JP2000163297A - File device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make detectable a data file being written incompletely by judging that the data file has been written abnormally when the I/O sequential number added at the head of the data file and the current I/O sequential number registered in an I/O sequential number management file are different from each other. SOLUTION: The record of the data file 1 is read in and an I/O sequential number extracting means 23 extracts the I/O sequential number A written at the head of the record. Further, an I/O sequential number inspecting means 24 judges whether the data file 1 is written normally or whether the writing is interrupted owing to some abnormality in the writing according to the sequential number A of an I/O taken out of the record of the data file 1 and the current I/O sequential number 31 registered in the I/O sequential number management table 3. Then, write. data are passed to a file writing means 13 and written as the data file 1 in a disk drive 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a file device for writing and reading a file.

[0002]

2. Description of the Related Art A journal file system is usually used to recover a file failure from a system failure of a computer system or the like. This journal file system outputs the pre-update image to a journal file, which is a separate file from the data file, as an before-image journal before actually updating the data file. Output.

In this system, a data record for which a commit journal has not been output in a recovery process from a failure can be restored by writing back the pre-update image journal, that is, rollback can be performed. Therefore, even if the system goes down during access, data inconsistency does not occur. However, for rollback, it is necessary to output the pre-update image journal to the journal file and update the data record. Therefore, there is a problem that the update amount increases and the overhead increases. If the contents of the data record that failed to be updated due to the system failure can be discarded, the overhead can be reduced.

[0004]

By the way, in a file device consisting of a plurality of records in units of fixed-size records, a system failure occurs for some reason while an application for updating an existing record by random access is operating. Then, since the physical I / O unit of the disk does not always match the record size, there is a problem that the record being written is written in an incomplete state.

The present invention has been made in view of the above-described problems, and has as its object to provide a file device capable of detecting incomplete writing of a file.

[0006]

In order to achieve the above object, according to the present invention, an I / O sequential number updated according to writing of a file is registered as a current I / O sequential number. When writing the sequential number management file and the file as a data file to the storage means, the I / O sequential number is updated and added to the head of the data file, and only when the data file file has been normally written, File writing means for updating and registering the current I / O sequential number registered in the I / O sequential number management file, reading the data file, and checking the I / O sequential number added to the head of the data file and the I / O sequential number / O
When the current I / O sequential number registered in the sequential number management file is different from the current I / O sequential number, a unit having a file reading inspection unit that determines that there is a writing error in the data file is adopted.

In the above means, the storage means may be a disk device for storing the I / O sequential number management file together with the data file.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a file device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a functional configuration of the present embodiment. As shown in this figure, the file device includes a file writing unit 1, a file reading inspection unit 2, an I / O sequential number management table 3, a disk device 4,
(Storage means) and an initial processing means 5.

The I / O sequential number management table 3 is a table for registering the current I / O sequential number 31 for each file (file 1, file 2,...) Stored in the disk device 4. The I / O sequential number is a signed management number having a length that can store the number of I / Os generated from the start to the end of each file. Each time a file is written, “1” is set. It is added. Therefore, the current I / O sequential number 31 is:
This indicates the latest I / O sequential number.

The disk device 4 has an I / O sequential number management file 41 for storing the I / O sequential number management table 3 and a data file 42 for storing data. The I / O sequential number management file 41 stores the I / O
This is a file for storing the number management table 3 sequentially. The data file 42 is divided into records of a fixed length,
I / O is performed on a record-by-record basis, and data is independent for each record, and the file holds data that must be kept consistent within the record. At the beginning of each record, the I / O
/ O A sequential number A is added.

File write means 1 is a write request receiving means 11 for receiving a write request to a file.
And I / O for adding I / O sequential number A to the head of data
Sequential numbering means 12 and file writing means 13 for writing data with I / O sequential numbers to a file
The current I / O sequential number 32 stored in the I / O sequential number management table 3 is updated by adding “1” to the current I / O sequential number 32, and the I / O sequential number management file 41 stored in the disk device 4 is updated. I / O sequential number updating means 14 for updating
And a write result returning means 15 for returning an I / O result to the request source.

The file read check means 2 is a read request receiving means 21 for receiving a file read request.
File reading means 22 for reading the record of the requested data file, I / O sequential number extracting means 23 for extracting the I / O sequential number A added to the head of the record, and the I / O sequential number I / O sequential number checking means 24 for checking whether or not the record of the data file has been normally written based on A and the current I / O sequential number 31 retrieved from the I / O sequential number management table 3. And a read result return means 25 for reporting the inspection result of the I / O sequential number inspection means 24 to the request source.
It is composed of

The initial processing means 5 includes a table creating means 51 for creating an I / O sequential number management table from the I / O sequential number management file 41 on a main storage device (not shown) of the present file device; / O sequential number management table 3
And a file inspection unit 52 for inspecting a file based on the file reading inspection unit 2.

Next, the detailed operation of the present file apparatus having the above configuration will be described with reference to FIG.

