Btrfs: Replace extent tree preallocation code with some bit radix magic.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

fs/btrfs/ctree.h

@@ -299,12 +299,7 @@ struct btrfs_fs_info {
 	struct radix_tree_root block_group_radix;
 	struct radix_tree_root block_group_data_radix;
 	struct radix_tree_root extent_map_radix;
-
-	u64 extent_tree_insert[BTRFS_MAX_LEVEL * 6];
-	int extent_tree_insert_nr;
-	u64 extent_tree_prealloc[BTRFS_MAX_LEVEL * 6];
-	int extent_tree_prealloc_nr;
-
+	struct radix_tree_root extent_ins_radix;
 	u64 generation;
 	struct btrfs_transaction *running_transaction;
 	struct btrfs_super_block *disk_super;

fs/btrfs/disk-io.c

@@ -427,6 +427,7 @@ struct btrfs_root *open_ctree(struct super_block *sb)
 	init_bit_radix(&fs_info->pinned_radix);
 	init_bit_radix(&fs_info->pending_del_radix);
 	init_bit_radix(&fs_info->extent_map_radix);
+	init_bit_radix(&fs_info->extent_ins_radix);
 	INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
 	INIT_RADIX_TREE(&fs_info->block_group_radix, GFP_KERNEL);
 	INIT_RADIX_TREE(&fs_info->block_group_data_radix, GFP_KERNEL);
@@ -443,8 +444,6 @@ struct btrfs_root *open_ctree(struct super_block *sb)
 	fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
 	fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
 	fs_info->do_barriers = 1;
-	fs_info->extent_tree_insert_nr = 0;
-	fs_info->extent_tree_prealloc_nr = 0;
 	fs_info->closing = 0;
 
 	INIT_DELAYED_WORK(&fs_info->trans_work, btrfs_transaction_cleaner);

fs/btrfs/transaction.c

@@ -109,6 +109,8 @@ struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
 	h->blocks_reserved = num_blocks;
 	h->blocks_used = 0;
 	h->block_group = NULL;
+	h->alloc_exclude_nr = 0;
+	h->alloc_exclude_start = 0;
 	root->fs_info->running_transaction->use_count++;
 	mutex_unlock(&root->fs_info->trans_mutex);
 	return h;

fs/btrfs/transaction.h

@@ -39,6 +39,8 @@ struct btrfs_trans_handle {
 	unsigned long blocks_used;
 	struct btrfs_transaction *transaction;
 	struct btrfs_block_group_cache *block_group;
+	u64 alloc_exclude_start;
+	u64 alloc_exclude_nr;
 };