Btrfs: optimize tree-log.c:count_inode_refs()

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>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index d12696db9ada..d45c04b30690 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -1312,6 +1312,7 @@ 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 ||
@@ -1332,6 +1333,10 @@ 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);
         }