Reclaiming space from a file system

摘要

Technologies are provided for reclaiming a file system coupled to a block device. In these technologies, a dummy file is created. The dummy file is expanded to fill a volume in the block device. A mapping of the dummy file to locations in the volume is retrieved. When the mapping of the dummy file to the locations in the volume is retrieved, corresponding space in the volume is reclaimed. This space may include the locations in the volume corresponding to the mapping of the dummy file. When this space in the volume is reclaimed, the dummy file is deleted.

主权项

1. A computer-implemented method for avoiding unnecessary read-modify-write operations in a storage system, comprising:
writing a first file having a predetermined block size to a volume in a logical block; taking a snapshot of the volume, the snapshot including an image of the logical block; deleting the first file from the volume; marking the first file as unwritten or invalid; and writing a second file having a size less than the predetermined block size to the volume in the logical block, wherein the second file is written without performing a read-modify-write operation on data in the snapshot.