Btrfs: Do more extensive readahead during tree searches
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 51eea5c..c0782a5 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -43,8 +43,10 @@
{
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
* 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 @@
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);