Commit b524bfee authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Lachlan McIlroy
Browse files

[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: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarLachlan McIlroy <lachlan@sgi.com>
Signed-off-by: default avatarBill O'Donnell <billodo@sgi.com>
Signed-off-by: default avatarDavid Chinner <david@fromorbit.com>
parent e99ab90d

fs/xfs/xfs_bmap_btree.c

+7 −8
Original line number Diff line number Diff line
@@ -1721,8 +1721,9 @@ xfs_bmbt_decrement( 
	XFS_BMBT_TRACE_CURSOR(cur, ENTRY);

	XFS_BMBT_TRACE_ARGI(cur, level);

	ASSERT(level < cur->bc_nlevels);

	if (level < cur->bc_nlevels - 1)



	xfs_btree_readahead(cur, level, XFS_BTCUR_LEFTRA);



	if (--cur->bc_ptrs[level] > 0) {

		XFS_BMBT_TRACE_CURSOR(cur, EXIT);

		*stat = 1;
@@ -1743,7 +1744,6 @@ xfs_bmbt_decrement( 
	for (lev = level + 1; lev < cur->bc_nlevels; lev++) {

		if (--cur->bc_ptrs[lev] > 0)

			break;

		if (lev < cur->bc_nlevels - 1)

		xfs_btree_readahead(cur, lev, XFS_BTCUR_LEFTRA);

	}

	if (lev == cur->bc_nlevels) {
@@ -1995,7 +1995,7 @@ xfs_bmbt_increment( 
	XFS_BMBT_TRACE_CURSOR(cur, ENTRY);

	XFS_BMBT_TRACE_ARGI(cur, level);

	ASSERT(level < cur->bc_nlevels);

	if (level < cur->bc_nlevels - 1)



	xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);

	block = xfs_bmbt_get_block(cur, level, &bp);

#ifdef DEBUG
@@ -2024,7 +2024,6 @@ xfs_bmbt_increment( 
#endif

		if (++cur->bc_ptrs[lev] <= be16_to_cpu(block->bb_numrecs))

			break;

		if (lev < cur->bc_nlevels - 1)

		xfs_btree_readahead(cur, lev, XFS_BTCUR_RIGHTRA);

	}

	if (lev == cur->bc_nlevels) {

fs/xfs/xfs_btree.c

+68 −50
Original line number Diff line number Diff line
@@ -725,68 +725,86 @@ xfs_btree_reada_bufs( 
	xfs_baread(mp->m_ddev_targp, d, mp->m_bsize * count);

}



/*

 * 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 */

	int			lev,		/* level in btree */

	int			lr)		/* left/right bits */

STATIC int

xfs_btree_readahead_lblock(

	struct xfs_btree_cur	*cur,

	int			lr,

	struct xfs_btree_block	*block)

{

	xfs_alloc_block_t	*a;

	xfs_bmbt_block_t	*b;

	xfs_inobt_block_t	*i;

	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);



	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);

	if ((lr & XFS_BTCUR_LEFTRA) && left != NULLDFSBNO) {

		xfs_btree_reada_bufl(cur->bc_mp, left, 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);



	if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLDFSBNO) {

		xfs_btree_reada_bufl(cur->bc_mp, right, 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++;



	return 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) {



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,

				be32_to_cpu(i->bb_leftsib), 1);

				     left, 1);

		rval++;

	}

		if ((lr & XFS_BTCUR_RIGHTRA) && be32_to_cpu(i->bb_rightsib) != NULLAGBLOCK) {



	if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLAGBLOCK) {

		xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,

				be32_to_cpu(i->bb_rightsib), 1);

				     right, 1);

		rval++;

	}

		break;

	default:

		ASSERT(0);

	}



	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(

	struct xfs_btree_cur	*cur,		/* btree cursor */

	int			lev,		/* level in btree */

	int			lr)		/* left/right bits */

{

	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;



	cur->bc_ra[lev] |= lr;

	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);

}



/*

 * Set the buffer for level "lev" in the cursor to bp, releasing

 * any previous buffer.

fs/xfs/xfs_btree.h

+1 −14
Original line number Diff line number Diff line
@@ -421,23 +421,10 @@ xfs_btree_reada_bufs( 
 * 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);

}



	int			lr);	/* left/right bits */



/*

 * Set the buffer for level "lev" in the cursor to bp, releasing

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