Patent ID: 9177177
Filing Date: 2015-11-03
Classification: G06F

Abstract:
1. A computer-implemented method for securing storage space, at least a portion of the method being performed by a computing device comprising at least one processor, the method comprising: identifying a deallocation operation directed to a block, within a storage system, whose contents comprise non-zeroed data, wherein the block was previously allocated for use in an old thin-provisioned logical disk; in response to identifying the deallocation operation, marking a block map to indicate that the block is to return, in response to read operations, zeroed data instead of the contents of the block; marking an additional block map to indicate that the block is subject to a pending trim operation by the storage system and to represent the block as a free but previously allocated block in response to identifying the deallocation operation directed to the block, wherein the additional block map was copied from the block map and is updated in parallel with the block map; wherein marking the block map to indicate that the block is to return zeroed data comprises marking the block map to indicate that the block is to return zeroed data before the trim operation is performed; identifying a read operation directed to the block; determining, in response to identifying the read operation, that the block map indicates that the block is currently allocated for use in a new thin-provisioned logical disk while still comprising data from the old thin-provisioned logical disk and is to return, in response to read operations, zeroed data instead of the contents of the block; returning, in response to the read operation, zeroed data instead of the contents of the block in response to determining that the block map indicates that the block is to return zeroed data instead of the contents of the block in order to protect potentially sensitive data previously stored on the old thin-provisioned logical disk.