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: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c
index d3faa0b..300c2bc 100644
--- a/fs/nilfs2/btree.c
+++ b/fs/nilfs2/btree.c
@@ -504,9 +504,11 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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;