diff --git a/fs/befs/befs.h b/fs/befs/befs.h
index 35d19e8..e0f59263a 100644
--- a/fs/befs/befs.h
+++ b/fs/befs/befs.h
@@ -116,7 +116,7 @@
 }
 
 static inline befs_blocknr_t
-iaddr2blockno(struct super_block *sb, befs_inode_addr * iaddr)
+iaddr2blockno(struct super_block *sb, const befs_inode_addr *iaddr)
 {
 	return ((iaddr->allocation_group << BEFS_SB(sb)->ag_shift) +
 		iaddr->start);
@@ -141,7 +141,7 @@
 }
 
 static inline int
-befs_iaddr_is_empty(befs_inode_addr * iaddr)
+befs_iaddr_is_empty(const befs_inode_addr *iaddr)
 {
 	return (!iaddr->allocation_group) && (!iaddr->start) && (!iaddr->len);
 }
diff --git a/fs/befs/btree.c b/fs/befs/btree.c
index 22c16628..307645f9 100644
--- a/fs/befs/btree.c
+++ b/fs/befs/btree.c
@@ -88,15 +88,15 @@
 static const befs_off_t befs_bt_inval = 0xffffffffffffffffULL;
 
 /* local functions */
-static int befs_btree_seekleaf(struct super_block *sb, befs_data_stream * ds,
+static int befs_btree_seekleaf(struct super_block *sb, const befs_data_stream *ds,
 			       befs_btree_super * bt_super,
 			       struct befs_btree_node *this_node,
 			       befs_off_t * node_off);
 
-static int befs_bt_read_super(struct super_block *sb, befs_data_stream * ds,
+static int befs_bt_read_super(struct super_block *sb, const befs_data_stream *ds,
 			      befs_btree_super * sup);
 
-static int befs_bt_read_node(struct super_block *sb, befs_data_stream * ds,
+static int befs_bt_read_node(struct super_block *sb, const befs_data_stream *ds,
 			     struct befs_btree_node *node,
 			     befs_off_t node_off);
 
@@ -134,7 +134,7 @@
  * On failure, BEFS_ERR is returned.
  */
 static int
-befs_bt_read_super(struct super_block *sb, befs_data_stream * ds,
+befs_bt_read_super(struct super_block *sb, const befs_data_stream *ds,
 		   befs_btree_super * sup)
 {
 	struct buffer_head *bh;
@@ -193,7 +193,7 @@
  */
 
 static int
-befs_bt_read_node(struct super_block *sb, befs_data_stream * ds,
+befs_bt_read_node(struct super_block *sb, const befs_data_stream *ds,
 		  struct befs_btree_node *node, befs_off_t node_off)
 {
 	uint off = 0;
@@ -247,7 +247,7 @@
  *   actuall value stored with the key.
  */
 int
-befs_btree_find(struct super_block *sb, befs_data_stream * ds,
+befs_btree_find(struct super_block *sb, const befs_data_stream *ds,
 		const char *key, befs_off_t * value)
 {
 	struct befs_btree_node *this_node;
@@ -416,7 +416,7 @@
  *   until the (key_no)th key is found or the tree is out of keys.
  */
 int
-befs_btree_read(struct super_block *sb, befs_data_stream * ds,
+befs_btree_read(struct super_block *sb, const befs_data_stream *ds,
 		loff_t key_no, size_t bufsize, char *keybuf, size_t * keysize,
 		befs_off_t * value)
 {
@@ -548,7 +548,7 @@
  * Also checks for an empty tree. If there are no keys, returns BEFS_BT_EMPTY.
  */
 static int
-befs_btree_seekleaf(struct super_block *sb, befs_data_stream * ds,
+befs_btree_seekleaf(struct super_block *sb, const befs_data_stream *ds,
 		    befs_btree_super *bt_super,
 		    struct befs_btree_node *this_node,
 		    befs_off_t * node_off)
diff --git a/fs/befs/btree.h b/fs/befs/btree.h
index 92e781e..f2a8f63 100644
--- a/fs/befs/btree.h
+++ b/fs/befs/btree.h
@@ -4,10 +4,10 @@
  */
 
 
-int befs_btree_find(struct super_block *sb, befs_data_stream * ds,
+int befs_btree_find(struct super_block *sb, const befs_data_stream *ds,
 		    const char *key, befs_off_t * value);
 
-int befs_btree_read(struct super_block *sb, befs_data_stream * ds,
+int befs_btree_read(struct super_block *sb, const befs_data_stream *ds,
 		    loff_t key_no, size_t bufsize, char *keybuf,
 		    size_t * keysize, befs_off_t * value);
 
diff --git a/fs/befs/datastream.c b/fs/befs/datastream.c
index ebd5071..dde0b79 100644
--- a/fs/befs/datastream.c
+++ b/fs/befs/datastream.c
@@ -21,16 +21,16 @@
 const befs_inode_addr BAD_IADDR = { 0, 0, 0 };
 
 static int befs_find_brun_direct(struct super_block *sb,
-				 befs_data_stream * data,
+				 const befs_data_stream *data,
 				 befs_blocknr_t blockno, befs_block_run * run);
 
 static int befs_find_brun_indirect(struct super_block *sb,
-				   befs_data_stream * data,
+				   const befs_data_stream *data,
 				   befs_blocknr_t blockno,
 				   befs_block_run * run);
 
 static int befs_find_brun_dblindirect(struct super_block *sb,
-				      befs_data_stream * data,
+				      const befs_data_stream *data,
 				      befs_blocknr_t blockno,
 				      befs_block_run * run);
 
