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Commit 3719094e authored by Philipp Reisner's avatar Philipp Reisner
Browse files

drbd: Starting with protocol 96 we can allow app-IO while receiving the bitmap 



* C_STARTING_SYNC_S, C_STARTING_SYNC_T In these states the bitmap gets
  written to disk. Locking out of app-IO is done by using the
  drbd_queue_bitmap_io() and drbd_bitmap_io() functions these days.
  It is no longer necessary to lock out app-IO based on the connection
  state.
  App-IO that may come in after the BITMAP_IO flag got cleared before the
  state transition to C_SYNC_(SOURCE|TARGET) does not get mirrored, sets
  a bit in the local bitmap, that is already set, therefore changes nothing.

* C_WF_BITMAP_S In this state we send updates (P_OUT_OF_SYNC packets).
  With that we make sure they have the same number of bits when going
  into the C_SYNC_(SOURCE|TARGET) connection state.

* C_UNCONNECTED: The receiver starts, no need to lock out IO.

* C_DISCONNECTING: in drbd_disconnect() we had a wait_event()
  to wait until ap_bio_cnt reaches 0. Removed that.

* C_TIMEOUT, C_BROKEN_PIPE, C_NETWORK_FAILURE
  C_PROTOCOL_ERROR, C_TEAR_DOWN: Same as C_DISCONNECTING

* C_WF_REPORT_PARAMS: IO still possible since that is still
  like C_WF_CONNECTION.

And we do not need to send barriers in C_WF_BITMAP_S connection state.

Allow concurrent accesses to the bitmap when receiving the bitmap.
Everything gets ORed anyways.

A drbd_free_tl_hash() is in after_state_chg_work(). At that point
all the work items of the last connections must have been processed.

Introduced a call to drbd_free_tl_hash() into drbd_free_mdev()
for paranoia reasons.

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent ab17b68f

drivers/block/drbd/drbd_int.h

+12 −7
Original line number Diff line number Diff line
@@ -2213,8 +2213,9 @@ static inline int drbd_get_max_buffers(struct drbd_conf *mdev) 
	return mxb;

}



static inline int drbd_state_is_stable(union drbd_state s)

static inline int drbd_state_is_stable(struct drbd_conf *mdev)

{

	union drbd_state s = mdev->state;



	/* DO NOT add a default clause, we want the compiler to warn us

	 * for any newly introduced state we may have forgotten to add here */
@@ -2233,11 +2234,7 @@ static inline int drbd_state_is_stable(union drbd_state s) 
	case C_PAUSED_SYNC_T:

	case C_AHEAD:

	case C_BEHIND:

		/* maybe stable, look at the disk state */

		break;



	/* no new io accepted during tansitional states

	 * like handshake or teardown */

		/* transitional states, IO allowed */

	case C_DISCONNECTING:

	case C_UNCONNECTED:

	case C_TIMEOUT:
@@ -2248,7 +2245,15 @@ static inline int drbd_state_is_stable(union drbd_state s) 
	case C_WF_REPORT_PARAMS:

	case C_STARTING_SYNC_S:

	case C_STARTING_SYNC_T:

		break;



		/* Allow IO in BM exchange states with new protocols */

	case C_WF_BITMAP_S:

		if (mdev->agreed_pro_version < 96)

			return 0;

		break;



		/* no new io accepted in these states */

	case C_WF_BITMAP_T:

	case C_WF_SYNC_UUID:

	case C_MASK:
@@ -2297,7 +2302,7 @@ static inline int __inc_ap_bio_cond(struct drbd_conf *mdev) 
	 * to start during "stable" states. */



	/* no new io accepted when attaching or detaching the disk */

	if (!drbd_state_is_stable(mdev->state))

	if (!drbd_state_is_stable(mdev))

		return 0;



	/* since some older kernels don't have atomic_add_unless,

drivers/block/drbd/drbd_main.c

+1 −0
Original line number Diff line number Diff line
@@ -3334,6 +3334,7 @@ void drbd_free_mdev(struct drbd_conf *mdev) 
	put_disk(mdev->vdisk);

	blk_cleanup_queue(mdev->rq_queue);

	free_cpumask_var(mdev->cpu_mask);

	drbd_free_tl_hash(mdev);

	kfree(mdev);

}

drivers/block/drbd/drbd_receiver.c

+2 −11
Original line number Diff line number Diff line
@@ -3468,9 +3468,7 @@ static int receive_bitmap(struct drbd_conf *mdev, enum drbd_packets cmd, unsigne 
	int ok = FALSE;

	struct p_header80 *h = &mdev->data.rbuf.header.h80;



	wait_event(mdev->misc_wait, !atomic_read(&mdev->ap_bio_cnt));



	drbd_bm_lock(mdev, "receive bitmap");

