Rolling XOR protection in efficient pipeline
Systems, apparatus and methods for generation of XOR signature metadata and XOR signature management are presented. In one or more embodiments, a storage device controller includes a host interface, configured to receive one or more string lines (SLs) of data from a host, the one or more SLs to be programmed into a non-volatile memory (NVM), and processing circuitry. The processing circuitry is configured to, for each of the one or more SLs, generate signature metadata and provide the signature metadata in a header of the SL. The processing circuitry is still further configured to XOR two or more of the SLs with their respective signature metadata to generate a snapshot, and write the snapshot to the NVM.
1. An apparatus, comprising:
means for determining, following an ungraceful shutdown (UGSD), whether a write process to a multi-level cell (MLC) non-volatile memory (NVM) was ongoing;
means for reading metadata of a last written XOR signature to a single cell (SLC) NVM, the XOR signature protecting data being written to the MLC NVM;
means for determining if the last written XOR signature is a partial signature; and
means for reading a metadata portion of the XOR signature to determine if there are any missing string lines (SLs) in the XOR signature.
2. An apparatus, comprising:
means for determining, following an ungraceful shutdown (UGSD), whether a write process to a multi-level cell (MLC) non-volatile memory (NVM) was ongoing;
means for reading metadata of a last written XOR signature to a single cell (SLC) NVM, the XOR signature protecting data being written to the MLC NVM;
means for determining if the last written XOR signature is a partial signature;
means for completing the XOR signature; and
means for writing the completed XOR signature to SLC NVM.
3. The apparatus of claim 2 , wherein the means for reading metadata further comprises means for obtaining memory locations that were indicated as absent from the last XOR signature.
4. The apparatus of claim 2 , further comprising:
an interface configured to receive one or more string lines (SLs) of data from a host device; and
a non-volatile storage interface for communicating with the MLC NVM and SLC NVM.
5. The apparatus of claim 3 , further comprising a memory management module comprising a CPU and XRAM.
6. The apparatus of claim 2 , wherein the apparatus is further configured to determine that a write process was ongoing at a time of a UGSD.
7. The apparatus of claim 6 , wherein the apparatus is further configured to read metadata of a last written SLC XOR signature.
8. The apparatus of claim 7 , wherein the apparatus is further configured to read MLC locations that were indicated as absent from the last written SLC XOR signature.
9. The apparatus of claim 2 , further comprising memory means.
10. The apparatus of claim 9 , wherein the memory means comprises the MLC NVM and the SLC NVM.
11. An apparatus, comprising:
means for determining, following an ungraceful shutdown (UGSD), whether a write process to a multi-level cell (MLC) non-volatile memory (NVM) was ongoing;
means for reading metadata of a last written XOR signature to a single cell (SLC) NVM, the XOR signature protecting data being written to the MLC NVM; and
means for determining if the last written XOR signature is a partial signature;
wherein the apparatus is configured to:
receive a string line (SL) of a set of protected data for including in a signature;
generate updated signature metadata for the SL; and
store the updated signature metadata in temporary storage.
12. The apparatus of claim 11 , wherein storing the updated signature metadata in temporary storage comprises overwriting a previous version of the metadata.
13. The apparatus of claim 12 , wherein the apparatus is further configured to XOR the SL with a previous version of the signature in temporary storage to generate an updated signature.
14. The apparatus of claim 13 , wherein the apparatus is further configured to overwrite a previous version of the signature with the updated signature.
15. The apparatus of claim 14 , wherein the apparatus is further configured to determine whether there is another SL to include in the signature.
16. The apparatus of claim 15 , wherein the apparatus is further configured to, upon determining that there is another SL to include in the signature:
copy the updated metadata from temporary storage;
append the updated metadata to the updated signature; and
program the updated metadata and updated signature to a SLC block.
17. The apparatus of claim 15 , wherein the apparatus is further configured to, upon determining that there is not another SL to include in the signature:
receive a string line (SL) of a set of protected data for including in a signature;
generate updated signature metadata for the SL; and
store the updated signature metadata in temporary storage.
18. An apparatus, comprising:
means for determining, following an ungraceful shutdown (UGSD), whether a write process to a multi-level cell (MLC) non-volatile memory (NVM) was ongoing;
means for reading metadata of a last written XOR signature to a single cell (SLC) NVM, the XOR signature protecting data being written to the MLC NVM; and
means for determining if the last written XOR signature is a partial signature;
wherein the apparatus is configured to:
determine that a write process was ongoing at a time of a UGSD;
read metadata of a last written SLC XOR signature;
read MLC locations that were indicated as absent from the last written SLC XOR signature;
use missing host data to complete the last written SLC XOR signature; and
write the last written SLC XOR signature to SLC.
19. An apparatus, comprising:
means for determining, following an ungraceful shutdown (UGSD), whether a write process to a multi-level cell (MLC) non-volatile memory (NVM) was ongoing;
means for reading metadata of a last written XOR signature to a single cell (SLC) NVM, the XOR signature protecting data being written to the MLC NVM; and
means for determining if the last written XOR signature is a partial signature;
wherein the apparatus is further configured to update a RAM database with XOR signature metadata.
20. The apparatus of claim 19 , wherein the apparatus is further configured to periodically program the RAM database to a management block.