JPH07141245A - Remote file lock system - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To provide a remote file lock system that prevents the deterioration of communication response and ensures the integrity of files. [Configuration] When transferring a sharable file from the remote disk device 1 to the client 2, the transfer unit 21 connects the communication line 3, and the remote file lock unit 22 requests the file management unit 11 to lock and copy the file. . The file management table 11a locks the requested file and transfers a replica of this file to the remote disk device 1. When the transfer of the replica is completed, the transfer unit 21 disconnects the communication line 3. When transferring a replica from the client 2 to the remote disk device 1, the transfer unit 21 connects the communication line 3, the remote file unlock unit 23 requests the file management unit 11 to unlock the file, and the replica management unit 24 Transfer the replica.
The file management unit 11 unlocks the file corresponding to the replica, and the transfer unit 21 disconnects the communication line 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remote file lock system, and more specifically, a single or a plurality of servers and a plurality of clients are communicably connected to each other via a communication line, and the communication is performed. The present invention relates to a remote file lock system that transfers a file that can be shared by each client from a server to a predetermined client after connecting a line and stores the file transferred to the predetermined client in the server again.

[0002]

2. Description of the Related Art In recent years, WAN (Wide Area Network) has been utilized by utilizing a small computer such as a personal computer or a workstation whose processing capacity has been remarkably improved, in place of a conventional large general-purpose computer.
k) etc. are becoming more active. The shift to such a small machine is called "downsizing", and is mainly carried out for the purpose of cost reduction and improvement of processing capacity. Further, under downsizing, a client-server method is adopted in which the roles of small computers are distributed in the system. Even in the field of sales management systems and the like in which it is required to submit a business report within the same day, downsizing is rapidly progressing and a client-server system is adopted. For example, each salesman is handed a mobile communication device as a client, and while sharing various files of a server installed at a sales office, each salesman uses the mobile communication device to concurrently Sales management systems that perform predetermined file processing are becoming popular.

In such a sales management system, for example, Ne developed by Sun Micro Systems Co.
network File System (NFS) and Remote File developed by Bell Laboratories.
It is conceivable to use System (RFS) or AFS developed by Carnegie Mellon University. NFS, RF
In S, in order to prevent modification of data in a file from another client while updating data in the file in one client, reading and writing of a file targeted for transfer by another client in the server are prohibited, That is, a lock mechanism for locking and unlocking, that is, unlocking is provided. Based on the lock / unlock request from a given client, the server
Lock / unlock files and manage files. The client issues a file read / write request to the server separately from the file lock / unlock request. In AFS, the client keeps a replica of the server file regardless of whether the file is locked or unlocked. For this reason,
The client can read / write to the replica while the communication line is disconnected, making effective use of the communication line.
You can edit the data on the replica.

[0004]

Under NFS and RFS, firstly, it is considered that the communication line between the server and the client is always connected. Secondly, it is possible to frequently connect / disconnect the communication line at the time of a lock request, an unlock request, a file read request, and a file write request. However, in the first case, since there is no communication between the server and the client during the lock period, the communication line cannot be effectively used, and the communication cost is wasted. is there. Further, in the second case, since the number of times the communication line is connected between the server and the client increases, the time required for connecting the communication line becomes long and the communication response deteriorates. Further, under AFS, each client can update the data of the replica regardless of whether the file of the server is locked or unlocked. Therefore, if the replica is returned from each client to the server, it becomes difficult to maintain the file integrity. There is a problem that

The present invention solves the above-mentioned technical problems, makes effective use of the communication line and reduces the communication cost, prevents the deterioration of the response of the communication, and secures the integrity of the file. The purpose is to provide.

[0006]

The invention according to claim 1 is
A single or multiple servers and multiple clients are connected so that they can communicate with each other via a communication line, and at the time of connection of the communication line, the files that can be shared by each client are transferred from the server to a predetermined client. A remote file lock system for re-storing a file transferred to a predetermined client in the server, the first line connection means connecting a communication line in transferring a sharable file from the server to the predetermined client After the connection of the communication line by the first line connection unit, after the connection of the communication line by the lock unit for prohibiting the reading and writing of the file which is the object of transfer by another client, , A replica of a file whose reading and writing is prohibited by locking means is specified by the client from the server. And a first line disconnecting unit for disconnecting the communication line after the replica transferring unit transfers the replica, and a second line connecting the communication line for transferring the replica from the predetermined client to the server. File connection means for transferring a replica as a sharable file from a predetermined client to a server after connecting the communication line by the second line connection means and the communication line by the second line connection means After that, reading and writing are prohibited by the locking means, unlocking means for releasing reading and writing prohibition of the file corresponding to the replica transferred by the file transfer means, and communication after the file transfer means transfers the replica Second line disconnecting means for disconnecting the line.

