for block type */
    __be16      bb_level;   /* 0 is a leaf */
    __be16      bb_numrecs; /* current # of data records */
    union {
        struct {
            __be32      bb_leftsib;
            __be32      bb_rightsib;
        } s;            /* short form pointers */
        struct  {
            __be64      bb_leftsib;
            __be64      bb_rightsib;
        } l;            /* long form pointers */
    } bb_u;             /* rest */
};

#define XFS_BTREE_SBLOCK_LEN    16  /* size of a short form block */
#define XFS_BTREE_LBLOCK_LEN    24  /* size of a long form block */


/*
 * Generic key, ptr and record wrapper structures.
 *
 * These are disk format structures, and are converted where necessary
 * by the btree specific code that needs to interpret them.
 */
union xfs_btree_ptr {
    __be32          s;  /* short form ptr */
    __be64          l;  /* long form ptr */
};

union xfs_btree_key {
    xfs_bmbt_key_t      bmbt;
    xfs_bmdr_key_t      bmbr;   /* bmbt root block */
    xfs_alloc_key_t     alloc;
    xfs_inobt_key_t     inobt;
};

union xfs_btree_rec {
    xfs_bmbt_rec_t      bmbt;
    xfs_bmdr_rec_t      bmbr;   /* bmbt root block */
    xfs_alloc_rec_t     alloc;
    xfs_inobt_rec_t     inobt;
};

/*
 * For logging record fields.
 */
#define XFS_BB_MAGIC        0x01
#define XFS_BB_LEVEL        0x02
#define XFS_BB_NUMRECS      0x04
#define XFS_BB_LEFTSIB      0x08
#define XFS_BB_RIGHTSIB     0x10
#define XFS_BB_NUM_BITS     5
#define XFS_BB_ALL_BITS     ((1 << XFS_BB_NUM_BITS) - 1)

/*
 * Magic numbers for btree blocks.
 */
extern const __uint32_t xfs_magics[];

/*
 * Generic stats interface
 */
#define __XFS_BTREE_STATS_INC(type, stat) \
    XFS_STATS_INC(xs_ ## type ## _2_ ## stat)
#define XFS_BTREE_STATS_INC(cur, stat)  \
do {    \
    switch (cur->bc_btnum) {  \
    case XFS_BTNUM_BNO: __XFS_BTREE_STATS_INC(abtb, stat); break;   \
    case XFS_BTNUM_CNT: __XFS_BTREE_STATS_INC(abtc, stat); break;   \
    case XFS_BTNUM_BMAP: __XFS_BTREE_STATS_INC(bmbt, stat); break;  \
    case XFS_BTNUM_INO: __XFS_BTREE_STATS_INC(ibt, stat); break;    \
    case XFS_BTNUM_MAX: ASSERT(0); /* fucking gcc */ ; break;   \
    }       \
} while (0)

#define __XFS_BTREE_STATS_ADD(type, stat, val) \
    XFS_STATS_ADD(xs_ ## type ## _2_ ## stat, val)
#define XFS_BTREE_STATS_ADD(cur, stat, val)  \
do {    \
    switch (cur->bc_btnum) {  \
    case XFS_BTNUM_BNO: __XFS_BTREE_STATS_ADD(abtb, stat, val); break; \
    case XFS_BTNUM_CNT: __XFS_BTREE_STATS_ADD(abtc, stat, val); break; \
    case XFS_BTNUM_BMAP: __XFS_BTREE_STATS_ADD(bmbt, stat, val); break; \
    case XFS_BTNUM_INO: __XFS_BTREE_STATS_ADD(ibt, stat, val); break; \
    case XFS_BTNUM_MAX: ASSERT(0); /* fucking gcc */ ; break;   \
    }       \
} while (0)

#define XFS_BTREE_MAXLEVELS 8   /* max of all btrees */

struct xfs_btree_ops {
    /* size of the key and record structures */
    size_t  key_len;
    size_t  rec_len;

    /* cursor operations */
    struct xfs_btree_cur *(*dup_cursor)(struct xfs_btree_cur *);
    void    (*update_cursor)(struct xfs_btree_cur *src,
                 struct xfs_btree_cur *dst);

