[Libguestfs] [PATCH nbdkit] streaming plugin: Add support for a sliding window

[Sorry, can't use git-send-email at the moment ...] These patches implement a sliding window for the streaming plugin[1] in nbdkit. I would like to be able to stream a filesystem from tools such as 'virt-make-fs'[2]. This is a fairly frequently requested feature. Unfortunately: (a) The patches make the code significantly more complex and therefore likely to have bugs. (b) They are not practically useful. 'parted' likes to write to the beginning and end of a disk, even when creating a simple MBR, and of course 'mkfs' scribbles the group headers across the whole disk when creating a filesystem. A simple window approach is obviously not sufficient. A better approach might be something like a sparse, size-limited map recording writes at any point in the disk. But that has the problem that you don't know when you can commit a write to the stream -- some heuristic would have to be used. I'm posting them to the mailing list for the record and in case anyone has any better ideas. Rich. [1] http://rwmj.wordpress.com/2014/10/14/streaming-nbd-server/#content [2] http://libguestfs.org/virt-make-fs.1.html -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com Fedora Windows cross-compiler. Compile Windows programs, test, and build Windows installers. Over 100 libraries supported. http://fedoraproject.org/wiki/MinGW