4 files changed, 28 insertions, 8 deletions

diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index 3410ea8109f8..f5c715c32dcd 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -61,13 +61,13 @@ static int get_exclusive(struct ubi_device *ubi, struct ubi_volume_desc *desc)
         struct ubi_volume *vol = desc->vol;
 
         spin_lock(&vol->ubi->volumes_lock);
-        users = vol->readers + vol->writers + vol->exclusive;
+        users = vol->readers + vol->writers + vol->exclusive + vol->metaonly;
         ubi_assert(users > 0);
         if (users > 1) {
                 ubi_err(ubi, "%d users for volume %d", users, vol->vol_id);
                 err = -EBUSY;
         } else {
-                vol->readers = vol->writers = 0;
+                vol->readers = vol->writers = vol->metaonly = 0;
                 vol->exclusive = 1;
                 err = desc->mode;
                 desc->mode = UBI_EXCLUSIVE;
@@ -87,13 +87,15 @@ static void revoke_exclusive(struct ubi_volume_desc *desc, int mode)
         struct ubi_volume *vol = desc->vol;
 
         spin_lock(&vol->ubi->volumes_lock);
-        ubi_assert(vol->readers == 0 && vol->writers == 0);
+        ubi_assert(vol->readers == 0 && vol->writers == 0 && vol->metaonly == 0);
         ubi_assert(vol->exclusive == 1 && desc->mode == UBI_EXCLUSIVE);
         vol->exclusive = 0;
         if (mode == UBI_READONLY)
                 vol->readers = 1;
         else if (mode == UBI_READWRITE)
                 vol->writers = 1;
+        else if (mode == UBI_METAONLY)
+                vol->metaonly = 1;
         else
                 vol->exclusive = 1;
         spin_unlock(&vol->ubi->volumes_lock);
diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c
index f3bab669f6bb..589c423fac2d 100644
--- a/drivers/mtd/ubi/kapi.c
+++ b/drivers/mtd/ubi/kapi.c
@@ -137,7 +137,7 @@ struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
                 return ERR_PTR(-EINVAL);
 
         if (mode != UBI_READONLY && mode != UBI_READWRITE &&
-            mode != UBI_EXCLUSIVE)
+            mode != UBI_EXCLUSIVE && mode != UBI_METAONLY)
                 return ERR_PTR(-EINVAL);
 
         /*
@@ -182,10 +182,17 @@ struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
                 break;
 
         case UBI_EXCLUSIVE:
-                if (vol->exclusive || vol->writers || vol->readers)
+                if (vol->exclusive || vol->writers || vol->readers ||
+                    vol->metaonly)
                         goto out_unlock;
                 vol->exclusive = 1;
                 break;
+
+        case UBI_METAONLY:
+                if (vol->metaonly || vol->exclusive)
+                        goto out_unlock;
+                vol->metaonly = 1;
+                break;
         }
         get_device(&vol->dev);
         vol->ref_count += 1;
@@ -343,6 +350,10 @@ void ubi_close_volume(struct ubi_volume_desc *desc)
                 break;
         case UBI_EXCLUSIVE:
                 vol->exclusive = 0;
+                break;
+        case UBI_METAONLY:
+                vol->metaonly = 0;
+                break;
         }
         vol->ref_count -= 1;
         spin_unlock(&ubi->volumes_lock);
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index f80ffaba9058..20cabc060b61 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -261,6 +261,7 @@ struct ubi_fm_pool {
  * @readers: number of users holding this volume in read-only mode
  * @writers: number of users holding this volume in read-write mode
  * @exclusive: whether somebody holds this volume in exclusive mode
+ * @metaonly: whether somebody is altering only meta data of this volume
  *
  * @reserved_pebs: how many physical eraseblocks are reserved for this volume
  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
@@ -309,6 +310,7 @@ struct ubi_volume {
         int readers;
         int writers;
         int exclusive;
+        int metaonly;
 
         int reserved_pebs;
         int vol_type;
@@ -339,7 +341,8 @@ struct ubi_volume {
 /**
  * struct ubi_volume_desc - UBI volume descriptor returned when it is opened.
  * @vol: reference to the corresponding volume description object
- * @mode: open mode (%UBI_READONLY, %UBI_READWRITE, or %UBI_EXCLUSIVE)
+ * @mode: open mode (%UBI_READONLY, %UBI_READWRITE, %UBI_EXCLUSIVE
+ * or %UBI_METAONLY)
  */
 struct ubi_volume_desc {
         struct ubi_volume *vol;
@@ -390,7 +393,8 @@ struct ubi_debug_info {
  * @volumes_lock: protects @volumes, @rsvd_pebs, @avail_pebs, beb_rsvd_pebs,
  *                @beb_rsvd_level, @bad_peb_count, @good_peb_count, @vol_count,
  *                @vol->readers, @vol->writers, @vol->exclusive,
- *                @vol->ref_count, @vol->mapping and @vol->eba_tbl.
+ *                @vol->metaonly, @vol->ref_count, @vol->mapping and
+ *                @vol->eba_tbl.
  * @ref_count: count of references on the UBI device
  * @image_seq: image sequence number recorded on EC headers
  *
diff --git a/include/linux/mtd/ubi.h b/include/linux/mtd/ubi.h
index c3918a0684fe..8fa2753316e8 100644
--- a/include/linux/mtd/ubi.h
+++ b/include/linux/mtd/ubi.h
@@ -34,11 +34,14 @@
  * UBI_READONLY: read-only mode
  * UBI_READWRITE: read-write mode
  * UBI_EXCLUSIVE: exclusive mode
+ * UBI_METAONLY: modify only the volume meta-data,
+ *  i.e. the data stored in the volume table, but not in any of volume LEBs.
  */
 enum {
         UBI_READONLY = 1,
         UBI_READWRITE,
-        UBI_EXCLUSIVE
+        UBI_EXCLUSIVE,
+        UBI_METAONLY
 };
 
 /**