United States Patent   Patent Number: 5,175,852
Johnson et al.  Date of Patent: Dec. 29, 1992
4.527,237 7/1985 Fneder et al 364/200
4,819.159 4/1989 Shipley et al 364/200
Rifkin et al., "RFS Architectual Overview", pp. 1-12.
Primary Examiner—David L. Clark
Assistant Examiner—Maria N. Von Buhr
Attorney, Agent, or Firm—Whitham & Marhoefer
A distributed file management system (DFS) with a plurality of nodes and a plurality of files is disclosed. The DFS uses the UNIX operating system tree structure employing inodes (data structures containing the administrative information of each File) to manage the local files and surrogate inodes (s_inode) to manage access to files existing on another node. In addition, the DFS uses a file access structure lock (fas_lock) to manage multiple requests to a single file. The primary reason for the addition of the fas_lock for each file is to avoid the problem of deadlocks. The inodes and s_inodes use the fas_lock to synchronize their accesses to a file and avoid a deadlock situation where both s_inode and inode await the use of a file that is locked by the other.
18 Claims, 18 Drawing Sheets