xfs: move the fork format fields into struct xfs_ifork

Both the data and attr fork have a format that is stored in the legacy
idinode.  Move it into the xfs_ifork structure instead, where it uses
up padding.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/xfs_iomap.c

@@ -856,7 +856,7 @@ xfs_buffered_write_iomap_begin(
 
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
 
-	if (XFS_IS_CORRUPT(mp, !xfs_ifork_has_extents(ip, XFS_DATA_FORK)) ||
+	if (XFS_IS_CORRUPT(mp, !xfs_ifork_has_extents(&ip->i_df)) ||
 	    XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BMAPIFORMAT)) {
 		error = -EFSCORRUPTED;
 		goto out_unlock;
@@ -1263,7 +1263,7 @@ xfs_xattr_iomap_begin(
 		goto out_unlock;
 	}
 
-	ASSERT(ip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL);
+	ASSERT(ip->i_afp->if_format != XFS_DINODE_FMT_LOCAL);
 	error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
 			       &nimaps, XFS_BMAPI_ATTRFORK);
 out_unlock: