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authorChristoph Hellwig <hch@infradead.org>2008-10-30 16:54:43 +1100
committerLachlan McIlroy <lachlan@sgi.com>2008-10-30 16:54:43 +1100
commitb524bfeee2152fa64b6210f28ced80489b9d2439 (patch)
tree226355f2fc34b50975c9c756a211446901dbecbe /fs/xfs/xfs_btree.c
parente99ab90d6a9e8ac92f05d2c31d44aa7feee15394 (diff)
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[XFS] refactor xfs_btree_readahead
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>
Diffstat (limited to 'fs/xfs/xfs_btree.c')
-rw-r--r--fs/xfs/xfs_btree.c118
1 files changed, 68 insertions, 50 deletions
diff --git a/fs/xfs/xfs_btree.c b/fs/xfs/xfs_btree.c
index 59796b4..4d793e4 100644
--- a/fs/xfs/xfs_btree.c
+++ b/fs/xfs/xfs_btree.c
@@ -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);
}
/*