drbd: base completion and destruction of requests on ref counts
cherry-picked and adapted from drbd 9 devel branch
The logic for when to get or put a reference is in mod_rq_state().
To not get confused in the freeze/thaw respectively resend/restart
paths, or when cleaning up requests waiting for P_BARRIER_ACK, this
also introduces additional state flags:
RQ_COMPLETION_SUSP, and RQ_EXP_BARR_ACK.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index ae894af..329528d 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -85,7 +85,9 @@
INIT_LIST_HEAD(&req->tl_requests);
INIT_LIST_HEAD(&req->w.list);
+ /* one reference to be put by __drbd_make_request */
atomic_set(&req->completion_ref, 1);
+ /* one kref as long as completion_ref > 0 */
kref_init(&req->kref);
return req;
}
@@ -94,7 +96,16 @@
{
struct drbd_request *req = container_of(kref, struct drbd_request, kref);
struct drbd_conf *mdev = req->w.mdev;
- const unsigned long s = req->rq_state;
+ const unsigned s = req->rq_state;
+
+ if ((req->master_bio && !(s & RQ_POSTPONED)) ||
+ atomic_read(&req->completion_ref) ||
+ (s & RQ_LOCAL_PENDING) ||
+ ((s & RQ_NET_MASK) && !(s & RQ_NET_DONE))) {
+ dev_err(DEV, "drbd_req_destroy: Logic BUG rq_state = 0x%x, completion_ref = %d\n",
+ s, atomic_read(&req->completion_ref));
+ return;
+ }
/* remove it from the transfer log.
* well, only if it had been there in the first
@@ -180,44 +191,6 @@
wake_up(&mdev->misc_wait);
}
-static void maybe_wakeup_conflicting_requests(struct drbd_request *req)
-{
- const unsigned long s = req->rq_state;
- if (s & RQ_LOCAL_PENDING && !(s & RQ_LOCAL_ABORTED))
- return;
- if (req->i.waiting)
- /* Retry all conflicting peer requests. */
- wake_up(&req->w.mdev->misc_wait);
-}
-
-static
-void req_may_be_done(struct drbd_request *req)
-{
- const unsigned long s = req->rq_state;
-
- /* req->master_bio still present means: Not yet completed.
- *
- * Unless this is RQ_POSTPONED, which will cause drbd_req_destroy() to
- * queue it on the retry workqueue instead of destroying it.
- */
- if (req->master_bio && !(s & RQ_POSTPONED))
- return;
-
- /* Local still pending, even though master_bio is already completed?
- * may happen for RQ_LOCAL_ABORTED requests. */
- if (s & RQ_LOCAL_PENDING)
- return;
-
- if ((s & RQ_NET_MASK) == 0 || (s & RQ_NET_DONE)) {
- /* this is disconnected (local only) operation,
- * or protocol A, B, or C P_BARRIER_ACK,
- * or killed from the transfer log due to connection loss. */
- kref_put(&req->kref, drbd_req_destroy);
- }
- /* else: network part and not DONE yet. that is
- * protocol A, B, or C, barrier ack still pending... */
-}
-
/* Helper for __req_mod().
* Set m->bio to the master bio, if it is fit to be completed,
* or leave it alone (it is initialized to NULL in __req_mod),
@@ -225,10 +198,12 @@
* If m->bio is set, the error status to be returned is placed in m->error.
*/
static
-void req_may_be_completed(struct drbd_request *req, struct bio_and_error *m)
+void drbd_req_complete(struct drbd_request *req, struct bio_and_error *m)
{
- const unsigned long s = req->rq_state;
+ const unsigned s = req->rq_state;
struct drbd_conf *mdev = req->w.mdev;
+ int rw;
+ int error, ok;
/* we must not complete the master bio, while it is
* still being processed by _drbd_send_zc_bio (drbd_send_dblock)
@@ -239,116 +214,208 @@
* the receiver,
* the bio_endio completion callbacks.
