[RFC][PATCH v3 21/55] merging pick_link() with get_link(), part 4

Al Viro
2020-03-01T21:52:50Z

Move the call of get_link() into walk_component(). Change the
calling conventions for walk_component() to returning the link
body to follow (if any).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/namei.c | 59 ++++++++++++++++++++++++++---------------------------------
1 file changed, 26 insertions(+), 33 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 46cd3e5cb052..21bd4cebd71b 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1868,7 +1868,7 @@ static int step_into(struct nameidata *nd, int flags,
return pick_link(nd, &path, inode, seq);
}

-static int walk_component(struct nameidata *nd, int flags)
+static const char *walk_component(struct nameidata *nd, int flags)
{
struct dentry *dentry;
struct inode *inode;
@@ -1883,17 +1883,22 @@ static int walk_component(struct nameidata *nd, int flags)
err = handle_dots(nd, nd->last_type);
if (!(flags & WALK_MORE) && nd->depth)
put_link(nd);
- return err;
+ return ERR_PTR(err);
}
dentry = lookup_fast(nd, &inode, &seq);
if (IS_ERR(dentry))
- return PTR_ERR(dentry);
+ return ERR_CAST(dentry);
if (unlikely(!dentry)) {
dentry = lookup_slow(&nd->last, nd->path.dentry, nd->flags);
if (IS_ERR(dentry))
- return PTR_ERR(dentry);
+ return ERR_CAST(dentry);
}
- return step_into(nd, flags, dentry, inode, seq);
+ err = step_into(nd, flags, dentry, inode, seq);
+ if (!err)
+ return NULL;
+ if (err > 0)
+ return get_link(nd);
+ return ERR_PTR(err);
}

/*
@@ -2145,6 +2150,7 @@ static int link_path_walk(const char *name, struct nameidata *nd)

/* At this point we know we have a real path component. */
for(;;) {
+ const char *link;
u64 hash_len;
int type;

@@ -2202,24 +2208,18 @@ static int link_path_walk(const char *name, struct nameidata *nd)
if (!name)
return 0;
/* last component of nested symlink */
- err = walk_component(nd, WALK_FOLLOW);
+ link = walk_component(nd, WALK_FOLLOW);
} else {
/* not the last component */
- err = walk_component(nd, WALK_FOLLOW | WALK_MORE);
+ link = walk_component(nd, WALK_FOLLOW | WALK_MORE);
}
- if (err < 0)
- return err;
-
- if (err) {
- const char *s = get_link(nd);
-
- if (IS_ERR(s))
- return PTR_ERR(s);
- if (likely(s)) {
- nd->stack[nd->depth - 1].name = name;
- name = s;
- continue;
- }
+ if (unlikely(link)) {
+ if (IS_ERR(link))
+ return PTR_ERR(link);
+ /* a symlink to follow */
+ nd->stack[nd->depth - 1].name = name;
+ name = link;
+ continue;
}
if (unlikely(!d_can_lookup(nd->path.dentry))) {
if (nd->flags & LOOKUP_RCU) {
@@ -2335,24 +2335,17 @@ static const char *path_init(struct nameidata *nd, unsigned flags)

static inline const char *lookup_last(struct nameidata *nd)
{
- int err;
+ 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;
- err = walk_component(nd, 0);
- if (unlikely(err)) {
- const char *s;
- if (err < 0)
- return PTR_ERR(err);
- s = get_link(nd);
- if (s) {
- nd->flags |= LOOKUP_PARENT;
- nd->stack[0].name = NULL;
- return s;
- }
+ link = walk_component(nd, 0);
+ if (link) {
+ nd->flags |= LOOKUP_PARENT;
+ nd->stack[0].name = NULL;
}
- return NULL;
+ return link;
}

static int handle_lookup_down(struct nameidata *nd)
--
2.11.0