+/* the function only is used to change dev->read_only when this file system
+ * is remounted.
+ */
+static int yaffs_remount_fs(struct super_block *sb, int *flags, char *data)
+{
+ int read_only = 0;
+ int was_read_only = 0;
+ struct mtd_info *mtd;
+ struct yaffs_dev *dev = 0;
+
+ /* Get the device */
+ mtd = get_mtd_device(NULL, MINOR(sb->s_dev));
+ if (!mtd) {
+ yaffs_trace(YAFFS_TRACE_ALWAYS,
+ "MTD device #%u doesn't appear to exist",
+ MINOR(sb->s_dev));
+ return 1;
+ }
+
+ /* Check it's NAND */
+ if (mtd->type != MTD_NANDFLASH) {
+ yaffs_trace(YAFFS_TRACE_ALWAYS,
+ "MTD device is not NAND it's type %d",
+ mtd->type);
+ return 1;
+ }
+
+ read_only = ((*flags & MS_RDONLY) != 0);
+ if (!read_only && !(mtd->flags & MTD_WRITEABLE)) {
+ read_only = 1;
+ printk(KERN_INFO
+ "yaffs: mtd is read only, setting superblock read only");
+ *flags |= MS_RDONLY;
+ }
+
+ dev = sb->s_fs_info;
+ was_read_only = dev->read_only;
+ dev->read_only = read_only;
+
+ if (was_read_only && !read_only) {
+ yaffs_gross_lock(dev);
+ yaffs_guts_cleanup(dev);
+ yaffs_gross_unlock(dev);
+ yaffs_bg_start(dev);
+ } else if (!was_read_only && read_only) {
+ yaffs_bg_stop(dev);
+ }