JP2000010842A - Method and system for file management - Google Patents

Abstract

PROBLEM TO BE SOLVED: To arrange file information under the same directory in a continuous area as much as possible by a block-by-block allocation by managing a file information table by block. SOLUTION: The file information management unit table 23 has flags showing whether or not respective blocks are currently in use and bit information showing whether or not respective entries in the blocks are currently in use so as to manage a certain number of successive entries of the file information table 32 in blocks. A file control means 21 analyzes a file generation request and requests a file information managing means 22 to allocate an entry. The file information managing means 22 allocates entries of one unused block to a new directory by referring to the file information management table 23 and allocates one of them to one file. The remaining entries are reserved for next and succeeding file generation requests. All the entries in the block are used as a result of repetitive file generation and when a request is further made, an unused block is added for allocation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a file management method and method, and more particularly, to a file management method and method in a shared storage device in which a plurality of file systems are configured under a plurality of directories.

[0002]

2. Description of the Related Art In a recent networked information processing system, a plurality of users on a network share a large-capacity external storage device, and files of each user are managed under independent directories. hand,
2. Description of the Related Art A plurality of file systems (a group of files under one directory is called a file system) are configured in one external storage device.

In an external storage device used for this type of application, a storage area is divided into a plurality of areas called partitions, and each partition is further divided into a file area in which a file entity is stored and file management information (storage location, A file information table including a plurality of entries (a unit area for storing management information of one file is referred to as an entry) is provided in the management area. A device is used. In this case, JP-A-64-86389 and JP-A-63-1
As described in Japanese Patent Publication No. 00549, if one partition corresponds to one file system, the file information table can be used as a directory as it is, but the number of file systems that can be stored is limited to the number of partitions. There is a drawback that the use efficiency of the system becomes poor. As a countermeasure against this, a directory is treated as one file, and one file entry is created in the file area using one entry of the file information table, similarly to the files under the directory, so that a large number of file systems can be created regardless of the number of partitions. Being able to accommodate is being done.

In the conventional file management system based on the above-described concept, when a new file is created under a directory, an unused entry located near a directory entry is searched and assigned each time. Hereinafter, the disk device for storing the file is
, P + 1 (p is a positive integer) cylinder groups C ₀ -C grouped for each of a plurality of cylinders
_p is divided into, a case will be described in which cylinder group C ₀ -C respective file information table T in position in the management area of the _{p 0} through T _p is provided.

In this state, while the number of file systems accommodated in the disk device is small, the file information tables T _{0 to} T _p are stored in the directory of the file system.
Is allocated, but when the number of file systems exceeds p + 1, a plurality of directories are allocated in the same file information table T _k (k = 0 to p).

A directory is a cylinder group C ₀
When searching for an unused entry in the file information table T ₀ in the same directory and creating a new file under the directory, the file information table T ₀ in the same cylinder group C ₀ as the directory is searched first,
Assign the unused entry closest to the directory entry. However, if the file information table T ₀ is not found unused entries searches the file information table T ₁ of the next cylinder group C _1. In this way, an unused entry is searched and assigned each time from a position as close as possible to a directory entry.

[0007]

However, in the above-described conventional file management system, the number of file systems that can be accommodated is not limited, and the device can be used efficiently.
After the creation and deletion of files under many directories are repeated, the files under the same directory are distributed and placed on the storage device, and the entries of the files under the same directory are stored in the same file information table. Dispersion without continuity is inevitable.

When the entries of files under the same directory are dispersed as described above, only a file name and a pointer to an entry for managing the file are recorded in a directory created as a file as necessary minimum information. Therefore, there is no problem in displaying a list of only file names, but when displaying a list of file attributes, there is a problem that extra time is required for searching, collecting, and editing necessary information.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a file management method and system which eliminates the above-mentioned problems as much as possible and which is compatible with the utilization efficiency of device resources.

[0010]

According to a first aspect of the present invention, there is provided a file management method for a shared storage device accommodating a plurality of groups of files belonging to a directory. The file information table storing the management information including the above is divided into blocks made up of a plurality of continuous entries, and a file information management table made up of management entries for managing the use status of each block and belonging entries is provided. An entry of the file information table used by each file under the directory is allocated to the directory in block units with reference to the file information management table.

According to a second aspect of the present invention, there is provided a file management method according to the first aspect.
In the file management method described above, the file information management table is provided one by one corresponding to each of a plurality of divided storage areas on a recording medium configuring the shared storage device, and the file information management table is , One file information table is provided in common.

