[safe/jmp/linux-2.6] / fs / xfs / xfs_btree.h

/*
 * 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)

/*
 * Short form header: space allocation btrees.
 */
typedef struct xfs_btree_sblock {
        __be32          bb_magic;       /* magic number for block type */
        __be16          bb_level;       /* 0 is a leaf */
        __be16          bb_numrecs;     /* current # of data records */
        __be32          bb_leftsib;     /* left sibling block or NULLAGBLOCK */
        __be32          bb_rightsib;    /* right sibling block or NULLAGBLOCK */
} xfs_btree_sblock_t;

/*
 * Long form header: bmap btrees.
 */
typedef struct xfs_btree_lblock {
        __be32          bb_magic;       /* magic number for block type */
        __be16          bb_level;       /* 0 is a leaf */
        __be16          bb_numrecs;     /* current # of data records */
        __be64          bb_leftsib;     /* left sibling block or NULLDFSBNO */
        __be64          bb_rightsib;    /* right sibling block or NULLDFSBNO */
} xfs_btree_lblock_t;

/*
 * Combined header and structure, used by common code.
 */
typedef 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 */
} xfs_btree_block_t;

/*
 * 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[];

/*
 * Maximum and minimum records in a btree block.
 * Given block size, type prefix, and leaf flag (0 or 1).
 * The divisor below is equivalent to lf ? (e1) : (e2) but that produces
 * compiler warnings.
 */
#define XFS_BTREE_BLOCK_MAXRECS(bsz,t,lf)       \
        ((int)(((bsz) - (uint)sizeof(t ## _block_t)) / \
         (((lf) * (uint)sizeof(t ## _rec_t)) + \
          ((1 - (lf)) * \
           ((uint)sizeof(t ## _key_t) + (uint)sizeof(t ## _ptr_t))))))
#define XFS_BTREE_BLOCK_MINRECS(bsz,t,lf)       \
        (XFS_BTREE_BLOCK_MAXRECS(bsz,t,lf) / 2)

/*
 * Record, key, and pointer address calculation macros.
 * Given block size, type prefix, block pointer, and index of requested entry
 * (first entry numbered 1).
 */
#define XFS_BTREE_REC_ADDR(t,bb,i)      \
        ((t ## _rec_t *)((char *)(bb) + sizeof(t ## _block_t) + \
         ((i) - 1) * sizeof(t ## _rec_t)))
#define XFS_BTREE_KEY_ADDR(t,bb,i)      \
        ((t ## _key_t *)((char *)(bb) + sizeof(t ## _block_t) + \
         ((i) - 1) * sizeof(t ## _key_t)))
#define XFS_BTREE_PTR_ADDR(t,bb,i,mxr)  \
        ((t ## _ptr_t *)((char *)(bb) + sizeof(t ## _block_t) + \
         (mxr) * sizeof(t ## _key_t) + ((i) - 1) * sizeof(t ## _ptr_t)))

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

struct xfs_btree_ops {
        /* cursor operations */
        struct xfs_btree_cur *(*dup_cursor)(struct xfs_btree_cur *);
};

/*
 * 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_NOERROR       0
#define XFS_BTREE_ERROR         1

/*
 * Convert from buffer to btree block header.
 */
#define XFS_BUF_TO_BLOCK(bp)    ((xfs_btree_block_t *)XFS_BUF_PTR(bp))
#define XFS_BUF_TO_LBLOCK(bp)   ((xfs_btree_lblock_t *)XFS_BUF_PTR(bp))
#define XFS_BUF_TO_SBLOCK(bp)   ((xfs_btree_sblock_t *)XFS_BUF_PTR(bp))


#ifdef __KERNEL__

#ifdef DEBUG
/*
 * Debug routine: check that block header is ok.
 */
void
xfs_btree_check_block(
        xfs_btree_cur_t         *cur,   /* btree cursor */
        xfs_btree_block_t       *block, /* generic btree block pointer */
        int                     level,  /* level of the btree block */
        struct xfs_buf          *bp);   /* buffer containing block, if any */

/*
 * Debug routine: check that keys are in the right order.
 */
void
xfs_btree_check_key(
        xfs_btnum_t             btnum,  /* btree identifier */
        void                    *ak1,   /* pointer to left (lower) key */
        void                    *ak2);  /* pointer to right (higher) key */

