Preparations to caching root in path_walk()

Split do_path_lookup(), opencode the call from do_filp_open()
do_filp_open() is the only caller of do_path_lookup() that
cares about root afterwards (it keeps resolving symlinks on
O_CREAT path after it'd done LOOKUP_PARENT walk).  So when
we start caching fs->root in path_walk(), it'll need a different
treatment.

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

1 files changed, 21 insertions, 10 deletions

diff --git a/fs/namei.c b/fs/namei.c
index c82805d088e1..895733efc6b9 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1017,9 +1017,7 @@ static int path_walk(const char *name, struct nameidata *nd)
         return link_path_walk(name, nd);
 }
 
-/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
-static int do_path_lookup(int dfd, const char *name,
-                                unsigned int flags, struct nameidata *nd)
+static int path_init(int dfd, const char *name, unsigned int flags, struct nameidata *nd)
 {
         int retval = 0;
         int fput_needed;
@@ -1063,17 +1061,25 @@ static int do_path_lookup(int dfd, const char *name,
 
                 fput_light(file, fput_needed);
         }
+        return 0;
 
-        retval = path_walk(name, nd);
+fput_fail:
+        fput_light(file, fput_needed);
+out_fail:
+        return retval;
+}
+
+/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
+static int do_path_lookup(int dfd, const char *name,
+                                unsigned int flags, struct nameidata *nd)
+{
+        int retval = path_init(dfd, name, flags, nd);
+        if (!retval)
+                retval = path_walk(name, nd);
         if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry &&
                                 nd->path.dentry->d_inode))
                 audit_inode(name, nd->path.dentry);
-out_fail:
         return retval;
-
-fput_fail:
-        fput_light(file, fput_needed);
-        goto out_fail;
 }
 
 int path_lookup(const char *name, unsigned int flags,
@@ -1676,9 +1682,14 @@ struct file *do_filp_open(int dfd, const char *pathname,
         /*
          * Create - we need to know the parent.
          */
-        error = do_path_lookup(dfd, pathname, LOOKUP_PARENT, &nd);
+        error = path_init(dfd, pathname, LOOKUP_PARENT, &nd);
         if (error)
                 return ERR_PTR(error);
+        error = path_walk(pathname, &nd);
+        if (error)
+                return ERR_PTR(error);
+        if (unlikely(!audit_dummy_context()))
+                audit_inode(pathname, nd.path.dentry);
 
         /*
          * We have the parent and last component. First of all, check