xfsdocs: fix some small discrepancies with libxfs

Fix some small discrepancies between the current libxfs code and this doc.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
diff --git a/design/XFS_Filesystem_Structure/btrees.asciidoc b/design/XFS_Filesystem_Structure/btrees.asciidoc
index 91a53c4..19680d0 100644
--- a/design/XFS_Filesystem_Structure/btrees.asciidoc
+++ b/design/XFS_Filesystem_Structure/btrees.asciidoc
@@ -104,7 +104,7 @@
 *bb_level*::
 The level of the tree in which this block is found.  If this value is 0, this
 is a leaf block and contains records; otherwise, it is a node block and
-contains keys and pointers.
+contains keys and pointers.  Level values increase towards the root.
 
 *bb_numrecs*::
 Number of records in this block.
diff --git a/design/XFS_Filesystem_Structure/dabtrees.asciidoc b/design/XFS_Filesystem_Structure/dabtrees.asciidoc
index 18247ca..29cfdab 100644
--- a/design/XFS_Filesystem_Structure/dabtrees.asciidoc
+++ b/design/XFS_Filesystem_Structure/dabtrees.asciidoc
@@ -170,7 +170,9 @@
 Number of node entries in this block.
 
 *level*::
-The level of this block in the B+tree.
+The level of this block in the B+tree.  Levels start at 1 for blocks
+that point to directory or attribute data blocks and increase towards
+the root.
 
 *hashval*::
 The hash value of a particular record.
@@ -206,7 +208,9 @@
 Number of node entries in this block.
 
 *level*::
-The level of this block in the B+tree.
+The level of this block in the B+tree.  Levels start at 1 for blocks
+that point to directory or attribute data blocks, and increase towards
+the root.
 
 *pad32*::
 Padding to maintain alignment.
diff --git a/design/XFS_Filesystem_Structure/extended_attributes.asciidoc b/design/XFS_Filesystem_Structure/extended_attributes.asciidoc
index bb773d5..7df2d3d 100644
--- a/design/XFS_Filesystem_Structure/extended_attributes.asciidoc
+++ b/design/XFS_Filesystem_Structure/extended_attributes.asciidoc
@@ -473,6 +473,7 @@
      __u8                       holes;
      __u8                       pad1;
      xfs_attr_leaf_map_t        freemap[3];
+     __be32                     pad2;
 } xfs_attr3_leaf_hdr_t;
 
 
diff --git a/design/XFS_Filesystem_Structure/internal_inodes.asciidoc b/design/XFS_Filesystem_Structure/internal_inodes.asciidoc
index e6bf75f..f5c2654 100644
--- a/design/XFS_Filesystem_Structure/internal_inodes.asciidoc
+++ b/design/XFS_Filesystem_Structure/internal_inodes.asciidoc
@@ -59,7 +59,7 @@
 };
 struct xfs_dqblk {
      struct xfs_disk_dquot dd_diskdq;
-     char                  dd_fill[32];
+     char                  dd_fill[4];
 
      /* version 5 filesystem fields begin here */
      __be32                dd_crc;