According to a third aspect of the present invention, there is provided a file management system for a shared storage device accommodating a plurality of groups of files belonging to a directory, wherein management information including storage locations of files to be stored is stored. And a management entry for dividing the file information table into blocks made up of a plurality of continuous entries and managing the use status of each block and belonging entries in block units. Analyzes a file information management table and a file operation request to control the transfer of information to and from the shared storage device, and allocates entries of the file information table used by the file in the case of a file creation request File control means for requesting Refers to the file information management table is configured to include a file information management means for allocating a block or entry.

According to a fourth aspect of the present invention, there is provided a file management system.
In the file management method described above, each management entry of the file information management table indicates a block number area for storing a block number for identifying a block managed by the management entry, and indicates whether the block has been allocated. An allocation flag area for storing flag information, an entry usage bitmap area for storing a bit string indicating the usage status of each belonging entry in the block, and a management entry for the next block added and allocated to the same directory. A pointer area for storing pointer information, wherein each entry of the file information table is a block number area for storing identification information of a management entry when the entry is allocated for a directory; and file or directory management information. From the management information area to store It is characterized in Rukoto.

According to a fifth aspect of the present invention, there is provided a file management system according to the third aspect.
5. The file management method according to claim 4, wherein the file information management table is provided one by one for each of a plurality of divided storage areas on a recording medium configuring the shared storage device, and It is characterized in that one information management table is provided in common for a plurality of the file information tables.

According to a sixth aspect of the present invention, in the file management system according to the third, fourth, or fifth aspect, the file information management table stores management information of a file for creating a directory. , And a second entry group for storing management information of files under the directory, and only the second entry group is divided into blocks.

[0016]

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

FIG. 1 is a block diagram showing the configuration of the embodiment of the present invention. The embodiment shown in FIG. 1 includes an input device 1 such as a keyboard, a computer 2 that operates under program control, and a storage device 3 such as a magnetic disk device. The computer 2 includes a file control unit 21, a file information management unit 22, a file information management table 23, and an input / output control unit 24 as functions necessary for file management, and the storage area of the storage device 3 stores a file entity. File area 31, and a file information table 32 which is a set of entries for storing management information of files and directories stored in the file area 31.
And are included.

The file control means 21 manages and controls all file systems accommodated in the storage device 3, and analyzes a file operation request such as creation or deletion of a file input by the input device 1. In addition to transmitting and receiving information to and from the storage device 3 via the input / output control means 24, in the case of a file creation request, the assignment of entries in the file information table 32 used by the file is Request to the management means 22.

The file information management means 22 manages the file information table 32 by dividing the file information table 32 into a plurality of blocks each consisting of a continuous fixed number of entries. The use status of the file is grasped, and an entry is assigned to a newly created file in response to a request from the file control means 21.

If the file creation request is from, for example, a new user and it is necessary to open a new file system and create a new directory, the file information management table 23 is referred to for unused files. An entry group of one block is allocated, and the head entry of the block is allocated for a new directory. Subsequently, the second entry in the block allocated to the directory is allocated to the file requested to be created. The remaining entries in the block are reserved for subsequent file creation requests. If the file creation is repeated and there is a further request using all entries in the block, an unused block is added and allocated. In this way, the operation is performed so that the entries used by the files existing under the directory are continuously arranged in block units.

As shown in FIG. 1, the file information management table 23 has (n + 1) (n is a positive integer) for managing entries of the file information table 32 in block units.
Each management entry includes a block number area for storing a block number B _i (i = 0 to n) for identifying a block, and flag information indicating whether or not the block has already been allocated. It comprises an allocation flag area for storing, an entry use status bitmap area for storing a bit string indicating whether each entry in the block is in use, and a pointer area. Entry usage bitmap, m + 1 or from M _i0 to M _im (m
Is a set of bits of 1-bit ON / OF
F indicates whether the entry of the corresponding entry number M _ij (i = 0 to n, j = 0 to m) of the file information table 32 is in use or unused. When a plurality of blocks are allocated to one directory, a block number is stored in the pointer section as pointer information indicating a management entry of a subsequent block. The state in FIG. 1 shows that blocks with block numbers B ₀ , B ₁ and B ₃ are assigned to directories and are in use, and two blocks with block numbers B ₀ and B ₁ are assigned to the same directory. ing.