[0007]

According to the first aspect of the present invention, the reading and writing of a file and the transfer of the file from the server of the replica to the predetermined client are associated with each other to connect and disconnect the communication line, and the predetermined client of the replica is connected. Connection from the server to the server and the read / write prohibition of the file corresponding to this replica are linked to connect the communication line.
Disconnect. Therefore, since the number of times the communication line is connected is reduced and the communication line is disconnected during the lock period, it is possible to effectively use the communication line, reduce the communication cost, and prevent a decrease in communication response. Further, during the lock period, the file that is the target of transfer to the predetermined client cannot be read or written by another client, so that the consistency of the file can be secured.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of a remote file lock system according to an embodiment of the present invention. In FIG. 1, a remote disk device (one shown in the drawing, remote device name “label”) 1 as a single or a plurality of servers, and a plurality of clients (one shown in the drawing, client name “silv”).
er ") 2 are communicably connected to each other via a telephone line, a wired or wireless communication line 3 such as ISDN.
The remote disk device 1 includes a file management unit 11 as a lock unit, an unlock unit, and a replica transfer unit,
And a file group 12 composed of a plurality of sharable files stored in a hard disk device or the like. The file management unit 11 includes a file management table 11a, and manages a plurality of files in the file group 12 with the file management table 11a.

FIG. 2 shows the file management table 11 of FIG.
It is a figure which shows an example of a. In FIG. 2, the file management table 11a has a file name column and a lock destination client name column. In the file name field,
File names of files included in the file group 12 are “aa”.
“A”, “bbb”, “ccc”, ... Are described. In the lock destination client name column, the name of the client that locked the files included in the file group 12 is “silve”.
r "," pink ", ... Are described. Note that the file name in the left column is locked by entering the client name in the lock destination client name column, and the client name is deleted from the lock destination client name column, that is, "/" Indicates that the file in the column is unlocked. Therefore, each client 2 can share a file whose lock destination client name column is "/", for example, "bbb".

When there is a lock request from the client 2, the file management unit 11 describes the requested client name in the right column of the requested file, that is, locks the requested file and makes a request based on the copy request. The replica of the created file is transferred to the client 2. After the lock, even if there is a read request or a write request for the file “aaa” from another client, for example, “pink”, the file management unit 11 does not accept this request.
Further, when there is an unlock request from the client 2, the file management unit 11 overwrites the file group 12 with a file that can be shared with the replica transferred from the client 2, for example, “aaa”, and locks the client name field. Client name "silver" from "/"
To

The client 2 includes a plurality of applications 20a to 20n and a transfer unit 2 as first and second line connecting means and first and second line disconnecting means.
1, a remote file lock unit 22, a remote file unlock unit 23, a replica management unit 24 as a file transfer unit, and a replica database 25 composed of a single or a plurality of replicas stored in a hard disk device or the like. . Each of the applications 20a to 20n operates in multitasking and can edit replica data in the replica database 25. In addition, the applications 20a to 20n request the remote file lock unit 22 to lock the file of the remote disk device 1 when editing the replica data of the replica database 25, and the remote file unlock unit 23 after editing the replica data. Requests unlocking of files on the remote disk device 1. The transfer unit 21 connects the communication line 3 with the remote disk device 1 to transfer the file of the remote disk device 1 to the client 2, transfers the file of the remote disk device 1 to the client 2, and then transfers the communication line 3 to the client 2.
Disconnect. Further, the transfer unit 21 connects the communication line 3 in transferring the replica as a sharable file from the client 2 to the remote disk device 1, and disconnects the communication line 3 after transferring the replica. The remote file lock unit 22 receives a file lock request of the remote disk device 1 output from the applications 20a to 20n, and when the communication line 3 is connected, the remote file device 1 sends a file lock request to the remote disk device 1 via the transfer unit 21. Request locks and copying of files. Remote file unlock unit 23
Accepts a file unlock request of the remote disk device 1 output from the applications 20a to 20n, and requests the remote disk device 1 to unlock the file via the transfer unit 21 when the communication line 3 is connected. To do. The replica management unit 24 uses the replica management table 24.
a, and manages a replica of the replica database 25 with the replica management table 24a.

FIG. 3 shows the replica management table 24 of FIG.
It is a figure which shows an example of a. In FIG. 3, the replica management table 24a includes a replica name column and a remote disk device name column. The replica name column contains a replica database 25 copied from each remote disk device.
Replica names "aaa", "dd" of the replicas included in
d ”, ... Are described. In the field of remote disk device name,
The names of the remote disk devices that return the replicas contained in the replica database 25 copied from each remote disk device, "label", "harmony", ... Are described. In addition, the remote disk device name "remote disk device" b
In "abel", "harmony", ..., The files "aaa", "ddd", ... Corresponding to the replicas "aaa", "ddd", ... Are locked. The replica management unit 24 registers / deletes a replica in response to a request from the remote file lock unit 22 and the remote file unlock unit 23. When deleting a replica, that is, when returning the replica to the remote disk device 1, the remote disk device 1 is requested to transfer the replica.

