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Commit 464ece88 authored by Ryusuke Konishi's avatar Ryusuke Konishi
Browse files

nilfs2: add btree get block function with readahead option 



This adds __nilfs_btree_get_block() function that can issue a series
of read-ahead requests for sibling btree nodes.

This read-ahead needs parent node block, so nilfs_btree_readahead_info
structure is added to pass the information that
__nilfs_btree_get_block() needs.

This also replaces the previous nilfs_btree_get_block() implementation
with a wrapper function of __nilfs_btree_get_block().

Signed-off-by: default avatarRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
parent 26dfdd8e

fs/nilfs2/btree.c

+68 −26
Original line number Original line Diff line number Diff line
@@ -66,32 +66,6 @@ static void nilfs_btree_free_path(struct nilfs_btree_path *path) 
/*

/*

 * B-tree node operations

 * B-tree node operations

 */

 */

static int nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,

				 struct buffer_head **bhp)

{

	struct address_space *btnc = &NILFS_BMAP_I(btree)->i_btnode_cache;

	struct buffer_head *bh;

	sector_t pbn = 0;

	int err;



	err = nilfs_btnode_submit_block(btnc, ptr, pbn, READ, bhp, &pbn);

	if (err)

		return err == -EEXIST ? 0 : err;



	bh = *bhp;

	wait_on_buffer(bh);

	if (!buffer_uptodate(bh)) {

		brelse(bh);

		return -EIO;

	}

	if (nilfs_btree_broken_node_block(bh)) {

		clear_buffer_uptodate(bh);

		brelse(bh);

		return -EINVAL;

	}

	return 0;

}



static int nilfs_btree_get_new_block(const struct nilfs_bmap *btree,

static int nilfs_btree_get_new_block(const struct nilfs_bmap *btree,

				     __u64 ptr, struct buffer_head **bhp)

				     __u64 ptr, struct buffer_head **bhp)

{

{
@@ -452,6 +426,74 @@ nilfs_btree_bad_node(struct nilfs_btree_node *node, int level) 
	return 0;

	return 0;

}

}





struct nilfs_btree_readahead_info {

	struct nilfs_btree_node *node;	/* parent node */

	int max_ra_blocks;		/* max nof blocks to read ahead */

	int index;			/* current index on the parent node */

	int ncmax;			/* nof children in the parent node */

};



static int __nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,

				   struct buffer_head **bhp,

				   const struct nilfs_btree_readahead_info *ra)

{

	struct address_space *btnc = &NILFS_BMAP_I(btree)->i_btnode_cache;

	struct buffer_head *bh, *ra_bh;

	sector_t submit_ptr = 0;

	int ret;



	ret = nilfs_btnode_submit_block(btnc, ptr, 0, READ, &bh, &submit_ptr);

	if (ret) {

		if (ret != -EEXIST)

			return ret;

		goto out_check;

	}



	if (ra) {

		int i, n;

		__u64 ptr2;



		/* read ahead sibling nodes */

		for (n = ra->max_ra_blocks, i = ra->index + 1;

		     n > 0 && i < ra->ncmax; n--, i++) {

			ptr2 = nilfs_btree_node_get_ptr(ra->node, i, ra->ncmax);



			ret = nilfs_btnode_submit_block(btnc, ptr2, 0, READA,

							&ra_bh, &submit_ptr);

			if (likely(!ret || ret == -EEXIST))

				brelse(ra_bh);

			else if (ret != -EBUSY)

				break;

			if (!buffer_locked(bh))

				goto out_no_wait;

		}

	}



	wait_on_buffer(bh);



 out_no_wait:

	if (!buffer_uptodate(bh)) {

		brelse(bh);

		return -EIO;

	}



 out_check:

	if (nilfs_btree_broken_node_block(bh)) {

		clear_buffer_uptodate(bh);

		brelse(bh);

		return -EINVAL;

	}



	*bhp = bh;

	return 0;

}



static int nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,

				   struct buffer_head **bhp)

{

	return __nilfs_btree_get_block(btree, ptr, bhp, NULL);

}



static int nilfs_btree_do_lookup(const struct nilfs_bmap *btree,

static int nilfs_btree_do_lookup(const struct nilfs_bmap *btree,

				 struct nilfs_btree_path *path,

				 struct nilfs_btree_path *path,

				 __u64 key, __u64 *ptrp, int minlevel)

				 __u64 key, __u64 *ptrp, int minlevel)