Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit d612d309 authored by Philipp Reisner's avatar Philipp Reisner
Browse files

drbd: No longer answer P_RS_DATA_REQUEST packets when in C_AHEAD mode 



When the sync source node replies to a P_RS_DATA_REQUEST packet
when it is already in ahead mode. I.e. those two packets
crossed each other on the wire, that may lead to diverging
bitmaps.

  This never happens in a well-tuned-system. In a well-tuned-
  system the resync controller has reduced the resync speed
  to zero long before we got into ahead-mode.

But we have to be prepared for the not-well-tuned-system
of course as well.
Because -> diverging bitmaps = non terminating resync.

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent 617049aa

drivers/block/drbd/drbd_int.h

+2 −1
Original line number Diff line number Diff line
@@ -205,8 +205,9 @@ enum drbd_packets { 
	/* P_CKPT_DISABLE_REQ    = 0x26, * currently reserved for protocol D */

	P_DELAY_PROBE         = 0x27, /* is used on BOTH sockets */

	P_OUT_OF_SYNC         = 0x28, /* Mark as out of sync (Outrunning), data socket */

	P_RS_CANCEL           = 0x29, /* meta: Used to cancel RS_DATA_REQUEST packet by SyncSource */



	P_MAX_CMD	      = 0x28,

	P_MAX_CMD	      = 0x2A,

	P_MAY_IGNORE	      = 0x100, /* Flag to test if (cmd > P_MAY_IGNORE) ... */

	P_MAX_OPT_CMD	      = 0x101,

drivers/block/drbd/drbd_receiver.c

+11 −1
Original line number Diff line number Diff line
@@ -4361,7 +4361,16 @@ static int got_NegRSDReply(struct drbd_conf *mdev, struct p_header80 *h) 


	if (get_ldev_if_state(mdev, D_FAILED)) {

		drbd_rs_complete_io(mdev, sector);

		switch (be16_to_cpu(h->command)) {

		case P_NEG_RS_DREPLY:

			drbd_rs_failed_io(mdev, sector, size);

		case P_RS_CANCEL:

			break;

		default:

			D_ASSERT(0);

			put_ldev(mdev);

			return false;

		}

		put_ldev(mdev);

	}
@@ -4459,6 +4468,7 @@ static struct asender_cmd *get_asender_cmd(int cmd) 
	[P_STATE_CHG_REPLY] = { sizeof(struct p_req_state_reply), got_RqSReply },

	[P_RS_IS_IN_SYNC]   = { sizeof(struct p_block_ack), got_IsInSync },

	[P_DELAY_PROBE]     = { sizeof(struct p_delay_probe93), got_skip },

	[P_RS_CANCEL]       = { sizeof(struct p_block_ack), got_NegRSDReply},

	[P_MAX_CMD]	    = { 0, NULL },

	};

	if (cmd > P_MAX_CMD || asender_tbl[cmd].process == NULL)

drivers/block/drbd/drbd_worker.c

+3 −1
Original line number Diff line number Diff line
@@ -988,7 +988,9 @@ int w_e_end_rsdata_req(struct drbd_conf *mdev, struct drbd_work *w, int cancel) 
		put_ldev(mdev);

	}



	if (likely((e->flags & EE_WAS_ERROR) == 0)) {

	if (mdev->state.conn == C_AHEAD) {

		ok = drbd_send_ack(mdev, P_RS_CANCEL, e);

	} else if (likely((e->flags & EE_WAS_ERROR) == 0)) {

		if (likely(mdev->state.pdsk >= D_INCONSISTENT)) {

			inc_rs_pending(mdev);

			ok = drbd_send_block(mdev, P_RS_DATA_REPLY, e);