1 files changed, 42 insertions, 0 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 7feeec6f7c39..9f5468fb06da 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3541,6 +3541,48 @@ static int ext4_get_sb(struct file_system_type *fs_type,
         return get_sb_bdev(fs_type, flags, dev_name, data, ext4_fill_super, mnt);
 }
 
+#ifdef CONFIG_PROC_FS
+static int ext4_ui_proc_show(struct seq_file *m, void *v)
+{
+        unsigned int *p = m->private;
+
+        seq_printf(m, "%u\n", *p);
+        return 0;
+}
+
+static int ext4_ui_proc_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, ext4_ui_proc_show, PDE(inode)->data);
+}
+
+static ssize_t ext4_ui_proc_write(struct file *file, const char __user *buf,
+                               size_t cnt, loff_t *ppos)
+{
+        unsigned int *p = PDE(file->f_path.dentry->d_inode)->data;
+        char str[32];
+        unsigned long value;
+
+        if (cnt >= sizeof(str))
+                return -EINVAL;
+        if (copy_from_user(str, buf, cnt))
+                return -EFAULT;
+        value = simple_strtol(str, NULL, 0);
+        if (value < 0)
+                return -ERANGE;
+        *p = value;
+        return cnt;
+}
+
+const struct file_operations ext4_ui_proc_fops = {
+        .owner          = THIS_MODULE,
+        .open           = ext4_ui_proc_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
+        .write          = ext4_ui_proc_write,
+};
+#endif
+
 static struct file_system_type ext4dev_fs_type = {
         .owner          = THIS_MODULE,
         .name           = "ext4dev",