Folks. In the cifs client we use FSCTL_SET_ZERO_DATA when userspace wants to punch a hole in a file. SET_ZERO_DATA maps quite well to the PUNCH_HOLE semantics in that it will deallocate what it can and overwrite what it can not with 0. On windows 16/ntfs the deallocate blocksize is 64k. Does anyone know if this is always 64k or if there is a way to query the server for this? regards ronnie sahlberg