    /* update btree root pointer */
    void    (*set_root)(struct xfs_btree_cur *cur,
                union xfs_btree_ptr *nptr, int level_change);

    /* block allocation / freeing */
    int (*alloc_block)(struct xfs_btree_cur *cur,
                   union xfs_btree_ptr *start_bno,
                   union xfs_btree_ptr *new_bno,
                   int length, int *stat);
    int (*free_block)(struct xfs_btree_cur *cur, struct xfs_buf *bp);

    /* update last record information */
    void    (*update_lastrec)(struct xfs_btree_cur *cur,
                  struct xfs_btree_block *block,
                  union xfs_btree_rec *rec,
                  int ptr, int reason);

    /* records in block/level */
    int (*get_minrecs)(struct xfs_btree_cur *cur, int level);
    int (*get_maxrecs)(struct xfs_btree_cur *cur, int level);

    /* records on disk.  Matter for the root in inode case. */
    int (*get_dmaxrecs)(struct xfs_btree_cur *cur, int level);

    /* init values of btree structures */
    void    (*init_key_from_rec)(union xfs_btree_key *key,
                     union xfs_btree_rec *rec);
    void    (*init_rec_from_key)(union xfs_btree_key *key,
                     union xfs_btree_rec *rec);
    void    (*init_rec_from_cur)(struct xfs_btree_cur *cur,
                     union xfs_btree_rec *rec);
    void    (*init_ptr_from_cur)(struct xfs_btree_cur *cur,
                     union xfs_btree_ptr *ptr);

    /* difference between key value and cursor value */
    __int64_t (*key_diff)(struct xfs_btree_cur *cur,
                  union xfs_btree_key *key);

#ifdef DEBUG
    /* check that k1 is lower than k2 */
    int (*keys_inorder)(struct xfs_btree_cur *cur,
                union xfs_btree_key *k1,
                union xfs_btree_key *k2);

    /* check that r1 is lower than r2 */
    int (*recs_inorder)(struct xfs_btree_cur *cur,
                union xfs_btree_rec *r1,
                union xfs_btree_rec *r2);
#endif
};

/*
 * Reasons for the update_lastrec method to be called.
 */
#define LASTREC_UPDATE  0
#define LASTREC_INSREC  1
#define LASTREC_DELREC  2


/*
 * Btree cursor structure.
 * This collects all information needed by the btree code in one place.
 */
typedef struct xfs_btree_cur
{
    struct xfs_trans    *bc_tp; /* transaction we're in, if any */
    struct xfs_mount    *bc_mp; /* file system mount struct */
    const struct xfs_btree_ops *bc_ops;
    uint            bc_flags; /* btree features - below */
    union {
        xfs_alloc_rec_incore_t  a;
        xfs_bmbt_irec_t     b;
        xfs_inobt_rec_incore_t  i;
    }       bc_rec;     /* current insert/search record value */
    struct xfs_buf  *bc_bufs[XFS_BTREE_MAXLEVELS];  /* buf ptr per level */
    int     bc_ptrs[XFS_BTREE_MAXLEVELS];   /* key/record # */
    __uint8_t   bc_ra[XFS_BTREE_MAXLEVELS]; /* readahead bits */
#define XFS_BTCUR_LEFTRA    1   /* left sibling has been read-ahead */
#define XFS_BTCUR_RIGHTRA   2   /* right sibling has been read-ahead */
    __uint8_t   bc_nlevels; /* number of levels in the tree */
    __uint8_t   bc_blocklog;    /* log2(blocksize) of btree blocks */
    xfs_btnum_t bc_btnum;   /* identifies which btree type */
    union {
        struct {            /* needed for BNO, CNT, INO */
            struct xfs_buf  *agbp;  /* agf/agi buffer pointer */
            xfs_agnumber_t  agno;   /* ag number */
        } a;
        struct {            /* needed for BMAP */
            struct xfs_inode *ip;   /* pointer to our inode */
            struct xfs_bmap_free *flist;    /* list to free after */
            xfs_fsblock_t   firstblock; /* 1st blk allocated */
            int     allocated;  /* count of alloced */
            short       forksize;   /* fork's inode space */
            char        whichfork;  /* data or attr fork */
            char        flags;      /* flags */
#define XFS_BTCUR_BPRV_WASDEL   1           /* was delayed */
        } b;
    }       bc_private; /* per-btree type data */
} xfs_btree_cur_t;

