[RFC][PATCH v3 18/55] merging pick_link() with get_link(), part 1

Al Viro
2020-03-01T21:55:31Z

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>
---
fs/namei.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 3eed5784942a..3594f6a4998b 100644
--- 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 : "";
}

--
2.11.0