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SubjectRe: [patch 00/13] vfs: add helpers to check r/o bind mounts
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> > >  You are right - we do have races there.  Always had.
> > > And nfsd_permission() is the next target for continuation of ro-bind
> > > series. Assuming that we don't simply make r/w export to hold will_write
> > > all along, in which case all these checks around calls of vfs_...() in
> > > there simply go away - that's also an arguable option.
> >
> > Yes. And that _still_ doesn't make the path_*() interface wrong.
>
> It would make it bloody useless for nfsd. With ecryptfs being a piss-poor
> argument in favour of anything other than git rm, what's left? Another
> stack frame in fs/namei.c syscalls?

Since all the vfs_* functions will become static with path_* being the
only caller, the compiler will be happy to get rid of that stack frame
too.

What is left is the guarantee, that the race-free r/o remounts will
always work and some obscure caller didn't forget to surround it with
the r/o checks.

I think it's definitely worth it.

Miklos


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