A method for garbage collection of a volume in a log-structured file system is disclosed. The volume comprises a plurality of segments. Each of the segments comprises a plurality of blocks. An invalid block count of each of the segments is determined. The invalid block count is used as an index for ordering the segments in a garbage collection queue. A plurality of range areas are determined for the index. A migration rate of each range area is determined, and the migration rate of a given range area reflects an intensity of segment migration into/out of the given range area. A negative migration rate reflects a segment migration into the given range area. Garbage collection is performed based upon the migration rate.