Attempt to recognize "seeding-only" chunks early

Send a distinct reply to POST /chunk.

apps/arweave/src/ar_data_sync.erl

@@ -134,7 +134,7 @@ add_chunk(DataRoot, DataPath, Chunk, Offset, TXSize) ->
 				case ar_kv:get(DiskPoolChunksIndex, DiskPoolChunkKey) of
 					{ok, _DiskPoolChunk} ->
 						%% The chunk is already in disk pool.
-						synced;
+						{synced_disk_pool, EndOffset2};
 					not_found ->
 						case DataRootOffsetReply of
 							not_found ->
@@ -164,6 +164,13 @@ add_chunk(DataRoot, DataPath, Chunk, Offset, TXSize) ->
 	case CheckSynced of
 		synced ->
 			ok;
+		{synced_disk_pool, EndOffset4} ->
+			case is_estimated_long_term_chunk(DataRootOffsetReply, EndOffset4) of
+				false ->
+					temporary;
+				true ->
+					ok
+			end;
 		{error, _} = Error4 ->
 			Error4;
 		{ok, {DataPathHash2, DiskPoolChunkKey2, {EndOffset3, PassesBase3, PassesStrict3,
@@ -199,11 +206,43 @@ add_chunk(DataRoot, DataPath, Chunk, Offset, TXSize) ->
 							ets:update_counter(ar_data_sync_state, disk_pool_size,
 									{2, ChunkSize}),
 							prometheus_gauge:inc(pending_chunks_size, ChunkSize),
-							ok
+							case is_estimated_long_term_chunk(DataRootOffsetReply, EndOffset3) of
+								false ->
+									temporary;
+								true ->
+									ok
+							end
 					end
 			end
 	end.
 
+%% @doc Return true if we expect the chunk with the given data root index value and
+%% relative end offset to end up in one of the configured storage modules.
+is_estimated_long_term_chunk(DataRootOffsetReply, EndOffset) ->
+	WeaveSize = ar_node:get_current_weave_size(),
+	case DataRootOffsetReply of
+		not_found ->
+			%% A chunk from a pending transaction.
+			is_offset_vicinity_covered(WeaveSize);
+		{ok, {TXStartOffset, _}} ->
+			WeaveSize = ar_node:get_current_weave_size(),
+			Size = ar_node:get_recent_max_block_size(),
+			AbsoluteEndOffset = TXStartOffset + EndOffset,
+			case AbsoluteEndOffset > WeaveSize - Size * 4 of
+				true ->
+					%% A relatively recent offset - do not expect this chunk to be
+					%% persisted unless we have some storage modules configured for
+					%% the space ahead (the data may be rearranged during after a reorg).
+					is_offset_vicinity_covered(AbsoluteEndOffset);
+				false ->
+					ar_storage_module:has_any(AbsoluteEndOffset)
+			end
+	end.
+
+is_offset_vicinity_covered(Offset) ->
+	Size = ar_node:get_recent_max_block_size(),
+	ar_storage_module:has_range(max(0, Offset - Size * 2), Offset + Size * 2).
+
 %% @doc Notify the server about the new pending data root (added to mempool).
 %% The server may accept pending chunks and store them in the disk pool.
 add_data_root_to_disk_pool(_, 0, _) ->

apps/arweave/src/ar_http_iface_middleware.erl

@@ -2128,6 +2128,8 @@ handle_post_chunk(validate_proof, Proof, Req) ->
 	receive
 		ok ->
 			{200, #{}, <<>>, Req};
+		temporary ->
+			{303, #{}, <<>>, Req};
 		{error, data_root_not_found} ->
 			{400, #{}, jiffy:encode(#{ error => data_root_not_found }), Req};
 		{error, exceeds_disk_pool_size_limit} ->

apps/arweave/src/ar_node.erl

@@ -14,7 +14,8 @@
 		get_recent_txs_map/0, get_mempool_size/0,
 		get_block_shadow_from_cache/1, get_recent_partition_upper_bound_by_prev_h/1,
 		get_block_txs_pairs/0, get_partition_upper_bound/1, get_nth_or_last/2,
-		get_partition_number/1, get_max_partition_number/1]).
+		get_partition_number/1, get_max_partition_number/1,
+		get_current_weave_size/0, get_recent_max_block_size/0]).
 
 -include_lib("arweave/include/ar.hrl").
 -include_lib("arweave/include/ar_config.hrl").
@@ -293,6 +294,18 @@ get_max_partition_number(infinity) ->
 get_max_partition_number(PartitionUpperBound) ->
 	max(0, PartitionUpperBound div ?PARTITION_SIZE - 1).
 