*/
- if (s & RQ_LOCAL_PENDING && !(s & RQ_LOCAL_ABORTED))
+ if ((s & RQ_LOCAL_PENDING && !(s & RQ_LOCAL_ABORTED)) ||
+ (s & RQ_NET_QUEUED) || (s & RQ_NET_PENDING) ||
+ (s & RQ_COMPLETION_SUSP)) {
+ dev_err(DEV, "drbd_req_complete: Logic BUG rq_state = 0x%x\n", s);
return;
- if (s & RQ_NET_QUEUED)
- return;
- if (s & RQ_NET_PENDING)
- return;
-
- /* FIXME
- * instead of all the RQ_FLAGS, actually use the completion_ref
- * to decide if this is ready to be completed. */
- if (req->master_bio) {
- int complete = atomic_dec_and_test(&req->completion_ref);
- D_ASSERT(complete != 0);
- } else
- D_ASSERT(atomic_read(&req->completion_ref) == 0);
-
- if (req->master_bio) {
- int rw = bio_rw(req->master_bio);
-
- /* this is DATA_RECEIVED (remote read)
- * or protocol C P_WRITE_ACK
- * or protocol B P_RECV_ACK
- * or protocol A "HANDED_OVER_TO_NETWORK" (SendAck)
- * or canceled or failed,
- * or killed from the transfer log due to connection loss.
- */
-
- /*
- * figure out whether to report success or failure.
- *
- * report success when at least one of the operations succeeded.
- * or, to put the other way,
- * only report failure, when both operations failed.
- *
- * what to do about the failures is handled elsewhere.
- * what we need to do here is just: complete the master_bio.
- *
- * local completion error, if any, has been stored as ERR_PTR
- * in private_bio within drbd_request_endio.
- */
- int ok = (s & RQ_LOCAL_OK) || (s & RQ_NET_OK);
- int error = PTR_ERR(req->private_bio);
-
- /* remove the request from the conflict detection
- * respective block_id verification hash */
- if (!drbd_interval_empty(&req->i)) {
- struct rb_root *root;
-
- if (rw == WRITE)
- root = &mdev->write_requests;
- else
- root = &mdev->read_requests;
- drbd_remove_request_interval(root, req);
- } else if (!(s & RQ_POSTPONED))
- D_ASSERT((s & (RQ_NET_MASK & ~RQ_NET_DONE)) == 0);
-
- /* Before we can signal completion to the upper layers,
- * we may need to close the current transfer log epoch.
- * We are within the request lock, so we can simply compare
- * the request epoch number with the current transfer log
- * epoch number. If they match, increase the current_tle_nr,
- * and reset the transfer log epoch write_cnt.
- */
- if (rw == WRITE &&
- req->epoch == atomic_read(&mdev->tconn->current_tle_nr))
- start_new_tl_epoch(mdev->tconn);
-
- /* Update disk stats */
- _drbd_end_io_acct(mdev, req);
-
- /* If READ failed,
- * have it be pushed back to the retry work queue,
- * so it will re-enter __drbd_make_request(),
- * and be re-assigned to a suitable local or remote path,
- * or failed if we do not have access to good data anymore.
- *
- * Unless it was failed early by __drbd_make_request(),
- * because no path was available, in which case
- * it was not even added to the transfer_log.
- *
- * READA may fail, and will not be retried.
- *
- * WRITE should have used all available paths already.
- */
- if (!ok && rw == READ && !list_empty(&req->tl_requests))
- req->rq_state |= RQ_POSTPONED;
-
- if (!(req->rq_state & RQ_POSTPONED)) {
- m->error = ok ? 0 : (error ?: -EIO);
- m->bio = req->master_bio;
- req->master_bio = NULL;
- } else {
- /* Assert that this will be _req_is_done()
- * with this very invokation. */
- /* FIXME:
- * what about (RQ_LOCAL_PENDING | RQ_LOCAL_ABORTED)?
- */
- D_ASSERT(!(s & RQ_LOCAL_PENDING));
- D_ASSERT((s & RQ_NET_MASK) == 0 || (s & RQ_NET_DONE));
- }
}
- req_may_be_done(req);
+
+ if (!req->master_bio) {
+ dev_err(DEV, "drbd_req_complete: Logic BUG, master_bio == NULL!\n");
+ return;
+ }
+
+ rw = bio_rw(req->master_bio);
+
+ /*
+ * figure out whether to report success or failure.
+ *
+ * report success when at least one of the operations succeeded.
+ * or, to put the other way,
+ * only report failure, when both operations failed.
+ *
+ * what to do about the failures is handled elsewhere.
+ * what we need to do here is just: complete the master_bio.
+ *
+ * local completion error, if any, has been stored as ERR_PTR
+ * in private_bio within drbd_request_endio.
