[PATCH] highmem.c: fix bio error propagation

Found a subtle bug that caused mount errors on a SATA drive with
barriers on reiser and ext3, where it should have recovered and just
turned off barriers. The problem is that the EOPNOTSUPP error isn't
being propagated properly to the bounced bio. This patch fixes that by
correctly passing error all the way down.
Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

mm/highmem.c

@@ -305,14 +305,14 @@ static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
 	}
 }
 
-static void bounce_end_io(struct bio *bio, mempool_t *pool)
+static void bounce_end_io(struct bio *bio, mempool_t *pool, int err)
 {
 	struct bio *bio_orig = bio->bi_private;
 	struct bio_vec *bvec, *org_vec;
-	int i, err = 0;
+	int i;
 
-	if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
-		err = -EIO;
+	if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags))
+		set_bit(BIO_EOPNOTSUPP, &bio_orig->bi_flags);
 
 	/*
 	 * free up bounce indirect pages used
@@ -334,7 +334,7 @@ static int bounce_end_io_write(struct bio *bio, unsigned int bytes_done,int err)
 	if (bio->bi_size)
 		return 1;
 
-	bounce_end_io(bio, page_pool);
+	bounce_end_io(bio, page_pool, err);
 	return 0;
 }
 
@@ -343,18 +343,18 @@ static int bounce_end_io_write_isa(struct bio *bio, unsigned int bytes_done, int
 	if (bio->bi_size)
 		return 1;
 
-	bounce_end_io(bio, isa_page_pool);
+	bounce_end_io(bio, isa_page_pool, err);
 	return 0;
 }
 
-static void __bounce_end_io_read(struct bio *bio, mempool_t *pool)
+static void __bounce_end_io_read(struct bio *bio, mempool_t *pool, int err)
 {
 	struct bio *bio_orig = bio->bi_private;
 
 	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
 		copy_to_high_bio_irq(bio_orig, bio);
 
-	bounce_end_io(bio, pool);
+	bounce_end_io(bio, pool, err);
 }
 
 static int bounce_end_io_read(struct bio *bio, unsigned int bytes_done, int err)
@@ -362,7 +362,7 @@ static int bounce_end_io_read(struct bio *bio, unsigned int bytes_done, int err)
 	if (bio->bi_size)
 		return 1;
 
-	__bounce_end_io_read(bio, page_pool);
+	__bounce_end_io_read(bio, page_pool, err);
 	return 0;
 }
 
@@ -371,7 +371,7 @@ static int bounce_end_io_read_isa(struct bio *bio, unsigned int bytes_done, int
 	if (bio->bi_size)
 		return 1;
 
-	__bounce_end_io_read(bio, isa_page_pool);
+	__bounce_end_io_read(bio, isa_page_pool, err);
 	return 0;
 }