diff --git a/fs/hpfs/buffer.c b/fs/hpfs/buffer.c
index 793cb9d..7cef5d5 100644
--- a/fs/hpfs/buffer.c
+++ b/fs/hpfs/buffer.c
@@ -32,6 +32,8 @@
 {
 	struct buffer_head *bh;
 
+	hpfs_lock_assert(s);
+
 	cond_resched();
 
 	*bhp = bh = sb_bread(s, secno);
@@ -50,6 +52,8 @@
 	struct buffer_head *bh;
 	/*return hpfs_map_sector(s, secno, bhp, 0);*/
 
+	hpfs_lock_assert(s);
+
 	cond_resched();
 
 	if ((*bhp = bh = sb_getblk(s, secno)) != NULL) {
@@ -70,6 +74,8 @@
 	struct buffer_head *bh;
 	char *data;
 
+	hpfs_lock_assert(s);
+
 	cond_resched();
 
 	if (secno & 3) {
@@ -125,6 +131,8 @@
 {
 	cond_resched();
 
+	hpfs_lock_assert(s);
+
 	if (secno & 3) {
 		printk("HPFS: hpfs_get_4sectors: unaligned read\n");
 		return NULL;