Aggregating block mapping metadata to improve linked clone read performance

A computer system comprising:

• a processor;
• and
• a non-transitory computer readable medium having stored thereon program code executable by the processor, the program code causing the processor to:
• generate a child clone;
• generate a logical map for the child clone, the logical map for the child clone comprising:
• a local logical extent comprising a logical block address (LBA) for data in a data region of the child clone and a physical sector address (PSA) corresponding to the LBA for the data in the data region of the child clone, and
• an inherited logical extent spanning logical extents that are accessible to the child clone, the inherited logical extent inherited from a first ancestor of the child clone and comprising an LBA for data in a data region of the first ancestor and an ancestor identifier (ID) of the first ancestor;
• receive a read request having a read request LBA;
• upon at least determining that r the read request LBA corresponds to the LBA in the local logical extent, return the data from the data region of the child clone;
• and
• upon at least determining that the read request LBA does not correspond to the LBA in the local logical extent, determine that the read request LBA corresponds to the LBA in the inherited logical extent, identify the first ancestor directly using the ancestor ID that is mapped to the LBA in the inherited logical extent, and return the data from the data region of the identified first ancestor.

A non-transitory computer storage medium having stored thereon program code executable by a processor, the program code embodying a method comprising:

• generating a child clone;
• generating a logical map for the child clone, the logical map for the child clone comprising:
• a local logical extent comprising a logical block address (LBA) for data in a data region of the child clone and a physical sector address (PSA) corresponding to the LBA for the data in the data region of the child clone, and
• an inherited logical extent spanning logical extents that are accessible to the child clone, the inherited logical extent inherited from a first ancestor of the child clone and comprising an LBA for data in a data region of the first ancestor and an ancestor identifier (ID) of the first ancestor;
• receiving a read request having a read request LBA;
• upon at least determining that the read request LBA corresponds to the LBA in the local logical extent, returning the data from the data region of the child clone;
• and
• upon at least determining that the read request LBA does not correspond to the LBA in the local logical extent, determining that the read request LBA corresponds to the LBA in the inherited logical extent, identifying the first ancestor directly using the ancestor ID that is mapped to the LBA in the inherited logical extent, and returning the data from the data region of the identified first ancestor.