jbd2: correctly unescape journal data blocks

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]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Duane Griffin 2008-03-19 17:00:54 -07:00 • committed by Linus Torvalds
commit d00256766a

View file

@ -535,7 +535,7 @@ static int do_one_pass(journal_t *journal,
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);
}