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SubjectRe: reiser4: maybe just fix bugs?
Theodore Tso wrote:
> On Tue, Aug 01, 2006 at 11:55:57AM -0500, David Masover wrote:
>> If I understand it right, the original Reiser4 model of file metadata is
>> the file-as-directory stuff that caused such a furor the last big push
>> for inclusion (search for "Silent semantic changes in Reiser4"):
>
> The furor was caused by concerns Al Viro expressed about
> locking/deadlock issues that reiser4 introduced.

Which, I believe, was about file-as-dir. Which also had problems with
things like directory loops. That's sort of a disk space memory leak.

> The bigger issue with xattr support is two-fold. First of all, there
> are the progams that are expecting the existing extended attribute
> interface,

Yeah...

> More importantly are the system-level extended attributes, such as
> those used by SELINUX, which by definition are not supposed to be
> visible to the user at all,

I don't see why either of these are issues. The SELINUX stuff can be a
plugin which doesn't necessarily have a user-level interface.
Cryptocompress, for instance, exists independent of its user-level
interface (probably the file-as-dir stuff), and will probably be
implemented in some sort of stable form as a system-wide default for new
files.

So, certainly metadata (xattrs) as a plugin could be implemented with no
UI at all, or any given UI.

... Anyway, I still see no reason why these cannot be implemented in
Reiser4, other than the possibility that if it uses "plugins", I
guarantee that at least one or two people will hate the implementation
for that reason alone.

> Not supporting xattrs means that those distro's that use SELINUX by
> default (i.e., RHEL, Fedora, etc.) won't want to use reiser4, because
> SELINUX won't work on reiser4 filesytstems.

Right. So they will be implemented, eventually.

> Whether or not Hans cares about this is up to him....

He does, or he should. Reiser4 needs every bit of acceptance it can get
right now, as long as it can get them without compromising its goals or
philosophy. Extended attributes only compromise these because it
provides less incentive to learn any other metadata interface that
Reiser4 provides. But that's irrelevant if Reiser4 doesn't gain enough
acceptance due to lack of xattr support, anything it has will be
irrelevant anyway.

So just as we provide the standard interface to Unix permissions (even
though we intend to implement things like acls and views, and even
though there was a file/.pseudo/rwx interface), we should provide the
standard xattr interface, and the standard direct IO interface, and
anything else that's practical. Be a good, standard filesystem first,
and an innovative filesystem second.
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