2008-03-21 22:52:32

by Chris Wright

[permalink] [raw]
Subject: [patch 70/76] jbd2: correctly unescape journal data blocks

-stable review patch. If anyone has any objections, please let us know.
---------------------

From: Duane Griffin <[email protected]>

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 JBD2_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 <[email protected]>
Acked-by: Jan Kara <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Chris Wright <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/jbd2/recovery.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -488,7 +488,7 @@ static int do_one_pass(journal_t *journa
memcpy(nbh->b_data, obh->b_data,
journal->j_blocksize);
if (flags & JBD2_FLAG_ESCAPE) {
- *((__be32 *)bh->b_data) =
+ *((__be32 *)nbh->b_data) =
cpu_to_be32(JBD2_MAGIC_NUMBER);
}


--