merging pick_link() with get_link(), part 1

Move restoring LOOKUP_PARENT and zeroing nd->stack.name[0] past
the call of get_link() (nothing _currently_ uses them in there).
That allows to moved the call of may_follow_link() into get_link()
as well, since now the presence of LOOKUP_PARENT distinguishes
the callers from each other (link_path_walk() has it, trailing_symlink()
doesn't).

Preparations for folding trailing_symlink() into callers (lookup_last()
and do_last()) and changing the calling conventions of those.  Next
stage after that will have get_link() call migrate into walk_component(),
then - into step_into().  It's tricky enough to warrant doing that
in stages, unfortunately...

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

diff --git a/fs/namei.c b/fs/namei.c
index e339351..d39be45 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1115,6 +1115,12 @@ const char *get_link(struct nameidata *nd)
        int error;
        const char *res;
 
+       if (!(nd->flags & LOOKUP_PARENT)) {
+               error = may_follow_link(nd);
+               if (unlikely(error))
+                       return ERR_PTR(error);
+       }
+
        if (unlikely(nd->flags & LOOKUP_NO_SYMLINKS))
                return ERR_PTR(-ELOOP);
 
@@ -2329,13 +2335,9 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
 
 static const char *trailing_symlink(struct nameidata *nd)
 {
-       const char *s;
-       int error = may_follow_link(nd);
-       if (unlikely(error))
-               return ERR_PTR(error);
+       const char *s = get_link(nd);
        nd->flags |= LOOKUP_PARENT;
        nd->stack[0].name = NULL;
-       s = get_link(nd);
        return s ? s : "";
 }