+ */
+ ok = (s & RQ_LOCAL_OK) || (s & RQ_NET_OK);
+ error = PTR_ERR(req->private_bio);
+
+ /* remove the request from the conflict detection
+ * respective block_id verification hash */
+ if (!drbd_interval_empty(&req->i)) {
+ struct rb_root *root;
+
+ if (rw == WRITE)
+ root = &mdev->write_requests;
+ else
+ root = &mdev->read_requests;
+ drbd_remove_request_interval(root, req);
+ } else if (!(s & RQ_POSTPONED))
+ D_ASSERT((s & (RQ_NET_MASK & ~RQ_NET_DONE)) == 0);
+
+ /* Before we can signal completion to the upper layers,
+ * we may need to close the current transfer log epoch.
+ * We are within the request lock, so we can simply compare
+ * the request epoch number with the current transfer log
+ * epoch number. If they match, increase the current_tle_nr,
+ * and reset the transfer log epoch write_cnt.
+ */
+ if (rw == WRITE &&
+ req->epoch == atomic_read(&mdev->tconn->current_tle_nr))
+ start_new_tl_epoch(mdev->tconn);
+
+ /* Update disk stats */
+ _drbd_end_io_acct(mdev, req);
+
+ /* If READ failed,
+ * have it be pushed back to the retry work queue,
+ * so it will re-enter __drbd_make_request(),
+ * and be re-assigned to a suitable local or remote path,
+ * or failed if we do not have access to good data anymore.
+ *
+ * Unless it was failed early by __drbd_make_request(),
+ * because no path was available, in which case
+ * it was not even added to the transfer_log.
+ *
+ * READA may fail, and will not be retried.
+ *
+ * WRITE should have used all available paths already.
+ */
+ if (!ok && rw == READ && !list_empty(&req->tl_requests))
+ req->rq_state |= RQ_POSTPONED;
+
+ if (!(req->rq_state & RQ_POSTPONED)) {
+ m->error = ok ? 0 : (error ?: -EIO);
+ m->bio = req->master_bio;
+ req->master_bio = NULL;
+ } else {
+ /* Assert that this will be drbd_req_destroy()ed
+ * with this very invokation. */
+ D_ASSERT(atomic_read(&req->kref.refcount) == 1);
+ }
}
-static void req_may_be_completed_not_susp(struct drbd_request *req, struct bio_and_error *m)
+static int drbd_req_put_completion_ref(struct drbd_request *req, struct bio_and_error *m, int put)
{
struct drbd_conf *mdev = req->w.mdev;
+ D_ASSERT(m || (req->rq_state & RQ_POSTPONED));
- if (!drbd_suspended(mdev))
- req_may_be_completed(req, m);
+ if (!atomic_sub_and_test(put, &req->completion_ref))
+ return 0;
+
+ if (drbd_suspended(mdev)) {
+ /* We do not allow completion while suspended. Re-get a
+ * reference, so whatever happens when this is resumed
+ * may put and complete. */
+
+ D_ASSERT(!(req->rq_state & RQ_COMPLETION_SUSP));
+ req->rq_state |= RQ_COMPLETION_SUSP;
+ atomic_inc(&req->completion_ref);
+ return 0;
+ }
+
+ /* else */
+ drbd_req_complete(req, m);
+ return 1;
+}
+
+/* I'd like this to be the only place that manipulates
+ * req->completion_ref and req->kref. */
+static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m,
+ int clear, int set)
+{
+ struct drbd_conf *mdev = req->w.mdev;
+ unsigned s = req->rq_state;
+ int c_put = 0;
+ int k_put = 0;
+
+ /* apply */
+
+ req->rq_state &= ~clear;
+ req->rq_state |= set;
+
+ /* no change? */
+ if (req->rq_state == s)
+ return;
+
+ /* intent: get references */
