3.16.37-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Anthony Romano <[email protected]>

commit b9b4bb26af017dbe930cd4df7f9b2fc3a0497bfe upstream.

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.

Fixes: 1635f6a74152f1d ("tmpfs: undo fallocation on failure")
Link: 
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Anthony Romano <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Brandon Philips <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
[bwh: Backported to 3.16: use PAGE_CACHE_SHIFT instead of PAGE_SHIFT]
Signed-off-by: Ben Hutchings <[email protected]>
---
 mm/shmem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1867,7 +1867,7 @@ static long shmem_fallocate(struct file
                        /* Remove the !PageUptodate pages we added */
                        shmem_undo_range(inode,
                                (loff_t)start << PAGE_CACHE_SHIFT,
-                               (loff_t)index << PAGE_CACHE_SHIFT, true);
+                               ((loff_t)index << PAGE_CACHE_SHIFT) - 1, true);
                        goto undone;
                }
 

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