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jbd2: correctly unescape journal data blocks

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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>
This commit is contained in:
Duane Griffin 2008-03-19 17:00:54 -07:00 committed by Linus Torvalds
parent 439aeec639
commit d00256766a
1 changed files with 1 additions and 1 deletions
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2
fs/jbd2/recovery.c
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@ -535,7 +535,7 @@ static int do_one_pass(journal_t *journal,
memcpy(nbh->b_data, obh->b_data, memcpy(nbh->b_data, obh->b_data,
journal->j_blocksize); journal->j_blocksize);
if (flags & JBD2_FLAG_ESCAPE) { if (flags & JBD2_FLAG_ESCAPE) {
*((__be32 *)bh->b_data) = *((__be32 *)nbh->b_data) =
cpu_to_be32(JBD2_MAGIC_NUMBER); cpu_to_be32(JBD2_MAGIC_NUMBER);
} }