--- zzzz-none-000/linux-5.4.213/fs/squashfs/super.c	2022-09-15 10:04:56.000000000 +0000
+++ alder-5690pro-762/linux-5.4.213/fs/squashfs/super.c	2024-08-14 09:02:08.000000000 +0000
@@ -26,6 +26,9 @@
 #include <linux/module.h>
 #include <linux/magic.h>
 #include <linux/xattr.h>
+#include <linux/root_dev.h>
+#include <linux/syscalls.h>
+#include <linux/mtd/mtd.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
@@ -101,7 +104,8 @@
 
 	if (IS_ERR(sblk)) {
 		errorf(fc, "unable to read squashfs_super_block");
-		err = PTR_ERR(sblk);
+		/*--- err = PTR_ERR(sblk); ---*//*--- JZ-27891 mit err = -EIO wird kein anderes FS mehr gemountet ---*/
+        	err = -EINVAL;
 		sblk = NULL;
 		goto failed_mount;
 	}
@@ -130,8 +134,11 @@
 	   block device */
 	msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
 	if (msblk->bytes_used < 0 || msblk->bytes_used >
-			i_size_read(sb->s_bdev->bd_inode))
+			i_size_read(sb->s_bdev->bd_inode)){
+		pr_err("SQFS-Size %llu is to big for given device size %llu. Is mtdram1 too small?\n",
+			msblk->bytes_used, i_size_read(sb->s_bdev->bd_inode));
 		goto failed_mount;
+	}
 
 	/* Check block size for sanity */
 	msblk->block_size = le32_to_cpu(sblk->block_size);
@@ -343,8 +350,44 @@
 	return err;
 }
 
+/* copy from init/do_mounts.h */
+static inline int create_dev(char *name, dev_t dev)
+{
+	ksys_unlink(name);
+	return ksys_mknod(name, S_IFBLK|0600, new_encode_dev(dev));
+}
+
+static void squashfs_mount(struct fs_context *fc)
+{
+	if (!strncmp(fc->source, "mtd:", 4) || !strncmp(fc->source, "ubi:", 4)) {
+		struct mtd_info *mtd = get_mtd_device_nm("ubi_rootfs");
+
+		if (!IS_ERR(mtd)) {
+			void *bdev;
+			char *dev;
+			dev = kmalloc(32, GFP_KERNEL);
+
+			scnprintf(dev, 32, "/dev/mtdblock%d", mtd->index);
+			bdev = blkdev_get_by_path(dev, FMODE_READ, fc->fs_type);
+
+			if (!IS_ERR(bdev)) {
+				kfree(fc->source);
+				fc->source = dev;
+			} else if (PTR_ERR(bdev) == -ENOENT) {
+				create_dev(dev,
+					MKDEV(MTD_BLOCK_MAJOR, mtd->index));
+				kfree(fc->source);
+				fc->source = dev;
+			} else
+				kfree(dev);
+		}
+	}
+
+}
+
 static int squashfs_get_tree(struct fs_context *fc)
 {
+	squashfs_mount(fc);
 	return get_tree_bdev(fc, squashfs_fill_super);
 }