[PATCH] namei fixes (5/19)

fix for too early mntput() in open_namei() - we pin path.mnt down for the
duration of __do_follow_link().  Otherwise we could get the fs where our
symlink lived unmounted while we were in __do_follow_link().  That would end
up with dentry of symlink staying pinned down through the fs shutdown.

Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>