include the piece index that failed in disk errors

include/libtorrent/disk_io_thread.hpp

@@ -120,6 +120,9 @@ namespace libtorrent
 		// the error code from the file operation
 		error_code error;
 
+		// the piece the error occurred on
+		int error_piece;
+
 		// this is called when operation completes
 		boost::function<void(int, disk_io_job const&)> callback;
 	};

include/libtorrent/storage.hpp

@@ -289,6 +289,7 @@ namespace libtorrent
 
 		error_code const& error() const { return m_storage->error(); }
 		std::string const& error_file() const { return m_storage->error_file(); }
+		int last_piece() const { return m_last_piece; }
 		void clear_error() { m_storage->clear_error(); }
 
 		int slot_for(int piece) const;
@@ -418,14 +419,17 @@ namespace libtorrent
 		disk_buffer_holder m_scratch_buffer2;
 		// the piece that is in the scratch buffer
 		int m_scratch_piece;
-		
+
+		// the last piece we wrote to or read from
+		int m_last_piece;
+
 		// this is saved in case we need to instantiate a new
 		// storage (osed when remapping files)
 		storage_constructor_type m_storage_constructor;
 
 		// this maps a piece hash to piece index. It will be
 		// build the first time it is used (to save time if it
-		// isn't needed) 				
+		// isn't needed)
 		std::multimap<sha1_hash, int> m_hash_to_piece;
 	
 		// this map contains partial hashes for downloading

src/disk_io_thread.cpp

@@ -1248,6 +1248,7 @@ namespace libtorrent
 			j.str = ec.message();
 			j.error = ec;
 			j.error_file = j.storage->error_file();
+			j.error_piece = j.storage->last_piece();
 			j.storage->clear_error();
 #ifdef TORRENT_DEBUG
 			std::cout << "ERROR: '" << j.str << "' " << j.error_file << std::endl;
@@ -1421,6 +1422,7 @@ namespace libtorrent
 					{
 						ret = -1;
 						j.error = error_code(ENOMEM, get_posix_category());
+						j.error_piece = -1;
 						j.str = j.error.message();
 						break;
 					}
@@ -1447,6 +1449,7 @@ namespace libtorrent
 						j.storage->mark_failed(j.piece);
 						j.error = error_code(errors::failed_hash_check, libtorrent_category);
 						j.str = j.error.message();
+						j.error_piece = j.storage->last_piece();
 						j.buffer = 0;
 						break;
 					}
@@ -1473,6 +1476,7 @@ namespace libtorrent
 					{
 						ret = -1;
 						j.error = error_code(ENOMEM, get_posix_category());
+						j.error_piece = -1;
 						j.str = j.error.message();
 						break;
 					}
@@ -1505,6 +1509,7 @@ namespace libtorrent
 							j.error = error_code(errors::file_too_short, libtorrent_category);
 							j.error_file.clear();
 							j.str = j.error.message();
+							j.error_piece = j.storage->last_piece();
 							ret = -1;
 							break;
 						}

src/storage.cpp

@@ -1484,6 +1484,7 @@ ret:
 		, m_scratch_buffer(io, 0)
 		, m_scratch_buffer2(io, 0)
 		, m_scratch_piece(-1)
+		, m_last_piece(-1)
 		, m_storage_constructor(sc)
 		, m_io_thread(io)
 		, m_torrent(torrent)
@@ -1745,6 +1746,7 @@ ret:
 		TORRENT_ASSERT(bufs);
 		TORRENT_ASSERT(offset >= 0);
 		TORRENT_ASSERT(num_bufs > 0);
+		m_last_piece = piece_index;
 		int slot = slot_for(piece_index);
 		return m_storage->readv(bufs, slot, offset, num_bufs);
 	}
@@ -1764,6 +1766,7 @@ ret:
 
 		file::iovec_t* iov = TORRENT_ALLOCA(file::iovec_t, num_bufs);
 		std::copy(bufs, bufs + num_bufs, iov);
+		m_last_piece = piece_index;
 		int slot = allocate_slot_for_piece(piece_index);
 		int ret = m_storage->writev(bufs, slot, offset, num_bufs);
 		// only save the partial hash if the write succeeds
@@ -2336,7 +2339,10 @@ ret:
 
 			// the slot where this piece belongs is
 			// free. Just move the piece there.
+			m_last_piece = piece;
 			m_storage->move_slot(m_current_slot, piece);
+			if (m_storage->error()) return -1;
+
 			m_piece_to_slot[piece] = piece;
 			m_slot_to_piece[m_current_slot] = unassigned;
 			m_slot_to_piece[piece] = piece;
@@ -2560,6 +2566,7 @@ ret:
 			}
 
 			bool ret = false;
+			m_last_piece = piece_index;
 			if (other_piece >= 0)
 				ret |= m_storage->swap_slots(other_slot, m_current_slot);
 			else
@@ -2598,6 +2605,7 @@ ret:
 				ret |= m_storage->move_slot(other_slot, m_current_slot);
 
 			}
+			m_last_piece = other_piece;
 			if (ret) return skip_file();
 
 			TORRENT_ASSERT(m_slot_to_piece[m_current_slot] == unassigned
@@ -2636,6 +2644,7 @@ ret:
 				TORRENT_ASSERT(piece1 == m_current_slot);
 				TORRENT_ASSERT(piece_index == slot1);
 
+				m_last_piece = piece_index;
 				m_storage->swap_slots(m_current_slot, slot1);
 
 				TORRENT_ASSERT(m_slot_to_piece[m_current_slot] == unassigned
@@ -2682,6 +2691,7 @@ ret:
 					ret |= m_storage->move_slot(slot2, m_current_slot);
 				}
 
+				m_last_piece = piece_index;
 				if (ret) return skip_file();
 
 				TORRENT_ASSERT(m_slot_to_piece[m_current_slot] == unassigned
@@ -2827,6 +2837,7 @@ ret:
 				m_piece_to_slot[piece_index]
 				, m_piece_to_slot[piece_at_our_slot]);
 
+			m_last_piece = piece_index;
 			m_storage->move_slot(piece_index, slot_index);
 
 			TORRENT_ASSERT(m_slot_to_piece[piece_index] == piece_index);
@@ -2870,6 +2881,7 @@ ret:
 			int new_free_slot = pos;
 			if (m_piece_to_slot[pos] != has_no_slot)
 			{
+				m_last_piece = pos;
 				new_free_slot = m_piece_to_slot[pos];
 				m_storage->move_slot(new_free_slot, pos);
 				m_slot_to_piece[pos] = pos;