Commit d0025676 authored Mar 19, 2008 by Duane Griffin Committed by Linus Torvalds Mar 19, 2008

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 <duaneg@dghda.com>
Acked-by: Jan Kara <jack@suse.cz>
Cc: <linux-ext4@vger.kernel.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 439aeec6

fs/jbd2/recovery.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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);
		}

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