Data transfer device, data receiving system and data receiving method

1. A data transfer system comprising:

a host CPU configured to specify an identifier of target file data; and

a data transfer device which receives the target file data having the identifier from a communication device in a network and writes the target file data into a storage device, the storage device being configured to manage data on a block basis and arranged outside the host CPU,

wherein the host CPU

reads out map information from a predetermined area of the storage device, the map information including one or more metadata each indicating correspondence between an identifier of file data and an area which the file data is stored in the storage device,

specifies an available area to write the target file data in the storage device based on the map information and a size of the target file data, the available area including a plurality of blocks in the storage device,

generates target metadata indicating correspondence between the specified available area and the identifier of the target file data, and

adds the target metadata into the map information stored in the predetermined area of the storage device,

wherein the data transfer device includes

a receiving buffer configured to store data therein;

a communication processor configured to

receive a reception instruction of the target file data from the host CPU, the reception instruction including the identifier of the target file data and session information indicating a session for reception of the target file data,

establish the session according to the session information with the communication device,

receive a plurality of packets from the network,

check whether a session of each of the received packets coincides with the established session, and

determine an address for writing data of each of the received packets in the receiving buffer based on a relative position of the data within the target file data, the data of each of the received packets being part of the target file data, if the session of each of the received packets coincides with the established session, and write the data of each of the received packets at the determined address in the receiving buffer; and

a command issuance controller to

receive the target metadata from the host CPU,

monitor the receiving buffer to determine whether a block size of continuous data is stored in the receiving buffer at addresses corresponding to the block size in order from a head of the target file data,

issue a write command for writing the block size of continuous data at a corresponding block of the plurality of blocks in the storage device if the block size of continuous data is stored in the receiving buffer, and

send the write command to the storage device which executes the write command, and

wherein the receiving buffer outputs the continuous data of the block size to the storage device to write the block size of continuous data at the corresponding block in the storage device.

2. The system according to claim 1 , wherein

the command issuance controller determines whether an entirety of the data corresponding to each of the blocks is stored in the receiving buffer, and issues the write command for writing the entirety of the data corresponding to each of the blocks when the entirety of the data corresponding to each of the blocks is stored in the receiving buffer.

3. The system according to claim 2 , wherein

the packets received via the session indicated in the session information include sequence numbers and parts of the target file data, and

the command issuance controller

stores the data of each of the received packets at an address corresponding to a sequence number of each of the received packets in the receiving buffer,

manages correspondence between the blocks and the sequence numbers, and

determines whether the entirety of the data corresponding to each of the blocks is stored in the receiving buffer based whether all of the packets including the sequence numbers corresponding to each of the block are received.

4. The system according to claim 1 , wherein the command issuance controller specifies a range of data having been stored continuously from the head of the target file data in the receiving buffer, and transmits first information indicating the specified range to the communication device in the network.

5. The system according to claim 4 , wherein the command issuance controller transmits information indicating a smallest sequence number of data which follows the specified range and which is not yet stored in the receiving buffer.

6. The system according to claim 1 , wherein the session indicated in the session information is a session of TCP/IP.

7. The system according to claim 1 , wherein the transfer device further comprises a notifier to receive a completion notice of execution of the write command from the storage device each time the execution of the write command is completed, and in the case that writing of the target file data is completed, notify a write completion response to the host CPU.

8. The system according to claim 1 , wherein the command issuance controller receives a write request of the target metadata from the host CPU, generates a write command for writing the target metadata into the predetermined area, and sends the write command of the target metadata to the storage device.

9. A data receiving method using a host CPU configured to specify an identifier of target file data: and a data transfer device which receives the target file data having the identifier from a communication device in a network and writes the target file data into a storage device, the storage device being configured to manage data on a block basis and arranged outside the host CPU, the method comprising:

reading out, by the host CPU, map information from a predetermined area of the storage device, the map information including one or more metadata each indicating correspondence between an identifier of file data and an area which the file data is stored in the storage device;

specifying, by the host CPU, an available area to write the target file data in the storage device based on the map information and a size of the target file data, the available area including a plurality of blocks in the storage device;

generating, by the host CPU, target metadata indicating correspondence between the specified available area and the identifier of the target file data;

adding, by the host CPU, the target metadata into the map information stored in the predetermined area of the storage device;

receiving, by the data transfer device, a reception instruction of the target file data from the host CPU, the reception instruction including the identifier of the target file data and session information indicating a session for reception of the target file data;

establishing, by the data transfer device, the session according to the session information with the communication device;

receiving, by the data transfer device, a plurality of packets from the network;

checking, by the data transfer device, whether a session of each of the received packets coincides with the session indicated in the session information;

receiving, by the data transfer device, the target metadata from the host CPU;

determining, by the data transfer device, an address for write of data of each of the received packets in a receiving buffer based on a relative position of the data within the target file data if the session of each of the received packets coincides with the session indicated in the session information, the data of each of the received packets being part of the target file data, and writing the data of each of the received packets at the determined address in the receiving buffer;

monitoring, by the data transfer device, the receiving buffer based on the target metadata to determine whether a block size of continuous data is stored in the receiving buffer at addresses corresponding to the block size in order from a head of the target file data;

issuing, by the data transfer device, a write command for writing the block size of continuous data at a corresponding block of the plurality of blocks in the storage device if the block size of continuous data is stored in the receiving buffer;

sending, by the data transfer device, the write command to the storage device which executes the write command; and

outputting the block size of continuous data from the receiving buffer to the storage device to write the block size of continuous data at the corresponding block in the storage device.

10. The system according to claim 1 , wherein the packets received via the established session include parts of the target file data.

11. The system according to claim 1 , wherein

the packets received via the established session include sequence numbers wherein the sequence numbers are associated with addresses of the receiving buffer, and

the command issuance controller determines the address for writing data of each of the received packets based on the sequence number of each of the received packets.