Merge tag 'for-5.5/disk-revalidate-20191122' of git://git.kernel.dk/linux-block

Pull disk revalidation updates from Jens Axboe:
 "This continues the work that Jan Kara started to thoroughly cleanup
  and consolidate how we handle rescans and revalidations"

* tag 'for-5.5/disk-revalidate-20191122' of git://git.kernel.dk/linux-block:
  block: move clearing bd_invalidated into check_disk_size_change
  block: remove (__)blkdev_reread_part as an exported API
  block: fix bdev_disk_changed for non-partitioned devices
  block: move rescan_partitions to fs/block_dev.c
  block: merge invalidate_partitions into rescan_partitions
  block: refactor rescan_partitions

1 files changed, 37 insertions, 11 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index d612468ee66b..ee63c2732fa2 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1416,8 +1416,8 @@ static void flush_disk(struct block_device *bdev, bool kill_dirty)
  * and adjusts it if it differs. When shrinking the bdev size, its all caches
  * are freed.
  */
-void check_disk_size_change(struct gendisk *disk, struct block_device *bdev,
-		bool verbose)
+static void check_disk_size_change(struct gendisk *disk,
+		struct block_device *bdev, bool verbose)
 {
 	loff_t disk_size, bdev_size;
 
@@ -1433,6 +1433,7 @@ void check_disk_size_change(struct gendisk *disk, struct block_device *bdev,
 		if (bdev_size > disk_size)
 			flush_disk(bdev, false);
 	}
+	bdev->bd_invalidated = 0;
 }
 
 /**
@@ -1462,7 +1463,6 @@ int revalidate_disk(struct gendisk *disk)
 
 		mutex_lock(&bdev->bd_mutex);
 		check_disk_size_change(disk, bdev, ret == 0);
-		bdev->bd_invalidated = 0;
 		mutex_unlock(&bdev->bd_mutex);
 		bdput(bdev);
 	}
@@ -1508,18 +1508,44 @@ EXPORT_SYMBOL(bd_set_size);
 
 static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
 
-static void bdev_disk_changed(struct block_device *bdev, bool invalidate)
+int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 {
-	if (disk_part_scan_enabled(bdev->bd_disk)) {
-		if (invalidate)
-			invalidate_partitions(bdev->bd_disk, bdev);
-		else
-			rescan_partitions(bdev->bd_disk, bdev);
+	struct gendisk *disk = bdev->bd_disk;
+	int ret;
+
+	lockdep_assert_held(&bdev->bd_mutex);
+
+rescan:
+	ret = blk_drop_partitions(disk, bdev);
+	if (ret)
+		return ret;
+
+	if (invalidate)
+		set_capacity(disk, 0);
+	else if (disk->fops->revalidate_disk)
+		disk->fops->revalidate_disk(disk);
+
+	check_disk_size_change(disk, bdev, !invalidate);
+
+	if (get_capacity(disk)) {
+		ret = blk_add_partitions(disk, bdev);
+		if (ret == -EAGAIN)
+			goto rescan;
 	} else {
-		check_disk_size_change(bdev->bd_disk, bdev, !invalidate);
-		bdev->bd_invalidated = 0;
+		/*
+		 * Tell userspace that the media / partition table may have
+		 * changed.
+		 */
+		kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
 	}
+
+	return ret;
 }
+/*
+ * Only exported for for loop and dasd for historic reasons.  Don't use in new
+ * code!
+ */
+EXPORT_SYMBOL_GPL(bdev_disk_changed);
 
 /*
  * bd_mutex locking: