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[XFS] implement generic xfs_btree_split

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Make the btree split code generic. Based on a patch from David Chinner
with lots of changes to follow the original btree implementations more
closely. While this loses some of the generic helper routines for
inserting/moving/removing records it also solves some of the one off bugs
in the original code and makes it easier to verify.

SGI-PV: 985583

SGI-Modid: xfs-linux-melb:xfs-kern:32198a

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>
This commit is contained in:
Christoph Hellwig
2008-10-30 16:57:03 +11:00
committed by Lachlan McIlroy
parent 687b890a18
commit f5eb8e7ca5
5 changed files with 460 additions and 503 deletions
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200
fs/xfs/xfs_alloc_btree.c
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@@ -35,6 +35,7 @@
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_btree_trace.h"
#include "xfs_ialloc.h"
#include "xfs_alloc.h"
#include "xfs_error.h"
@@ -48,8 +49,6 @@ STATIC void xfs_alloc_log_keys(xfs_btree_cur_t *, xfs_buf_t *, int, int);
STATIC void xfs_alloc_log_ptrs(xfs_btree_cur_t *, xfs_buf_t *, int, int);
STATIC void xfs_alloc_log_recs(xfs_btree_cur_t *, xfs_buf_t *, int, int);
STATIC int xfs_alloc_newroot(xfs_btree_cur_t *, int *);
STATIC int xfs_alloc_split(xfs_btree_cur_t *, int, xfs_agblock_t *,
xfs_alloc_key_t *, xfs_btree_cur_t **, int *);
/*
* Internal functions.
@@ -695,15 +694,18 @@ xfs_alloc_insrec(
if (i)
optr = ptr = cur->bc_ptrs[level];
else {
union xfs_btree_ptr bno = { .s = cpu_to_be32(nbno) };
/*
* Next, try splitting the current block in
* half. If this works we have to re-set our
* variables because we could be in a
* different block now.
*/
if ((error = xfs_alloc_split(cur, level, &nbno,
&nkey, &ncur, &i)))
if ((error = xfs_btree_split(cur, level, &bno,
(union xfs_btree_key *)&nkey,
&ncur, &i)))
return error;
nbno = be32_to_cpu(bno.s);
if (i) {
bp = cur->bc_bufs[level];
block = XFS_BUF_TO_ALLOC_BLOCK(bp);
@@ -1089,160 +1091,6 @@ xfs_alloc_newroot(
return 0;
}
/*
* Split cur/level block in half.
* Return new block number and its first record (to be inserted into parent).
*/
STATIC int /* error */
xfs_alloc_split(
xfs_btree_cur_t *cur, /* btree cursor */
int level, /* level to split */
xfs_agblock_t *bnop, /* output: block number allocated */
xfs_alloc_key_t *keyp, /* output: first key of new block */
xfs_btree_cur_t **curp, /* output: new cursor */
int *stat) /* success/failure */
{
int error; /* error return value */
int i; /* loop index/record number */
xfs_agblock_t lbno; /* left (current) block number */
xfs_buf_t *lbp; /* buffer for left block */
xfs_alloc_block_t *left; /* left (current) btree block */
xfs_agblock_t rbno; /* right (new) block number */
xfs_buf_t *rbp; /* buffer for right block */
xfs_alloc_block_t *right; /* right (new) btree block */
/*
* Allocate the new block from the freelist.
* If we can't do it, we're toast. Give up.
*/
error = xfs_alloc_get_freelist(cur->bc_tp,
cur->bc_private.a.agbp, &rbno, 1);
if (error)
return error;
if (rbno == NULLAGBLOCK) {
*stat = 0;
return 0;
}
xfs_trans_agbtree_delta(cur->bc_tp, 1);
rbp = xfs_btree_get_bufs(cur->bc_mp, cur->bc_tp, cur->bc_private.a.agno,
rbno, 0);
/*
* Set up the new block as "right".
*/
right = XFS_BUF_TO_ALLOC_BLOCK(rbp);
/*
* "Left" is the current (according to the cursor) block.
*/
lbp = cur->bc_bufs[level];
left = XFS_BUF_TO_ALLOC_BLOCK(lbp);
#ifdef DEBUG
if ((error = xfs_btree_check_sblock(cur, left, level, lbp)))
return error;
#endif
/*
* Fill in the btree header for the new block.
*/
right->bb_magic = cpu_to_be32(xfs_magics[cur->bc_btnum]);
right->bb_level = left->bb_level;
right->bb_numrecs = cpu_to_be16(be16_to_cpu(left->bb_numrecs) / 2);
/*
* Make sure that if there's an odd number of entries now, that
* each new block will have the same number of entries.
*/
if ((be16_to_cpu(left->bb_numrecs) & 1) &&
cur->bc_ptrs[level] <= be16_to_cpu(right->bb_numrecs) + 1)
be16_add_cpu(&right->bb_numrecs, 1);
i = be16_to_cpu(left->bb_numrecs) - be16_to_cpu(right->bb_numrecs) + 1;
/*
* For non-leaf blocks, copy keys and addresses over to the new block.