The file information table 32 is a set of structures having information on one file or directory, and each of these structures is called an entry. FIG.
FIG. 4 is an explanatory diagram showing an example of a data configuration of a file information table 32. File information table 32, as shown in FIG. 2, is divided n + 1 blocks B ₀ .about.B _n consisting of m + 1 entries, each entry, entry number M _ij for identifying an entry, respectively (i = 0
To n, j = 0 to m), a block number area for storing a block number of a first block allocated to the directory when used for a directory, and file or directory management information ( Storage area, size, identification information, etc.). The state in FIG.
Entry Entry No. M ₃₀ entries and block B ₃ of the entry number M ₀₀ of the block B ₀ represents a that has been used for the directory.

FIG. 3 is a flowchart showing the operation of the file information management means of FIG. Hereinafter, the operation of the embodiment of FIG. 1 will be described in detail according to the flowchart of FIG. 3 with reference to FIG. 1 and FIG.

First, when a file operation request is input from the input device 1, the file control means 21 analyzes the given file operation request. The file control means 21
The directory entries of all the file systems contained in the storage device 3 are managed by a comparison list or the like. If the file operation request is a file creation request under an existing directory, the file operation request is assigned to the directory in which the file is created. The input / output control unit 24 requests the input / output control unit 24 to read the entry. Next, the input / output control means 24
Supplies the entry read from the storage device 3 to the file information management means 22, and requests allocation of a newly created file entry. On the other hand, if the file operation request is a request to create a file under the new directory, it requests the file information management unit 22 to allocate an entry for creating a directory.

The file information management means 22 determines whether the allocation request from the file control means 21 is for a new directory or for a file under an existing directory (step S1). In the case of an allocation request for a file under the existing directory, the block number area of the passed entry is referred to, the management entry of the corresponding block number in the file information management table 23 is searched, and the entry usage bitmap area is changed. Check (step S2). For example, if the block number B ₃ is stored in the block number area of the passed entry, M ₃₀ to M ₃₀ stored in the entry use bitmap area of the management entry of the block number B ₃
Search for unused bits from the _3m bit string. As a result of the search, if an unused bit is found, the bit is updated to the use state (step S5), the entry number corresponding to the bit changed to the use state is notified to the file control means 21, and the process is terminated (step S5). S6).

If the allocation request is for a new directory in step S1 and if there is no unused bit in the entry usage bitmap area of the management entry in step S2, the file information management is performed to allocate a new block. Table 23
(Step S3). As a result, if there is an unused management entry in which the use flag is not set, one of them is selected based on a predetermined criterion, the use flag is set in the allocation flag area, and the block is allocated. (Step S4) The process proceeds to step S5 to update the bit corresponding to the first entry in the entry use status bitmap area to the use state, and notify the file control unit 21 of the entry number of the first entry corresponding to the changed bit. The process ends. The block number of the block allocated in step S4 is stored in the pointer area of the previous management entry or the block number area of the entry allocated to the directory.
In addition, as a criterion for selecting an allocation block from unused blocks, a block adjacent to an already allocated block in the case of additional allocation to an existing directory, and an unused block before and after in the case of allocation to a new directory are allocated. It is desirable to set so as to preferentially select a certain block.

If there is no unused management entry in step S3, the file information management means 2
2 notifies the file control means 21 of the non-assignment and ends the process (step S7).

In the case of a file creation request under a new directory, the file control means 21 creates a directory using the head entry of the block allocated for the directory, and creates a block in the block number area of the directory entry. After the number is registered, the file information management unit 22 is requested to assign a file entry under the directory.

The file information management table 23 provided in the computer 2 and the comparison list used by the file control means 21 are management information corresponding to the file storage state of the storage device 3 and are stored in the management area of the storage device 3. It is desirable to store the information together with the information table 32. Therefore, it is called at the start of operation and is expanded on the memory of the computer 2.

According to the configuration and operation described above, entries of the file information table are secured under the directory in block units, so that at least m entries (m + 1 entries including those for directories) under the directory are stored. Since the information is arranged in a continuous area in the area, search and collection of information can be easily performed when a list of file attributes is displayed. If the number m of entries forming a block is large, the number of entries secured in the directory and remaining unused increases, and the utilization efficiency of the storage device decreases. Therefore, the number m of block entries is not increased so much, and the number of blocks n Should be larger than the number of file systems accommodated in the storage device.

