Commit a929904c authored by David Sterba's avatar David Sterba
Browse files

btrfs: add unlikely annotations to branches leading to transaction abort 



The unlikely() annotation is a static prediction hint that compiler may
use to reorder code out of hot path. We use it elsewhere (namely
tree-checker.c) for error branches that almost never happen.

Transaction abort is one such error, the btrfs_abort_transaction()
inlines code to check the state and print a warning, this ought to be
out of the hot path.

The most common pattern is when transaction abort is called after
checking a return value and the control flow leads to a quick return.
In other cases it may not be necessary to add unlikely() e.g. when the
function returns anyway or the control flow is not changed noticeably.

Reviewed-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent cc53bd20

fs/btrfs/block-group.c

+5 −5
Original line number Diff line number Diff line
@@ -3248,7 +3248,7 @@ static int cache_save_setup(struct btrfs_block_group *block_group, 
	 */

	BTRFS_I(inode)->generation = 0;

	ret = btrfs_update_inode(trans, BTRFS_I(inode));

	if (ret) {

	if (unlikely(ret)) {

		/*

		 * So theoretically we could recover from this, simply set the

		 * super cache generation to 0 so we know to invalidate the
@@ -3995,7 +3995,7 @@ static struct btrfs_block_group *do_chunk_alloc(struct btrfs_trans_handle *trans 
		struct btrfs_space_info *sys_space_info;



		sys_space_info = btrfs_find_space_info(trans->fs_info, sys_flags);

		if (!sys_space_info) {

		if (unlikely(!sys_space_info)) {

			ret = -EINVAL;

			btrfs_abort_transaction(trans, ret);

			goto out;
@@ -4009,17 +4009,17 @@ static struct btrfs_block_group *do_chunk_alloc(struct btrfs_trans_handle *trans 
		}



		ret = btrfs_chunk_alloc_add_chunk_item(trans, sys_bg);

		if (ret) {

		if (unlikely(ret)) {

			btrfs_abort_transaction(trans, ret);

			goto out;

		}



		ret = btrfs_chunk_alloc_add_chunk_item(trans, bg);

		if (ret) {

		if (unlikely(ret)) {

			btrfs_abort_transaction(trans, ret);

			goto out;

		}

	} else if (ret) {

	} else if (unlikely(ret)) {

		btrfs_abort_transaction(trans, ret);

		goto out;

	}

fs/btrfs/ctree.c

+25 −25
Original line number Diff line number Diff line
@@ -293,11 +293,11 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans, 


	if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) {

		ret = btrfs_inc_ref(trans, root, cow, 1);

		if (ret)

		if (unlikely(ret))

			btrfs_abort_transaction(trans, ret);

	} else {

		ret = btrfs_inc_ref(trans, root, cow, 0);

		if (ret)

		if (unlikely(ret))

			btrfs_abort_transaction(trans, ret);

	}

	if (ret) {
@@ -536,14 +536,14 @@ int btrfs_force_cow_block(struct btrfs_trans_handle *trans, 
	write_extent_buffer_fsid(cow, fs_info->fs_devices->metadata_uuid);



	ret = update_ref_for_cow(trans, root, buf, cow, &last_ref);

	if (ret) {

	if (unlikely(ret)) {

		btrfs_abort_transaction(trans, ret);

		goto error_unlock_cow;

	}



	if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {

		ret = btrfs_reloc_cow_block(trans, root, buf, cow);

		if (ret) {

		if (unlikely(ret)) {

			btrfs_abort_transaction(trans, ret);

			goto error_unlock_cow;

		}
@@ -556,7 +556,7 @@ int btrfs_force_cow_block(struct btrfs_trans_handle *trans, 
			parent_start = buf->start;



		ret = btrfs_tree_mod_log_insert_root(root->node, cow, true);

		if (ret < 0) {

		if (unlikely(ret < 0)) {

			btrfs_abort_transaction(trans, ret);

			goto error_unlock_cow;

		}
@@ -567,7 +567,7 @@ int btrfs_force_cow_block(struct btrfs_trans_handle *trans, 
					    parent_start, last_ref);

		free_extent_buffer(buf);

		add_root_to_dirty_list(root);

		if (ret < 0) {

		if (unlikely(ret < 0)) {

			btrfs_abort_transaction(trans, ret);

			goto error_unlock_cow;

		}
@@ -575,7 +575,7 @@ int btrfs_force_cow_block(struct btrfs_trans_handle *trans, 
		WARN_ON(trans->transid != btrfs_header_generation(parent));

		ret = btrfs_tree_mod_log_insert_key(parent, parent_slot,

						    BTRFS_MOD_LOG_KEY_REPLACE);

		if (ret) {

		if (unlikely(ret)) {

			btrfs_abort_transaction(trans, ret);

			goto error_unlock_cow;

