Enhancing efficiency of segment cleaning for a log-structured file system

A computer system for enhancing efficiency of segment cleaning for a log-structured file system (LFS) of a computer storage of the computer system, the computer system comprising:

• a processor;
• and
• a non-transitory computer readable medium having stored thereon program code for transferring data to another computer system, the program code causing the processor to:
• using a segment usage table (SUT) that indicates space available in log segments of the LFS, identify a plurality of log segments having contiguous sections that are candidates for segment cleaning;
• identify live blocks within the plurality of the identified log segments, the identifying comprising determining offsets corresponding to locations in the LFS and determining corresponding lengths of the live blocks in each contiguous section of the contiguous sections in the LFS, the live blocks representing blocks that hold current data;
• read the live blocks in the plurality of the identified log segments, each live block comprising a chunk holding data and an associated chunk identifier, wherein reading the live blocks includes reading data being held by the live blocks and chunk identifiers associated with the live blocks;
• coalesce the live blocks into a full segment, and write the coalesced live blocks into one new segment;
• perform a blind update of the chunk identifiers in a chunk map to indicate the new segment, the updating comprising mapping the updated chunk identifiers to a segment identifier of the new segment, wherein performing a blind update comprises using the chunk identifiers extracted from the LFS to identify a location in the chunk map for performing the update and writing update data to the identified location in the chunk map without reading from the chunk map;
• and
• allow the plurality of log segments to be over-written.

A non-transitory computer readable storage medium having stored thereon program code executable by a processor, the program code embodying a method for enhancing efficiency of segment cleaning of a log-structured file system (LFS) of a computer storage of a computer system, the method comprising:

• using a segment usage table (SUT) that indicates space available in log segments of the LFS, identifying a plurality of log segments having contiguous sections that are candidates for segment cleaning;
• identifying live blocks within the plurality of the identified log segments, the identifying comprising determining offsets corresponding to locations in the LFS and determining corresponding lengths of the live blocks in each contiguous section of the contiguous sections in the LFS, the live blocks representing blocks that hold current data;
• reading the live blocks in the plurality of the identified log segments, each live block comprising a chunk holding data and an associated chunk identifier, wherein reading the live blocks includes reading data being held by the live blocks and chunk identifiers associated with the live blocks;
• coalescing the live blocks into a full segment, and writing the coalesced live blocks into one new segment;
• performing a blind update of the chunk identifiers in a chunk map to indicate the new segment, the updating comprising mapping the updated chunk identifiers to a segment identifier of the new segment, wherein performing a blind update comprises using the chunk identifiers extracted from the LFS to identify a location in the chunk map for performing the update and writing update data to the identified location in the chunk map without reading from the chunk map;
• and
• allowing the plurality of log segments to be over-written.