btrfs: parent_start initialization cleanup

Code cleanup. parent_start is initialized multiple times when it is
not necessary to do so.
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/ctree.c

@@ -1100,7 +1100,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 	int level, ret;
 	int last_ref = 0;
 	int unlock_orig = 0;
-	u64 parent_start;
+	u64 parent_start = 0;
 
 	if (*cow_ret == buf)
 		unlock_orig = 1;
@@ -1119,13 +1119,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 	else
 		btrfs_node_key(buf, &disk_key, 0);
 
-	if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
-		if (parent)
-			parent_start = parent->start;
-		else
-			parent_start = 0;
-	} else
-		parent_start = 0;
+	if ((root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) && parent)
+		parent_start = parent->start;
 
 	cow = btrfs_alloc_tree_block(trans, root, parent_start,
 			root->root_key.objectid, &disk_key, level,
@@ -1168,8 +1163,6 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 		if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
 		    btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
 			parent_start = buf->start;
-		else
-			parent_start = 0;
 
 		extent_buffer_get(cow);
 		tree_mod_log_set_root_pointer(root, cow, 1);
@@ -1180,11 +1173,6 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 		free_extent_buffer(buf);
 		add_root_to_dirty_list(root);
 	} else {
-		if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
-			parent_start = parent->start;
-		else
-			parent_start = 0;
-
 		WARN_ON(trans->transid != btrfs_header_generation(parent));
 		tree_mod_log_insert_key(root->fs_info, parent, parent_slot,
 					MOD_LOG_KEY_REPLACE, GFP_NOFS);