convert alloc_super() to struct fs_context

IMO it's premature by several cycles - David might hope to get
rid of sget_userns() and friends, but it will take a while and
until that's done...  Let's just say that on-stack instances
of struct fs_context, skipping the normal constructors and not
being fed to destructor are Not Nice(tm) in general.  Yes, in
this particular case we are safe, but it really doesn't buy
us anything worthwhile.

*IF* all callers of alloc_super() end up with handy fs_context -
sure, this will be the obvious change.  Until then... I'm taking
that to the very end of the series lest it gets lost, but it's
not going to be in any pull requests this cycle.  And probably
the next cycle or two as well.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
1 file changed