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ZFS on Linux doesn't work unless it's linked against interfaces provided by Linux. This is a derivative work, and thus the combined work must be distributed un

ZFS on Linux doesn't work unless it's linked against interfaces provided by Linux. This is a derivative work, and thus the combined work must be distributed under GPLv2.

shmerl 11y ago
GPL doesn't stop you from linking post installation. See http://zfsonlinux.org/faq.html#WhatAboutTheLicensingIssue http://zfsonlinux.org/faq.html#WhatAboutTheLicensingIssue
jamespo 11y ago
Userland software doesn't work unless it can use system calls provided by the Linux kernel either.
- mjg59 11y ago
  The kernel copyright file expressly states that using the standard system call interface does not create a derivative work. There is no such statement about in-kernel symbols.
  - ryao 11y ago
    > The kernel copyright file expressly states that using the standard system call interface does not create a derivative work. There is no such statement about in-kernel symbols. There is no legal precedent suggesting that was actually necessary either. Or are you aware of a court case
  - prutschman 11y ago
    That's a good assurance that would probably estop a Linux copyright holder from later claiming that a binary using only the system call interface is an infringing derivative work. It doesn't have the power to define a binary module using an internal interface as a derivative work; that can only be done by a court interpreting copyright law in a particular jurisdiction. In the United States, different Federal Circuit courts have different views of what constitutes a derivative work in software.
ryao 11y ago
Linking does not matter for the GPL. What matters it he legal concept of a derivative work. It just so happens that linking to a dynamic library bears a strong resemblance to a derivative work. LKMs and plugins in general are an entirely different matter. GPL software that supports plugins implicitly allows proprietary software to be loaded into it. That is why the FSF had been opposed to allowing plugins in GCC for years until competition from Clang required that they become more tolerant or face irrelevance. That being said, would anyone who believes this "linking to the kernel" argument please explain what linking actually means and how it is related to the GPL when the term "link" is not even present in the GPL?
ryao 11y ago
Kernel modules are not derivative works of the kernel under copyright law (which was originally designed around literary works). Some might argue that kernel modules that were developed on Linux are, but ZFS itself is ported from another platform, so that is a moot point. The only case where you cannot distribute ZFS is if you link it into the vmlinux binary that your bootloader loads. In that case, it is no longer a LKM and you can claim the binary is a derived work of Linux. That is what I believe shmeri meant.

ZFS on Linux doesn't work unless it's linked against interfaces provided by Linux. This is a derivative work, and thus the combined work must be distributed under GPLv2.

shmerl 11y ago

GPL doesn't stop you from linking post installation. See http://zfsonlinux.org/faq.html#WhatAboutTheLicensingIssue http://zfsonlinux.org/faq.html#WhatAboutTheLicensingIssue

jamespo 11y ago

Userland software doesn't work unless it can use system calls provided by the Linux kernel either.

mjg59 11y ago
The kernel copyright file expressly states that using the standard system call interface does not create a derivative work. There is no such statement about in-kernel symbols.
- ryao 11y ago
  > The kernel copyright file expressly states that using the standard system call interface does not create a derivative work. There is no such statement about in-kernel symbols. There is no legal precedent suggesting that was actually necessary either. Or are you aware of a court case
- prutschman 11y ago
  That's a good assurance that would probably estop a Linux copyright holder from later claiming that a binary using only the system call interface is an infringing derivative work. It doesn't have the power to define a binary module using an internal interface as a derivative work; that can only be done by a court interpreting copyright law in a particular jurisdiction. In the United States, different Federal Circuit courts have different views of what constitutes a derivative work in software.

ryao 11y ago

Linking does not matter for the GPL. What matters it he legal concept of a derivative work. It just so happens that linking to a dynamic library bears a strong resemblance to a derivative work. LKMs and plugins in general are an entirely different matter. GPL software that supports plugins implicitly allows proprietary software to be loaded into it. That is why the FSF had been opposed to allowing plugins in GCC for years until competition from Clang required that they become more tolerant or face irrelevance. That being said, would anyone who believes this "linking to the kernel" argument please explain what linking actually means and how it is related to the GPL when the term "link" is not even present in the GPL?

ryao 11y ago

Kernel modules are not derivative works of the kernel under copyright law (which was originally designed around literary works). Some might argue that kernel modules that were developed on Linux are, but ZFS itself is ported from another platform, so that is a moot point. The only case where you cannot distribute ZFS is if you link it into the vmlinux binary that your bootloader loads. In that case, it is no longer a LKM and you can claim the binary is a derived work of Linux. That is what I believe shmeri meant.