From 6809384c7152c34e74e29a4033826a300eb94f11 Mon Sep 17 00:00:00 2001 From: Philipp Reisner Date: Thu, 30 Jun 2011 15:43:06 +0200 Subject: [PATCH] drbd: Improve compatibility with drbd's older than 8.3.7 Regression introduced with 8.3.11 commit: drbd: Take a more conservative approach when deciding max_bio_size Never ever tell an older drbd, that we support more than 32KiB in a single data request (packet). Never believe an older drbd, that is supports more than 32KiB in a single data request (packet) Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg --- drivers/block/drbd/drbd_main.c | 4 ++++ drivers/block/drbd/drbd_nl.c | 7 ++++--- 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index 8e83a40..a15135b 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -2112,6 +2112,10 @@ int drbd_send_sizes(struct drbd_conf *mdev, int trigger_reply, enum dds_flags fl max_bio_size = DRBD_MAX_BIO_SIZE; /* ... multiple BIOs per peer_request */ } + /* Never allow old drbd (up to 8.3.7) to see more than 32KiB */ + if (mdev->agreed_pro_version <= 94) + max_bio_size = min_t(int, max_bio_size, DRBD_MAX_SIZE_H80_PACKET); + p.d_size = cpu_to_be64(d_size); p.u_size = cpu_to_be64(u_size); p.c_size = cpu_to_be64(trigger_reply ? 0 : drbd_get_capacity(mdev->this_bdev)); diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index f7b5f7e..cabad39 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -845,9 +845,10 @@ void drbd_reconsider_max_bio_size(struct drbd_conf *mdev) Because new from 8.3.8 onwards the peer can use multiple BIOs for a single peer_request */ if (mdev->state.conn >= C_CONNECTED) { - if (mdev->agreed_pro_version < 94) - peer = mdev->peer_max_bio_size; - else if (mdev->agreed_pro_version == 94) + if (mdev->agreed_pro_version < 94) { + peer = min_t(int, mdev->peer_max_bio_size, DRBD_MAX_SIZE_H80_PACKET); + /* Correct old drbd (up to 8.3.7) if it believes it can do more than 32KiB */ + } else if (mdev->agreed_pro_version == 94) peer = DRBD_MAX_SIZE_H80_PACKET; else /* drbd 8.3.8 onwards */ peer = DRBD_MAX_BIO_SIZE; -- 2.7.4