/* cursor flags */
#define XFS_BTREE_LONG_PTRS     (1<<0)  /* pointers are 64bits long */
#define XFS_BTREE_ROOT_IN_INODE     (1<<1)  /* root may be variable size */
#define XFS_BTREE_LASTREC_UPDATE    (1<<2)  /* track last rec externally */


#define XFS_BTREE_NOERROR   0
#define XFS_BTREE_ERROR     1

/*
 * Convert from buffer to btree block header.
 */
#define XFS_BUF_TO_BLOCK(bp)    ((struct xfs_btree_block *)((bp)->b_addr))


/*
 * Check that block header is ok.
 */
int
xfs_btree_check_block(
    struct xfs_btree_cur    *cur,   /* btree cursor */
    struct xfs_btree_block  *block, /* generic btree block pointer */
    int         level,  /* level of the btree block */
    struct xfs_buf      *bp);   /* buffer containing block, if any */

/*
 * Check that (long) pointer is ok.
 */
int                 /* error (0 or EFSCORRUPTED) */
xfs_btree_check_lptr(
    struct xfs_btree_cur    *cur,   /* btree cursor */
    xfs_dfsbno_t        ptr,    /* btree block disk address */
    int         level); /* btree block level */

/*
 * Delete the btree cursor.
 */
void
xfs_btree_del_cursor(
    xfs_btree_cur_t     *cur,   /* btree cursor */
    int         error); /* del because of error */

/*
 * Duplicate the btree cursor.
 * Allocate a new one, copy the record, re-get the buffers.
 */
int                 /* error */
xfs_btree_dup_cursor(
    xfs_btree_cur_t     *cur,   /* input cursor */
    xfs_btree_cur_t     **ncur);/* output cursor */

/*
 * Get a buffer for the block, return it with no data read.
 * Long-form addressing.
 */
struct xfs_buf *                /* buffer for fsbno */
xfs_btree_get_bufl(
    struct xfs_mount    *mp,    /* file system mount point */
    struct xfs_trans    *tp,    /* transaction pointer */
    xfs_fsblock_t       fsbno,  /* file system block number */
    uint            lock);  /* lock flags for get_buf */

/*
 * Get a buffer for the block, return it with no data read.
 * Short-form addressing.
 */
struct xfs_buf *                /* buffer for agno/agbno */
xfs_btree_get_bufs(
    struct xfs_mount    *mp,    /* file system mount point */
    struct xfs_trans    *tp,    /* transaction pointer */
    xfs_agnumber_t      agno,   /* allocation group number */
    xfs_agblock_t       agbno,  /* allocation group block number */
    uint            lock);  /* lock flags for get_buf */

/*
 * Check for the cursor referring to the last block at the given level.
 */
int                 /* 1=is last block, 0=not last block */
xfs_btree_islastblock(
    xfs_btree_cur_t     *cur,   /* btree cursor */
    int         level); /* level to check */

/*
 * Compute first and last byte offsets for the fields given.
 * Interprets the offsets table, which contains struct field offsets.
 */
void
xfs_btree_offsets(
    __int64_t       fields, /* bitmask of fields */
    const short     *offsets,/* table of field offsets */
    int         nbits,  /* number of bits to inspect */
    int         *first, /* output: first byte offset */
    int         *last); /* output: last byte offset */

/*
 * Get a buffer for the block, return it read in.
 * Long-form addressing.
 */
int                 /* error */
xfs_btree_read_bufl(
    struct xfs_mount    *mp,    /* file system mount point */
    struct xfs_trans    *tp,    /* transaction pointer */
    xfs_fsblock_t       fsbno,  /* file system block number */
    uint            lock,   /* lock flags for read_buf */
    struct xfs_buf      **bpp,  /* buffer for fsbno */
    int         refval);/* ref count value for buffer */

/*
 * Read-ahead the block, don't wait for it, don't return a buffer.
 * Long-form addressing.
 */
void                    /* error */
xfs_btree_reada_bufl(
    struct xfs_mount    *mp,    /* file system mount point */
    xfs_fsblock_t       fsbno,  /* file system block number */
    xfs_extlen_t        count); /* count of filesystem blocks */