		}
@@ -586,14 +586,14 @@ int btrfs_force_cow_block(struct btrfs_trans_handle *trans, 
		btrfs_mark_buffer_dirty(trans, parent);

		if (last_ref) {

			ret = btrfs_tree_mod_log_free_eb(buf);

			if (ret) {

			if (unlikely(ret)) {

				btrfs_abort_transaction(trans, ret);

				goto error_unlock_cow;

			}

		}

		ret = btrfs_free_tree_block(trans, btrfs_root_id(root), buf,

					    parent_start, last_ref);

		if (ret < 0) {

		if (unlikely(ret < 0)) {

			btrfs_abort_transaction(trans, ret);

			goto error_unlock_cow;

		}
@@ -922,7 +922,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, 
		}



		ret = btrfs_tree_mod_log_insert_root(root->node, child, true);

		if (ret < 0) {

		if (unlikely(ret < 0)) {

			btrfs_tree_unlock(child);

			free_extent_buffer(child);

			btrfs_abort_transaction(trans, ret);
@@ -944,7 +944,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, 
		ret = btrfs_free_tree_block(trans, btrfs_root_id(root), mid, 0, 1);

		/* once for the root ptr */

		free_extent_buffer_stale(mid);

		if (ret < 0) {

		if (unlikely(ret < 0)) {

			btrfs_abort_transaction(trans, ret);

			goto out;

		}
@@ -1019,7 +1019,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, 
						    right, 0, 1);

			free_extent_buffer_stale(right);

			right = NULL;

			if (ret < 0) {

			if (unlikely(ret < 0)) {

				btrfs_abort_transaction(trans, ret);

				goto out;

			}
@@ -1028,7 +1028,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, 
			btrfs_node_key(right, &right_key, 0);

			ret = btrfs_tree_mod_log_insert_key(parent, pslot + 1,

					BTRFS_MOD_LOG_KEY_REPLACE);

			if (ret < 0) {

			if (unlikely(ret < 0)) {

				btrfs_abort_transaction(trans, ret);

				goto out;

			}
@@ -1080,7 +1080,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, 
		ret = btrfs_free_tree_block(trans, btrfs_root_id(root), mid, 0, 1);

		free_extent_buffer_stale(mid);

		mid = NULL;

		if (ret < 0) {

		if (unlikely(ret < 0)) {

			btrfs_abort_transaction(trans, ret);

			goto out;

		}
@@ -1090,7 +1090,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, 
		btrfs_node_key(mid, &mid_key, 0);

		ret = btrfs_tree_mod_log_insert_key(parent, pslot,

						    BTRFS_MOD_LOG_KEY_REPLACE);

		if (ret < 0) {

		if (unlikely(ret < 0)) {

			btrfs_abort_transaction(trans, ret);

			goto out;

		}
@@ -1195,7 +1195,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, 
			btrfs_node_key(mid, &disk_key, 0);

			ret = btrfs_tree_mod_log_insert_key(parent, pslot,

					BTRFS_MOD_LOG_KEY_REPLACE);

			if (ret < 0) {

			if (unlikely(ret < 0)) {

				btrfs_tree_unlock(left);

				free_extent_buffer(left);

				btrfs_abort_transaction(trans, ret);
@@ -1255,7 +1255,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, 
			btrfs_node_key(right, &disk_key, 0);

			ret = btrfs_tree_mod_log_insert_key(parent, pslot + 1,

					BTRFS_MOD_LOG_KEY_REPLACE);

			if (ret < 0) {

			if (unlikely(ret < 0)) {

				btrfs_tree_unlock(right);

				free_extent_buffer(right);

				btrfs_abort_transaction(trans, ret);
@@ -2737,7 +2737,7 @@ static int push_node_left(struct btrfs_trans_handle *trans, 
		return ret;

	}

	ret = btrfs_tree_mod_log_eb_copy(dst, src, dst_nritems, 0, push_items);

	if (ret) {

	if (unlikely(ret)) {

		btrfs_abort_transaction(trans, ret);

		return ret;

	}
@@ -2822,7 +2822,7 @@ static int balance_node_right(struct btrfs_trans_handle *trans, 


	ret = btrfs_tree_mod_log_eb_copy(dst, src, 0, src_nritems - push_items,

					 push_items);

	if (ret) {

	if (unlikely(ret)) {

		btrfs_abort_transaction(trans, ret);

		return ret;

