[RFC][PATCH v3 20/55] merging pick_link() with get_link(), part 3

Al Viro
2020-03-01T21:55:17Z

After a pure jump ("/" or procfs-style symlink) we don't need to
hold the link anymore. link_path_walk() dropped it if such case
had been detected, lookup_last/do_last() (i.e. old trailing_symlink())
left it on the stack - it ended up calling terminate_walk() shortly
anyway, which would've purged the entire stack.

Do it in get_link() itself instead. Simpler logics that way...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/namei.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 888b1e5b994e..46cd3e5cb052 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1154,7 +1154,9 @@ const char *get_link(struct nameidata *nd)
} else {
res = get(dentry, inode, &last->done);
}
- if (IS_ERR_OR_NULL(res))
+ if (!res)
+ goto all_done;
+ if (IS_ERR(res))
return res;
}
if (*res == '/') {
@@ -1164,9 +1166,11 @@ const char *get_link(struct nameidata *nd)
while (unlikely(*++res == '/'))
;
}
- if (!*res)
- res = NULL;
- return res;
+ if (*res)
+ return res;
+all_done: // pure jump
+ put_link(nd);
+ return NULL;
}

/*
@@ -2211,11 +2215,7 @@ static int link_path_walk(const char *name, struct nameidata *nd)

if (IS_ERR(s))
return PTR_ERR(s);
- err = 0;
- if (unlikely(!s)) {
- /* jumped */
- put_link(nd);
- } else {
+ if (likely(s)) {
nd->stack[nd->depth - 1].name = name;
name = s;
continue;
--
2.11.0