Patent ID: 7979416

Claim:
A method for operating a data storage system, comprising: maintaining a user-accessible namespace to hold user-accessible files, the user-accessible namespace having a first set of inodes pointing to the user-accessible files; maintaining a metadirectory namespace, the metadirectory namespace to hold names of protected files, the metadirectory namespace having a second set of inodes pointing to the protected files; maintaining a flag in the first set of inodes and the second set of inodes, and indicating by the flag in a selected inode having a first value that the selected inode points to the user-accessible files and indicating by the flag having a second value that the selected inode points to the protected files; receiving from a requesting client a data access request for a requested file; checking the flag in an inode pointing to the requested file; when the flag in the inode pointing to the requested file has the first value, permitting the data access request to the requested file; and when the flag in the inode pointing to the requested file has the second value, checking an access control list, and if the requesting client is permitted by the access control list to access the requested file permitting the data access request to the requested file, and if the requesting client is not permitted by the access control list to access the requested file denying the data access request to the requested file.