3 files changed, 142 insertions, 27 deletions

diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index 7561431af50d..ae9411773397 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -38,17 +38,14 @@
 static int comp_tree_refs(struct btrfs_delayed_tree_ref *ref2,
                           struct btrfs_delayed_tree_ref *ref1)
 {
-        if (ref1->node.type == BTRFS_TREE_BLOCK_REF_KEY) {
-                if (ref1->root < ref2->root)
-                        return -1;
-                if (ref1->root > ref2->root)
-                        return 1;
-        } else {
-                if (ref1->parent < ref2->parent)
-                        return -1;
-                if (ref1->parent > ref2->parent)
-                        return 1;
-        }
+        if (ref1->root < ref2->root)
+                return -1;
+        if (ref1->root > ref2->root)
+                return 1;
+        if (ref1->parent < ref2->parent)
+                return -1;
+        if (ref1->parent > ref2->parent)
+                return 1;
         return 0;
 }
 
@@ -85,7 +82,8 @@ static int comp_data_refs(struct btrfs_delayed_data_ref *ref2,
  * type of the delayed backrefs and content of delayed backrefs.
  */
 static int comp_entry(struct btrfs_delayed_ref_node *ref2,
-                      struct btrfs_delayed_ref_node *ref1)
+                      struct btrfs_delayed_ref_node *ref1,
+                      bool compare_seq)
 {
         if (ref1->bytenr < ref2->bytenr)
                 return -1;
@@ -102,10 +100,12 @@ static int comp_entry(struct btrfs_delayed_ref_node *ref2,
         if (ref1->type > ref2->type)
                 return 1;
         /* merging of sequenced refs is not allowed */
-        if (ref1->seq < ref2->seq)
-                return -1;
-        if (ref1->seq > ref2->seq)
-                return 1;
+        if (compare_seq) {
+                if (ref1->seq < ref2->seq)
+                        return -1;
+                if (ref1->seq > ref2->seq)
+                        return 1;
+        }
         if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
             ref1->type == BTRFS_SHARED_BLOCK_REF_KEY) {
                 return comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref2),
@@ -139,7 +139,7 @@ static struct btrfs_delayed_ref_node *tree_insert(struct rb_root *root,
                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
                                  rb_node);
 
-                cmp = comp_entry(entry, ins);
+                cmp = comp_entry(entry, ins, 1);
                 if (cmp < 0)
                         p = &(*p)->rb_left;
                 else if (cmp > 0)
@@ -233,6 +233,114 @@ int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
         return 0;
 }
 