Next, the operation of the remote file lock system shown in FIG. 1 will be described. FIG. 4 is a flowchart in the lock mode, and FIG. 5 is a flowchart in the unlock mode. First, the lock mode will be described. In FIG. 4, the application of the client 2 requests the remote file lock unit 22 to lock a file (for example, “aaa”) existing in the remote disk device 1 (step S1). The remote file lock unit 22 inquires of the replica management unit 24 whether or not a replica of the lock target file exists in the replica database 25 (step S2). The replica management unit 24 checks whether or not the file exists in the replica database 25 by referring to the replica management table 24a (see FIG. 3) (step S3), and notifies the remote file lock unit 22 of the check result. When the file to be locked exists in the replica database 25, the remote file lock unit 22 that has received the notification notifies the application requesting the lock that the file to be locked cannot be locked (step S4). This ends the lock mode. Therefore, by investigating the replica management table, it can be seen that the file cannot be locked, and it is possible to prevent the unnecessary connection of the communication line 3 and the unnecessary request for the file lock to the remote disk device 1. Note that step S
3 and 4 occur when another application tries to lock the file of the remote disk device 1 corresponding to this replica while another application is editing the data of the replica. As a result, it is possible to prevent the replica data from being modified by the application that requested the lock later, and it is possible to maintain the consistency of the replica in the client 2.

If no replica of the file exists in the replica database 25 in step S3, the transfer unit 21 connects the communication line 3 to the remote disk device 1 in order to lock the file in the remote disk device 1. (Step S5). This allows the client 2
Can communicate with the remote disk device 1. The remote file lock unit 22 which has received the notification that the replica of the file does not exist in the replica database 25 receives the remote disk device 1 via the transfer unit 21 and the communication line 3.
To lock the file and copy the file to the client 2 (step S6).

The file management unit 11 of the remote disk device 1 that has received the file locking and copying request may have the requested file already locked by another client, so the file management table 11a.
Referring to the column of the lock destination client name (see FIG. 2), it is checked whether or not the requested file is locked (step S7). If a client such as “silver” or “pink” is already described in the lock destination client name field, the requested file (see FIG. 2).
The files "aaa" and "ccc") are already locked. In this case, the file management unit 11 notifies the remote file lock unit 22 via the communication line 3 and the transfer unit 21 of the client 2 that the requested file cannot be locked (step S8). When notified that the lock cannot be made, the transfer unit 21 of the client 2 disconnects the communication line 3 (step S9). Therefore, useless extension of the connection of the communication line 3 can be prevented. Further, the remote file lock unit 22 that has received the notification that the file cannot be locked notifies the application that requested the lock that the file to be processed has already been locked by another client (step S10). This ends the lock mode.

In step S7, if nothing is written in the lock destination client name field of the file management table 11a shown in FIG. 2, that is, if it is "/", the requested file is not locked. . In this case, the process proceeds from step S7 to step S11, and the file management unit 11 enters the lock destination client name column on the right side of the requested file (for example, the file “aaa” in FIG. 2) in the file management table 11a. Register the name "silver" of the client 2. That is, lock the requested file. In addition, the file management unit 11 notifies the remote file lock unit 22 of the client 2 that the lock of the requested file via the communication line 3 and the transfer unit 21 has been successful, and the file to be processed from the file group 12 is notified. And transfers a replica of the requested file to the replica management unit 24 of the client 2.

When the transfer of the replica is completed, the transfer unit 21 of the client 2 disconnects the communication line 3 with the remote disk device 1 (step S12). Accordingly, it is possible to prevent useless extension of the connection of the communication line 3. The remote file lock unit 22 notifies the application that has requested the lock that the requested file has been successfully locked in the remote disk device 1 (step S13).

The replica management unit 24 registers the transferred replica in the column of the replica name of the replica management table 24a shown in FIG. 3, and stores the replica in the replica database 25.
(Step S14). This ends the lock mode. Therefore, with the file of the remote disk device 1 locked and the communication line 3 disconnected,
The applications 20a to 20n requesting the lock are
The data of the replica held in the client 2 can be edited. When the editing of the data of the replica by the applications 20a to 20n is completed, the replica is returned to the remote disk device 1, and therefore the unlock mode is entered.