+
+ if (!(s & RQ_LOCAL_PENDING) && (set & RQ_LOCAL_PENDING))
+ atomic_inc(&req->completion_ref);
+
+ if (!(s & RQ_NET_PENDING) && (set & RQ_NET_PENDING)) {
+ inc_ap_pending(mdev);
+ atomic_inc(&req->completion_ref);
+ }
+
+ if (!(s & RQ_NET_QUEUED) && (set & RQ_NET_QUEUED))
+ atomic_inc(&req->completion_ref);
+
+ if (!(s & RQ_EXP_BARR_ACK) && (set & RQ_EXP_BARR_ACK))
+ kref_get(&req->kref); /* wait for the DONE */
+
+ if (!(s & RQ_NET_SENT) && (set & RQ_NET_SENT))
+ atomic_add(req->i.size >> 9, &mdev->ap_in_flight);
+
+ /* progress: put references */
+
+ if ((s & RQ_COMPLETION_SUSP) && (clear & RQ_COMPLETION_SUSP))
+ ++c_put;
+
+ if (!(s & RQ_LOCAL_ABORTED) && (set & RQ_LOCAL_ABORTED)) {
+ D_ASSERT(req->rq_state & RQ_LOCAL_PENDING);
+ /* local completion may still come in later,
+ * we need to keep the req object around. */
+ kref_get(&req->kref);
+ ++c_put;
+ }
+
+ if ((s & RQ_LOCAL_PENDING) && (clear & RQ_LOCAL_PENDING)) {
+ if (req->rq_state & RQ_LOCAL_ABORTED)
+ ++k_put;
+ else
+ ++c_put;
+ }
+
+ if ((s & RQ_NET_PENDING) && (clear & RQ_NET_PENDING)) {
+ dec_ap_pending(mdev);
+ ++c_put;
+ }
+
+ if ((s & RQ_NET_QUEUED) && (clear & RQ_NET_QUEUED))
+ ++c_put;
+
+ if ((s & RQ_EXP_BARR_ACK) && !(s & RQ_NET_DONE) && (set & RQ_NET_DONE)) {
+ if (req->rq_state & RQ_NET_SENT)
+ atomic_sub(req->i.size >> 9, &mdev->ap_in_flight);
+ ++k_put;
+ }
+
+ /* potentially complete and destroy */
+
+ if (k_put || c_put) {
+ /* Completion does it's own kref_put. If we are going to
+ * kref_sub below, we need req to be still around then. */
+ int at_least = k_put + !!c_put;
+ int refcount = atomic_read(&req->kref.refcount);
+ if (refcount < at_least)
+ dev_err(DEV,
+ "mod_rq_state: Logic BUG: %x -> %x: refcount = %d, should be >= %d\n",
+ s, req->rq_state, refcount, at_least);
+ }
+
+ /* If we made progress, retry conflicting peer requests, if any. */
+ if (req->i.waiting)
+ wake_up(&mdev->misc_wait);
+
+ if (c_put)
+ k_put += drbd_req_put_completion_ref(req, m, c_put);
+ if (k_put)
+ kref_sub(&req->kref, k_put, drbd_req_destroy);
}
/* obviously this could be coded as many single functions
@@ -388,7 +455,6 @@
/* reached via __drbd_make_request
* and from w_read_retry_remote */
D_ASSERT(!(req->rq_state & RQ_NET_MASK));
- req->rq_state |= RQ_NET_PENDING;
rcu_read_lock();
nc = rcu_dereference(mdev->tconn->net_conf);
p = nc->wire_protocol;
@@ -396,13 +462,13 @@
req->rq_state |=
p == DRBD_PROT_C ? RQ_EXP_WRITE_ACK :
p == DRBD_PROT_B ? RQ_EXP_RECEIVE_ACK : 0;
- inc_ap_pending(mdev);
+ mod_rq_state(req, m, 0, RQ_NET_PENDING);
break;
case TO_BE_SUBMITTED: /* locally */
/* reached via __drbd_make_request */
D_ASSERT(!(req->rq_state & RQ_LOCAL_MASK));
- req->rq_state |= RQ_LOCAL_PENDING;
+ mod_rq_state(req, m, 0, RQ_LOCAL_PENDING);
break;
case COMPLETED_OK:
@@ -411,44 +477,23 @@
else
mdev->read_cnt += req->i.size >> 9;
- req->rq_state |= (RQ_LOCAL_COMPLETED|RQ_LOCAL_OK);
- req->rq_state &= ~RQ_LOCAL_PENDING;
-
- maybe_wakeup_conflicting_requests(req);
- req_may_be_completed_not_susp(req, m);
+ mod_rq_state(req, m, RQ_LOCAL_PENDING,
+ RQ_LOCAL_COMPLETED|RQ_LOCAL_OK);
break;
case ABORT_DISK_IO:
