Btrfs: Add inode item and backref in one insert, reducing cpu usage

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

1 files changed, 25 insertions, 14 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 84ad53e06b3a..fb2e2bd506c8 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -2332,27 +2332,34 @@ int btrfs_extend_item(struct btrfs_trans_handle *trans,
  * Given a key and some data, insert an item into the tree.
  * This does all the path init required, making room in the tree if needed.
  */
-int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
+int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
                             struct btrfs_root *root,
                             struct btrfs_path *path,
-                            struct btrfs_key *cpu_key, u32 data_size)
+                            struct btrfs_key *cpu_key, u32 *data_size,
+                            int nr)
 {
         struct extent_buffer *leaf;
         struct btrfs_item *item;
         int ret = 0;
         int slot;
         int slot_orig;
+        int i;
         u32 nritems;
+        u32 total_size = 0;
+        u32 total_data = 0;
         unsigned int data_end;
         struct btrfs_disk_key disk_key;
 
-        btrfs_cpu_key_to_disk(&disk_key, cpu_key);
+        for (i = 0; i < nr; i++) {
+                total_data += data_size[i];
+        }
 
         /* create a root if there isn't one */
         if (!root->node)
                 BUG();
 
-        ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1);
+        total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
+        ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
         if (ret == 0) {
                 return -EEXIST;
         }
@@ -2366,10 +2373,10 @@ int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
         data_end = leaf_data_end(root, leaf);
 
         if (btrfs_leaf_free_space(root, leaf) <
-            sizeof(struct btrfs_item) + data_size) {
+            sizeof(struct btrfs_item) + total_size) {
                 btrfs_print_leaf(root, leaf);
                 printk("not enough freespace need %u have %d\n",
-                       data_size, btrfs_leaf_free_space(root, leaf));
+                       total_size, btrfs_leaf_free_space(root, leaf));
                 BUG();
         }
 
@@ -2404,7 +2411,7 @@ int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
                         }
 
                         ioff = btrfs_item_offset(leaf, item);
-                        btrfs_set_item_offset(leaf, item, ioff - data_size);
+                        btrfs_set_item_offset(leaf, item, ioff - total_data);
                 }
                 if (leaf->map_token) {
                         unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
@@ -2412,23 +2419,27 @@ int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
                 }
 
                 /* shift the items */
-                memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
+                memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
                               btrfs_item_nr_offset(slot),
                               (nritems - slot) * sizeof(struct btrfs_item));
 
                 /* shift the data */
                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
-                              data_end - data_size, btrfs_leaf_data(leaf) +
+                              data_end - total_data, btrfs_leaf_data(leaf) +
                               data_end, old_data - data_end);
                 data_end = old_data;
         }
 
         /* setup the item for the new data */
-        btrfs_set_item_key(leaf, &disk_key, slot);
-        item = btrfs_item_nr(leaf, slot);
-        btrfs_set_item_offset(leaf, item, data_end - data_size);
-        btrfs_set_item_size(leaf, item, data_size);
-        btrfs_set_header_nritems(leaf, nritems + 1);
+        for (i = 0; i < nr; i++) {
+                btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
+                btrfs_set_item_key(leaf, &disk_key, slot + i);
+                item = btrfs_item_nr(leaf, slot + i);
+                btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
+                data_end -= data_size[i];
+                btrfs_set_item_size(leaf, item, data_size[i]);
+        }
+        btrfs_set_header_nritems(leaf, nritems + nr);
         btrfs_mark_buffer_dirty(leaf);
 
         ret = 0;