1 files changed, 24 insertions, 17 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 09d6f7229db9..b8abccd03e5d 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -79,7 +79,7 @@ static void kill_bdev(struct block_device *bdev)
 {
 	struct address_space *mapping = bdev->bd_inode->i_mapping;
 
-	if (mapping->nrpages == 0 && mapping->nrexceptional == 0)
+	if (mapping_empty(mapping))
 		return;
 
 	invalidate_bh_lrus();
@@ -1240,14 +1240,16 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
 int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 {
 	struct gendisk *disk = bdev->bd_disk;
-	int ret;
+	int ret = 0;
 
 	lockdep_assert_held(&bdev->bd_mutex);
 
 rescan:
-	ret = blk_drop_partitions(bdev);
-	if (ret)
-		return ret;
+	if (bdev->bd_part_count)
+		return -EBUSY;
+	sync_blockdev(bdev);
+	invalidate_bdev(bdev);
+	blk_drop_partitions(disk);
 
 	clear_bit(GD_NEED_PART_SCAN, &disk->state);
 
@@ -1263,9 +1265,6 @@ rescan:
 		if (disk_part_scan_enabled(disk) ||
 		    !(disk->flags & GENHD_FL_REMOVABLE))
 			set_capacity(disk, 0);
-	} else {
-		if (disk->fops->revalidate_disk)
-			disk->fops->revalidate_disk(disk);
 	}
 
 	if (get_capacity(disk)) {
@@ -1437,10 +1436,6 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 	if (ret)
 		return ERR_PTR(ret);
 
-	/*
-	 * If we lost a race with 'disk' being deleted, try again.  See md.c.
-	 */
-retry:
 	bdev = blkdev_get_no_open(dev);
 	if (!bdev)
 		return ERR_PTR(-ENXIO);
@@ -1487,8 +1482,6 @@ abort_claiming:
 	disk_unblock_events(disk);
 put_blkdev:
 	blkdev_put_no_open(bdev);
-	if (ret == -ERESTARTSYS)
-		goto retry;
 	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL(blkdev_get_by_dev);
@@ -1684,6 +1677,7 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	struct inode *bd_inode = bdev_file_inode(file);
 	loff_t size = i_size_read(bd_inode);
 	struct blk_plug plug;
+	size_t shorted = 0;
 	ssize_t ret;
 
 	if (bdev_read_only(I_BDEV(bd_inode)))
@@ -1701,12 +1695,17 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT)
 		return -EOPNOTSUPP;
 
-	iov_iter_truncate(from, size - iocb->ki_pos);
+	size -= iocb->ki_pos;
+	if (iov_iter_count(from) > size) {
+		shorted = iov_iter_count(from) - size;
+		iov_iter_truncate(from, size);
+	}
 
 	blk_start_plug(&plug);
 	ret = __generic_file_write_iter(iocb, from);
 	if (ret > 0)
 		ret = generic_write_sync(iocb, ret);
+	iov_iter_reexpand(from, iov_iter_count(from) + shorted);
 	blk_finish_plug(&plug);
 	return ret;
 }
@@ -1718,13 +1717,21 @@ ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
 	struct inode *bd_inode = bdev_file_inode(file);
 	loff_t size = i_size_read(bd_inode);
 	loff_t pos = iocb->ki_pos;
+	size_t shorted = 0;
+	ssize_t ret;
 
 	if (pos >= size)
 		return 0;
 
 	size -= pos;
-	iov_iter_truncate(to, size);
-	return generic_file_read_iter(iocb, to);
+	if (iov_iter_count(to) > size) {
+		shorted = iov_iter_count(to) - size;
+		iov_iter_truncate(to, size);
+	}
+
+	ret = generic_file_read_iter(iocb, to);
+	iov_iter_reexpand(to, iov_iter_count(to) + shorted);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(blkdev_read_iter);