	}
@@ -2892,7 +2892,7 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans, 


		btrfs_clear_buffer_dirty(trans, c);

		ret2 = btrfs_free_tree_block(trans, btrfs_root_id(root), c, 0, 1);

		if (ret2 < 0)

		if (unlikely(ret2 < 0))

			btrfs_abort_transaction(trans, ret2);

		btrfs_tree_unlock(c);

		free_extent_buffer(c);
@@ -2937,7 +2937,7 @@ static int insert_ptr(struct btrfs_trans_handle *trans, 
		if (level) {

			ret = btrfs_tree_mod_log_insert_move(lower, slot + 1,

					slot, nritems - slot);

			if (ret < 0) {

			if (unlikely(ret < 0)) {

				btrfs_abort_transaction(trans, ret);

				return ret;

			}
@@ -2950,7 +2950,7 @@ static int insert_ptr(struct btrfs_trans_handle *trans, 
	if (level) {

		ret = btrfs_tree_mod_log_insert_key(lower, slot,

						    BTRFS_MOD_LOG_KEY_ADD);

		if (ret < 0) {

		if (unlikely(ret < 0)) {

			btrfs_abort_transaction(trans, ret);

			return ret;

		}
@@ -3026,7 +3026,7 @@ static noinline int split_node(struct btrfs_trans_handle *trans, 
	ASSERT(btrfs_header_level(c) == level);



	ret = btrfs_tree_mod_log_eb_copy(split, c, 0, mid, c_nritems - mid);

	if (ret) {

	if (unlikely(ret)) {

		btrfs_tree_unlock(split);

		free_extent_buffer(split);

		btrfs_abort_transaction(trans, ret);
@@ -4383,7 +4383,7 @@ int btrfs_del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root, 
		if (level) {

			ret = btrfs_tree_mod_log_insert_move(parent, slot,

					slot + 1, nritems - slot - 1);

			if (ret < 0) {

			if (unlikely(ret < 0)) {

				btrfs_abort_transaction(trans, ret);

				return ret;

			}
@@ -4396,7 +4396,7 @@ int btrfs_del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root, 
	} else if (level) {

		ret = btrfs_tree_mod_log_insert_key(parent, slot,

						    BTRFS_MOD_LOG_KEY_REMOVE);

		if (ret < 0) {

		if (unlikely(ret < 0)) {

			btrfs_abort_transaction(trans, ret);

			return ret;

		}

fs/btrfs/delayed-inode.c

+3 −3
Original line number Diff line number Diff line
@@ -1038,7 +1038,7 @@ static int __btrfs_update_delayed_inode(struct btrfs_trans_handle *trans, 
		 * transaction, because we could leave the inode with the

		 * improper counts behind.

		 */

		if (ret != -ENOENT)

		if (unlikely(ret != -ENOENT))

			btrfs_abort_transaction(trans, ret);

		goto out;

	}
@@ -1066,7 +1066,7 @@ static int __btrfs_update_delayed_inode(struct btrfs_trans_handle *trans, 


		btrfs_release_path(path);

		ret = btrfs_search_slot(trans, root, &key, path, -1, 1);

		if (ret < 0) {

		if (unlikely(ret < 0)) {

			btrfs_abort_transaction(trans, ret);

			goto err_out;

		}
@@ -1175,7 +1175,7 @@ static int __btrfs_run_delayed_items(struct btrfs_trans_handle *trans, int nr) 
	while (curr_node && (!count || nr--)) {

		ret = __btrfs_commit_inode_delayed_items(trans, path,

							 curr_node);

		if (ret) {

		if (unlikely(ret)) {

			btrfs_abort_transaction(trans, ret);

			break;

		}

fs/btrfs/extent-tree.c

+19 −19
Original line number Diff line number Diff line
@@ -2157,7 +2157,7 @@ int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans, u64 min_bytes) 
	delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);

#endif

	ret = __btrfs_run_delayed_refs(trans, min_bytes);

	if (ret < 0) {

	if (unlikely(ret < 0)) {

		btrfs_abort_transaction(trans, ret);

		return ret;

	}
@@ -2982,26 +2982,26 @@ static int do_free_extent_accounting(struct btrfs_trans_handle *trans, 


		csum_root = btrfs_csum_root(trans->fs_info, bytenr);

		ret = btrfs_del_csums(trans, csum_root, bytenr, num_bytes);

		if (ret) {

		if (unlikely(ret)) {

			btrfs_abort_transaction(trans, ret);

			return ret;

		}



		ret = btrfs_delete_raid_extent(trans, bytenr, num_bytes);

		if (ret) {

		if (unlikely(ret)) {

			btrfs_abort_transaction(trans, ret);

			return ret;

		}

	}



	ret = btrfs_record_squota_delta(trans->fs_info, delta);

	if (ret) {

	if (unlikely(ret)) {

		btrfs_abort_transaction(trans, ret);

		return ret;

	}



	ret = btrfs_add_to_free_space_tree(trans, bytenr, num_bytes);

	if (ret) {

	if (unlikely(ret)) {

		btrfs_abort_transaction(trans, ret);

		return ret;