	/* drbd_bm_lock(mdev, "receive bitmap"); By intention no bm_lock */



	/* maybe we should use some per thread scratch page,

	 * and allocate that during initial device creation? */
@@ -3542,7 +3540,7 @@ static int receive_bitmap(struct drbd_conf *mdev, enum drbd_packets cmd, unsigne 


	ok = TRUE;

 out:

	drbd_bm_unlock(mdev);

	/* drbd_bm_unlock(mdev); by intention no lock */

	if (ok && mdev->state.conn == C_WF_BITMAP_S)

		drbd_start_resync(mdev, C_SYNC_SOURCE);

	free_page((unsigned long) buffer);
@@ -3804,13 +3802,6 @@ static void drbd_disconnect(struct drbd_conf *mdev) 
	if (os.conn == C_DISCONNECTING) {

		wait_event(mdev->net_cnt_wait, atomic_read(&mdev->net_cnt) == 0);



		if (!is_susp(mdev->state)) {

			/* we must not free the tl_hash

			 * while application io is still on the fly */

			wait_event(mdev->misc_wait, !atomic_read(&mdev->ap_bio_cnt));

			drbd_free_tl_hash(mdev);

		}



		crypto_free_hash(mdev->cram_hmac_tfm);

		mdev->cram_hmac_tfm = NULL;

drivers/block/drbd/drbd_req.c

+24 −13
Original line number Diff line number Diff line
@@ -142,7 +142,7 @@ static void _about_to_complete_local_write(struct drbd_conf *mdev, 


	/* before we can signal completion to the upper layers,

	 * we may need to close the current epoch */

	if (mdev->state.conn >= C_CONNECTED && mdev->state.conn < C_AHEAD &&

	if (mdev->state.conn >= C_WF_BITMAP_T && mdev->state.conn < C_AHEAD &&

	    req->epoch == mdev->newest_tle->br_number)

		queue_barrier(mdev);
@@ -757,6 +757,23 @@ static int drbd_may_do_local_read(struct drbd_conf *mdev, sector_t sector, int s 
	return 0 == drbd_bm_count_bits(mdev, sbnr, ebnr);

}



static int drbd_should_do_remote(struct drbd_conf *mdev)

{

	union drbd_state s = mdev->state;



	return s.pdsk == D_UP_TO_DATE ||

		(s.pdsk >= D_INCONSISTENT &&

		 s.conn >= C_WF_BITMAP_T &&

		 s.conn < C_AHEAD);

}

static int drbd_should_send_oos(struct drbd_conf *mdev)

{

	union drbd_state s = mdev->state;



	return s.pdsk >= D_INCONSISTENT &&

		(s.conn == C_AHEAD || s.conn == C_WF_BITMAP_S);

}



static int drbd_make_request_common(struct drbd_conf *mdev, struct bio *bio, unsigned long start_time)

{

	const int rw = bio_rw(bio);
@@ -828,12 +845,9 @@ static int drbd_make_request_common(struct drbd_conf *mdev, struct bio *bio, uns 
		drbd_al_begin_io(mdev, sector);

	}



	remote = remote && (mdev->state.pdsk == D_UP_TO_DATE ||

			    (mdev->state.pdsk >= D_INCONSISTENT &&

			     mdev->state.conn >= C_CONNECTED &&

			     mdev->state.conn < C_AHEAD));

	send_oos = (rw == WRITE && mdev->state.conn == C_AHEAD &&

		    mdev->state.pdsk >= D_INCONSISTENT);

	remote = remote && drbd_should_do_remote(mdev);

	send_oos = rw == WRITE && drbd_should_send_oos(mdev);

	D_ASSERT(!(remote && send_oos));



	if (!(local || remote) && !is_susp(mdev->state)) {

		if (__ratelimit(&drbd_ratelimit_state))
@@ -873,12 +887,9 @@ static int drbd_make_request_common(struct drbd_conf *mdev, struct bio *bio, uns 
	}



	if (remote || send_oos) {

		remote = (mdev->state.pdsk == D_UP_TO_DATE ||

			    (mdev->state.pdsk >= D_INCONSISTENT &&

			     mdev->state.conn >= C_CONNECTED &&

			     mdev->state.conn < C_AHEAD));

		send_oos = (rw == WRITE && mdev->state.conn == C_AHEAD &&

			    mdev->state.pdsk >= D_INCONSISTENT);

		remote = drbd_should_do_remote(mdev);

		send_oos = rw == WRITE && drbd_should_send_oos(mdev);

		D_ASSERT(!(remote && send_oos));



		if (!(remote || send_oos))

			dev_warn(DEV, "lost connection while grabbing the req_lock!\n");