From: Eryu Guan <guaneryu@gmail.com>
Date: Sun, 21 Feb 2016 23:38:44 +0000 (-0500)
Subject: ext4: iterate over buffer heads correctly in move_extent_per_page()
X-Git-Tag: v3.16.35~247
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=d0ba59c19fe16e626abf93aed98266c56b2a6863;p=thirdparty%2Fkernel%2Fstable.git

ext4: iterate over buffer heads correctly in move_extent_per_page()

commit 6ffe77bad545f4a7c8edd2a4ee797ccfcd894ab4 upstream.

In commit bcff24887d00 ("ext4: don't read blocks from disk after extents
being swapped") bh is not updated correctly in the for loop and wrong
data has been written to disk. generic/324 catches this on sub-page
block size ext4.

Fixes: bcff24887d00 ("ext4: don't read blocks from disk after extentsbeing swapped")
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---

diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index 146f8cd627b22..2423b0068183f 100644
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -1037,6 +1037,7 @@ data_copy:
 		*err = ext4_get_block(orig_inode, orig_blk_offset + i, bh, 0);
 		if (*err < 0)
 			break;
+		bh = bh->b_this_page;
 	}
 	if (!*err)
 		*err = block_commit_write(pagep[0], from, from + replaced_size);