First, at the start of the system, the table creating means 51 stores the I / O sequential number management table 3 in the main storage device based on the I / O sequential number management file 41 stored in the disk device 4. create. At the time of initial startup, the I / O sequential number management file 41
Are not registered in the disk device 4, the I / O sequential numbers in the I / O sequential number management table 3 are all "0".
Initially set to

Here, for example, when a read request for the data file 1 is issued, the read request receiving means 21 receives the read request and the file read means 2
2 is the data file 1 specified in the read request
And I / O sequential number extracting means 2
No. 3 takes out the I / O sequential number A written at the head of the record.

The I / O sequential number checking means 24
I / extracted from the record of the data file 1
Based on the O sequential number A and the current I / O sequential number 31 registered in the I / O sequential number management table 3, whether the data file 1 has been normally written or some abnormality has occurred during the writing. To determine whether the writing has been interrupted.

That is, when writing the file 1, the write request receiving means 11 receives the write request for the file 1. Then, the I / O sequential number adding means 12 adds the I / O sequential number A obtained by adding “1” to the current I / O sequential number 32 to the head of the record of the data file 1 corresponding to the file 1, At the beginning of the record.

For example, the current I of the data file 1 is
“102” obtained by adding “1” to the value “101” of the / O sequential number 32 is added to the head of the write data of the data file 1 as the I / O sequential number A. And
This write data is transferred to the file writing means 13 and written as the data file 1 in the disk device 4.

Then, the data file 1
Is completed, the I / O sequential number updating means 14 updates the I / O sequential number management table 3 in the main storage device.
, The current I / O sequential number 31 of the file 1 is updated. That is, the current I / O sequential number 31 of the file 1 in the I / O sequential number management table 3 is “10
The number is updated from “1” to “102” and written to the disk device 4 as an I / O sequential number management file 41.

When the writing to the I / O sequential number management file 41 is completed, the writing result returning means 15 reports the result to the writing request source. Here, when any error occurs in the file writing unit 1, the writing result returning unit 15 immediately notifies the I / O request source of the occurrence of this error. Therefore, the case where the writing result returning means 15 reports that the writing has been completed normally is the case where the writing has been completed normally.

On the other hand, if the writing of the data file 1 has not been completed to the end for some reason, that is, if normal writing cannot be performed during the writing of the data file 1, the I / O sequential number A is Is added to the beginning of the write data, so that it is written at the beginning of the record in the data file 1,
The I / O sequential number updating unit 14 is a unit that updates the current I / O sequential number 31 related to the file 1 in the I / O sequential number management table 3.
Do not update That is, the current I /
The O sequential number 31 is maintained at the value “101” before the writing of the data file 1.

Therefore, the I / O sequential number checking means 24
Can determine whether or not the data file 1 is defective by determining whether or not the following conditional expression (1) is satisfied when reading the data file 1 described above. (I / O sequential number A)-(current I / O sequential number 31) = 1 (1)

When the I / O sequential number checking means 24 determines that the data file 1 is abnormal, the reading result returning means 25 sets such I / O sequential number checking means 24.
Is returned to the I / O request source.

According to the present embodiment, since only basic functions such as reading and writing of files on a disk are used, a special file system such as a journal file system is not required. Therefore, the present invention can be implemented without separately acquiring a journal file system.

Also, since the record contents of the data file for which writing has failed cannot be stored under the condition that the record contents of the data file can be discarded, the required disk area is reduced as compared with the case where a journal file system is used. can do.

In the above-described embodiment, the I / O sequential number management file 41 is arranged in the disk device 4. However, the storage means may be any storage means whose contents are taken over before and after the system goes down. Instead of the device 4, a memory or the like backed up by a battery may be used.

[0029]

As described above, according to the file apparatus according to the present invention, a file having a writing error can be detected without introducing a special file system such as a journal file system as in the prior art. It is possible to

[Brief description of the drawings]

FIG. 1 is a block diagram showing a functional configuration of an embodiment of the present invention.

[Explanation of symbols]

 A ... I / O sequential number 1 ... File writing means 2 ... File reading inspection means 3 ... I / O sequential number management table 4 ... Disk device (storage means) 5 ... Initial processing means 11 ... Write Request receiving means 12 ... I / O sequential number adding means 13 ... File writing means 14 ... I / O sequential number updating means 15 ... Write result returning means 21 Read request receiving means 22 ... File reading means 23 ... I / O sequential number extracting means 24 ... I / O sequential number checking means 25 ... Reading result returning means 31 ... I / O sequential number 41 ... I / O sequential number management file 42 ... Data file

Claims (2)

[Claims] An I / O sequential number management file (41) in which an I / O sequential number updated according to writing of a file is registered as a current I / O sequential number (31); When writing to the storage means (4), the I / O sequential number is updated and added to the beginning of the data file, and the I / O sequence number is written.
The current I / O registered in the / O sequential number management file
File writing means for updating and registering O sequential numbers (1)
When the I / O sequential number added to the head of the data file is different from the current I / O sequential number registered in the I / O sequential number management file, the data file is read. File reading means (2) for determining that there has been a writing error in the data file. 2. The storage means stores an I / O together with a data file.
O A file device characterized by being a disk device for storing a sequential number management file.