From: Mark Fasheh <mfasheh@suse.de>
Date: Tue, 30 Jun 2015 21:42:04 +0000 (-0700)
Subject: btrfs: pass unaligned length to btrfs_cmp_data()
X-Git-Tag: v4.1.12-110.0.20170822_0730~26
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=e08fe6d0fac9ea5729a75ac396600c7582434c2d;p=users%2Fjedix%2Flinux-maple.git

btrfs: pass unaligned length to btrfs_cmp_data()

In the case that we dedupe the tail of a file, we might expand the dedupe
len out to the end of our last block. We don't want to compare data past
i_size however, so pass the original length to btrfs_cmp_data().

Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
(Cherry picked from commit 207910ddeeda38fd54544d94f8c8ca5a9632cc25)

Orabug: 26251039

Signed-off-by: Shan Hai <shan.hai@oracle.com>
Acked-by: Shannon Nelson <shannon.nelson@oracle.com>
Acked-by: John Haxby <john.haxby@oracle.com>
---

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 111d14d2ec657..ca6af45f6c433 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2992,7 +2992,8 @@ static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
 		goto out_unlock;
 	}
 
-	ret = btrfs_cmp_data(src, loff, dst, dst_loff, len);
+	/* pass original length for comparison so we stay within i_size */
+	ret = btrfs_cmp_data(src, loff, dst, dst_loff, olen);
 	if (ret == 0)
 		ret = btrfs_clone(src, dst, loff, olen, len, dst_loff);