From: Duane Griffin <duaneg@dghda.com>
Date: Thu, 20 Mar 2008 02:45:06 +0000 (+0000)
Subject: jbd: correctly unescape journal data blocks
X-Git-Tag: v2.6.24.4~8
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=d447e76ecaa4d4bb005eef4de5655a8418a4d60d;p=karo-tx-linux.git

jbd: correctly unescape journal data blocks

commit: 439aeec639d7c57f3561054a6d315c40fd24bb74

Fix a long-standing typo (predating git) that will cause data corruption if a
journal data block needs unescaping.  At the moment the wrong buffer head's
data is being unescaped.

To test this case mount a filesystem with data=journal, start creating and
deleting a bunch of files containing only JFS_MAGIC_NUMBER (0xc03b3998), then
pull the plug on the device.  Without this patch the files will contain zeros
instead of the correct data after recovery.

Signed-off-by: Duane Griffin <duaneg@dghda.com>
Acked-by: Jan Kara <jack@suse.cz>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/fs/jbd/recovery.c b/fs/jbd/recovery.c
index c5d9694b6a2f..9aaa4fa31423 100644
--- a/fs/jbd/recovery.c
+++ b/fs/jbd/recovery.c
@@ -478,7 +478,7 @@ static int do_one_pass(journal_t *journal,
 					memcpy(nbh->b_data, obh->b_data,
 							journal->j_blocksize);
 					if (flags & JFS_FLAG_ESCAPE) {
-						*((__be32 *)bh->b_data) =
+						*((__be32 *)nbh->b_data) =
 						cpu_to_be32(JFS_MAGIC_NUMBER);
 					}