xfs: move the per-fork nextents fields into struct xfs_ifork

There are there are three extents counters per inode, one for each of
the forks.  Two are in the legacy icdinode and one is directly in
struct xfs_inode.  Switch to a single counter in the xfs_ifork structure
where it uses up padding at the end of the structure.  This simplifies
various bits of code that just wants the number of extents counter and
can now directly dereference it.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Chandan Babu R <[email protected]>
Reviewed-by: Brian Foster <[email protected]>
Reviewed-by: Darrick J. Wong <[email protected]>
Signed-off-by: Darrick J. Wong <[email protected]>

Author: Christoph Hellwig

fs/xfs/libxfs/xfs_attr.c

@@ -62,7 +62,7 @@ xfs_inode_hasattr(
 {
 	if (!XFS_IFORK_Q(ip) ||
 	    (ip->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS &&
-	     ip->i_d.di_anextents == 0))
+	     ip->i_afp->if_nextents == 0))
 		return 0;
 	return 1;
 }
@@ -214,7 +214,7 @@ xfs_attr_set_args(
 	 */
 	if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL ||
 	    (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS &&
-	     dp->i_d.di_anextents == 0)) {
+	     dp->i_afp->if_nextents == 0)) {
 
 		/*
 		 * Build initial attribute list (if required).

fs/xfs/libxfs/xfs_attr_leaf.c

@@ -718,11 +718,12 @@ xfs_attr_fork_remove(
 	struct xfs_inode	*ip,
 	struct xfs_trans	*tp)
 {
+	ASSERT(ip->i_afp->if_nextents == 0);
+
 	xfs_idestroy_fork(ip, XFS_ATTR_FORK);
 	ip->i_d.di_forkoff = 0;
 	ip->i_d.di_aformat = XFS_DINODE_FMT_EXTENTS;
 
-	ASSERT(ip->i_d.di_anextents == 0);
 	ASSERT(ip->i_afp == NULL);
 
 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);