btrfs: add a comp_refs() helper

Instead of open-coding the delayed ref comparisons, add a helper to do
the comparisons generically and use that everywhere.  We compare
sequence numbers last for following patches.

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index bc940bb374cfb8d9e06ba0bd5529bdde94dba2cf..8c7d7db01f7aa750d0ea280b4be21520db7e00ed 100644 (file)
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -85,6 +85,34 @@ static int comp_data_refs(struct btrfs_delayed_data_ref *ref1,
        return 0;
 }
 
+static int comp_refs(struct btrfs_delayed_ref_node *ref1,
+                    struct btrfs_delayed_ref_node *ref2,
+                    bool check_seq)
+{
+       int ret = 0;
+
+       if (ref1->type < ref2->type)
+               return -1;
+       if (ref1->type > ref2->type)
+               return 1;
+       if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
+           ref1->type == BTRFS_SHARED_BLOCK_REF_KEY)
+               ret = comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref1),
+                                    btrfs_delayed_node_to_tree_ref(ref2));
+       else
+               ret = comp_data_refs(btrfs_delayed_node_to_data_ref(ref1),
+                                    btrfs_delayed_node_to_data_ref(ref2));
+       if (ret)
+               return ret;
+       if (check_seq) {
+               if (ref1->seq < ref2->seq)
+                       return -1;
+               if (ref1->seq > ref2->seq)
+                       return 1;
+       }
+       return 0;
+}
+
 /* insert a new ref to head ref rbtree */
 static struct btrfs_delayed_ref_head *htree_insert(struct rb_root *root,
                                                   struct rb_node *node)
@@ -217,18 +245,7 @@ static bool merge_ref(struct btrfs_trans_handle *trans,
                if (seq && next->seq >= seq)
                        goto next;
 
-               if (next->type != ref->type)
-                       goto next;
-
-               if ((ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
-                    ref->type == BTRFS_SHARED_BLOCK_REF_KEY) &&
-                   comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref),
-                                  btrfs_delayed_node_to_tree_ref(next)))
-                       goto next;
-               if ((ref->type == BTRFS_EXTENT_DATA_REF_KEY ||
-                    ref->type == BTRFS_SHARED_DATA_REF_KEY) &&
-                   comp_data_refs(btrfs_delayed_node_to_data_ref(ref),
-                                  btrfs_delayed_node_to_data_ref(next)))
+               if (comp_refs(ref, next, false))
                        goto next;
 
                if (ref->action == next->action) {
@@ -402,18 +419,7 @@ add_delayed_ref_tail_merge(struct btrfs_trans_handle *trans,
        exist = list_entry(href->ref_list.prev, struct btrfs_delayed_ref_node,
                           list);
        /* No need to compare bytenr nor is_head */
-       if (exist->type != ref->type || exist->seq != ref->seq)
-               goto add_tail;
-
-       if ((exist->type == BTRFS_TREE_BLOCK_REF_KEY ||
-            exist->type == BTRFS_SHARED_BLOCK_REF_KEY) &&
-           comp_tree_refs(btrfs_delayed_node_to_tree_ref(exist),
-                          btrfs_delayed_node_to_tree_ref(ref)))
-               goto add_tail;
-       if ((exist->type == BTRFS_EXTENT_DATA_REF_KEY ||
-            exist->type == BTRFS_SHARED_DATA_REF_KEY) &&
-           comp_data_refs(btrfs_delayed_node_to_data_ref(exist),
-                          btrfs_delayed_node_to_data_ref(ref)))
+       if (comp_refs(exist, ref, true))
                goto add_tail;
 
        /* Now we are sure we can merge */