[stable][PATCH < 2.6.19] Fix data corruption with dm-crypt over RAID5

[Christophe Saout <christophe@saout.de>]

Fix corruption issue with dm-crypt on top of software raid5. Cancelled
readahead bio's that report no error, just have BIO_UPTODATE cleared
were reported as successful reads to the higher layers (and leaving
random content in the buffer cache). Already fixed in 2.6.19.

Signed-off-by: Christophe Saout <christophe@saout.de>


--- linux-2.6.18.orig/drivers/md/dm-crypt.c	2006-09-20 05:42:06.000000000 +0200
+++ linux-2.6.18/drivers/md/dm-crypt.c	2006-12-02 03:03:36.000000000 +0100
@@ -717,13 +717,15 @@
 	if (bio->bi_size)
 		return 1;
 
+	if (!bio_flagged(bio, BIO_UPTODATE) && !error)
+		error = -EIO;
+                        
 	bio_put(bio);
 
 	/*
 	 * successful reads are decrypted by the worker thread
 	 */
-	if ((bio_data_dir(bio) == READ)
-	    && bio_flagged(bio, BIO_UPTODATE)) {
+	if (bio_data_dir(io->bio) == READ && !error) {
 		kcryptd_queue_io(io);
 		return 0;
 	}