Btrfs: CPU usage optimizations in push and the extent_map code

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

1 files changed, 24 insertions, 20 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 17a322663f3b..e8466940fa30 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1588,6 +1588,11 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
         if (!path->nodes[1])
                 return 1;
 
+        right_nritems = btrfs_header_nritems(right);
+        if (right_nritems == 0) {
+                return 1;
+        }
+
         left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
                                slot - 1), root->leafsize);
         free_space = btrfs_leaf_free_space(root, left);
@@ -1604,18 +1609,13 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
                 free_extent_buffer(left);
                 return 1;
         }
+
         free_space = btrfs_leaf_free_space(root, left);
         if (free_space < data_size + sizeof(struct btrfs_item)) {
                 free_extent_buffer(left);
                 return 1;
         }
 
-        right_nritems = btrfs_header_nritems(right);
-        if (right_nritems == 0) {
-                free_extent_buffer(left);
-                return 1;
-        }
-
         for (i = 0; i < right_nritems - 1; i++) {
                 item = btrfs_item_nr(right, i);
                 if (!right->map_token) {
@@ -1772,21 +1772,25 @@ static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
         struct btrfs_disk_key disk_key;
 
         /* first try to make some room by pushing left and right */
-        wret = push_leaf_left(trans, root, path, data_size);
-        if (wret < 0) {
-                return wret;
-        }
-        if (wret) {
+        if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
                 wret = push_leaf_right(trans, root, path, data_size);
-                if (wret < 0)
+                if (wret < 0) {
                         return wret;
-        }
-        l = path->nodes[0];
+                }
+                if (wret) {
+                        wret = push_leaf_left(trans, root, path, data_size);
+                        if (wret < 0)
+                                return wret;
+                }
+                l = path->nodes[0];
 
-        /* did the pushes work? */
-        if (btrfs_leaf_free_space(root, l) >=
-            sizeof(struct btrfs_item) + data_size) {
-                return 0;
+                /* did the pushes work? */
+                if (btrfs_leaf_free_space(root, l) >=
+                    sizeof(struct btrfs_item) + data_size) {
+                        return 0;
+                }
+        } else {
+                l = path->nodes[0];
         }
 
         if (!path->nodes[1]) {
@@ -2388,13 +2392,13 @@ int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                         slot = path->slots[1];
                         extent_buffer_get(leaf);
 
-                        wret = push_leaf_left(trans, root, path, 1);
+                        wret = push_leaf_right(trans, root, path, 1);
                         if (wret < 0 && wret != -ENOSPC)
                                 ret = wret;
 
                         if (path->nodes[0] == leaf &&
                             btrfs_header_nritems(leaf)) {
-                                wret = push_leaf_right(trans, root, path, 1);
+                                wret = push_leaf_left(trans, root, path, 1);
                                 if (wret < 0 && wret != -ENOSPC)
                                         ret = wret;
                         }