teach set_nameidata() to handle setting the root as well

That way we don't need the callers to mess with manually setting any fields
of nameidata instances.  Old set_nameidata() gets renamed (__set_nameidata()),
new becomes an inlined helper that takes a struct path pointer and deals
with setting nd->root and putting ND_ROOT_PRESET in nd->state when new
argument is non-NULL.

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

diff --git a/fs/namei.c b/fs/namei.c
index 622b9f15bf1ca3a7ab795c7d70521b137a9c6317..40ffb249aa7f77793f8a7489f277373d5e7c6ed9 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -577,7 +577,7 @@ struct nameidata {
 #define ND_ROOT_GRABBED 2
 #define ND_JUMPED 4
 
-static void set_nameidata(struct nameidata *p, int dfd, struct filename *name)
+static void __set_nameidata(struct nameidata *p, int dfd, struct filename *name)
 {
        struct nameidata *old = current->nameidata;
        p->stack = p->internal;
@@ -587,10 +587,20 @@ static void set_nameidata(struct nameidata *p, int dfd, struct filename *name)
        p->path.dentry = NULL;
        p->total_link_count = old ? old->total_link_count : 0;
        p->saved = old;
-       p->state = 0;
        current->nameidata = p;
 }
 
+static inline void set_nameidata(struct nameidata *p, int dfd, struct filename *name,
+                         const struct path *root)
+{
+       __set_nameidata(p, dfd, name);
+       p->state = 0;
+       if (unlikely(root)) {
+               p->state = ND_ROOT_PRESET;
+               p->root = *root;
+       }
+}
+
 static void restore_nameidata(void)
 {
        struct nameidata *now = current->nameidata, *old = now->saved;
@@ -2454,11 +2464,7 @@ int filename_lookup(int dfd, struct filename *name, unsigned flags,
        struct nameidata nd;
        if (IS_ERR(name))
                return PTR_ERR(name);
-       set_nameidata(&nd, dfd, name);
-       if (unlikely(root)) {
-               nd.root = *root;
-               nd.state = ND_ROOT_PRESET;
-       }
+       set_nameidata(&nd, dfd, name, root);
        retval = path_lookupat(&nd, flags | LOOKUP_RCU, path);
        if (unlikely(retval == -ECHILD))
                retval = path_lookupat(&nd, flags, path);
@@ -2499,7 +2505,7 @@ static struct filename *filename_parentat(int dfd, struct filename *name,
 
        if (IS_ERR(name))
                return name;
-       set_nameidata(&nd, dfd, name);
+       set_nameidata(&nd, dfd, name, NULL);
        retval = path_parentat(&nd, flags | LOOKUP_RCU, parent);
        if (unlikely(retval == -ECHILD))
                retval = path_parentat(&nd, flags, parent);
@@ -3530,7 +3536,7 @@ struct file *do_filp_open(int dfd, struct filename *pathname,
        int flags = op->lookup_flags;
        struct file *filp;
 
-       set_nameidata(&nd, dfd, pathname);
+       set_nameidata(&nd, dfd, pathname, NULL);
        filp = path_openat(&nd, op, flags | LOOKUP_RCU);
        if (unlikely(filp == ERR_PTR(-ECHILD)))
                filp = path_openat(&nd, op, flags);
@@ -3555,9 +3561,7 @@ struct file *do_file_open_root(const struct path *root,
        if (IS_ERR(filename))
                return ERR_CAST(filename);
 
-       set_nameidata(&nd, -1, filename);
-       nd.root = *root;
-       nd.state = ND_ROOT_PRESET;
+       set_nameidata(&nd, -1, filename, root);
        file = path_openat(&nd, op, flags | LOOKUP_RCU);
        if (unlikely(file == ERR_PTR(-ECHILD)))
                file = path_openat(&nd, op, flags);