Hi Pádraig, Thanks for your comments!
> On 08/10/2011 10:31 AM, Jeff Liu wrote: >> Hello, >> >> I just found a cool feature in Btrfs for cloning partially source file >> to the destination by specifying the desired offset and length to be copied. >> >> The call interface is something like below: >> struct btrfs_clone_range_args cr; >> cr.src_fd = source_desc; >> cr.src_offset = (uint64_t) offset; >> cr.src_length = (uint64_t) length; >> cr.dest_offset = (uint64_t) d_offset; >> ioctl(dest_fd, BTRFS_IOC_CLONE_RANGE, &args); >> >> cp(1) has already works with "reflink" supported for a long time, IMHO, >> this new feature could improve it to some extent. >> Is it acceptable to add a new option like >> "--reflink-range=src_offset,src_length,dst_offset" to clone partially >> source file? >> In this way, if reflink-range is triggered, cp(1) will try to parse the >> offset and length which are separated by comma, >> then try to clone src_length bytes from src_offset to the destination >> file started at dst_offset. >> if reflink-range failed, just let cp(1) fail with appropriate error info. >> >> I'd like to implement it if you guys think it does make sense. :-P. > > IMHO I don't think this level of control is needed in `cp`. If you think it became useful to other coreutils stuff in the future, please let me know, I would like to work on it. Regards, -Jeff > > cheers, > Pádraig.
