Commit 03bdb5ac authored by Ryusuke Konishi's avatar Ryusuke Konishi
Browse files

nilfs2: apply read-ahead for nilfs_btree_lookup_contig 



This applies read-ahead to nilfs_btree_do_lookup and
nilfs_btree_lookup_contig functions and extends them to read ahead
siblings of level 1 btree nodes that hold data blocks.

At present, the read-ahead is not applied to most btree operations;
only get_block() callback function, which is used during read of
regular files or directories, receives the benefit.

Signed-off-by: default avatarRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
parent 4e13e66b

fs/nilfs2/btree.c

+33 −17
Original line number Diff line number Diff line
@@ -504,9 +504,11 @@ static int nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr, 


static int nilfs_btree_do_lookup(const struct nilfs_bmap *btree,

				 struct nilfs_btree_path *path,

				 __u64 key, __u64 *ptrp, int minlevel)

				 __u64 key, __u64 *ptrp, int minlevel,

				 int readahead)

{

	struct nilfs_btree_node *node;

	struct nilfs_btree_readahead_info p, *ra;

	__u64 ptr;

	int level, index, found, ncmax, ret;
@@ -523,10 +525,20 @@ static int nilfs_btree_do_lookup(const struct nilfs_bmap *btree, 


	ncmax = nilfs_btree_nchildren_per_block(btree);



	for (level--; level >= minlevel; level--) {

		ret = nilfs_btree_get_block(btree, ptr, &path[level].bp_bh);

	while (--level >= minlevel) {

		ra = NULL;

		if (level == NILFS_BTREE_LEVEL_NODE_MIN && readahead) {

			p.node = nilfs_btree_get_node(btree, path, level + 1,

						      &p.ncmax);

			p.index = index;

			p.max_ra_blocks = 7;

			ra = &p;

		}

		ret = __nilfs_btree_get_block(btree, ptr, &path[level].bp_bh,

					      ra);

		if (ret < 0)

			return ret;



		node = nilfs_btree_get_nonroot_node(path, level);

		if (nilfs_btree_bad_node(node, level))

			return -EINVAL;
@@ -601,7 +613,7 @@ static int nilfs_btree_lookup(const struct nilfs_bmap *btree, 
	if (path == NULL)

		return -ENOMEM;



	ret = nilfs_btree_do_lookup(btree, path, key, ptrp, level);

	ret = nilfs_btree_do_lookup(btree, path, key, ptrp, level, 0);



	nilfs_btree_free_path(path);
@@ -618,12 +630,13 @@ static int nilfs_btree_lookup_contig(const struct nilfs_bmap *btree, 
	sector_t blocknr;

	int level = NILFS_BTREE_LEVEL_NODE_MIN;

	int ret, cnt, index, maxlevel, ncmax;

	struct nilfs_btree_readahead_info p;



	path = nilfs_btree_alloc_path();

	if (path == NULL)

		return -ENOMEM;



	ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level);

	ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level, 1);

	if (ret < 0)

		goto out;
@@ -662,17 +675,20 @@ static int nilfs_btree_lookup_contig(const struct nilfs_bmap *btree, 
			break;



		/* look-up right sibling node */

		node = nilfs_btree_get_node(btree, path, level + 1, &ncmax);

		index = path[level + 1].bp_index + 1;

		if (index >= nilfs_btree_node_get_nchildren(node) ||

		    nilfs_btree_node_get_key(node, index) != key + cnt)

		p.node = nilfs_btree_get_node(btree, path, level + 1, &p.ncmax);

		p.index = path[level + 1].bp_index + 1;

		p.max_ra_blocks = 7;

		if (p.index >= nilfs_btree_node_get_nchildren(p.node) ||

		    nilfs_btree_node_get_key(p.node, p.index) != key + cnt)

			break;

		ptr2 = nilfs_btree_node_get_ptr(node, index, ncmax);

		path[level + 1].bp_index = index;

		ptr2 = nilfs_btree_node_get_ptr(p.node, p.index, p.ncmax);

		path[level + 1].bp_index = p.index;



		brelse(path[level].bp_bh);

		path[level].bp_bh = NULL;

		ret = nilfs_btree_get_block(btree, ptr2, &path[level].bp_bh);



		ret = __nilfs_btree_get_block(btree, ptr2, &path[level].bp_bh,

					      &p);

		if (ret < 0)

			goto out;

		node = nilfs_btree_get_nonroot_node(path, level);
@@ -1147,7 +1163,7 @@ static int nilfs_btree_insert(struct nilfs_bmap *btree, __u64 key, __u64 ptr) 
		return -ENOMEM;



	ret = nilfs_btree_do_lookup(btree, path, key, NULL,

				    NILFS_BTREE_LEVEL_NODE_MIN);

				    NILFS_BTREE_LEVEL_NODE_MIN, 0);

	if (ret != -ENOENT) {

		if (ret == 0)

			ret = -EEXIST;
@@ -1484,7 +1500,7 @@ static int nilfs_btree_delete(struct nilfs_bmap *btree, __u64 key) 
		return -ENOMEM;



	ret = nilfs_btree_do_lookup(btree, path, key, NULL,

				    NILFS_BTREE_LEVEL_NODE_MIN);

				    NILFS_BTREE_LEVEL_NODE_MIN, 0);

	if (ret < 0)

		goto out;
@@ -1955,7 +1971,7 @@ static int nilfs_btree_propagate(struct nilfs_bmap *btree, 
		level = NILFS_BTREE_LEVEL_DATA;

	}



	ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1);

	ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1, 0);

	if (ret < 0) {

		if (unlikely(ret == -ENOENT))

			printk(KERN_CRIT "%s: key = %llu, level == %d\n",
@@ -2147,7 +2163,7 @@ static int nilfs_btree_assign(struct nilfs_bmap *btree, 
		level = NILFS_BTREE_LEVEL_DATA;

	}



	ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1);

	ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1, 0);

	if (ret < 0) {

		WARN_ON(ret == -ENOENT);

		goto out;
@@ -2201,7 +2217,7 @@ static int nilfs_btree_mark(struct nilfs_bmap *btree, __u64 key, int level) 
	if (path == NULL)

		return -ENOMEM;



	ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level + 1);

	ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level + 1, 0);

	if (ret < 0) {

		WARN_ON(ret == -ENOENT);

		goto out;

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