[RFC][PATCH v4 30/69] namei: have link_path_walk() maintain LOOKUP_PARENT

Al Viro
2020-03-13T23:55:51Z

set on entry, clear when we get to the last component.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/namei.c | 17 ++++++-----------
1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 04c1d798013f..b45ec86dc7b3 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2124,6 +2124,7 @@ static int link_path_walk(const char *name, struct nameidata *nd)
int err;

nd->last_type = LAST_ROOT;
+ nd->flags |= LOOKUP_PARENT;
if (IS_ERR(name))
return PTR_ERR(name);
while (*name=='/')
@@ -2184,8 +2185,10 @@ static int link_path_walk(const char *name, struct nameidata *nd)
if (unlikely(!*name)) {
OK:
/* pathname or trailing symlink, done */
- if (!depth)
+ if (!depth) {
+ nd->flags &= ~LOOKUP_PARENT;
return 0;
+ }
/* last component of nested symlink */
name = nd->stack[--depth].name;
link = walk_component(nd, 0);
@@ -2222,7 +2225,7 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
if (flags & LOOKUP_RCU)
rcu_read_lock();

- nd->flags = flags | LOOKUP_JUMPED | LOOKUP_PARENT;
+ nd->flags = flags | LOOKUP_JUMPED;
nd->depth = 0;

nd->m_seq = __read_seqcount_begin(&mount_lock.seqcount);
@@ -2314,16 +2317,10 @@ static const char *path_init(struct nameidata *nd, unsigned flags)

static inline const char *lookup_last(struct nameidata *nd)
{
- const char *link;
if (nd->last_type == LAST_NORM && nd->last.name[nd->last.len])
nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;

- nd->flags &= ~LOOKUP_PARENT;
- link = walk_component(nd, WALK_TRAILING);
- if (link) {
- nd->flags |= LOOKUP_PARENT;
- }
- return link;
+ return walk_component(nd, WALK_TRAILING);
}

static int handle_lookup_down(struct nameidata *nd)
@@ -3174,7 +3171,6 @@ static const char *do_last(struct nameidata *nd,
const char *res;
int error;

- nd->flags &= ~LOOKUP_PARENT;
nd->flags |= op->intent;

if (nd->last_type != LAST_NORM) {
@@ -3275,7 +3271,6 @@ static const char *do_last(struct nameidata *nd,
put_link(nd);
res = step_into(nd, WALK_TRAILING, dentry, inode, seq);
if (unlikely(res)) {
- nd->flags |= LOOKUP_PARENT;
nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);
return res;
}
--
2.11.0