Patent ID: 11868256
Assignee: EMC IP HOLDING COMPANY LLC
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 0:
1. A computer-implemented method comprising:
receiving a write request to update second metadata from a second entry of a second metadata page;
recording a first metadata change in a metadata log, wherein the first metadata change indicates to update the second entry of the second metadata page with the second metadata as an updated value; and
performing first processing to destage the first metadata change from the metadata log, wherein the first processing to destage the first metadata change from the metadata log includes:
determining whether the first metadata change overwrites an existing value of the second entry of the second metadata page where the existing value is needed in performing second processing prior to overwriting the existing value with the second metadata as the updated value; and
responsive to determining that the first metadata change overwrites an existing value of the second entry of the second metadata page where the existing value is needed in performing said second processing prior to overwriting the existing value with the second metadata as the updated value, performing said second processing comprising:
reading from non-volatile storage a stored version of the second metadata page;
obtaining, from the stored version of the second metadata page, the existing value of the second entry of the second metadata page;
performing third processing using the existing value of the second entry of the second metadata page; and
after completing the third processing, applying one or more metadata changes to the second metadata page, wherein the one or more metadata changes include the first metadata change that overwrites the existing value of the second entry of the second metadata page with the second metadata.