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Commit d0025676 authored by Duane Griffin's avatar Duane Griffin Committed by Linus Torvalds
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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: default avatarDuane Griffin <duaneg@dghda.com>
Acked-by: default avatarJan Kara <jack@suse.cz>
Cc: <linux-ext4@vger.kernel.org>
Cc: <stable@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus 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);

					}