+%% @doc Return the current weave size. Assume the node has joined the network and
+%% initialized the state.
+get_current_weave_size() ->
+	[{_, WeaveSize}] = ets:lookup(node_state, weave_size),
+	WeaveSize.
+
+%% @doc Return the maximum block size among the latest ?BLOCK_INDEX_HEAD_LEN blocks.
+%% Assume the node has joined the network and initialized the state.
+get_recent_max_block_size() ->
+	[{_, MaxBlockSize}] = ets:lookup(node_state, recent_max_block_size),
+	MaxBlockSize.
+
 %%%===================================================================
 %%% Tests.
 %%%===================================================================

apps/arweave/src/ar_node_worker.erl

@@ -396,8 +396,10 @@ handle_info({event, nonce_limiter, initialized}, State) ->
 	BlockTXPairs = [block_txs_pair(Block) || Block <- Blocks],
 	{BlockAnchors, RecentTXMap} = get_block_anchors_and_recent_txs_map(BlockTXPairs),
 	{Rate, ScheduledRate} = {B#block.usd_to_ar_rate, B#block.scheduled_usd_to_ar_rate},
+	RecentBI2 = lists:sublist(BI, ?BLOCK_INDEX_HEAD_LEN),
 	ets:insert(node_state, [
-		{recent_block_index,	lists:sublist(BI, ?BLOCK_INDEX_HEAD_LEN)},
+		{recent_block_index,	RecentBI2},
+		{recent_max_block_size, get_max_block_size(RecentBI2)},
 		{is_joined,				true},
 		{current,				Current},
 		{timestamp,				B#block.timestamp},
@@ -1023,6 +1025,17 @@ get_block_anchors_and_recent_txs_map(BlockTXPairs) ->
 		lists:sublist(BlockTXPairs, ?MAX_TX_ANCHOR_DEPTH)
 	).
 
+get_max_block_size([_SingleElement]) ->
+	0;
+get_max_block_size([{_BH, WeaveSize, _TXRoot} | BI]) ->
+	get_max_block_size(BI, WeaveSize, 0).
+
+get_max_block_size([], _WeaveSize, Max) ->
+	Max;
+get_max_block_size([{_BH, PrevWeaveSize, _TXRoot} | BI], WeaveSize, Max) ->
+	Max2 = max(Max, WeaveSize - PrevWeaveSize),
+	get_max_block_size(BI, PrevWeaveSize, Max2).
+
 apply_block(State) ->
 	case ar_block_cache:get_earliest_not_validated_from_longest_chain(block_cache) of
 		not_found ->
@@ -1536,6 +1549,7 @@ apply_validated_block2(State, B, PrevBlocks, Orphans, RecentBI, BlockTXPairs) ->
 	ar_storage:store_block_time_history_part(AddedBlocks, lists:last(PrevBlocks)),
 	ets:insert(node_state, [
 		{recent_block_index,	RecentBI2},
+		{recent_max_block_size, get_max_block_size(RecentBI2)},
 		{current,				B#block.indep_hash},
 		{timestamp,				B#block.timestamp},
 		{wallet_list,			B#block.wallet_list},

apps/arweave/src/ar_storage.erl

@@ -680,6 +680,8 @@ write_tx_data(DataRoot, DataTree, Data, SizeTaggedChunks, TXID) ->
 				case ar_data_sync:add_chunk(DataRoot, DataPath, Chunk, Offset - 1, TXSize) of
 					ok ->
 						Acc;
+					temporary ->
+						Acc;
 					{error, Reason} ->
 						?LOG_WARNING([{event, failed_to_write_tx_chunk},
 								{tx, ar_util:encode(TXID)},

apps/arweave/src/ar_storage_module.erl

@@ -1,12 +1,17 @@
 -module(ar_storage_module).
 
 -export([id/1, label/1, address_label/1, label_by_id/1,
-		get_by_id/1, get_range/1, get_packing/1, get_size/1, get/2, get_all/1, get_all/2]).
+		get_by_id/1, get_range/1, get_packing/1, get_size/1, get/2, get_all/1, get_all/2,
+		has_any/1, has_range/2]).
+
+-export([get_unique_sorted_intervals/1]).
 
 -include_lib("arweave/include/ar.hrl").
 -include_lib("arweave/include/ar_consensus.hrl").
 -include_lib("arweave/include/ar_config.hrl").
 
+-include_lib("eunit/include/eunit.hrl").
+
 %% The overlap makes sure a 100 MiB recall range can always be fetched
 %% from a single storage module.
 -ifdef(DEBUG).
@@ -172,6 +177,23 @@ get_all(Start, End) ->
 	{ok, Config} = application:get_env(arweave, config),
 	get_all(Start, End, Config#config.storage_modules, []).
 
+%% @doc Return true if the given Offset belongs to at least one storage module.
+has_any(Offset) ->
+	{ok, Config} = application:get_env(arweave, config),
+	has_any(Offset, Config#config.storage_modules).
+
+%% @doc Return true if the given range is covered by the configured storage modules.
+has_range(Start, End) ->
+	{ok, Config} = application:get_env(arweave, config),
+	case ets:lookup(?MODULE, unique_sorted_intervals) of
+		[] ->
+			Intervals = get_unique_sorted_intervals(Config#config.storage_modules),
+			ets:insert(?MODULE, {unique_sorted_intervals, Intervals}),
+			has_range(Start, End, Intervals);
+		[{_, Intervals}] ->
+			has_range(Start, End, Intervals)
+	end.
+
 %%%===================================================================
 %%% Private functions.
 %%%===================================================================
@@ -204,3 +226,63 @@ get_all(Start, End, [StorageModule | StorageModules], FoundModules) ->
 	get_all(Start, End, StorageModules, [StorageModule | FoundModules]);
 get_all(_Start, _End, [], FoundModules) ->
 	FoundModules.
+
+has_any(_Offset, []) ->
+	false;
+has_any(Offset, [{BucketSize, Bucket, _Packing} | StorageModules]) ->
+	case Offset > Bucket * BucketSize andalso Offset =< (Bucket + 1) * BucketSize + ?OVERLAP of
+		true ->
+			true;
+		false ->
+			has_any(Offset, StorageModules)
+	end.
+
+get_unique_sorted_intervals(StorageModules) ->
+	get_unique_sorted_intervals(StorageModules, ar_intervals:new()).
+
+get_unique_sorted_intervals([], Intervals) ->
+	[{Start, End} || {End, Start} <- ar_intervals:to_list(Intervals)];
+get_unique_sorted_intervals([{BucketSize, Bucket, _Packing} | StorageModules], Intervals) ->
+	End = (Bucket + 1) * BucketSize,
+	Start = Bucket * BucketSize,
+	get_unique_sorted_intervals(StorageModules, ar_intervals:add(Intervals, End, Start)).
+
+has_range(PartitionStart, PartitionEnd, _Intervals)
+		when PartitionStart >= PartitionEnd ->
+	true;
+has_range(_PartitionStart, _PartitionEnd, []) ->
+	false;
+has_range(PartitionStart, _PartitionEnd, [{Start, _End} | _Intervals])
+		when PartitionStart < Start ->
+	%% The given intervals are unique and sorted.
+	false;
+has_range(PartitionStart, PartitionEnd, [{_Start, End} | Intervals])
+		when PartitionStart >= End ->
+	has_range(PartitionStart, PartitionEnd, Intervals);
+has_range(_PartitionStart, PartitionEnd, [{_Start, End} | Intervals]) ->
+	has_range(End, PartitionEnd, Intervals).
+
+%%%===================================================================
+%%% Tests.
+%%%===================================================================
+
+has_any_test() ->
+	?assertEqual(false, has_any(0, [])),
+	?assertEqual(false, has_any(0, [{10, 1, p}])),
+	?assertEqual(false, has_any(10, [{10, 1, p}])),
+	?assertEqual(true, has_any(11, [{10, 1, p}])),
+	?assertEqual(true, has_any(20 + ?OVERLAP, [{10, 1, p}])),
+	?assertEqual(false, has_any(20 + ?OVERLAP + 1, [{10, 1, p}])).
+
+get_unique_sorted_intervals_test() ->
+	?assertEqual([{0, 24}, {90, 120}],
+			get_unique_sorted_intervals([{10, 0, p}, {30, 3, p}, {20, 0, p}, {12, 1, p}])).
+
+has_range_test() ->
+	?assertEqual(false, has_range(0, 10, [])),
+	?assertEqual(false, has_range(0, 10, [{0, 9}])),
+	?assertEqual(true, has_range(0, 10, [{0, 10}])),
+	?assertEqual(true, has_range(0, 10, [{0, 11}])),
+	?assertEqual(true, has_range(0, 10, [{0, 9}, {9, 10}])),
+	?assertEqual(true, has_range(5, 10, [{0, 9}, {9, 10}])),
+	?assertEqual(true, has_range(5, 10, [{0, 2}, {2, 9}, {9, 10}])).

