Re: [PATCH 04/13] sysfs: Simplify sysfs_chmod_file semantics

From: Serge E. Hallyn
Date: Tue Nov 03 2009 - 23:55:57 EST

Quoting Eric W. Biederman (ebiederm@xxxxxxxxxxxx):
> "Serge E. Hallyn" <serue@xxxxxxxxxx> writes:
> > Quoting Eric W. Biederman (ebiederm@xxxxxxxxxxxx):
> >> From: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
> >>
> >> Currently every caller of sysfs_chmod_file happens at either
> >> file creation time to set a non-default mode or in response
> >> to a specific user requested space change in policy. Making
> >> timestamps of when the chmod happens and notification of
> >> a file changing mode uninteresting.
> >
> > But these changes can occur by togging values in sysfs files
> > (i.e. f71805f.c), right? Is this (specifically not doing inotify)
> > definately uncontroversial?
> The fs_notify_change was not introduced to deliberately support
> a feature but as a side effect of other cleanups. So there
> is no indication that anyone cares about inotify support.
> > I can't exactly picture an admin sitting there watching
> > nautilus for a sysfs file to become writeable, but could
> > imagine some site's automation getting hung... Or am I way
> > off base?
> I would be stunned if the shell script in the automation that writes
> to a sysfs file to make things writeable doesn't on it's next line
> kick off whatever needs it to be writable.
> With no benefit to using inotify and with only a handful of sysfs
> files affected I don't expect this change to break anything in
> userspace and I have been happily running with it for a year or so on
> all of our machines at work with no one problems.
> The reason I am making the change is that the goal of this patchset is
> to get sysfs to act like any other distributed filesystem in linux,
> and to use the same interfaces in roughly the same ways as other
> distributed filesystems. Unfortunately there is not a good interface
> for distributed filesystems to support inotify or I would use it.
> Eric

Ok - I personally agree, but I know there are admins out there with
very different mindsets from mine

Acked-by: Serge Hallyn <serue@xxxxxxxxxx>

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