于 2012-7-9 17:13, Paolo Bonzini 写道: > Il 09/07/2012 10:54, Wenchao Xia ha scritto: >> Following is my implementing plan draft: >> 1 introduce libqblock.so in sub directory in qemu. >> 2 write a nbd client in libqblock, similar to qemu nbd client. Then >> use it to talk with nbd server, by default is qemu-nbd, to get access >> to images. In this way, libqblock.so could be friendly LGPL licensed. > > Did you actually assess the license situation of the block layer? > block.c and large parts of block/* are under a BSD license, for example. > If the library only has to support raw files, it might do so using > synchronous I/O only. This would remove a large body of GPL-licensed code. > If the library was built as nbd-client communicating with nbd-server, which then employ the BSO licensed code, could the library ignore the server side's license problem? The reason using nbd-client approach are: work around qemu block layer license issue and easy to implement, if other tool found this labrary useful then considering about directly employ the qemu block code.
>> 3 still not got a good way to get additional info in (2)(3)(4), >> currently in my head is patch qemu-nbd to add an additional nbd command, >> "image-info", in which returns related info. > > On the Linux kernel mailing list I would have no qualms labeling such > command as "crap". However, since the social standards on qemu-devel > are a bit higher, I'll ask instead: what information would the command > provide beyond the size? > The API need to report the image format it is using, such as "qcow2". And also API should report if a block at offset have been allocated or it is a hole. > Paolo > -- Best Regards Wenchao Xia
