Method for reducing fragments of log structure file system and flash memory storage system

The invention discloses a method for reducing fragments of a log structure file system and a flash memory storage system, which belong to the field of computer information storage. The method comprisethe following steps of: when a target data block is written into a log structure file system, extracting file characteristics to identify whether a file is a temporary writing file or not; if yes, setting a type mark for the target data block, and writing the target data block into a pre-allocated temporary logic log segment; otherwise, setting a type mark according to the cold and hot attributesof the target data block, and writing the target data block into a corresponding logic log segment; adding type marks in a submitted block request and a data item of an annular buffer area, and respectively creating request queues for different types of data; and when the data in the request queues is written into a flash memory medium, allocating independent physical addresses to different typesof data, so as to enable the data types in the same physical log segment to be the same. According to the method, fragments in the log structure file system can be effectively reduced, logic fragments and physical fragments are cooperatively managed, and the performance of the storage system is improved.