Abstract: A method for access control of data in a filesystem is provided. The method includes storing a map in a server, the map coupled to an agent, the map associating access control rules, filenames in a namespace in a first filesystem, and owners of files. The method includes determining a block filename in a namespace in a second filesystem, based on an I/O request from a data node to the second filesystem regarding a data block. The method includes determining a username of the I/O request and determining a filename in the namespace in the first filesystem, based on the block filename in the namespace in the second filesystem. The method includes applying to the data block and the username an access control rule that the map associates with an owner of a file having the filename in the namespace in the first filesystem.

Abstract: A method for interposing on operating system calls in a host is provided. The method includes patching an operating system kernel function, the patching comprising adding a first pointer that invokes an agent function, the patching performed by an agent. The method includes executing the agent function, responsive to a system call stub calling the operating system kernel function, which invokes the agent function via the first pointer, wherein at least one action of the method is performed by a processor of a host having an operating system.

Abstract: A method for interposing on operating system calls in a host is provided. The method includes patching an operating system kernel function, the patching comprising adding a first pointer that invokes an agent function, the patching performed by an agent. The method includes executing the agent function, responsive to a system call stub calling the operating system kernel function, which invokes the agent function via the first pointer, wherein at least one action of the method is performed by a processor of a host having an operating system.

Abstract: A method for access control of data in a filesystem is provided. The method includes storing a map in a server, the map coupled to an agent, the map associating access control rules, filenames in a namespace in a first filesystem, and owners of files. The method includes determining a block filename in a namespace in a second filesystem, based on an I/O request from a data node to the second filesystem regarding a data block. The method includes determining a username of the I/O request and determining a filename in the namespace in the first filesystem, based on the block filename in the namespace in the second filesystem. The method includes applying to the data block and the username an access control rule that the map associates with an owner of a file having the filename in the namespace in the first filesystem.