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65f1eaeac0
linux-next/fs/xfs/xfs_btree.h
Christoph Hellwig 65f1eaeac0 [XFS] add helpers for addressing entities inside a btree block 
Add new helpers in xfs_btree.c to find the record, key and block pointer
entries inside a btree block. To implement this genericly the
->get_maxrecs methods and two new xfs_btree_ops entries for the key and
record sizes are used. Also add a big comment describing how the
addressing inside a btree block works.

Note that these helpers are unused until users are introduced in the next
patches and this patch will thus cause some harmless compiler warnings.

SGI-PV: 985583

SGI-Modid: xfs-linux-melb:xfs-kern:32189a

Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Bill O'Donnell <billodo@sgi.com>
Signed-off-by: David Chinner <david@fromorbit.com>
2008-10-30 16:55:34 +11:00

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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)
/*
* 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[];
/*
* 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)
/*
* 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 {
/* 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 *);
/* records in block/level */
int (*get_maxrecs)(struct xfs_btree_cur *cur, int level);
/* btree tracing */
#ifdef XFS_BTREE_TRACE
void (*trace_enter)(struct xfs_btree_cur *, const char *,
char *, int, int, __psunsigned_t,
__psunsigned_t, __psunsigned_t,
__psunsigned_t, __psunsigned_t,
__psunsigned_t, __psunsigned_t,
__psunsigned_t, __psunsigned_t,
__psunsigned_t, __psunsigned_t);
void (*trace_cursor)(struct xfs_btree_cur *, __uint32_t *,
__uint64_t *, __uint64_t *);
void (*trace_key)(struct xfs_btree_cur *,
union xfs_btree_key *, __uint64_t *,
__uint64_t *);
void (*trace_record)(struct xfs_btree_cur *,
union xfs_btree_rec *, __uint64_t *,
__uint64_t *, __uint64_t *);
#endif
};
/*
* 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__
/*
* Check that long form block header is ok.
*/
int /* error (0 or EFSCORRUPTED) */
xfs_btree_check_lblock(
struct xfs_btree_cur *cur, /* btree cursor */
struct xfs_btree_lblock *block, /* btree long form block pointer */
int level, /* level of the btree block */
struct xfs_buf *bp); /* buffer containing block, if any */
/*
* Check that short form block header is ok.
*/
int /* error (0 or EFSCORRUPTED) */
xfs_btree_check_sblock(
struct xfs_btree_cur *cur, /* btree cursor */
struct xfs_btree_sblock *block, /* btree short form block pointer */
int level, /* level of the btree block */
struct xfs_buf *bp); /* buffer containing block */
/*
* 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 */
#define xfs_btree_check_lptr_disk(cur, ptr, level) \
xfs_btree_check_lptr(cur, be64_to_cpu(ptr), level)
/*
* Check that (short) pointer is ok.
*/
int /* error (0 or EFSCORRUPTED) */
xfs_btree_check_sptr(
struct xfs_btree_cur *cur, /* btree cursor */
xfs_agblock_t ptr, /* btree block disk address */
int level); /* btree block level */
/*
* Check that (short) pointer is ok.
*/
int /* error (0 or EFSCORRUPTED) */
xfs_btree_check_ptr(
struct xfs_btree_cur *cur, /* btree cursor */
union xfs_btree_ptr *ptr, /* btree block disk address */
int index, /* offset from ptr to check */
int level); /* btree block level */
#ifdef DEBUG
/*
* 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_key(a, b, c)
#define xfs_btree_check_rec(a, b, c)
#endif /* DEBUG */
/*
* 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(
xfs_btree_cur_t *cur, /* btree cursor */
int lev, /* level in btree */
int lr); /* left/right bits */
/*
* 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 */
/*
* Helpers.
*/
static inline int xfs_btree_get_level(struct xfs_btree_block *block)
{
return be16_to_cpu(block->bb_level);
}
#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__ */
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