diff --git a/fs/sysv/super.c b/fs/sysv/super.c
index 7491c33..a38e87b 100644
--- a/fs/sysv/super.c
+++ b/fs/sysv/super.c
@@ -368,6 +368,7 @@
 
 	sbi->s_sb = sb;
 	sbi->s_block_base = 0;
+	mutex_init(&sbi->s_lock);
 	sb->s_fs_info = sbi;
 
 	sb_set_blocksize(sb, BLOCK_SIZE);