vfs: d_alloc_root() gone

all callers converted to d_make_root() by now
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Documentation/filesystems/porting

@@ -429,3 +429,9 @@ filemap_write_and_wait_range() so that all dirty pages are synced out properly.
 You must also keep in mind that ->fsync() is not called with i_mutex held
 anymore, so if you require i_mutex locking you must make sure to take it and
 release it yourself.
+
+--
+[mandatory]
+	d_alloc_root() is gone, along with a lot of bugs caused by code
+misusing it.  Replacement: d_make_root(inode).  The difference is,
+d_make_root() drops the reference to inode if dentry allocation fails.  

fs/dcache.c

@@ -1443,30 +1443,6 @@ struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode)
 
 EXPORT_SYMBOL(d_instantiate_unique);
 
-/**
- * d_alloc_root - allocate root dentry
- * @root_inode: inode to allocate the root for
- *
- * Allocate a root ("/") dentry for the inode given. The inode is
- * instantiated and returned. %NULL is returned if there is insufficient
- * memory or the inode passed is %NULL.
- */
- 
-struct dentry * d_alloc_root(struct inode * root_inode)
-{
-	struct dentry *res = NULL;
-
-	if (root_inode) {
-		static const struct qstr name = { .name = "/", .len = 1 };
-
-		res = __d_alloc(root_inode->i_sb, &name);
-		if (res)
-			d_instantiate(res, root_inode);
-	}
-	return res;
-}
-EXPORT_SYMBOL(d_alloc_root);
-
 struct dentry *d_make_root(struct inode *root_inode)
 {
 	struct dentry *res = NULL;

include/linux/dcache.h

@@ -222,7 +222,6 @@ extern void shrink_dcache_for_umount(struct super_block *);
 extern int d_invalidate(struct dentry *);
 
 /* only used at mount-time */
-extern struct dentry * d_alloc_root(struct inode *);
 extern struct dentry * d_make_root(struct inode *);
 
 /* <clickety>-<click> the ramfs-type tree */