- req->rq_state |= RQ_LOCAL_ABORTED;
- req_may_be_completed_not_susp(req, m);
- break;
-
- case WRITE_COMPLETED_WITH_ERROR:
- req->rq_state |= RQ_LOCAL_COMPLETED;
- req->rq_state &= ~RQ_LOCAL_PENDING;
-
- __drbd_chk_io_error(mdev, false);
- maybe_wakeup_conflicting_requests(req);
- req_may_be_completed_not_susp(req, m);
- break;
-
- case READ_AHEAD_COMPLETED_WITH_ERROR:
- /* it is legal to fail READA */
- req->rq_state |= RQ_LOCAL_COMPLETED;
- req->rq_state &= ~RQ_LOCAL_PENDING;
- req_may_be_completed_not_susp(req, m);
+ mod_rq_state(req, m, 0, RQ_LOCAL_ABORTED);
break;
case READ_COMPLETED_WITH_ERROR:
drbd_set_out_of_sync(mdev, req->i.sector, req->i.size);
-
- req->rq_state |= RQ_LOCAL_COMPLETED;
- req->rq_state &= ~RQ_LOCAL_PENDING;
-
- D_ASSERT(!(req->rq_state & RQ_NET_MASK));
-
+ /* fall through. */
+ case WRITE_COMPLETED_WITH_ERROR:
__drbd_chk_io_error(mdev, false);
- req_may_be_completed_not_susp(req, m);
+ /* fall through. */
+ case READ_AHEAD_COMPLETED_WITH_ERROR:
+ /* it is legal to fail READA, no __drbd_chk_io_error in that case. */
+ mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED);
break;
case QUEUE_FOR_NET_READ:
@@ -461,7 +506,7 @@
/* So we can verify the handle in the answer packet.
* Corresponding drbd_remove_request_interval is in
- * req_may_be_completed() */
+ * drbd_req_complete() */
D_ASSERT(drbd_interval_empty(&req->i));
drbd_insert_interval(&mdev->read_requests, &req->i);
@@ -469,7 +514,7 @@
D_ASSERT(req->rq_state & RQ_NET_PENDING);
D_ASSERT((req->rq_state & RQ_LOCAL_MASK) == 0);
- req->rq_state |= RQ_NET_QUEUED;
+ mod_rq_state(req, m, 0, RQ_NET_QUEUED);
req->w.cb = w_send_read_req;
drbd_queue_work(&mdev->tconn->sender_work, &req->w);
break;
@@ -479,7 +524,7 @@
/* from __drbd_make_request only */
/* Corresponding drbd_remove_request_interval is in
- * req_may_be_completed() */
+ * drbd_req_complete() */
D_ASSERT(drbd_interval_empty(&req->i));
drbd_insert_interval(&mdev->write_requests, &req->i);
@@ -504,7 +549,7 @@
/* queue work item to send data */
D_ASSERT(req->rq_state & RQ_NET_PENDING);
- req->rq_state |= RQ_NET_QUEUED;
+ mod_rq_state(req, m, 0, RQ_NET_QUEUED|RQ_EXP_BARR_ACK);
req->w.cb = w_send_dblock;
drbd_queue_work(&mdev->tconn->sender_work, &req->w);
@@ -519,7 +564,7 @@
break;
case QUEUE_FOR_SEND_OOS:
- req->rq_state |= RQ_NET_QUEUED;
+ mod_rq_state(req, m, 0, RQ_NET_QUEUED);
req->w.cb = w_send_out_of_sync;
drbd_queue_work(&mdev->tconn->sender_work, &req->w);
break;
@@ -529,64 +574,43 @@
case SEND_FAILED:
/* real cleanup will be done from tl_clear. just update flags
* so it is no longer marked as on the worker queue */
- req->rq_state &= ~RQ_NET_QUEUED;
- /* if we did it right, tl_clear should be scheduled only after
- * this, so this should not be necessary! */
- req_may_be_completed_not_susp(req, m);
+ mod_rq_state(req, m, RQ_NET_QUEUED, 0);
break;
case HANDED_OVER_TO_NETWORK:
/* assert something? */
- if (bio_data_dir(req->master_bio) == WRITE)
- atomic_add(req->i.size >> 9, &mdev->ap_in_flight);
-
if (bio_data_dir(req->master_bio) == WRITE &&
!(req->rq_state & (RQ_EXP_RECEIVE_ACK | RQ_EXP_WRITE_ACK))) {
/* this is what is dangerous about protocol A:
