[PATCH] Btrfs: optimize tree-log.c:count_inode_refs()

[Filipe David Borba Manana <fdmanana@gmail.com>]

Avoid repeated tree searches by processing all inode ref items in
a leaf at once instead of processing one at a time, followed by a
path release and a tree search for a key with a decremented offset.

Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
---
 fs/btrfs/tree-log.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 849b729..7b077a8 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -1307,6 +1307,7 @@ static int count_inode_refs(struct btrfs_root *root,
 				break;
 			path->slots[0]--;
 		}
+process_slot:
 		btrfs_item_key_to_cpu(path->nodes[0], &key,
 				      path->slots[0]);
 		if (key.objectid != ino ||
@@ -1327,6 +1328,10 @@ static int count_inode_refs(struct btrfs_root *root,
 
 		if (key.offset == 0)
 			break;
+		if (path->slots[0] > 0) {
+			path->slots[0]--;
+			goto process_slot;
+		}
 		key.offset--;
 		btrfs_release_path(path);
 	}
-- 
1.7.9.5