apps/arweave/test/ar_data_sync_tests.erl

@@ -221,7 +221,7 @@ test_rejects_chunks_exceeding_disk_pool_limit() ->
 	Data1 = crypto:strong_rand_bytes(
 		(?DEFAULT_MAX_DISK_POOL_DATA_ROOT_BUFFER_MB * 1024 * 1024) + 1
 	),
-	Chunks1 = split(?DATA_CHUNK_SIZE, Data1),
+	Chunks1 = imperfect_split(Data1),
 	{DataRoot1, _} = ar_merkle:generate_tree(
 		ar_tx:sized_chunks_to_sized_chunk_ids(
 			ar_tx:chunks_to_size_tagged_chunks(Chunks1)
@@ -249,7 +249,7 @@ test_rejects_chunks_exceeding_disk_pool_limit() ->
 			?DEFAULT_MAX_DISK_POOL_DATA_ROOT_BUFFER_MB - 1
 		) * 1024 * 1024
 	),
-	Chunks2 = split(Data2),
+	Chunks2 = imperfect_split(Data2),
 	{DataRoot2, _} = ar_merkle:generate_tree(
 		ar_tx:sized_chunks_to_sized_chunk_ids(
 			ar_tx:chunks_to_size_tagged_chunks(Chunks2)
@@ -275,7 +275,7 @@ test_rejects_chunks_exceeding_disk_pool_limit() ->
 		byte_size(Data2),
 	?assert(Left < ?DEFAULT_MAX_DISK_POOL_DATA_ROOT_BUFFER_MB * 1024 * 1024),
 	Data3 = crypto:strong_rand_bytes(Left + 1),
-	Chunks3 = split(Data3),
+	Chunks3 = imperfect_split(Data3),
 	{DataRoot3, _} = ar_merkle:generate_tree(
 		ar_tx:sized_chunks_to_sized_chunk_ids(
 			ar_tx:chunks_to_size_tagged_chunks(Chunks3)
@@ -303,12 +303,14 @@ test_rejects_chunks_exceeding_disk_pool_limit() ->
 	true = ar_util:do_until(
 		fun() ->
 			%% After a block is mined, the chunks receive their absolute offsets, which
-			%% end up above the rebase threshold and so the node discovers the very last
-			%% chunks of the last two transactions are invalid under these offsets and
-			%% frees up 131072 + 131072 bytes in the disk pool => we can submit a 262144-byte
-			%% chunk.
+			%% end up above the strict data split threshold and so the node discovers
+			%% the very last chunks of the last two transactions are invalid under these
+			%% offsets and frees up 131072 + 131072 bytes in the disk pool => we can submit
+			%% a 262144-byte chunk. Also, expect 303 instead of 200 because the last block
+			%% was large such that the configured partitions do not cover at least two
+			%% times as much space ahead of the current weave size.
 			case ar_test_node:post_chunk(main, ar_serialize:jsonify(FirstProof3)) of
-				{ok, {{<<"200">>, _}, _, _, _, _}} ->
+				{ok, {{<<"303">>, _}, _, _, _, _}} ->
 					true;
 				_ ->
 					false
@@ -1012,23 +1014,24 @@ v2_standard_split_get_chunks(<< _:262144/binary, LastChunk/binary >> = Rest, Chu
 v2_standard_split_get_chunks(<< Chunk:262144/binary, Rest/binary >>, Chunks, MinSize) ->
     v2_standard_split_get_chunks(Rest, [Chunk | Chunks], MinSize).
 
-split(Data) ->
-	split(?DATA_CHUNK_SIZE, Data).
+imperfect_split(Data) ->
+	imperfect_split(?DATA_CHUNK_SIZE, Data).
 
-split(_ChunkSize, Bin) when byte_size(Bin) == 0 ->
+imperfect_split(_ChunkSize, Bin) when byte_size(Bin) == 0 ->
 	[];
-split(ChunkSize, Bin) when byte_size(Bin) < ChunkSize ->
+imperfect_split(ChunkSize, Bin) when byte_size(Bin) < ChunkSize ->
 	[Bin];
-split(ChunkSize, Bin) ->
+imperfect_split(ChunkSize, Bin) ->
 	<<ChunkBin:ChunkSize/binary, Rest/binary>> = Bin,
 	HalfSize = ChunkSize div 2,
 	case byte_size(Rest) < HalfSize of
 		true ->
-			HalfSize = ChunkSize div 2,
 			<<ChunkBin2:HalfSize/binary, Rest2/binary>> = Bin,
+			%% If Rest is <<>>, both chunks are HalfSize - the chunks are invalid
+			%% after the strict data split threshold.
 			[ChunkBin2, Rest2];
 		false ->
-			[ChunkBin | split(ChunkSize, Rest)]
+			[ChunkBin | imperfect_split(ChunkSize, Rest)]
 	end.
 
 build_proofs(B, TX, Chunks) ->