*/
if (level > 0) {
xfs_alloc_key_t *lkp; /* left btree key pointer */
xfs_alloc_ptr_t *lpp; /* left btree address pointer */
xfs_alloc_key_t *rkp; /* right btree key pointer */
xfs_alloc_ptr_t *rpp; /* right btree address pointer */
lkp = XFS_ALLOC_KEY_ADDR(left, i, cur);
lpp = XFS_ALLOC_PTR_ADDR(left, i, cur);
rkp = XFS_ALLOC_KEY_ADDR(right, 1, cur);
rpp = XFS_ALLOC_PTR_ADDR(right, 1, cur);
#ifdef DEBUG
for (i = 0; i < be16_to_cpu(right->bb_numrecs); i++) {
if ((error = xfs_btree_check_sptr(cur, be32_to_cpu(lpp[i]), level)))
return error;
}
#endif
memcpy(rkp, lkp, be16_to_cpu(right->bb_numrecs) * sizeof(*rkp));
memcpy(rpp, lpp, be16_to_cpu(right->bb_numrecs) * sizeof(*rpp));
xfs_alloc_log_keys(cur, rbp, 1, be16_to_cpu(right->bb_numrecs));
xfs_alloc_log_ptrs(cur, rbp, 1, be16_to_cpu(right->bb_numrecs));
*keyp = *rkp;
}
/*
* For leaf blocks, copy records over to the new block.
*/
else {
xfs_alloc_rec_t *lrp; /* left btree record pointer */
xfs_alloc_rec_t *rrp; /* right btree record pointer */
lrp = XFS_ALLOC_REC_ADDR(left, i, cur);
rrp = XFS_ALLOC_REC_ADDR(right, 1, cur);
memcpy(rrp, lrp, be16_to_cpu(right->bb_numrecs) * sizeof(*rrp));
xfs_alloc_log_recs(cur, rbp, 1, be16_to_cpu(right->bb_numrecs));
keyp->ar_startblock = rrp->ar_startblock;
keyp->ar_blockcount = rrp->ar_blockcount;
}
/*
* Find the left block number by looking in the buffer.
* Adjust numrecs, sibling pointers.
*/
lbno = XFS_DADDR_TO_AGBNO(cur->bc_mp, XFS_BUF_ADDR(lbp));
be16_add_cpu(&left->bb_numrecs, -(be16_to_cpu(right->bb_numrecs)));
right->bb_rightsib = left->bb_rightsib;
left->bb_rightsib = cpu_to_be32(rbno);
right->bb_leftsib = cpu_to_be32(lbno);
xfs_alloc_log_block(cur->bc_tp, rbp, XFS_BB_ALL_BITS);
xfs_alloc_log_block(cur->bc_tp, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
/*
* If there's a block to the new block's right, make that block
* point back to right instead of to left.
*/
if (be32_to_cpu(right->bb_rightsib) != NULLAGBLOCK) {
xfs_alloc_block_t *rrblock; /* rr btree block */
xfs_buf_t *rrbp; /* buffer for rrblock */
if ((error = xfs_btree_read_bufs(cur->bc_mp, cur->bc_tp,
cur->bc_private.a.agno, be32_to_cpu(right->bb_rightsib), 0,
&rrbp, XFS_ALLOC_BTREE_REF)))
return error;
rrblock = XFS_BUF_TO_ALLOC_BLOCK(rrbp);
if ((error = xfs_btree_check_sblock(cur, rrblock, level, rrbp)))
return error;
rrblock->bb_leftsib = cpu_to_be32(rbno);
xfs_alloc_log_block(cur->bc_tp, rrbp, XFS_BB_LEFTSIB);
}
/*
* If the cursor is really in the right block, move it there.
* If it's just pointing past the last entry in left, then we'll
* insert there, so don't change anything in that case.
*/
if (cur->bc_ptrs[level] > be16_to_cpu(left->bb_numrecs) + 1) {
xfs_btree_setbuf(cur, level, rbp);
cur->bc_ptrs[level] -= be16_to_cpu(left->bb_numrecs);
}
/*
* If there are more levels, we'll need another cursor which refers to
* the right block, no matter where this cursor was.
*/
if (level + 1 < cur->bc_nlevels) {
if ((error = xfs_btree_dup_cursor(cur, curp)))
return error;
(*curp)->bc_ptrs[level + 1]++;
}
*bnop = rbno;
*stat = 1;
return 0;
}
/*
* Externally visible routines.
@@ -1396,6 +1244,41 @@ xfs_allocbt_dup_cursor(
cur->bc_btnum);
}
STATIC int
xfs_allocbt_alloc_block(
struct xfs_btree_cur *cur,
union xfs_btree_ptr *start,
union xfs_btree_ptr *new,
int length,
int *stat)
{
int error;
xfs_agblock_t bno;
XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
/* Allocate the new block from the freelist. If we can't, give up. */
error = xfs_alloc_get_freelist(cur->bc_tp, cur->bc_private.a.agbp,
&bno, 1);
if (error) {
XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
return error;
}
if (bno == NULLAGBLOCK) {
XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
*stat = 0;
return 0;
}
xfs_trans_agbtree_delta(cur->bc_tp, 1);
new->s = cpu_to_be32(bno);
XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
*stat = 1;
return 0;
}
/*
* Update the longest extent in the AGF
*/
@@ -1557,6 +1440,7 @@ static const struct xfs_btree_ops xfs_allocbt_ops = {
.key_len = sizeof(xfs_alloc_key_t),
.dup_cursor = xfs_allocbt_dup_cursor,
.alloc_block = xfs_allocbt_alloc_block,
.update_lastrec = xfs_allocbt_update_lastrec,
.get_maxrecs = xfs_allocbt_get_maxrecs,
.init_key_from_rec = xfs_allocbt_init_key_from_rec,