JPH0621995B2 - File simultaneous access control system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to the simultaneous use of file resources in a computer processing system, and in particular, the simultaneous use of files by block-level exclusive control from a process using a temporary file update function. Regarding access control method.

[Conventional technology]

Conventionally, this kind of simultaneous file access control method at the block level in the file occurs from the simultaneous access to the data content obtained as the access result by all the process groups that simultaneously access the file having the simultaneous file update control attribute. In order to guarantee that inconsistency does not occur, a method is generally used in which a file block access request is issued to the simultaneous file access control device to lock the related block, and the file is accessed only when it is already locked. Such a method is used as a file simultaneous access control method between processes that at least update files, not only refer to them.

Such a simultaneous file access control method is also used in simultaneous file access by a process that tests a file update using the temporary file update function and a process that does not use the temporary file update function.

The file temporary update function is for supporting a program that updates a file, and is a function that gives the same effect as accessing the real file to the program without destroying the real file body. It is realized by the method as shown in FIG. After that, the file is updated from the file temporary update function using process 1A to the temporary update file 5 via the file temporary update function file I / O control device 2 (see path a). Further, reading of an unupdated block into the process 1A is performed from the real file 4 (see path b), and reading of an updated block into the process 1A is performed from the temporary update file 5 (see path b '). .

[Problems to be solved by the invention]

The above-described conventional simultaneous file access control method is a method in which all processes that access a file make a lock request to the simultaneous file access control device in association with the access of the file, and if there is a lock conflict between the processes, The process is such that waiting between processes and deadlock occur. For this reason, if processes that use the temporary file update function and processes that do not use the temporary file update function coexist, a process that uses the temporary file update function may cause a process that does not use the temporary file update function to wait. There is a drawback that there is. this is,
In other words, the test process is waiting for the production process.

[Means for solving problems]

The simultaneous file access control system of the present invention writes an updated block image to a temporary update file in response to a file update request from a process, and writes the corresponding block to a temporary update file in response to a file reference request. File is read from the temporary update file, and if the corresponding block is not written to the temporary update file, it is read from the actual file.The process that uses the file temporary update function and the process that does not use the file temporary update function are files. In a file simultaneous access control system of a file management system that may simultaneously access files, an access request for either a real file with a simultaneous update control attribute that requires simultaneous access control or a temporary update file is Process that uses the feature A bypass means for bypassing the lock processing in the file simultaneous access accompanying the access request when it is determined that the access request is from the process using the file temporary update function. And a determining means for determining.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a simultaneous file access control system showing an embodiment of the present invention. The file simultaneous access control system of the present embodiment has two file update processes 1A and 1B, a file I / O control device 2, a file simultaneous access control device 3, a real file 4 with a simultaneous update control attribute, and a temporary update. File 5 and.

The file update process 1A uses the file temporary update function, and the file update process 1B does not use the file temporary update function. These processes 1A and 1B
Issues an access request to an actual file to the file I / O control device 2, and the file I / O control device 2 performs various controls for file access requests from the file update processes 1A and 1B. . In the figure,
In particular, the flow chart shows the determination process of the simultaneous file access control function and the determination process of the temporary file update function. That is, in step 21, it is determined whether the input / output is to the real file 4 with the simultaneous update control attribute. If yes (YES), in step 22 the file simultaneous access control device 3
Block lock request processing is performed, and if no (NO), simultaneous update control, that is, even if the request is an access request to an actual file that does not require lock processing, nothing is performed and the process proceeds to step 23. In step 23, it is determined whether the update is from the file temporary update function using process 1A. If yes, the temporary update file 5 is temporarily updated in step 24. If no, the step 25 is executed. File 4 is updated.

The file simultaneous access control device 3 manages resource at the block level of the file. In particular, as shown in the flowchart, in step 31, the process 1A using the temporary file update function is performed.
It is judged whether it is input / output from or not, and if it is NO, step 32
Lock the block with, and if yes, do not.

The real file 4 with the simultaneous update control attribute is a file that the file update processes 1A and 1B are trying to access simultaneously, and the temporary update file 5 is a temporary update file for the real file 4 and uses the file temporary update function. Store the updated image for file 4 from 1A.

Next, the operation when the file update processes 1A and 1B simultaneously access the real file 4 with the simultaneous update control attribute will be described.

When the process 1A makes an update request to the file 4, the determination in step 31 is exited with YES and step 32 is bypassed, so the related block is not locked, and the determination in step 23 is released with YES and updated in step 24. The image is stored in the temporary update file 5. Therefore, even if the corresponding block portion of the file 4 is locked by the process 1B, waiting does not occur, and the update image of the process 1B is not destroyed.

Also, when the process 1A makes a read request to the file 4, the related block is not locked, and if the block image is in the temporary update file 5, the data image obtained as a result of the read is added. Has no inconsistencies that can arise from simultaneous updates.

However, if the block image to be read is file 5
If the corresponding block portion of the real file 4 is not present in the file, the wait does not occur when that portion is locked by the process 1B, but the process 1A may read the block image in the inconsistent state. obtain. That is, the process 1A that uses the temporary file update function may use an inconsistent data image that arises from the simultaneous update of files in a special case, but the process 1B that does not use the temporary file update function does not. Not only is this impossible, but it is also unlikely that the process 1A will have to wait.

〔The invention's effect〕

As described above, according to the present invention, in the file simultaneous access control method in the case where a process that uses the temporary update function and a process that does not use the file temporary update function access the file at the same time, By ignoring (passing) the lock request of the block in the file of, the process that does not use the temporary file update function does not cause the waiting that occurs from the simultaneous access control of the file from the process that uses the temporary file update function, and Consistency of input data resulting from simultaneous access can be guaranteed for processes that do not use the temporary file update function. Therefore, under the environment in which the test-related work is executed simultaneously with the production-related work in the same computer system, it is possible to realize an environment in which the test-related work does not affect the production-related work.

[Brief description of drawings]

FIG. 1 is a block diagram of a simultaneous file access control system showing an embodiment of the present invention, and FIG. 2 is a schematic diagram for explaining a temporary file updating function. In the figure, 1A ... Process using temporary file update function, 1B ... Process not using temporary file update function, 2 ... File I / O control device, 3 ... Simultaneous file access control device, 4 ... Simultaneous update control attribute Attached real file, 5 ... Temporary update file.

Claims (1)

[Claims] 1. When a file update request from a process is issued, an update block image is written to a temporary update file, and when a file reference request is made, a temporary update is performed when the corresponding block is written to the temporary update file. A process that uses the file temporary update function and a process that does not use the file temporary update function may access at the same time by reading from a file and reading the actual file if the block is not written to the temporary update file. In the file simultaneous access control system of the file management system, the access request to either the real file with the simultaneous update control attribute that requires the simultaneous access control or the temporary update file is issued from the process using the file temporary update function. When it is determined that the A bypass means for bypassing the lock processing in the simultaneous file access associated with the access request, and a determining means for determining whether or not the access request is from a process using the temporary file update function. File simultaneous access control system.