From 2cc58cf24f69be8632a3b29d653c318bf3bd8c84 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Mon, 27 Aug 2007 16:49:44 -0400 Subject: [PATCH] Btrfs: Do more extensive readahead during tree searches Signed-off-by: Chris Mason --- fs/btrfs/ctree.c | 62 +++++++++++++++++++++++++++++++++--------- fs/btrfs/extent-tree.c | 4 +-- fs/btrfs/inode.c | 2 +- 3 files changed, 52 insertions(+), 16 deletions(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 51eea5ccb645..c0782a5b04c5 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -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); diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index b3641234473f..4049aadbeda9 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -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 @@ check_failed: 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) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 398484179d82..7e4cf62ada5a 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -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;