Next, the unlock mode will be described. In FIG. 5, the applications 20a to 20n of the client 2 request the remote file unlock unit 23 to unlock the file of the remote disk device 1 corresponding to the replica (step S21). The remote file unlock unit 23 that has received the unlock request requests the replica management unit 24 to return the replica to the remote disk device 1 (step S22). Then
The transfer unit 21 connects the communication line 3 to unlock the file in the remote disk device 1 (step S2).
3). This allows the client 2 to communicate with the remote disk device 1. Next, the replica management unit 24 deletes this replica entry from the replica management table 24a, requests the remote disk device 1 to transfer the replica via the transfer unit 21, and transfers the replica to the remote disk device 1. Notifies the remote file unlock unit 23 of the transfer end of the replica (step S2).
4). The remote file unlock unit 23 receives the notification of the completion of the transfer of the replica, and requests the remote disk device 1 to unlock the file (step S25).

The file management unit 11 of the remote disk device 1
Stores the replica as a sharable file in the file group 12 on the basis of the transfer request of the replica, and the file management table 1 on the basis of the unlock request.
Update the lock destination client name field of 1a to "/",
The remote file unlock unit 23 of the client 2 is notified of the unlock success (step S26). The file returned from the client 2 is overwritten on the unlocked file. Therefore, the original file is deleted and does not remain. The transfer unit 21 of the client 2 disconnects the communication line 3 with the remote disk device 1 when the notification of successful unlocking is given to the remote file unlock unit 23 (step S2).
7). Therefore, useless extension of the connection of the communication line 3 can be prevented. Remote file unlock unit 23
Is the application 20a-2 requesting the unlock
0n is notified that the unlock is successful (step S28). As a result, each client 2 can share the file in which the remote disk device 1 is unlocked.

In the above embodiment, the original file is deleted. However, the original file is left as a pack-up, and the original file and the replica transferred from the client 2 are version-controlled. Good.
Further, the remote file lock unit 22 and the remote file unlock unit 23 are provided in the client 2, but the remote file lock unit 22 and the remote file unlock unit 23 may be provided in the remote disk device 1. In this case, when there is a lock request or an unlock request from the applications 20a to 20n, the replica management unit 24 that receives these requests issues a lock request, a copy request, and an unlock request to the remote disk device 1. Good. In addition, the applications 20a to 20
When a read request or a write request is output from n, the client 2 may make a lock request or an unlock request to the remote disk device 1. Further, the file is locked / unlocked when the client 2 issues only a lock request or an unlock request to the remote disk device 1 or when the client 2 issues only a read request / write request to the remote disk device 1. You may make it transfer it.

[0022]

As described above, according to the first aspect of the present invention, the communication line is connected / disconnected in association with the prohibition of reading and writing of the file and the transfer of the replica of the file from the server to the predetermined client. , The connection from the specified client of the replica to the server and the release of prohibition of reading and writing of the file corresponding to this replica are connected / disconnected, so that the number of connection of the communication line is Since the number of communication lines is reduced and the communication line is disconnected during the lock period, effective use of the communication line and reduction of communication cost can be achieved, and deterioration of communication response can be prevented. Further, during the lock period, the file that is the target of transfer to the predetermined client cannot be read or written by another client, so that the consistency of the file can be secured.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a remote file lock system according to an exemplary embodiment of the present invention.

FIG. 2 is a diagram showing an example of a file management table 11a in FIG.

3 is a diagram showing an example of a replica management table 24a in FIG.

FIG. 4 is a flowchart in a lock mode.

FIG. 5 is a flowchart in an unlock mode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Remote disk device 2 ... File management part 3 ... Communication line 11 ... File management part 11a ... File management table 12 ... File group 21 ... Transfer part 22 ... Remote file lock part 23 ... Remote file unlock part 24 ... Replica management part 24a ... Replica management table 25 ... Replica database

Claims (1)

[Claims] 1. A single or a plurality of servers and a plurality of clients are communicably connected via a communication line,
A remote file lock system for transferring a file sharable by each client from a server to a predetermined client after connecting the communication line, and re-storing the file transferred to the predetermined client in the server, When transferring a sharable file from the server to the predetermined client, first line connecting means for connecting the communication line, and after connecting the communication line by the first line connecting means,
Locking means for prohibiting reading and writing of a file which is a transfer target by another client, and after connecting the communication line by the first line connecting means,
A replica transfer unit for transferring a replica of a file whose reading and writing is prohibited by the lock unit from the server to the predetermined client; and a first disconnecting the communication line after the replica transfer unit transfers the replica. Line disconnecting means, second line connecting means for connecting the communication line in transferring the replica from the predetermined client to the server, and after connecting the communication line by the second line connecting means,
A file transfer means for transferring a replica as a sharable file from the predetermined client to the server; and after connecting the communication line by the second line connecting means,
Read and write are prohibited by the lock means, unlock means for canceling read and write prohibition of the file corresponding to the replica transferred by the file transfer means, and after the file transfer means transfers the replica, A remote file lock system, comprising: a second line disconnecting means for disconnecting the communication line.