@@ -33,7 +33,7 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	char dummy;
 	int ret;
 
-	if (argc != 2) {
+	if ((argc < 2) || (argc > 3)) {
 		ti->error = "Invalid argument count";
 		return -EINVAL;
 	}

@@ -51,6 +51,18 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	}
 	lc->start = tmp;
 
+	ti->non_exclusive = false;
+	if (argc > 2) {
+		if (strcmp("noexcl", argv[2]) == 0)
+			ti->non_exclusive = true;
+		else if (strcmp("excl", argv[2]) == 0)
+			ti->non_exclusive = false;
+		else {
+			ti->error = "Invalid exclusive option";
+			return -EINVAL;
+		}
+	}
+
 	ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev);
 	if (ret) {
 		ti->error = "Device lookup failed";

@@ -322,7 +322,7 @@ static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
  * device and not to touch the existing bdev field in case
  * it is accessed concurrently.
  */
-static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
+static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode, bool non_exclusive,
 			struct mapped_device *md)
 {
 	int r;

@@ -330,8 +330,8 @@ static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
 
 	old_dev = dd->dm_dev;
 
-	r = dm_get_table_device(md, dd->dm_dev->bdev->bd_dev,
-				dd->dm_dev->mode | new_mode, &new_dev);
+	r = dm_get_table_device(md, dd->dm_dev->bdev->bd_dev, dd->dm_dev->mode | new_mode,
+				non_exclusive, &new_dev);
 	if (r)
 		return r;
 

@@ -387,7 +387,8 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
 		if (!dd)
 			return -ENOMEM;
 
-		if ((r = dm_get_table_device(t->md, dev, mode, &dd->dm_dev))) {
+		r = dm_get_table_device(t->md, dev, mode, ti->non_exclusive, &dd->dm_dev);
+		if (r) {
 			kfree(dd);
 			return r;
 		}

@@ -396,8 +397,9 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
 		list_add(&dd->list, &t->devices);
 		goto out;
 
-	} else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
-		r = upgrade_mode(dd, mode, t->md);
+	} else if ((dd->dm_dev->mode != (mode | dd->dm_dev->mode)) &&
+		   (dd->dm_dev->non_exclusive != ti->non_exclusive)) {
+		r = upgrade_mode(dd, mode, ti->non_exclusive, t->md);
 		if (r)
 			return r;
 	}

@@ -1117,33 +1117,44 @@ static void close_table_device(struct table_device *td, struct mapped_device *md
 	if (!td->dm_dev.bdev)
 		return;
 
-	bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md));
-	blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL);
+	if (td->dm_dev.non_exclusive)
+		blkdev_put(td->dm_dev.bdev, td->dm_dev.mode);
+	else {
+		bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md));
+		blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL);
+	}
+
+
+	blkdev_put(td->dm_dev.bdev, td->dm_dev.mode);
+
 	put_dax(td->dm_dev.dax_dev);
 	td->dm_dev.bdev = NULL;
 	td->dm_dev.dax_dev = NULL;
+	td->dm_dev.non_exclusive = false;
 }
 
 static struct table_device *find_table_device(struct list_head *l, dev_t dev,
-					      fmode_t mode)
+					      fmode_t mode, bool non_exclusive)
 {
 	struct table_device *td;
 
 	list_for_each_entry(td, l, list)
-		if (td->dm_dev.bdev->bd_dev == dev && td->dm_dev.mode == mode)
+		if (td->dm_dev.bdev->bd_dev == dev &&
+		    td->dm_dev.mode == mode &&
+		    td->dm_dev.non_exclusive == non_exclusive)
 			return td;
 
 	return NULL;
 }
 
-int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
+int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode, bool non_exclusive,
 			struct dm_dev **result)
 {
 	int r;
 	struct table_device *td;
 
 	mutex_lock(&md->table_devices_lock);
-	td = find_table_device(&md->table_devices, dev, mode);
+	td = find_table_device(&md->table_devices, dev, mode, non_exclusive);
 	if (!td) {
 		td = kmalloc_node(sizeof(*td), GFP_KERNEL, md->numa_node_id);
 		if (!td) {

@@ -1154,7 +1165,8 @@ int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
 		td->dm_dev.mode = mode;
 		td->dm_dev.bdev = NULL;
 
-		if ((r = open_table_device(td, dev, md))) {
+		r = open_table_device(td, dev, md, non_exclusive);
+		if (r) {
 			mutex_unlock(&md->table_devices_lock);
 			kfree(td);
 			return r;

@@ -179,7 +179,7 @@ int dm_open_count(struct mapped_device *md);
 int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only_deferred);
 int dm_cancel_deferred_remove(struct mapped_device *md);
 int dm_request_based(struct mapped_device *md);
-int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
+int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode, bool non_exclusive,
 			struct dm_dev **result);
 void dm_put_table_device(struct mapped_device *md, struct dm_dev *d);
 

@@ -150,6 +150,7 @@ struct dm_dev {
 	struct block_device *bdev;
 	struct dax_device *dax_dev;
 	fmode_t mode;
+	bool non_exclusive;
 	char name[16];
 };
 

@@ -325,6 +326,12 @@ struct dm_target {
 	 * whether or not its underlying devices have support.
 	 */
 	bool discards_supported:1;
+
+	/*
+	 * Set if this target needs to open device without FMODE_EXCL
+	 * mode.
+	 */
+	bool non_exclusive:1;
 };
 
 void *dm_per_bio_data(struct bio *bio, size_t data_size);