diff --git a/fs/block_dev.c b/fs/block_dev.c
index b3be92c..a6e1e06 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1086,7 +1086,9 @@
 {
 	unsigned bsize = bdev_logical_block_size(bdev);
 
-	bdev->bd_inode->i_size = size;
+	mutex_lock(&bdev->bd_inode->i_mutex);
+	i_size_write(bdev->bd_inode, size);
+	mutex_unlock(&bdev->bd_inode->i_mutex);
 	while (bsize < PAGE_CACHE_SIZE) {
 		if (size & bsize)
 			break;