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[XFS] refactor xfs_btree_readahead

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From: Dave Chinner <dgc@sgi.com>

Refactor xfs_btree_readahead to make it more readable:

(a) remove the inline xfs_btree_readahead wrapper and move all checks out

of line into the main routine.

(b) factor out helpers for short/long form btrees

(c) move check for root in inodes from the callers into
xfs_btree_readahead

[hch: split out from a big patch and minor cleanups]

SGI-PV: 985583

SGI-Modid: xfs-linux-melb:xfs-kern:32182a

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 16:54:43 +11:00
committed by Lachlan McIlroy
parent e99ab90d6a
commit b524bfeee2
3 changed files with 76 additions and 72 deletions
Download Patch File Download Diff File Expand all files Collapse all files

118
fs/xfs/xfs_btree.c
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@ -725,66 +725,84 @@ xfs_btree_reada_bufs(
xfs_baread(mp->m_ddev_targp, d, mp->m_bsize * count);
}
STATIC int
xfs_btree_readahead_lblock(
struct xfs_btree_cur *cur,
int lr,
struct xfs_btree_block *block)
{
int rval = 0;
xfs_fsblock_t left = be64_to_cpu(block->bb_u.l.bb_leftsib);
xfs_fsblock_t right = be64_to_cpu(block->bb_u.l.bb_rightsib);
if ((lr & XFS_BTCUR_LEFTRA) && left != NULLDFSBNO) {
xfs_btree_reada_bufl(cur->bc_mp, left, 1);
rval++;
}
if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLDFSBNO) {
xfs_btree_reada_bufl(cur->bc_mp, right, 1);
rval++;
}
return rval;
}
STATIC int
xfs_btree_readahead_sblock(
struct xfs_btree_cur *cur,
int lr,
struct xfs_btree_block *block)
{
int rval = 0;
xfs_agblock_t left = be32_to_cpu(block->bb_u.s.bb_leftsib);
xfs_agblock_t right = be32_to_cpu(block->bb_u.s.bb_rightsib);
if ((lr & XFS_BTCUR_LEFTRA) && left != NULLAGBLOCK) {
xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
left, 1);
rval++;
}
if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLAGBLOCK) {
xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
right, 1);
rval++;
}
return rval;
}
/*
* Read-ahead btree blocks, at the given level.
* Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
*/
int
xfs_btree_readahead_core(
xfs_btree_cur_t *cur, /* btree cursor */
xfs_btree_readahead(
struct xfs_btree_cur *cur, /* btree cursor */
int lev, /* level in btree */
int lr) /* left/right bits */
{
xfs_alloc_block_t *a;
xfs_bmbt_block_t *b;
xfs_inobt_block_t *i;
int rval = 0;
struct xfs_btree_block *block;
/*
* No readahead needed if we are at the root level and the
* btree root is stored in the inode.
*/
if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
(lev == cur->bc_nlevels - 1))
return 0;
if ((cur->bc_ra[lev] | lr) == cur->bc_ra[lev])
return 0;
ASSERT(cur->bc_bufs[lev] != NULL);
cur->bc_ra[lev] |= lr;
switch (cur->bc_btnum) {
case XFS_BTNUM_BNO:
case XFS_BTNUM_CNT:
a = XFS_BUF_TO_ALLOC_BLOCK(cur->bc_bufs[lev]);
if ((lr & XFS_BTCUR_LEFTRA) && be32_to_cpu(a->bb_leftsib) != NULLAGBLOCK) {
xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
be32_to_cpu(a->bb_leftsib), 1);
rval++;
}
if ((lr & XFS_BTCUR_RIGHTRA) && be32_to_cpu(a->bb_rightsib) != NULLAGBLOCK) {
xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
be32_to_cpu(a->bb_rightsib), 1);
rval++;
}
break;
case XFS_BTNUM_BMAP:
b = XFS_BUF_TO_BMBT_BLOCK(cur->bc_bufs[lev]);
if ((lr & XFS_BTCUR_LEFTRA) && be64_to_cpu(b->bb_leftsib) != NULLDFSBNO) {
xfs_btree_reada_bufl(cur->bc_mp, be64_to_cpu(b->bb_leftsib), 1);
rval++;
}
if ((lr & XFS_BTCUR_RIGHTRA) && be64_to_cpu(b->bb_rightsib) != NULLDFSBNO) {
xfs_btree_reada_bufl(cur->bc_mp, be64_to_cpu(b->bb_rightsib), 1);
rval++;
}
break;
case XFS_BTNUM_INO:
i = XFS_BUF_TO_INOBT_BLOCK(cur->bc_bufs[lev]);
if ((lr & XFS_BTCUR_LEFTRA) && be32_to_cpu(i->bb_leftsib) != NULLAGBLOCK) {
xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
be32_to_cpu(i->bb_leftsib), 1);
rval++;
}
if ((lr & XFS_BTCUR_RIGHTRA) && be32_to_cpu(i->bb_rightsib) != NULLAGBLOCK) {
xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
be32_to_cpu(i->bb_rightsib), 1);
rval++;
}
break;
default:
ASSERT(0);
}
return rval;
block = XFS_BUF_TO_BLOCK(cur->bc_bufs[lev]);
if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
return xfs_btree_readahead_lblock(cur, lr, block);
return xfs_btree_readahead_sblock(cur, lr, block);
}
/*