Abstract: A data storage system is disclosed. A flag is maintained in metadata pointing to a block of data. A first value of the flag indicates that the block of data is stored in a user accessible file. A second value of the flag indicates that the block of data is stored in a protected file. The flag pointing to the requested data block is checked upon receipt of a data access request. When the flag has the first value the data access request is permitted. When the flag has the second value, an access control list is checked, and if the requesting client is listed in the access control list permitting the data access request, and if the requesting client is not listed in the access control list denying the data access request.

Abstract: A metadirectory namespace is provided for storing files and directories “hidden” from one or more user-accessible namespaces. The metadirectory namespace is a separate, parallel namespace that coexists with other user-accessible namespaces in a storage operating system. Files and directories may be identified as being stored in a metadirectory based on their location or based on their associated flags. The metadirectory namespace may be selectively exported only to clients, users and applications given special file access permissions.

Abstract: A metadirectory namespace is provided for storing files and directories “hidden” from one or more user-accessible namespaces. The metadirectory namespace is a separate, parallel namespace that coexists with other user-accessible namespaces in a storage operating system. Files and directories may be identified as being stored in a metadirectory based on their location or based on their associated flags. The metadirectory namespace may be selectively exported only to clients, users and applications given special file access permissions.

Abstract: A system and method enable a storage operating system to partition data into fixed sized data blocks that can be written to disk without having to copy the contents of memory buffers (mbufs). The storage operating system receives data from a network and stores the data in chains of mbufs having various lengths. However, the operating system implements a file system that manipulates data in fixed sized data blocks. Therefore, a set of buffer pointers is generated by the file system to define a fixed sized block of data stored in the mbufs. The set of buffer pointers address various portions of data stored in one or more mbufs, and the union of the data portions form a single fixed sized data block. A buffer header stores the set of pointers associated with a given data block, and the buffer header is passed among different layers in the storage operating system.