Patent ID: 8260811

Claim:
An access controller that receives a file access request and uses an access control list (ACL) to control access with respect to a file designated by the file access request, comprising: a processor; and a memory, wherein in response to receiving the file access request, the processor determines whether the file designated by the file access request is associated with a first type of ACL, the first type of ACL corresponding to a first type of file system, wherein when the file designated by the file access request is associated with the first type of ACL, the processor determines whether the first type of ACL is stored in the memory, and when the first type of ACL is stored in the memory, the processor controls access to the file designated by the file access request by using the first type of ACL, wherein when the file designated by the file access request is not associated with the first type of ACL, and when the first type of ACL is not stored in the memory, the processor locks the file designated by the file access request, converts a second type of ACL to the first type of ACL, the second type of ACL corresponding to a second type of file system which is associated with the file designated by the file access request, and after conversion of the second type of ACL to the first type of ACL, the processor unlocks the file designated by the file access request, wherein in response to receiving an ACL conversion request to convert the second type of ACL to the first type of ACL for each of a plurality of files, the processor determines whether each of the plurality of files is associated with the first type of ACL, which corresponds to the first type of file system, wherein when each of the plurality of files is not associated with the first type of ACL, the processor converts the second type of ACL to the first type of ACL, and controls access to the file designated by the file access request by using the first type of ACL thus converted, and wherein execution of conversion of the file designated by the file access request occurs in parallel with conversion of the plurality of files, the plurality of files not including the file designated by the file access request.