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From: Anthony Romano <anthony.romano@coreos.com>
To: hughd@google.com
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Anthony Romano <anthony.romano@coreos.com>
Subject: [PATCH] tmpfs: don't undo fallocate past its last page
Date: Sun,  8 May 2016 06:16:27 -0700	[thread overview]
Message-ID: <1462713387-16724-1-git-send-email-anthony.romano@coreos.com> (raw)

When fallocate is interrupted it will undo a range that extends one byte
past its range of allocated pages. This can corrupt an in-use page by
zeroing out its first byte. Instead, undo using the inclusive byte range.

Signed-off-by: Anthony Romano <anthony.romano@coreos.com>
---
 mm/shmem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 719bd6b..f0f9405 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2238,7 +2238,7 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset,
 			/* Remove the !PageUptodate pages we added */
 			shmem_undo_range(inode,
 				(loff_t)start << PAGE_SHIFT,
-				(loff_t)index << PAGE_SHIFT, true);
+				((loff_t)index << PAGE_SHIFT) - 1, true);
 			goto undone;
 		}
 
-- 
2.8.1

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             reply	other threads:[~2016-05-08 13:14 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-08 13:16 Anthony Romano [this message]
2016-05-16 11:59 ` Vlastimil Babka
2016-05-16 13:55   ` Anthony Romano
2016-06-04  1:10   ` Brandon Philips
2016-06-06  4:05   ` Brandon Philips

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