namei: pass the struct path to store the result down into path_lookupat()

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

diff --git a/fs/namei.c b/fs/namei.c
index 177934c79a0456b0790e934e0db044c3ac5f4a6c..f4c9c0774b26b2ddaa78e1076ce84e7f68a3dad0 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2086,8 +2086,8 @@ static inline int lookup_last(struct nameidata *nd)
 }
 
 /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
-static int path_lookupat(int dfd, const struct filename *name,
-                               unsigned int flags, struct nameidata *nd)
+static int path_lookupat(int dfd, const struct filename *name, unsigned flags,
+                        struct nameidata *nd, struct path *path)
 {
        const char *s = path_init(dfd, name, flags, nd);
        int err;
@@ -2108,27 +2108,31 @@ static int path_lookupat(int dfd, const struct filename *name,
        if (!err && nd->flags & LOOKUP_DIRECTORY)
                if (!d_can_lookup(nd->path.dentry))
                        err = -ENOTDIR;
-       if (err)
-               terminate_walk(nd);
-
+       if (!err) {
+               *path = nd->path;
+               nd->path.mnt = NULL;
+               nd->path.dentry = NULL;
+       }
+       terminate_walk(nd);
        path_cleanup(nd);
        return err;
 }
 
-static int filename_lookup(int dfd, struct filename *name,
-                               unsigned int flags, struct nameidata *nd)
+static int filename_lookup(int dfd, struct filename *name, unsigned flags,
+                          struct nameidata *nd, struct path *path)
 {
        int retval;
        struct nameidata *saved_nd = set_nameidata(nd);
 
-       retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, nd);
+       retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, nd, path);
        if (unlikely(retval == -ECHILD))
-               retval = path_lookupat(dfd, name, flags, nd);
+               retval = path_lookupat(dfd, name, flags, nd, path);
        if (unlikely(retval == -ESTALE))
-               retval = path_lookupat(dfd, name, flags | LOOKUP_REVAL, nd);
+               retval = path_lookupat(dfd, name, flags | LOOKUP_REVAL,
+                                      nd, path); 
 
        if (likely(!retval))
-               audit_inode(name, nd->path.dentry, flags & LOOKUP_PARENT);
+               audit_inode(name, path->dentry, flags & LOOKUP_PARENT);
        restore_nameidata(saved_nd);
        return retval;
 }
@@ -2209,10 +2213,8 @@ int kern_path(const char *name, unsigned int flags, struct path *path)
        int res = PTR_ERR(filename);
 
        if (!IS_ERR(filename)) {
-               res = filename_lookup(AT_FDCWD, filename, flags, &nd);
+               res = filename_lookup(AT_FDCWD, filename, flags, &nd, path);
                putname(filename);
-               if (!res)
-                       *path = nd.path;
        }
        return res;
 }
@@ -2241,9 +2243,7 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
                nd.root.dentry = dentry;
                nd.root.mnt = mnt;
                err = filename_lookup(AT_FDCWD, filename,
-                                     flags | LOOKUP_ROOT, &nd);
-               if (!err)
-                       *path = nd.path;
+                                     flags | LOOKUP_ROOT, &nd, path);
                putname(filename);
        }
        return err;
@@ -2311,10 +2311,8 @@ int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
 
                BUG_ON(flags & LOOKUP_PARENT);
 
-               err = filename_lookup(dfd, tmp, flags, &nd);
+               err = filename_lookup(dfd, tmp, flags, &nd, path);
                putname(tmp);
-               if (!err)
-                       *path = nd.path;
        }
        return err;
 }
@@ -3261,44 +3259,42 @@ static int do_tmpfile(int dfd, struct filename *pathname,
                struct file *file, int *opened)
 {
        static const struct qstr name = QSTR_INIT("/", 1);
-       struct dentry *dentry, *child;
+       struct dentry *child;
        struct inode *dir;
+       struct path path;
        int error = path_lookupat(dfd, pathname,
-                                 flags | LOOKUP_DIRECTORY, nd);
+                                 flags | LOOKUP_DIRECTORY, nd, &path);
        if (unlikely(error))
                return error;
-       error = mnt_want_write(nd->path.mnt);
+       error = mnt_want_write(path.mnt);
        if (unlikely(error))
                goto out;
+       dir = path.dentry->d_inode;
        /* we want directory to be writable */
-       error = inode_permission(nd->inode, MAY_WRITE | MAY_EXEC);
+       error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
        if (error)
                goto out2;
-       dentry = nd->path.dentry;
-       dir = dentry->d_inode;
        if (!dir->i_op->tmpfile) {
                error = -EOPNOTSUPP;
                goto out2;
        }
-       child = d_alloc(dentry, &name);
+       child = d_alloc(path.dentry, &name);
        if (unlikely(!child)) {
                error = -ENOMEM;
                goto out2;
        }
-       nd->flags &= ~LOOKUP_DIRECTORY;
-       nd->flags |= op->intent;
-       dput(nd->path.dentry);
-       nd->path.dentry = child;
-       error = dir->i_op->tmpfile(dir, nd->path.dentry, op->mode);
+       dput(path.dentry);
+       path.dentry = child;
+       error = dir->i_op->tmpfile(dir, child, op->mode);
        if (error)
                goto out2;
-       audit_inode(pathname, nd->path.dentry, 0);
+       audit_inode(pathname, child, 0);
        /* Don't check for other permissions, the inode was just created */
-       error = may_open(&nd->path, MAY_OPEN, op->open_flag);
+       error = may_open(&path, MAY_OPEN, op->open_flag);
        if (error)
                goto out2;
-       file->f_path.mnt = nd->path.mnt;
-       error = finish_open(file, nd->path.dentry, NULL, opened);
+       file->f_path.mnt = path.mnt;
+       error = finish_open(file, child, NULL, opened);
        if (error)
                goto out2;
        error = open_check_o_direct(file);
@@ -3311,9 +3307,9 @@ static int do_tmpfile(int dfd, struct filename *pathname,
                spin_unlock(&inode->i_lock);
        }
 out2:
-       mnt_drop_write(nd->path.mnt);
+       mnt_drop_write(path.mnt);
 out:
-       path_put(&nd->path);
+       path_put(&path);
        return error;
 }