Btrfs: Add BH_Defrag to mark buffers that are in need of defragging
This allows the tree walking code to defrag only the newly allocated
buffers, it seems to be a good balance between perfect defragging and the
performance hit of repeatedly reallocating blocks.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index ee1ae00..7cf43da 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -175,6 +175,7 @@
int end_slot;
int i;
int err = 0;
+ int parent_level;
if (trans->transaction != root->fs_info->running_transaction) {
printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
@@ -188,6 +189,7 @@
}
parent_node = btrfs_buffer_node(parent);
parent_nritems = btrfs_header_nritems(&parent_node->header);
+ parent_level = btrfs_header_level(&parent_node->header);
start_slot = 0;
end_slot = parent_nritems;
@@ -215,13 +217,16 @@
cur_bh = btrfs_find_tree_block(root, blocknr);
if (!cur_bh || !buffer_uptodate(cur_bh) ||
- buffer_locked(cur_bh)) {
+ buffer_locked(cur_bh) || !buffer_defrag(cur_bh)) {
if (cache_only) {
brelse(cur_bh);
continue;
}
- brelse(cur_bh);
- cur_bh = read_tree_block(root, blocknr);
+ if (!cur_bh || !buffer_uptodate(cur_bh) ||
+ buffer_locked(cur_bh)) {
+ brelse(cur_bh);
+ cur_bh = read_tree_block(root, blocknr);
+ }
}
if (search_start == 0)
search_start = last_block & ~((u64)65535);
@@ -232,6 +237,9 @@
if (err)
break;
search_start = bh_blocknr(tmp_bh);
+ *last_ret = search_start;
+ if (parent_level == 1)
+ clear_buffer_defrag(tmp_bh);
brelse(tmp_bh);
}
return err;
@@ -811,16 +819,10 @@
clear_radix_bit(&found, blocknr);
if (nread > 32)
continue;
- if (direction > 0 && cluster_start <= blocknr &&
- cluster_start + 8 > blocknr) {
- cluster_start = blocknr;
+ if (close_blocks(cluster_start, blocknr)) {
readahead_tree_block(root, blocknr);
nread++;
- } else if (direction < 0 && cluster_start >= blocknr &&
- blocknr + 8 > cluster_start) {
cluster_start = blocknr;
- readahead_tree_block(root, blocknr);
- nread++;
}
}
}