Btrfs: Do more extensive readahead during tree searches

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2007-08-27 16:49:44 -04:00 committed by David Woodhouse
parent 3202061128
commit 2cc58cf24f
3 changed files with 52 additions and 16 deletions

View File

@ -43,8 +43,10 @@ struct btrfs_path *btrfs_alloc_path(void)
{
struct btrfs_path *path;
path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
if (path)
if (path) {
btrfs_init_path(path);
path->reada = 1;
}
return path;
}
@ -159,6 +161,34 @@ static int close_blocks(u64 blocknr, u64 other)
return 0;
}
static int should_defrag_leaf(struct buffer_head *bh)
{
struct btrfs_leaf *leaf = btrfs_buffer_leaf(bh);
struct btrfs_disk_key *key;
u32 nritems;
if (buffer_defrag(bh))
return 1;
nritems = btrfs_header_nritems(&leaf->header);
if (nritems == 0)
return 0;
key = &leaf->items[0].key;
if (btrfs_disk_key_type(key) == BTRFS_DIR_ITEM_KEY)
return 1;
key = &leaf->items[nritems-1].key;
if (btrfs_disk_key_type(key) == BTRFS_DIR_ITEM_KEY)
return 1;
if (nritems > 4) {
key = &leaf->items[nritems/2].key;
if (btrfs_disk_key_type(key) == BTRFS_DIR_ITEM_KEY)
return 1;
}
return 0;
}
int btrfs_realloc_node(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct buffer_head *parent,
int cache_only, u64 *last_ret)
@ -217,7 +247,9 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
cur_bh = btrfs_find_tree_block(root, blocknr);
if (!cur_bh || !buffer_uptodate(cur_bh) ||
buffer_locked(cur_bh) || !buffer_defrag(cur_bh)) {
buffer_locked(cur_bh) ||
(parent_level != 1 && !buffer_defrag(cur_bh)) ||
(parent_level == 1 && !should_defrag_leaf(cur_bh))) {
if (cache_only) {
brelse(cur_bh);
continue;
@ -297,6 +329,7 @@ static int check_node(struct btrfs_root *root, struct btrfs_path *path,
parent = btrfs_buffer_node(path->nodes[level + 1]);
slot = path->slots[level];
BUG_ON(!buffer_uptodate(path->nodes[level]));
BUG_ON(nritems == 0);
if (parent) {
struct btrfs_disk_key *parent_key;
@ -511,9 +544,6 @@ static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
err_on_enospc = 1;
left_buf = read_node_slot(root, parent_buf, pslot - 1);
right_buf = read_node_slot(root, parent_buf, pslot + 1);
/* first, try to make some room in the middle buffer */
if (left_buf) {
wret = btrfs_cow_block(trans, root, left_buf,
parent_buf, pslot - 1, &left_buf);
@ -521,6 +551,19 @@ static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
ret = wret;
goto enospc;
}
}
right_buf = read_node_slot(root, parent_buf, pslot + 1);
if (right_buf) {
wret = btrfs_cow_block(trans, root, right_buf,
parent_buf, pslot + 1, &right_buf);
if (wret) {
ret = wret;
goto enospc;
}
}
/* first, try to make some room in the middle buffer */
if (left_buf) {
left = btrfs_buffer_node(left_buf);
orig_slot += btrfs_header_nritems(&left->header);
wret = push_node_left(trans, root, left_buf, mid_buf);
@ -534,13 +577,6 @@ static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
* then try to empty the right most buffer into the middle
*/
if (right_buf) {
wret = btrfs_cow_block(trans, root, right_buf,
parent_buf, pslot + 1, &right_buf);
if (wret) {
ret = wret;
goto enospc;
}
right = btrfs_buffer_node(right_buf);
wret = push_node_left(trans, root, mid_buf, right_buf);
if (wret < 0 && wret != -ENOSPC)
@ -817,7 +853,7 @@ static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
for (i = 0; i < ret; i++) {
blocknr = gang[i];
clear_radix_bit(&found, blocknr);
if (nread > 32)
if (path->reada == 1 && nread > 16)
continue;
if (close_blocks(cluster_start, blocknr)) {
readahead_tree_block(root, blocknr);

View File

@ -52,7 +52,7 @@ static int cache_block_group(struct btrfs_root *root,
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->reada = 1;
path->reada = 2;
key.objectid = block_group->key.objectid;
key.flags = 0;
key.offset = 0;
@ -1015,7 +1015,7 @@ static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
ins->objectid = search_start;
ins->offset = 0;
start_found = 0;
path->reada = 1;
path->reada = 2;
ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
if (ret < 0)

View File

@ -827,7 +827,7 @@ static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
btrfs_set_key_type(&key, key_type);
key.offset = filp->f_pos;
path = btrfs_alloc_path();
path->reada = 1;
path->reada = 2;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto err;