Re: silent semantic changes with reiser4

David Masover
2004-09-06T18:53:27Z

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Horst von Brand wrote:
| Spam <spam@tnonline.net> said:
|
| [...]
|
|
|> The problem with the userspace library is standardization. What
|> would be needed is a userspace library that has a extensible plugin
|> interface that is standardized. Otherwise we would need lots of
|> different libraries, and I seriously doubt that 1) this will happen
|> and 2) we get all Linux programs to be patched to use it.
|
|
| What is the difference with a kernel implementation? Not by being
in-kernel
| will it make all the incompatible ways of doing this magically vanish, and
| give outstanding performance. Plus handling and maintaining the in-kernel
| stuff is _much_ harder than userspace libraries.

First of all, only the interface has to be in the kernel. I haven't
heard anyone suggest otherwise.

Second, there are quite a few things which I might want to do, which can
be done with this interface and without patching programs, but would
require massive patches to userspace. There have been numerous examples.

There are some things which can't be solved without patching. Version
control is one such thing. But then there can be more generic patches
- -- as soon as the transaction API is done, you only have to patch apps
to use that, and have a version control reiser4 plugin.

| I'd go the other way around: Get userspace to agree on a common framework,
| make it work in userspace; if (extensive, hopefully) experience shows that
| a pure userspace solution has issues that can't be solved except by kernel
| assistance, so be it.

We already have such a framework -- it's called "VFS".
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