[PATCH] Btrfs: be smarter about dropping things from the tree log

[Josef Bacik <jbacik@fusionio.com>]

When we truncate existing items in the tree log we've been searching for
each individual item and removing them.  This is unnecessary churn and
searching, just keep track of the slot we are on and how many items we need
to delete and delete them all at once.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
---
 fs/btrfs/tree-log.c |   16 ++++++++++++++--
 1 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 4e468a0..90e1c28 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2872,12 +2872,15 @@ static int drop_objectid_items(struct btrfs_trans_handle *trans,
 	int ret;
 	struct btrfs_key key;
 	struct btrfs_key found_key;
+	int start_slot;
+	int del_nr = 0;
 
 	key.objectid = objectid;
 	key.type = max_key_type;
 	key.offset = (u64)-1;
 
 	while (1) {
+		del_nr = 0;
 		ret = btrfs_search_slot(trans, log, &key, path, -1, 1);
 		BUG_ON(ret == 0);
 		if (ret < 0)
@@ -2885,20 +2888,29 @@ static int drop_objectid_items(struct btrfs_trans_handle *trans,
 
 		if (path->slots[0] == 0)
 			break;
-
+next_slot:
 		path->slots[0]--;
+
 		btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 				      path->slots[0]);
 
 		if (found_key.objectid != objectid)
 			break;
 
-		ret = btrfs_del_item(trans, log, path);
+		start_slot = path->slots[0];
+		del_nr++;
+		if (start_slot)
+			goto next_slot;
+
+		ret = btrfs_del_items(trans, log, path, start_slot, del_nr);
 		if (ret)
 			break;
 		btrfs_release_path(path);
 	}
+	if (!ret && del_nr)
+		ret = btrfs_del_items(trans, log, path, start_slot, del_nr);
 	btrfs_release_path(path);
+
 	if (ret > 0)
 		ret = 0;
 	return ret;
-- 
1.7.7.6