+static void inline drop_delayed_ref(struct btrfs_trans_handle *trans,
+                                    struct btrfs_delayed_ref_root *delayed_refs,
+                                    struct btrfs_delayed_ref_node *ref)
+{
+        rb_erase(&ref->rb_node, &delayed_refs->root);
+        ref->in_tree = 0;
+        btrfs_put_delayed_ref(ref);
+        delayed_refs->num_entries--;
+        if (trans->delayed_ref_updates)
+                trans->delayed_ref_updates--;
+}
+
+static int merge_ref(struct btrfs_trans_handle *trans,
+                     struct btrfs_delayed_ref_root *delayed_refs,
+                     struct btrfs_delayed_ref_node *ref, u64 seq)
+{
+        struct rb_node *node;
+        int merged = 0;
+        int mod = 0;
+        int done = 0;
+
+        node = rb_prev(&ref->rb_node);
+        while (node) {
+                struct btrfs_delayed_ref_node *next;
+
+                next = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
+                node = rb_prev(node);
+                if (next->bytenr != ref->bytenr)
+                        break;
+                if (seq && next->seq >= seq)
+                        break;
+                if (comp_entry(ref, next, 0))
+                        continue;
+
+                if (ref->action == next->action) {
+                        mod = next->ref_mod;
+                } else {
+                        if (ref->ref_mod < next->ref_mod) {
+                                struct btrfs_delayed_ref_node *tmp;
+
+                                tmp = ref;
+                                ref = next;
+                                next = tmp;
+                                done = 1;
+                        }
+                        mod = -next->ref_mod;
+                }
+
+                merged++;
+                drop_delayed_ref(trans, delayed_refs, next);
+                ref->ref_mod += mod;
+                if (ref->ref_mod == 0) {
+                        drop_delayed_ref(trans, delayed_refs, ref);
+                        break;
+                } else {
+                        /*
+                         * You can't have multiples of the same ref on a tree
+                         * block.
+                         */
+                        WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
+                                ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
+                }
+
+                if (done)
+                        break;
+                node = rb_prev(&ref->rb_node);
+        }
+
+        return merged;
+}
+
+void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
+                              struct btrfs_fs_info *fs_info,
+                              struct btrfs_delayed_ref_root *delayed_refs,
+                              struct btrfs_delayed_ref_head *head)
+{
+        struct rb_node *node;
+        u64 seq = 0;
+
+        spin_lock(&fs_info->tree_mod_seq_lock);
+        if (!list_empty(&fs_info->tree_mod_seq_list)) {
+                struct seq_list *elem;
+
+                elem = list_first_entry(&fs_info->tree_mod_seq_list,
+                                        struct seq_list, list);
+                seq = elem->seq;
+        }
+        spin_unlock(&fs_info->tree_mod_seq_lock);
+
+        node = rb_prev(&head->node.rb_node);
+        while (node) {
+                struct btrfs_delayed_ref_node *ref;
+
+                ref = rb_entry(node, struct btrfs_delayed_ref_node,
+                               rb_node);
+                if (ref->bytenr != head->node.bytenr)
+                        break;
+
+                /* We can't merge refs that are outside of our seq count */
+                if (seq && ref->seq >= seq)
+                        break;
+                if (merge_ref(trans, delayed_refs, ref, seq))
+                        node = rb_prev(&head->node.rb_node);
+                else
+                        node = rb_prev(node);
+        }
+}
+
 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
                             struct btrfs_delayed_ref_root *delayed_refs,
                             u64 seq)
@@ -336,18 +444,11 @@ update_existing_ref(struct btrfs_trans_handle *trans,
                  * every changing the extent allocation tree.
                  */
                 existing->ref_mod--;
-                if (existing->ref_mod == 0) {
-                        rb_erase(&existing->rb_node,
-                                 &delayed_refs->root);
-                        existing->in_tree = 0;
-                        btrfs_put_delayed_ref(existing);
-                        delayed_refs->num_entries--;
-                        if (trans->delayed_ref_updates)
-                                trans->delayed_ref_updates--;
-                } else {
+                if (existing->ref_mod == 0)
+                        drop_delayed_ref(trans, delayed_refs, existing);
+                else
                         WARN_ON(existing->type == BTRFS_TREE_BLOCK_REF_KEY ||
                                 existing->type == BTRFS_SHARED_BLOCK_REF_KEY);
-                }
         } else {
                 WARN_ON(existing->type == BTRFS_TREE_BLOCK_REF_KEY ||
                         existing->type == BTRFS_SHARED_BLOCK_REF_KEY);
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index 0d7c90c366b6..ab5300595847 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -167,6 +167,10 @@ int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
                                 struct btrfs_trans_handle *trans,
                                 u64 bytenr, u64 num_bytes,
                                 struct btrfs_delayed_extent_op *extent_op);
+void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
+                              struct btrfs_fs_info *fs_info,
+                              struct btrfs_delayed_ref_root *delayed_refs,
+                              struct btrfs_delayed_ref_head *head);
 
 struct btrfs_delayed_ref_head *
 btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index f16411d3c252..ba58024d40d3 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2252,6 +2252,16 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
                 }
 
                 /*
+                 * We need to try and merge add/drops of the same ref since we
+                 * can run into issues with relocate dropping the implicit ref
+                 * and then it being added back again before the drop can
+                 * finish.  If we merged anything we need to re-loop so we can
+                 * get a good ref.
+                 */
+                btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
+                                         locked_ref);
+
+                /*
                  * locked_ref is the head node, so we have to go one
                  * node back for any delayed ref updates
                  */