	}
@@ -3115,7 +3115,7 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans, 


	is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;



	if (!is_data && refs_to_drop != 1) {

	if (unlikely(!is_data && refs_to_drop != 1)) {

		btrfs_crit(info,

"invalid refs_to_drop, dropping more than 1 refs for tree block %llu refs_to_drop %u",

			   node->bytenr, refs_to_drop);
@@ -3172,7 +3172,7 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans, 
			/* Must be SHARED_* item, remove the backref first */

			ret = remove_extent_backref(trans, extent_root, path,

						    NULL, refs_to_drop, is_data);

			if (ret) {

			if (unlikely(ret)) {

				btrfs_abort_transaction(trans, ret);

				goto out;

			}
@@ -3221,7 +3221,7 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans, 
			"umm, got %d back from search, was looking for %llu, slot %d",

					  ret, bytenr, path->slots[0]);

			}

			if (ret < 0) {

			if (unlikely(ret < 0)) {

				btrfs_abort_transaction(trans, ret);

				goto out;

			}
@@ -3298,7 +3298,7 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans, 
		if (found_extent) {

			ret = remove_extent_backref(trans, extent_root, path,

						    iref, refs_to_drop, is_data);

			if (ret) {

			if (unlikely(ret)) {

				btrfs_abort_transaction(trans, ret);

				goto out;

			}
@@ -3363,7 +3363,7 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans, 


		ret = btrfs_del_items(trans, extent_root, path, path->slots[0],

				      num_to_del);

		if (ret) {

		if (unlikely(ret)) {

			btrfs_abort_transaction(trans, ret);

			goto out;

		}
@@ -5472,17 +5472,17 @@ static noinline int walk_down_proc(struct btrfs_trans_handle *trans, 
	if (!(wc->flags[level] & flag)) {

		ASSERT(path->locks[level]);

		ret = btrfs_inc_ref(trans, root, eb, 1);

		if (ret) {

		if (unlikely(ret)) {

			btrfs_abort_transaction(trans, ret);

			return ret;

		}

		ret = btrfs_dec_ref(trans, root, eb, 0);

		if (ret) {

		if (unlikely(ret)) {

			btrfs_abort_transaction(trans, ret);

			return ret;

		}

		ret = btrfs_set_disk_extent_flags(trans, eb, flag);

		if (ret) {

		if (unlikely(ret)) {

			btrfs_abort_transaction(trans, ret);

			return ret;

		}
@@ -5885,7 +5885,7 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans, 
				}

			} else {

				ret = btrfs_dec_ref(trans, root, eb, 0);

				if (ret) {

				if (unlikely(ret)) {

					btrfs_abort_transaction(trans, ret);

					return ret;

				}
@@ -6180,13 +6180,13 @@ int btrfs_drop_snapshot(struct btrfs_root *root, bool update_ref, bool for_reloc 
	while (1) {



		ret = walk_down_tree(trans, root, path, wc);

		if (ret < 0) {

		if (unlikely(ret < 0)) {

			btrfs_abort_transaction(trans, ret);

			break;

		}



		ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);

		if (ret < 0) {

		if (unlikely(ret < 0)) {

			btrfs_abort_transaction(trans, ret);

			break;

		}
@@ -6213,7 +6213,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root, bool update_ref, bool for_reloc 
			ret = btrfs_update_root(trans, tree_root,

						&root->root_key,

						root_item);

			if (ret) {

			if (unlikely(ret)) {

				btrfs_abort_transaction(trans, ret);

				goto out_end_trans;

			}
@@ -6249,7 +6249,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root, bool update_ref, bool for_reloc 
		goto out_end_trans;



	ret = btrfs_del_root(trans, &root->root_key);

	if (ret) {

	if (unlikely(ret)) {

		btrfs_abort_transaction(trans, ret);

		goto out_end_trans;

	}
@@ -6257,7 +6257,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root, bool update_ref, bool for_reloc 
	if (!is_reloc_root) {

		ret = btrfs_find_root(tree_root, &root->root_key, path,

				      NULL, NULL);

		if (ret < 0) {

		if (unlikely(ret < 0)) {

			btrfs_abort_transaction(trans, ret);

			goto out_end_trans;

		} else if (ret > 0) {

fs/btrfs/file-item.c

+1 −1
Original line number Diff line number Diff line
@@ -1011,7 +1011,7 @@ int btrfs_del_csums(struct btrfs_trans_handle *trans, 
			 * item changed size or key

			 */

			ret = btrfs_split_item(trans, root, path, &key, offset);

			if (ret && ret != -EAGAIN) {

			if (unlikely(ret && ret != -EAGAIN)) {

				btrfs_abort_transaction(trans, ret);

				break;

			}