btrfs: free list element sooner at log_new_dir_dentries()

At log_new_dir_dentries(), there's no need to keep the current list
element allocated while processing the leaves with directory items for
the current directory, and while logging other inodes. Plus in case we
find a subdirectory, we also end up allocating a new list element while
the current one is still allocated, temporarily using more memory than
necessary.

So free the current list element early on, before processing leaves.
Also make the removal and release of all list elements in case of an
error more simple by eliminating the label and goto, adding an explicit
loop to release all list elements in case an error happens.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/tree-log.c

@@ -6142,25 +6142,28 @@ static int log_new_dir_dentries(struct btrfs_trans_handle *trans,
 	while (!list_empty(&dir_list)) {
 		struct extent_buffer *leaf;
 		struct btrfs_key min_key;
+		u64 ino;
+		bool continue_curr_inode = true;
 		int nritems;
 		int i;
 
 		dir_elem = list_first_entry(&dir_list, struct btrfs_dir_list,
 					    list);
-		if (ret)
-			goto next_dir_inode;
+		ino = dir_elem->ino;
+		list_del(&dir_elem->list);
+		kfree(dir_elem);
 
-		min_key.objectid = dir_elem->ino;
+		min_key.objectid = ino;
 		min_key.type = BTRFS_DIR_INDEX_KEY;
 		min_key.offset = 0;
 again:
 		btrfs_release_path(path);
 		ret = btrfs_search_forward(root, &min_key, path, trans->transid);
 		if (ret < 0) {
-			goto next_dir_inode;
+			break;
 		} else if (ret > 0) {
 			ret = 0;
-			goto next_dir_inode;
+			continue;
 		}
 
 		leaf = path->nodes[0];
@@ -6169,14 +6172,15 @@ static int log_new_dir_dentries(struct btrfs_trans_handle *trans,
 			struct btrfs_dir_item *di;
 			struct btrfs_key di_key;
 			struct inode *di_inode;
-			struct btrfs_dir_list *new_dir_elem;
 			int log_mode = LOG_INODE_EXISTS;
 			int type;
 
 			btrfs_item_key_to_cpu(leaf, &min_key, i);
-			if (min_key.objectid != dir_elem->ino ||
-			    min_key.type != BTRFS_DIR_INDEX_KEY)
-				goto next_dir_inode;
+			if (min_key.objectid != ino ||
+			    min_key.type != BTRFS_DIR_INDEX_KEY) {
+				continue_curr_inode = false;
+				break;
+			}
 
 			di = btrfs_item_ptr(leaf, i, struct btrfs_dir_item);
 			type = btrfs_dir_type(leaf, di);
@@ -6190,7 +6194,7 @@ static int log_new_dir_dentries(struct btrfs_trans_handle *trans,
 			di_inode = btrfs_iget(fs_info->sb, di_key.objectid, root);
 			if (IS_ERR(di_inode)) {
 				ret = PTR_ERR(di_inode);
-				goto next_dir_inode;
+				goto out;
 			}
 
 			if (!need_log_inode(trans, BTRFS_I(di_inode))) {
@@ -6205,29 +6209,33 @@ static int log_new_dir_dentries(struct btrfs_trans_handle *trans,
 					      log_mode, ctx);
 			btrfs_add_delayed_iput(di_inode);
 			if (ret)
-				goto next_dir_inode;
+				goto out;
 			if (ctx->log_new_dentries) {
-				new_dir_elem = kmalloc(sizeof(*new_dir_elem),
-						       GFP_NOFS);
-				if (!new_dir_elem) {
+				dir_elem = kmalloc(sizeof(*dir_elem), GFP_NOFS);
+				if (!dir_elem) {
 					ret = -ENOMEM;
-					goto next_dir_inode;
+					goto out;
 				}
-				new_dir_elem->ino = di_key.objectid;
-				list_add_tail(&new_dir_elem->list, &dir_list);
+				dir_elem->ino = di_key.objectid;
+				list_add_tail(&dir_elem->list, &dir_list);
 			}
 			break;
 		}
-		if (min_key.offset < (u64)-1) {
+
+		if (continue_curr_inode && min_key.offset < (u64)-1) {
 			min_key.offset++;
 			goto again;
 		}
-next_dir_inode:
-		list_del(&dir_elem->list);
+	}
+out:
+	btrfs_free_path(path);
+	if (ret) {
+		struct btrfs_dir_list *next;
+
+		list_for_each_entry_safe(dir_elem, next, &dir_list, list)
 			kfree(dir_elem);
 	}
 
-	btrfs_free_path(path);
 	return ret;
 }