ocfs2/xattr: fix credits calculation during index create

When creating a xattr index block, the old calculation forget
to add credits for the meta change of the alloc file. So add
more credits and more comments to explain it.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 3e2e92d70594..73fb9f762512 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -2359,13 +2359,21 @@ meta_guess:
                 } else
                         xb = (struct ocfs2_xattr_block *)xbs->xattr_bh->b_data;
 
+                /*
+                 * If there is already an xattr tree, good, we can calculate
+                 * like other b-trees. Otherwise we may have the chance of
+                 * create a tree, the credit calculation is borrowed from
+                 * ocfs2_calc_extend_credits with root_el = NULL. And the
+                 * new tree will be cluster based, so no meta is needed.
+                 */
                 if (le16_to_cpu(xb->xb_flags) & OCFS2_XATTR_INDEXED) {
                         struct ocfs2_extent_list *el =
                                  &xb->xb_attrs.xb_root.xt_list;
                         meta_add += ocfs2_extend_meta_needed(el);
                         credits += ocfs2_calc_extend_credits(inode->i_sb,
                                                              el, 1);
-                }
+                } else
+                        credits += OCFS2_SUBALLOC_ALLOC + 1;
 
                 /*
                  * This cluster will be used either for new bucket or for