diff --git a/ChangeLog b/ChangeLog
index 088f6f848..0780a3691 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2011-12-13  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	* grub-core/fs/udf.c (read_string): Macroify GRUB_MAX_UTF8_PER_UTF16.
+	* grub-core/fs/jfs.c (grub_jfs_diropen): Likewise.
+	* grub-core/fs/fat.c (grub_fat_iterate_dir): Likewise.
+
 2011-12-13  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	* grub-core/term/at_keyboard.c (set_scancodes): Fix preprocessor
diff --git a/grub-core/fs/fat.c b/grub-core/fs/fat.c
index 0d32e229d..0569120fb 100644
--- a/grub-core/fs/fat.c
+++ b/grub-core/fs/fat.c
@@ -589,7 +589,7 @@ grub_fat_iterate_dir (grub_disk_t disk, struct grub_fat_data *data,
   char *filename;
 
   unibuf = grub_malloc (15 * 256 * 2);
-  filename = grub_malloc (15 * 256 * 4 + 1);
+  filename = grub_malloc (15 * 256 * GRUB_MAX_UTF8_PER_UTF16 + 1);
 
   while (1)
     {
@@ -696,7 +696,7 @@ grub_fat_iterate_dir (grub_disk_t disk, struct grub_fat_data *data,
     return grub_error (GRUB_ERR_BAD_FILE_TYPE, "not a directory");
 
   /* Allocate space enough to hold a long name.  */
-  filename = grub_malloc (0x40 * 13 * 4 + 1);
+  filename = grub_malloc (0x40 * 13 * GRUB_MAX_UTF8_PER_UTF16 + 1);
   unibuf = (grub_uint16_t *) grub_malloc (0x40 * 13 * 2);
   if (! filename || ! unibuf)
     {
diff --git a/grub-core/fs/jfs.c b/grub-core/fs/jfs.c
index 91497f143..3554803cb 100644
--- a/grub-core/fs/jfs.c
+++ b/grub-core/fs/jfs.c
@@ -241,7 +241,7 @@ struct grub_jfs_diropen
   /* On-disk name is at most 255 UTF-16 codepoints.
      Every UTF-16 codepoint is at most 4 UTF-8 bytes.
    */
-  char name[256 * 4 + 1];
+  char name[256 * GRUB_MAX_UTF8_PER_UTF16 + 1];
   grub_uint32_t ino;
 } __attribute__ ((packed));
 
diff --git a/grub-core/fs/udf.c b/grub-core/fs/udf.c
index e1f115015..4097fd2e6 100644
--- a/grub-core/fs/udf.c
+++ b/grub-core/fs/udf.c
@@ -820,7 +820,7 @@ read_string (grub_uint8_t *raw, grub_size_t sz)
       for (i = 0; i < utf16len; i++)
 	utf16[i] = (raw[2 * i + 1] << 8) | raw[2*i + 2];
     }
-  ret = grub_malloc (utf16len * 3 + 1);
+  ret = grub_malloc (utf16len * GRUB_MAX_UTF8_PER_UTF16 + 1);
   if (ret)
     *grub_utf16_to_utf8 ((grub_uint8_t *) ret, utf16, utf16len) = '\0';
   grub_free (utf16);