target/linux/generic/patches-4.3/491-ubi-auto-create-ubiblock-device-for-rootfs.patch

   1 From 0f3966579815f889bb2fcb4846152c35f65e79c4 Mon Sep 17 00:00:00 2001
   2 From: Daniel Golle <daniel@makrotopia.org>
   3 Date: Thu, 15 May 2014 21:06:33 +0200
   4 Subject: [PATCH 2/5] ubi: auto-create ubiblock device for rootfs
   5 To: openwrt-devel@lists.openwrt.org
   6
   7 Signed-off-by: Daniel Golle <daniel@makrotopia.org>
   8 ---
   9  drivers/mtd/ubi/block.c | 42 ++++++++++++++++++++++++++++++++++++++++++
  10  1 file changed, 42 insertions(+)
  11
  12 --- a/drivers/mtd/ubi/block.c
  13 +++ b/drivers/mtd/ubi/block.c
  14 @@ -628,6 +628,44 @@ static void __init ubiblock_create_from_
  15         }
  16  }
  17
  18 +#define UBIFS_NODE_MAGIC  0x06101831
  19 +static inline int ubi_vol_is_ubifs(struct ubi_volume_desc *desc)
  20 +{
  21 +       int ret;
  22 +       uint32_t magic_of, magic;
  23 +       ret = ubi_read(desc, 0, (char *)&magic_of, 0, 4);
  24 +       if (ret)
  25 +               return 0;
  26 +       magic = le32_to_cpu(magic_of);
  27 +       return magic == UBIFS_NODE_MAGIC;
  28 +}
  29 +
  30 +static void __init ubiblock_create_auto_rootfs(void)
  31 +{
  32 +       int ubi_num, ret, is_ubifs;
  33 +       struct ubi_volume_desc *desc;
  34 +       struct ubi_volume_info vi;
  35 +
  36 +       for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++) {
  37 +               desc = ubi_open_volume_nm(ubi_num, "rootfs", UBI_READONLY);
  38 +               if (IS_ERR(desc))
  39 +                       continue;
  40 +
  41 +               ubi_get_volume_info(desc, &vi);
  42 +               is_ubifs = ubi_vol_is_ubifs(desc);
  43 +               ubi_close_volume(desc);
  44 +               if (is_ubifs)
  45 +                       break;
  46 +
  47 +               ret = ubiblock_create(&vi);
  48 +               if (ret)
  49 +                       pr_err("UBI error: block: can't add '%s' volume, err=%d\n",
  50 +                               vi.name, ret);
  51 +               /* always break if we get here */
  52 +               break;
  53 +       }
  54 +}
  55 +
  56  static void ubiblock_remove_all(void)
  57  {
  58         struct ubiblock *next;
  59 @@ -658,6 +696,10 @@ int __init ubiblock_init(void)
  60          */
  61         ubiblock_create_from_param();
  62
  63 +       /* auto-attach "rootfs" volume if existing and non-ubifs */
  64 +       if (config_enabled(CONFIG_MTD_ROOTFS_ROOT_DEV))
  65 +               ubiblock_create_auto_rootfs();
  66 +
  67         /*
  68          * Block devices are only created upon user requests, so we ignore
  69          * existing volumes.