File system for a clustered processing system

• US 5,828,876 A
• Filed: 07/31/1996
• Issued: 10/27/1998
• Est. Priority Date: 07/31/1996
• Status: Expired due to Term

• Current Assignee: SIOS Technology Corp. (SIOS Corp.)
• Original Assignee: NCR Corporation
• Inventors: Fish, Robert W., Schroeder, Lawrence J.
• Primary Examiner(s): Kulik, Paul V.
• Application Number:
  US08/690,703
• Time in Patent Office: 818 Days
• Field of Search: 395/601, 395/618, 395/617, 395/616, 395/609, 395/726, 395/180
• US Class Current: 1/1
• CPC Class Codes: G06F 16/1858 Parallel file systems, i.e. file systems supporting multiple processors
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99939 Privileged access

Abstract

An improved file system for managing data storage and retrieval in a clustered UNIX computer system including a plurality of processing nodes and an interconnection network connecting the processing nodes. The improved file system includes a data storage device, such as a disk storage unit, connected via a shared SCSI interconnect with each one of the processing nodes, rather than connected directly with a single processing node. The structure layout for the file system, which is maintained on the data storage device, includes sufficient information to enable all of the processing nodes to access said file system. The layout comprises: superblocks containing offsets to all other file system structures within the file system; a free inode bit map containing a plurality of bits, each bit representing an inode within the file system; a modified inode journal containing a separate inode bit map for each superblock and identifying particular inodes which have been modified by the file system prior to a system failure; a plurality of inodes, each inode being a data structure which contains a definition for each particular file and directory in the file system; a free block bit map containing a bit map wherein each distinct bit represents a logical disk block in the file system; and data blocks containing data representing file contents. The file system interfaces with the computer system'"'"'s distributed lock manager (DLM) to coordinate file system usage.

Claims

1. In a clustered file system including a plurality of processing nodes, an interconnection network connecting said processing nodes, and a common data storage device connected via a shared interconnect with each one of said plurality of processing nodes, a method for directly accessing said common data storage device simultaneously from all of said plurality of processing nodes;

the method comprising the steps of;

providing a distributed lock manager (DLM) for coordinating file system access among said plurality of processing nodes;

providing a file system structure, saved to said common data storage device, which provides sufficient information to enable all of said processing nodes to access said file system;

providing a DLM Interface Daemon within each one of said plurality of processing nodes for interfacing said file system with said DLM to permit said file system to make requests to and receive responses from the DLM for coordinating file system utilization.

2. The method in accordance with claim 1, wherein said file system structure comprises:

superblocks containing offsets to all other file system structures within said file system;

a free inode bit map containing a plurality of bits, each bit representing an inode within said file system;

a modified inode journal containing a separate inode bit map for each superblock and identifying particular inodes which have been modified by the file system prior to a system failure;

a plurality of inodes, each inode being a data structure which contains a definition for each particular file and directory in the file system;

a free block bit map containing a bit map wherein each distinct bit represents a logical disk block in the file system; and

data blocks containing data representing file contents.

3. An improved file system for managing data storage and retrieval in a clustered computer system including a plurality of processing nodes and an interconnection network connecting said processing nodes, the improvement comprising:

a data storage device connected via a shared interconnect with each one of said plurality of processing nodes;

a file system structure maintained on said data storage device comprising;

superblocks containing offsets to all other file system structures within said file system;

a free inode bit map containing a plurality of bits, each bit representing an inode within said file system;

a modified inode journal containing a separate inode bit map for each superblock and identifying particular inodes which have been modified by the file system prior to a system failure;

a plurality of inodes, each inode being a data structure which contains a definition for each particular file and directory in the file system;

a free block bit map containing a bit map wherein each distinct bit represents a logical disk block in the file system; and

data blocks containing data representing file contents.

4. A file system layout for a clustered file system including a plurality of processing nodes, an interconnection network connecting said processing nodes, and a data storage device connected via a shared interconnect with each one of said plurality of processing nodes, the file system layout comprising:

superblocks containing offsets to all other file system structures within said file system;

a free inode bit map containing a plurality of bits, each bit representing an inode within said file system;

a modified inode journal containing a separate inode bit map for each superblock and identifying particular inodes which have been modified by the file system prior to a system failure;

a plurality of inodes, each inode being a data structure which contains a definition for each particular file and directory in the file system;

a free block bit map containing a bit map wherein each distinct bit represents a logical disk block in the file system; and

data blocks containing data representing file contents.

5. A clustered file system, comprising:

a plurality of processing nodes interconnected through a network;

a common data storage device;

an interconnection bus connecting said plurality of processing nodes with said common data storage device;

a distributed lock manager (DLM) for coordinating file system access among said plurality of processing nodes;

an internal file system contained within each one of said plurality of processing nodes; and

a DLM Interface Daemon contained within each one of said plurality of processing nodes for interfacing said internal file system with said DLM to permit said file system to make requests to and receive responses from the DLM for coordinating file system utilization.