__d_alloc(): treat NULL name as QSTR("/", 1)

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

diff --git a/fs/dcache.c b/fs/dcache.c
index 32ceae3..3cb98df 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1558,7 +1558,11 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
         * be overwriting an internal NUL character
         */
        dentry->d_iname[DNAME_INLINE_LEN-1] = 0;
-       if (name->len > DNAME_INLINE_LEN-1) {
+       if (unlikely(!name)) {
+               static const struct qstr anon = QSTR_INIT("/", 1);
+               name = &anon;
+               dname = dentry->d_iname;
+       } else if (name->len > DNAME_INLINE_LEN-1) {
                size_t size = offsetof(struct external_name, name[1]);
                struct external_name *p = kmalloc(size + name->len,
                                                  GFP_KERNEL_ACCOUNT);
@@ -1812,9 +1816,7 @@ struct dentry *d_make_root(struct inode *root_inode)
        struct dentry *res = NULL;
 
        if (root_inode) {
-               static const struct qstr name = QSTR_INIT("/", 1);
-
-               res = __d_alloc(root_inode->i_sb, &name);
+               res = __d_alloc(root_inode->i_sb, NULL);
                if (res)
                        d_instantiate(res, root_inode);
                else
@@ -1855,7 +1857,6 @@ EXPORT_SYMBOL(d_find_any_alias);
 
 static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected)
 {
-       static const struct qstr anonstring = QSTR_INIT("/", 1);
        struct dentry *tmp;
        struct dentry *res;
        unsigned add_flags;
@@ -1869,7 +1870,7 @@ static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected)
        if (res)
                goto out_iput;
 
-       tmp = __d_alloc(inode->i_sb, &anonstring);
+       tmp = __d_alloc(inode->i_sb, NULL);
        if (!tmp) {
                res = ERR_PTR(-ENOMEM);
                goto out_iput;