/*
 * Debug routine: check that records are in the right order.
 */
void
xfs_btree_check_rec(
        xfs_btnum_t             btnum,  /* btree identifier */
        void                    *ar1,   /* pointer to left (lower) record */
        void                    *ar2);  /* pointer to right (higher) record */
#else
#define xfs_btree_check_block(a,b,c,d)
#define xfs_btree_check_key(a,b,c)
#define xfs_btree_check_rec(a,b,c)
#endif  /* DEBUG */

/*
 * Checking routine: check that long form block header is ok.
 */
int                                     /* error (0 or EFSCORRUPTED) */
xfs_btree_check_lblock(
        xfs_btree_cur_t         *cur,   /* btree cursor */
        xfs_btree_lblock_t      *block, /* btree long form block pointer */
        int                     level,  /* level of the btree block */
        struct xfs_buf          *bp);   /* buffer containing block, if any */

/*
 * Checking routine: check that (long) pointer is ok.
 */
int                                     /* error (0 or EFSCORRUPTED) */
xfs_btree_check_lptr(
        xfs_btree_cur_t         *cur,   /* btree cursor */
        xfs_dfsbno_t            ptr,    /* btree block disk address */
        int                     level); /* btree block level */

#define xfs_btree_check_lptr_disk(cur, ptr, level) \
        xfs_btree_check_lptr(cur, be64_to_cpu(ptr), level)

/*
 * Checking routine: check that short form block header is ok.
 */
int                                     /* error (0 or EFSCORRUPTED) */
xfs_btree_check_sblock(
        xfs_btree_cur_t         *cur,   /* btree cursor */
        xfs_btree_sblock_t      *block, /* btree short form block pointer */
        int                     level,  /* level of the btree block */
        struct xfs_buf          *bp);   /* buffer containing block */

/*
 * Checking routine: check that (short) pointer is ok.
 */
int                                     /* error (0 or EFSCORRUPTED) */
xfs_btree_check_sptr(
        xfs_btree_cur_t         *cur,   /* btree cursor */
        xfs_agblock_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 */

/*
 * Change the cursor to point to the first record in the current block
 * at the given level.  Other levels are unaffected.
 */
int                                     /* success=1, failure=0 */
xfs_btree_firstrec(
        xfs_btree_cur_t         *cur,   /* btree cursor */
        int                     level); /* level to change */

/*
 * 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 */

/*
 * Change the cursor to point to the last record in the current block
 * at the given level.  Other levels are unaffected.
 */
int                                     /* success=1, failure=0 */
xfs_btree_lastrec(
        xfs_btree_cur_t         *cur,   /* btree cursor */
        int                     level); /* level to change */

/*
 * 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 */

/*
 * Get a buffer for the block, return it read in.
 * Short-form addressing.
 */
int                                     /* error */
xfs_btree_read_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 read_buf */
        struct xfs_buf          **bpp,  /* buffer for agno/agbno */
        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 */

/*
 * Read-ahead btree blocks, at the given level.
 * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
 */
int                                     /* readahead block count */
xfs_btree_readahead_core(
        xfs_btree_cur_t         *cur,   /* btree cursor */
        int                     lev,    /* level in btree */
        int                     lr);    /* left/right bits */

static inline int                       /* readahead block count */
xfs_btree_readahead(
        xfs_btree_cur_t         *cur,   /* btree cursor */
        int                     lev,    /* level in btree */
        int                     lr)     /* left/right bits */
{
        if ((cur->bc_ra[lev] | lr) == cur->bc_ra[lev])
                return 0;

        return xfs_btree_readahead_core(cur, lev, lr);
}


/*
 * Set the buffer for level "lev" in the cursor to bp, releasing
 * any previous buffer.
 */
void
xfs_btree_setbuf(
        xfs_btree_cur_t         *cur,   /* btree cursor */
        int                     lev,    /* level in btree */
        struct xfs_buf          *bp);   /* new buffer to set */

#endif  /* __KERNEL__ */


/*
 * 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)

#endif  /* __XFS_BTREE_H__ */