Patent ID: 7756831

Claim:
A method of cooperatively locking storage, comprising: receiving an indication that a first set of previous version data associated with a first set of one or more writes to a data space by a journaling process configured to write to the data space previous version data comprising copies of writes to a protected entity is required to be retained; adding to a first set of stored metadata record identifiers associated with the first set of previous version data, for each of a corresponding first set of one or more metadata records associated with the first set of one or more writes, an identifier that identifies the metadata record as one associated with a write that is to be retained by virtue of being associated with the first set of previous version data; receiving an indication that a second set of previous version data associated with a second set of one or more writes to the data space by the journaling process is required to be retained; and adding to a second set of stored metadata record identifiers associated with the second set of previous version data, for each of a corresponding second set of one or more metadata records associated with the second set of one or more writes, an identifier that identifies the metadata record as one associated with a write that is to be retained by virtue of being associated with the second set of previous version data.