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-rw-r--r--block/genhd.c30
-rw-r--r--block/ioctl.c2
2 files changed, 27 insertions, 5 deletions
diff --git a/block/genhd.c b/block/genhd.c
index 647f7d8d8831..85ae755913e9 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -359,6 +359,7 @@ EXPORT_SYMBOL_GPL(disk_uevent);
 int disk_scan_partitions(struct gendisk *disk, fmode_t mode)
 {
 	struct block_device *bdev;
+	int ret = 0;
 
 	if (disk->flags & (GENHD_FL_NO_PART | GENHD_FL_HIDDEN))
 		return -EINVAL;
@@ -368,11 +369,27 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode)
 		return -EBUSY;
 
 	set_bit(GD_NEED_PART_SCAN, &disk->state);
-	bdev = blkdev_get_by_dev(disk_devt(disk), mode, NULL);
+	/*
+	 * If the device is opened exclusively by current thread already, it's
+	 * safe to scan partitons, otherwise, use bd_prepare_to_claim() to
+	 * synchronize with other exclusive openers and other partition
+	 * scanners.
+	 */
+	if (!(mode & FMODE_EXCL)) {
+		ret = bd_prepare_to_claim(disk->part0, disk_scan_partitions);
+		if (ret)
+			return ret;
+	}
+
+	bdev = blkdev_get_by_dev(disk_devt(disk), mode & ~FMODE_EXCL, NULL);
 	if (IS_ERR(bdev))
-		return PTR_ERR(bdev);
-	blkdev_put(bdev, mode);
-	return 0;
+		ret =  PTR_ERR(bdev);
+	else
+		blkdev_put(bdev, mode);
+
+	if (!(mode & FMODE_EXCL))
+		bd_abort_claiming(disk->part0, disk_scan_partitions);
+	return ret;
 }
 
 /**
@@ -498,6 +515,11 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
 		if (ret)
 			goto out_unregister_bdi;
 
+		/* Make sure the first partition scan will be proceed */
+		if (get_capacity(disk) && !(disk->flags & GENHD_FL_NO_PART) &&
+		    !test_bit(GD_SUPPRESS_PART_SCAN, &disk->state))
+			set_bit(GD_NEED_PART_SCAN, &disk->state);
+
 		bdev_add(disk->part0, ddev->devt);
 		if (get_capacity(disk))
 			disk_scan_partitions(disk, FMODE_READ);
diff --git a/block/ioctl.c b/block/ioctl.c
index 6dd49d877584..9c5f637ff153 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -528,7 +528,7 @@ static int blkdev_common_ioctl(struct block_device *bdev, fmode_t mode,
 			return -EACCES;
 		if (bdev_is_partition(bdev))
 			return -EINVAL;
-		return disk_scan_partitions(bdev->bd_disk, mode & ~FMODE_EXCL);
+		return disk_scan_partitions(bdev->bd_disk, mode);
 	case BLKTRACESTART:
 	case BLKTRACESTOP:
 	case BLKTRACETEARDOWN: