From: Jan Kara <jack@suse.cz>
Date: Mon, 22 May 2017 02:34:23 +0000 (-0400)
Subject: ext4: fix off-by-in in loop termination in ext4_find_unwritten_pgoff()
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=3f1d5bad3fae983da07be01cff2fde13293bb7b9;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

ext4: fix off-by-in in loop termination in ext4_find_unwritten_pgoff()

There is an off-by-one error in loop termination conditions in
ext4_find_unwritten_pgoff() since 'end' may index a page beyond end of
desired range if 'endoff' is page aligned. It doesn't have any visible
effects but still it is good to fix it.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index bbea2dccd584..2b00bf84c05b 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -474,7 +474,7 @@ static int ext4_find_unwritten_pgoff(struct inode *inode,
 	endoff = (loff_t)end_blk << blkbits;
 
 	index = startoff >> PAGE_SHIFT;
-	end = endoff >> PAGE_SHIFT;
+	end = (endoff - 1) >> PAGE_SHIFT;
 
 	pagevec_init(&pvec, 0);
 	do {