From: Eryu Guan Subject: [PATCH] ext4: iterate over buffer heads correctly in move_extent_per_page() Date: Sun, 21 Feb 2016 23:57:29 +0800 Message-ID: <1456070249-29945-1-git-send-email-guaneryu@gmail.com> Cc: tytso@mit.edu, Eryu Guan To: linux-ext4@vger.kernel.org Return-path: Received: from mail-pf0-f178.google.com ([209.85.192.178]:35533 "EHLO mail-pf0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751999AbcBURhq (ORCPT ); Sun, 21 Feb 2016 12:37:46 -0500 Received: by mail-pf0-f178.google.com with SMTP id c10so81935261pfc.2 for ; Sun, 21 Feb 2016 09:37:46 -0800 (PST) Sender: linux-ext4-owner@vger.kernel.org List-ID: 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 --- Not sure why I didn't notice generic/324 failure in the first place, it fails every time for me with 4.5-rc5 kernel. Sorry about that! I tested this patch with 1k/2k/4k block size ext4 with all defrag related tests in xfstests (ext4/301 ext4/302 ext4/303 ext4/304 ext4/307 ext4/308 generic/324) and results showed no regression. Test with the reproducer in commit bcff24887d00 also passed. fs/ext4/move_extent.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c index e032a04..4098acc 100644 --- a/fs/ext4/move_extent.c +++ b/fs/ext4/move_extent.c @@ -390,6 +390,7 @@ 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); -- 2.5.0