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>

1 files changed, 30 insertions, 24 deletions

diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index bc940bb374cf..8c7d7db01f7a 100644
--- 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 */