From: Josef Bacik <jbacik@fb.com>
Date: Mon, 3 Dec 2018 10:20:29 -0500
Subject: btrfs: add btrfs_delete_ref_head helper
Git-commit: d7baffdaf9f9df8c9715aa507e3be2f409347c74
Patch-mainline: v5.0-rc1
References: bsc#1165949

We do this dance in cleanup_ref_head and check_ref_cleanup, unify it
into a helper and cleanup the calling functions.

Reviewed-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/delayed-ref.c |   14 ++++++++++++++
 fs/btrfs/delayed-ref.h |    3 ++-
 fs/btrfs/extent-tree.c |   21 ++-------------------
 3 files changed, 18 insertions(+), 20 deletions(-)

--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -409,6 +409,20 @@ again:
 	return head;
 }
 
+void btrfs_delete_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
+			   struct btrfs_delayed_ref_head *head)
+{
+	lockdep_assert_held(&delayed_refs->lock);
+	lockdep_assert_held(&head->lock);
+
+	rb_erase(&head->href_node, &delayed_refs->href_root);
+	RB_CLEAR_NODE(&head->href_node);
+	atomic_dec(&delayed_refs->num_entries);
+	delayed_refs->num_heads--;
+	if (head->processing == 0)
+		delayed_refs->num_heads_ready--;
+}
+
 /*
  * Helper to insert the ref_node to the tail or merge with tail.
  *
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -276,7 +276,8 @@ static inline void btrfs_delayed_ref_unl
 {
 	mutex_unlock(&head->mutex);
 }
-
+void btrfs_delete_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
+			   struct btrfs_delayed_ref_head *head);
 
 struct btrfs_delayed_ref_head *
 btrfs_select_ref_head(struct btrfs_trans_handle *trans);
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2608,12 +2608,9 @@ static int cleanup_ref_head(struct btrfs
 		spin_unlock(&delayed_refs->lock);
 		return 1;
 	}
-	delayed_refs->num_heads--;
-	rb_erase(&head->href_node, &delayed_refs->href_root);
-	RB_CLEAR_NODE(&head->href_node);
+	btrfs_delete_ref_head(delayed_refs, head);
 	spin_unlock(&delayed_refs->lock);
 	spin_unlock(&head->lock);
-	atomic_dec(&delayed_refs->num_entries);
 
 	trace_run_delayed_ref_head(fs_info, head, 0);
 
@@ -7174,21 +7171,7 @@ static noinline int check_ref_cleanup(st
 	if (!mutex_trylock(&head->mutex))
 		goto out;
 
-	/*
-	 * at this point we have a head with no other entries.  Go
-	 * ahead and process it.
-	 */
-	rb_erase(&head->href_node, &delayed_refs->href_root);
-	RB_CLEAR_NODE(&head->href_node);
-	atomic_dec(&delayed_refs->num_entries);
-
-	/*
-	 * we don't take a ref on the node because we're removing it from the
-	 * tree, so we just steal the ref the tree was holding.
-	 */
-	delayed_refs->num_heads--;
-	if (head->processing == 0)
-		delayed_refs->num_heads_ready--;
+	btrfs_delete_ref_head(delayed_refs, head);
 	head->processing = 0;
 	spin_unlock(&head->lock);
 	spin_unlock(&delayed_refs->lock);