/*
 * Read-ahead the block, don't wait for it, don't return a buffer.
 * Short-form addressing.
 */
void                    /* error */
xfs_btree_reada_bufs(
    struct xfs_mount    *mp,    /* file system mount point */
    xfs_agnumber_t      agno,   /* allocation group number */
    xfs_agblock_t       agbno,  /* allocation group block number */
    xfs_extlen_t        count); /* count of filesystem blocks */


/*
 * Common btree core entry points.
 */
int xfs_btree_increment(struct xfs_btree_cur *, int, int *);
int xfs_btree_decrement(struct xfs_btree_cur *, int, int *);
int xfs_btree_lookup(struct xfs_btree_cur *, xfs_lookup_t, int *);
int xfs_btree_update(struct xfs_btree_cur *, union xfs_btree_rec *);
int xfs_btree_new_iroot(struct xfs_btree_cur *, int *, int *);
int xfs_btree_insert(struct xfs_btree_cur *, int *);
int xfs_btree_delete(struct xfs_btree_cur *, int *);
int xfs_btree_get_rec(struct xfs_btree_cur *, union xfs_btree_rec **, int *);

/*
 * Internal btree helpers also used by xfs_bmap.c.
 */
void xfs_btree_log_block(struct xfs_btree_cur *, struct xfs_buf *, int);
void xfs_btree_log_recs(struct xfs_btree_cur *, struct xfs_buf *, int, int);

/*
 * Helpers.
 */
static inline int xfs_btree_get_numrecs(struct xfs_btree_block *block)
{
    return be16_to_cpu(block->bb_numrecs);
}

static inline void xfs_btree_set_numrecs(struct xfs_btree_block *block,
        __uint16_t numrecs)
{
    block->bb_numrecs = cpu_to_be16(numrecs);
}

static inline int xfs_btree_get_level(struct xfs_btree_block *block)
{
    return be16_to_cpu(block->bb_level);
}


/*
 * Min and max functions for extlen, agblock, fileoff, and filblks types.
 */
#define XFS_EXTLEN_MIN(a,b) min_t(xfs_extlen_t, (a), (b))
#define XFS_EXTLEN_MAX(a,b) max_t(xfs_extlen_t, (a), (b))
#define XFS_AGBLOCK_MIN(a,b)    min_t(xfs_agblock_t, (a), (b))
#define XFS_AGBLOCK_MAX(a,b)    max_t(xfs_agblock_t, (a), (b))
#define XFS_FILEOFF_MIN(a,b)    min_t(xfs_fileoff_t, (a), (b))
#define XFS_FILEOFF_MAX(a,b)    max_t(xfs_fileoff_t, (a), (b))
#define XFS_FILBLKS_MIN(a,b)    min_t(xfs_filblks_t, (a), (b))
#define XFS_FILBLKS_MAX(a,b)    max_t(xfs_filblks_t, (a), (b))

#define XFS_FSB_SANITY_CHECK(mp,fsb)    \
    (XFS_FSB_TO_AGNO(mp, fsb) < mp->m_sb.sb_agcount && \
        XFS_FSB_TO_AGBNO(mp, fsb) < mp->m_sb.sb_agblocks)

/*
 * Trace hooks.  Currently not implemented as they need to be ported
 * over to the generic tracing functionality, which is some effort.
 *
 * i,j = integer (32 bit)
 * b = btree block buffer (xfs_buf_t)
 * p = btree ptr
 * r = btree record
 * k = btree key
 */
#define XFS_BTREE_TRACE_ARGBI(c, b, i)
#define XFS_BTREE_TRACE_ARGBII(c, b, i, j)
#define XFS_BTREE_TRACE_ARGI(c, i)
#define XFS_BTREE_TRACE_ARGIPK(c, i, p, s)
#define XFS_BTREE_TRACE_ARGIPR(c, i, p, r)
#define XFS_BTREE_TRACE_ARGIK(c, i, k)
#define XFS_BTREE_TRACE_ARGR(c, r)
#define XFS_BTREE_TRACE_CURSOR(c, t)

#endif  /* __XFS_BTREE_H__ */