diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 2b00bf8..02ce7e7 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -481,7 +481,7 @@ static int ext4_find_unwritten_pgoff(struct inode *inode,
 		int i, num;
 		unsigned long nr_pages;
 
-		num = min_t(pgoff_t, end - index, PAGEVEC_SIZE);
+		num = min_t(pgoff_t, end - index, PAGEVEC_SIZE - 1) + 1;
 		nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index,
 					  (pgoff_t)num);
 		if (nr_pages == 0)