Messages in this thread | | | Date | Fri, 21 Dec 2018 11:28:13 -0500 | From | "Theodore Y. Ts'o" <> | Subject | Re: [PATCH v2 01/12] fs-verity: add a documentation file |
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On Fri, Dec 21, 2018 at 07:53:54AM -0800, Matthew Wilcox wrote: > In contrast to "we'll just fix it up later" (which usually applies > to in-kernel interfaces), we have a policy of not breaking userspace, > so accepting this interface means setting it in stone. We should get > it right.
I'm not convinced it's a "fix", but my point is that if later on you want to add extra complexity transforming
ioctl(fd, FS_IOC_ENABLE_VERITY);
so it does the equivalent of
ioctl(fd, FS_IOC_ENABLE_VERITY_NOW_WITH_EXTRA_USELESS_COMPLEXITY, fd, sizeof_data, sizeof_verity_data);
it adds essentially no complexity to provide this backwards compatibility. But if we need to implement FS_IOC_ENABLE_VERITY_NOW_WITH_EXTRA_USELESS_COMPLEXITY *now*, we gain nothing, other than pushing back when fsverity lands upstream. We'd have to provide that backwards compatibility interface anyway, since there are a lot of users for that existing interface.
So why?
- Ted
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