From 001a88687aff26d62f8b61d55c6973618cf0f72f Mon Sep 17 00:00:00 2001
From: Lars Ellenberg <lars.ellenberg@linbit.com>
Date: Thu, 8 Mar 2012 16:43:45 +0100
Subject: [PATCH] drbd: fix potential data corruption and protocol error
We assumed only bios with bi_idx == 0 would end up
in drbd_make_request().
That is wrong.
At least device mapper, in __clone_and_map(), may submit
clones only covering a partial bio, but sharing
the original bvec, by adjusting bi_idx and relevant
other bio members of the clone.
We used __bio_for_each_segment() in various places,
even though that is documented as
* drivers should not use the __ version unless they _really_ want to
* run through the entire bio and not just pending pieces
Impact: we would send the full bio bvec, even for the clone
with bi_idx > 0, which will cause data corruption on the
peer (because we submit wrong data at the clone offset),
and will cause a DRBD protocol error, disconnect/reconnect
and resync (thus fixing the corruption),
because the next package header would be expected right
in the middle of the sent data, causing DRBD magic mismatch.
Fix: drop the assert, and use bio_for_each_segment()
instead of the __ version.
Conflicts:
drbd/drbd_tracing.c
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
drivers/block/drbd/drbd_main.c | 4 ++--
drivers/block/drbd/drbd_req.c | 1 -
drivers/block/drbd/drbd_worker.c | 2 +-
3 files changed, 3 insertions(+), 4 deletions(-)
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 8ca8925520ad..f6cfc45b862a 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2734,7 +2734,7 @@ static int _drbd_send_bio(struct drbd_conf *mdev, struct bio *bio)
struct bio_vec *bvec;
int i;
/* hint all but last page with MSG_MORE */
- __bio_for_each_segment(bvec, bio, i, 0) {
+ bio_for_each_segment(bvec, bio, i) {
if (!_drbd_no_send_page(mdev, bvec->bv_page,
bvec->bv_offset, bvec->bv_len,
i == bio->bi_vcnt -1 ? 0 : MSG_MORE))
@@ -2748,7 +2748,7 @@ static int _drbd_send_zc_bio(struct drbd_conf *mdev, struct bio *bio)
struct bio_vec *bvec;
int i;
/* hint all but last page with MSG_MORE */
- __bio_for_each_segment(bvec, bio, i, 0) {
+ bio_for_each_segment(bvec, bio, i) {
if (!_drbd_send_page(mdev, bvec->bv_page,
bvec->bv_offset, bvec->bv_len,
i == bio->bi_vcnt -1 ? 0 : MSG_MORE))
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 4fc7f98d9856..de319ba54241 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -1106,7 +1106,6 @@ void drbd_make_request(struct request_queue *q, struct bio *bio)
*/
D_ASSERT(bio->bi_size > 0);
D_ASSERT((bio->bi_size & 0x1ff) == 0);
- D_ASSERT(bio->bi_idx == 0);
/* to make some things easier, force alignment of requests within the
* granularity of our hash tables */
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 56fd69e38298..14aa4a2d4dc4 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -308,7 +308,7 @@ void drbd_csum_bio(struct drbd_conf *mdev, struct crypto_hash *tfm, struct bio *
sg_init_table(&sg, 1);
crypto_hash_init(&desc);
- __bio_for_each_segment(bvec, bio, i, 0) {
+ bio_for_each_segment(bvec, bio, i) {
sg_set_page(&sg, bvec->bv_page, bvec->bv_len, bvec->bv_offset);
crypto_hash_update(&desc, &sg, sg.length);
}
--
2.34.1