In the embodiment of FIG. 1 described above, in order to explain the basic technical idea of the present invention, it has been described that one file information table 32 exists for all storage areas of the storage device 3. The technical idea of the present invention is not limited to a single file information table, but a storage area is divided into a plurality of partitions as shown in FIG. Also, the present invention can be applied to a case where the file information table is provided. In this case, the file information management table has a management entry for managing a plurality of file information tables on a block basis. That is, if the number of file information tables is p and each is divided into n blocks, the number of management entries in the file information management table is p × n.

In the above description of the embodiment, it is assumed that the entry at the head of the block is used as the entry of the file information table for creating the directory and is not specified in advance. On the other hand, the file information table is divided into a directory file and a general file, and only the file information table for the general file is divided into blocks and assigned, and the entry of the file information table for the directory is used from the beginning. You can also. Further, the number of entries in the block is the same, but is not limited to the same.

Further, the management entry of the file information management table has an entry use state bitmap for managing the use state of the entry belonging to the block, and each entry is managed by one bit. The present invention is not limited to this method. For example, the management can be performed by registering the number of the entry in use, and the configurations of the file information management table and the file information table are not limited to the examples.

[0034]

As described above in detail, according to the file management method and method of the present invention, a plurality of continuous file information tables for storing management information including storage locations of files and the like stored in a storage device are provided. And a file information management table for managing the use status of each block and block belonging entries is provided. For each entry of the file information table used for the directory, the entry used by the subordinate file is referred to as this file information. Since allocation is performed in block units with reference to the management table, file entries created under the same directory are arranged in continuous areas on the storage device in block units. Therefore, when displaying a list of the file attributes under the directory, the file information can be read from the continuous area of the storage device, and the display can be performed at high speed.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram showing a configuration example of a file information table in FIG. 1;

FIG. 3 is a flowchart showing an operation of the file information management means of FIG. 1;

FIG. 4 is an explanatory diagram showing a configuration example of a storage area of the shared magnetic disk device.

[Explanation of symbols]

1 input device 2 computer 3 memory 21 file control unit 22 the file information managing means 23 file information management table 24 output control unit 31 the file area 32 file information table C ₀ -C _p cylinder group T ₀ through T _p file information table

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hidetoshi Muida 1-10-23 Ichibancho, Aoba-ku, Sendai-shi, Miyagi F-term in Tohoku NEC Software Corporation 5B082 CA03 CA08 CA18 CA19 EA01 EA07 FA16 GC05

Claims (6)

[Claims] 1. A file management method for a shared storage device accommodating a plurality of file groups belonging to a directory, wherein a file information table for storing management information including a storage position of a file to be stored is continuously provided. A file information management table comprising management entries for managing the use status of each block and belonging entries, divided into blocks comprising a plurality of entries, wherein the files used by each file under the directory A file management method, wherein entries in an information table are allocated in block units with reference to the file information management table. 2. The file information management table is provided one by one corresponding to each of a plurality of divided storage areas on a recording medium constituting the shared storage device. 2. The file management method according to claim 1, wherein one file information table is provided in common for the file information tables. 3. A file management method for a shared storage device accommodating a plurality of groups of files belonging to a directory, comprising a plurality of entries for storing management information including storage locations of files to be stored. A file information management table for dividing the file information table into blocks each having a plurality of continuous entries and managing the use status of each block and belonging entries in block units;
File control means for analyzing a file operation request to control the transfer of information to and from the shared storage device and, in the case of a file creation request, requesting allocation of an entry of the file information table used by the file; And a file information management means for allocating blocks or entries by referring to the file information management table in response to a request from the file control means. 4. Each of the management entries in the file information management table has a block number area for storing a block number for identifying a block managed by the management entry, and flag information indicating whether or not the block has been allocated. , An entry usage bitmap area for storing a bit string indicating the usage status of each belonging entry in the block, and pointer information to a management entry of the next block additionally allocated to the same directory Each entry of the file information table stores a block number area for storing identification information of a management entry when the entry is allocated for a directory, and a file or directory management information. And a management information area for The file management method according to claim 4. 5. The file information management table is provided one by one corresponding to each of a plurality of divided storage areas on a recording medium constituting the shared storage device. 6. The file management method according to claim 4, wherein one file information table is provided in common for the file information tables. 6. A file information management table according to claim 1, wherein said file information management table stores management information of a file for creating a directory.
And a second entry group for storing management information of files under the directory, and only the second entry group is divided into blocks. The file management method according to claim 4 or claim 5.