diff --git a/fs/xfs.c b/fs/xfs.c
index 68a4b4f..b9d6628 100644
--- a/fs/xfs.c
+++ b/fs/xfs.c
@@ -46,7 +46,8 @@ struct grub_xfs_sblock
   grub_uint8_t unused4[20];
   grub_uint8_t label[12];
   grub_uint8_t log2_bsize;
-  grub_uint8_t unused5[2];
+  grub_uint8_t log2_sect;
+  grub_uint8_t log2_inode;
   grub_uint8_t log2_inop;
   grub_uint8_t log2_agblk;
   grub_uint8_t unused6[67];
@@ -194,7 +195,7 @@ grub_xfs_inode_block (struct grub_xfs_data *data,
   long long ag = GRUB_XFS_INO_AG (data, ino);
   long long block;
 
-  block = (inoinag >> 4) + ag * data->agsize;
+  block = (inoinag >> data->sblock.log2_inop) + ag * data->agsize;
   block <<= (data->sblock.log2_bsize - GRUB_DISK_SECTOR_BITS);
   return block;
 }
@@ -205,7 +206,8 @@ grub_xfs_inode_offset (struct grub_xfs_data *data,
 		       grub_uint64_t ino)
 {
   int inoag = GRUB_XFS_INO_INOINAG (data, ino);
-  return (inoag & ((1 << 4) - 1)) << 8;
+  return ((inoag & ((1 << data->sblock.log2_inop) - 1)) <<
+	  data->sblock.log2_inode);
 }