From: Edmund Nadolski <enadolski@suse.com>
Subject: btrfs: clean up extraneous computations in add_delayed_refs
References: bsc#974590 bsc#1030061 bsc#1022914 bsc#1017461
Git-commit: 01747e92a996cc2f2965c28fde485da932836ef8
Patch-mainline: v4.14-rc1

Repeating the same computation in multiple places is not
necessary.

Signed-off-by: Edmund Nadolski <enadolski@suse.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
---
 fs/btrfs/backref.c | 30 +++++++++++++-----------------
 1 file changed, 13 insertions(+), 17 deletions(-)

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 427f493..e2d206b 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -769,7 +769,7 @@ static int add_delayed_refs(const struct btrfs_fs_info *fs_info,
 	struct btrfs_key key;
 	struct btrfs_key tmp_op_key;
 	struct btrfs_key *op_key = NULL;
-	int sgn;
+	int count;
 	int ret = 0;
 
 	if (extent_op && extent_op->update_key) {
@@ -788,15 +788,15 @@ static int add_delayed_refs(const struct btrfs_fs_info *fs_info,
 			WARN_ON(1);
 			continue;
 		case BTRFS_ADD_DELAYED_REF:
-			sgn = 1;
+			count = node->ref_mod;
 			break;
 		case BTRFS_DROP_DELAYED_REF:
-			sgn = -1;
+			count = node->ref_mod * -1;
 			break;
 		default:
 			BUG_ON(1);
 		}
-		*total_refs += (node->ref_mod * sgn);
+		*total_refs += count;
 		switch (node->type) {
 		case BTRFS_TREE_BLOCK_REF_KEY: {
 			/* NORMAL INDIRECT METADATA backref */
@@ -805,9 +805,8 @@ static int add_delayed_refs(const struct btrfs_fs_info *fs_info,
 			ref = btrfs_delayed_node_to_tree_ref(node);
 			ret = add_indirect_ref(fs_info, preftrees, ref->root,
 					       &tmp_op_key, ref->level + 1,
-					       node->bytenr,
-					       node->ref_mod * sgn,
-					       sc, GFP_ATOMIC);
+					       node->bytenr, count, sc,
+					       GFP_ATOMIC);
 			break;
 		}
 		case BTRFS_SHARED_BLOCK_REF_KEY: {
@@ -816,9 +815,8 @@ static int add_delayed_refs(const struct btrfs_fs_info *fs_info,
 
 			ref = btrfs_delayed_node_to_tree_ref(node);
 
-			ret = add_direct_ref(fs_info, preftrees,
-					     ref->level + 1, ref->parent,
-					     node->bytenr, node->ref_mod * sgn,
+			ret = add_direct_ref(fs_info, preftrees, ref->level + 1,
+					     ref->parent, node->bytenr, count,
 					     sc, GFP_ATOMIC);
 			break;
 		}
@@ -841,9 +839,8 @@ static int add_delayed_refs(const struct btrfs_fs_info *fs_info,
 			}
 
 			ret = add_indirect_ref(fs_info, preftrees, ref->root,
-					       &key, 0, node->bytenr,
-					       node->ref_mod * sgn,
-					       sc, GFP_ATOMIC);
+					       &key, 0, node->bytenr, count, sc,
+					       GFP_ATOMIC);
 			break;
 		}
 		case BTRFS_SHARED_DATA_REF_KEY: {
@@ -852,10 +849,9 @@ static int add_delayed_refs(const struct btrfs_fs_info *fs_info,
 
 			ref = btrfs_delayed_node_to_data_ref(node);
 
-			ret = add_direct_ref(fs_info, preftrees, 0,
-					     ref->parent, node->bytenr,
-					     node->ref_mod * sgn,
-					     sc, GFP_ATOMIC);
+			ret = add_direct_ref(fs_info, preftrees, 0, ref->parent,
+					     node->bytenr, count, sc,
+					     GFP_ATOMIC);
 			break;
 		}
 		default:
-- 
2.10.2