@@ -45,7 +45,7 @@
  * if you don't need to know offset just set @off = NULL.
  */
 struct buffer_head *
-befs_read_datastream(struct super_block *sb, befs_data_stream * ds,
+befs_read_datastream(struct super_block *sb, const befs_data_stream *ds,
 		     befs_off_t pos, uint * off)
 {
 	struct buffer_head *bh = NULL;
@@ -87,7 +87,7 @@
  * 2001-11-15 Will Dyson
  */
 int
-befs_fblock2brun(struct super_block *sb, befs_data_stream * data,
+befs_fblock2brun(struct super_block *sb, const befs_data_stream *data,
 		 befs_blocknr_t fblock, befs_block_run * run)
 {
 	int err;
@@ -122,8 +122,8 @@
  * Returns the number of bytes read
  */
 size_t
-befs_read_lsymlink(struct super_block * sb, befs_data_stream * ds, void *buff,
-		   befs_off_t len)
+befs_read_lsymlink(struct super_block *sb, const befs_data_stream *ds,
+		   void *buff, befs_off_t len)
 {
 	befs_off_t bytes_read = 0;	/* bytes readed */
 	u16 plen;
@@ -163,7 +163,7 @@
 */
 
 befs_blocknr_t
-befs_count_blocks(struct super_block * sb, befs_data_stream * ds)
+befs_count_blocks(struct super_block *sb, const befs_data_stream *ds)
 {
 	befs_blocknr_t blocks;
 	befs_blocknr_t datablocks;	/* File data blocks */
@@ -243,11 +243,11 @@
 	2001-11-15 Will Dyson
 */
 static int
-befs_find_brun_direct(struct super_block *sb, befs_data_stream * data,
+befs_find_brun_direct(struct super_block *sb, const befs_data_stream *data,
 		      befs_blocknr_t blockno, befs_block_run * run)
 {
 	int i;
-	befs_block_run *array = data->direct;
+	const befs_block_run *array = data->direct;
 	befs_blocknr_t sum;
 	befs_blocknr_t max_block =
 	    data->max_direct_range >> BEFS_SB(sb)->block_shift;
@@ -304,7 +304,8 @@
 */
 static int
 befs_find_brun_indirect(struct super_block *sb,
-			befs_data_stream * data, befs_blocknr_t blockno,
+			const befs_data_stream *data,
+			befs_blocknr_t blockno,
 			befs_block_run * run)
 {
 	int i, j;
@@ -412,7 +413,8 @@
 */
 static int
 befs_find_brun_dblindirect(struct super_block *sb,
-			   befs_data_stream * data, befs_blocknr_t blockno,
+			   const befs_data_stream *data,
+			   befs_blocknr_t blockno,
 			   befs_block_run * run)
 {
 	int dblindir_indx;
diff --git a/fs/befs/datastream.h b/fs/befs/datastream.h
index 45e8a3c..91ba820 100644
--- a/fs/befs/datastream.h
+++ b/fs/befs/datastream.h
@@ -4,16 +4,17 @@
  */
 
 struct buffer_head *befs_read_datastream(struct super_block *sb,
-					 befs_data_stream * ds, befs_off_t pos,
-					 uint * off);
+					 const befs_data_stream *ds,
+					 befs_off_t pos, uint * off);
 
-int befs_fblock2brun(struct super_block *sb, befs_data_stream * data,
+int befs_fblock2brun(struct super_block *sb, const befs_data_stream *data,
 		     befs_blocknr_t fblock, befs_block_run * run);
 
-size_t befs_read_lsymlink(struct super_block *sb, befs_data_stream * data,
+size_t befs_read_lsymlink(struct super_block *sb, const befs_data_stream *data,
 			  void *buff, befs_off_t len);
 
-befs_blocknr_t befs_count_blocks(struct super_block *sb, befs_data_stream * ds);
+befs_blocknr_t befs_count_blocks(struct super_block *sb,
+			  const befs_data_stream *ds);
 
 extern const befs_inode_addr BAD_IADDR;
 
diff --git a/fs/befs/linuxvfs.c b/fs/befs/linuxvfs.c
index cc0e082..f168bc8f 100644
--- a/fs/befs/linuxvfs.c
+++ b/fs/befs/linuxvfs.c
@@ -157,7 +157,7 @@
 {
 	struct inode *inode = NULL;
 	struct super_block *sb = dir->i_sb;
-	befs_data_stream *ds = &BEFS_I(dir)->i_data.ds;
+	const befs_data_stream *ds = &BEFS_I(dir)->i_data.ds;
 	befs_off_t offset;
 	int ret;
 	int utfnamelen;
@@ -207,7 +207,7 @@
 {
 	struct inode *inode = file_inode(file);
 	struct super_block *sb = inode->i_sb;
-	befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
+	const befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
 	befs_off_t value;
 	int result;
 	size_t keysize;