reiserfs: fixup xattr_root caching

 The xattr_root caching was broken from my previous patch set. It wouldn't
 cause corruption, but could cause decreased performance due to allocating
 a larger chunk of the journal (~ 27 blocks) than it would actually use.

 This patch loads the xattr root dentry at xattr initialization and creates
 it on-demand. Since we're using the cached dentry, there's no point
 in keeping lookup_or_create_dir around, so that's removed.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/reiserfs_xattr.h b/include/linux/reiserfs_xattr.h
index fea1a8e..cdedc01 100644
--- a/include/linux/reiserfs_xattr.h
+++ b/include/linux/reiserfs_xattr.h
@@ -98,7 +98,7 @@
 
 	if ((REISERFS_I(inode)->i_flags & i_has_xattr_dir) == 0) {
 		nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
-		if (REISERFS_SB(inode->i_sb)->xattr_root == NULL)
+		if (!REISERFS_SB(inode->i_sb)->xattr_root->d_inode)
 			nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
 	}