* pretend it was successfully written on the peer. */
- if (req->rq_state & RQ_NET_PENDING) {
- dec_ap_pending(mdev);
- req->rq_state &= ~RQ_NET_PENDING;
- req->rq_state |= RQ_NET_OK;
- } /* else: neg-ack was faster... */
+ if (req->rq_state & RQ_NET_PENDING)
+ mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK);
+ /* else: neg-ack was faster... */
/* it is still not yet RQ_NET_DONE until the
* corresponding epoch barrier got acked as well,
* so we know what to dirty on connection loss */
}
- req->rq_state &= ~RQ_NET_QUEUED;
- req->rq_state |= RQ_NET_SENT;
- req_may_be_completed_not_susp(req, m);
+ mod_rq_state(req, m, RQ_NET_QUEUED, RQ_NET_SENT);
break;
case OOS_HANDED_TO_NETWORK:
/* Was not set PENDING, no longer QUEUED, so is now DONE
* as far as this connection is concerned. */
- req->rq_state &= ~RQ_NET_QUEUED;
- req->rq_state |= RQ_NET_DONE;
- req_may_be_completed_not_susp(req, m);
+ mod_rq_state(req, m, RQ_NET_QUEUED, RQ_NET_DONE);
break;
case CONNECTION_LOST_WHILE_PENDING:
/* transfer log cleanup after connection loss */
- /* assert something? */
- if (req->rq_state & RQ_NET_PENDING)
- dec_ap_pending(mdev);
-
- p = !(req->rq_state & RQ_WRITE) && req->rq_state & RQ_NET_PENDING;
-
- req->rq_state &= ~(RQ_NET_OK|RQ_NET_PENDING);
- req->rq_state |= RQ_NET_DONE;
- if (req->rq_state & RQ_NET_SENT && req->rq_state & RQ_WRITE)
- atomic_sub(req->i.size >> 9, &mdev->ap_in_flight);
-
- req_may_be_completed(req, m); /* Allowed while state.susp */
+ mod_rq_state(req, m,
+ RQ_NET_OK|RQ_NET_PENDING|RQ_COMPLETION_SUSP,
+ RQ_NET_DONE);
break;
case DISCARD_WRITE:
/* for discarded conflicting writes of multiple primaries,
* there is no need to keep anything in the tl, potential
* node crashes are covered by the activity log. */
- req->rq_state |= RQ_NET_DONE;
+ mod_rq_state(req, NULL, 0, RQ_NET_DONE);
/* fall through */
case WRITE_ACKED_BY_PEER_AND_SIS:
case WRITE_ACKED_BY_PEER:
@@ -605,13 +629,8 @@
* see also notes above in HANDED_OVER_TO_NETWORK about
* protocol != C */
ack_common:
- req->rq_state |= RQ_NET_OK;
D_ASSERT(req->rq_state & RQ_NET_PENDING);
- dec_ap_pending(mdev);
- atomic_sub(req->i.size >> 9, &mdev->ap_in_flight);
- req->rq_state &= ~RQ_NET_PENDING;
- maybe_wakeup_conflicting_requests(req);
- req_may_be_completed_not_susp(req, m);
+ mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK);
break;
case POSTPONE_WRITE:
@@ -622,64 +641,61 @@
*/
D_ASSERT(req->rq_state & RQ_NET_PENDING);
req->rq_state |= RQ_POSTPONED;
- maybe_wakeup_conflicting_requests(req);
- req_may_be_completed_not_susp(req, m);
+ if (req->i.waiting)
+ wake_up(&mdev->misc_wait);
+ /* Do not clear RQ_NET_PENDING. This request will make further
+ * progress via restart_conflicting_writes() or
+ * fail_postponed_requests(). Hopefully. */
break;
case NEG_ACKED:
- /* assert something? */
- if (req->rq_state & RQ_NET_PENDING) {
- dec_ap_pending(mdev);
- if (req->rq_state & RQ_WRITE)
- atomic_sub(req->i.size >> 9, &mdev->ap_in_flight);
- }
- req->rq_state &= ~(RQ_NET_OK|RQ_NET_PENDING);
-
- req->rq_state |= RQ_NET_DONE;
-
- maybe_wakeup_conflicting_requests(req);
- req_may_be_completed_not_susp(req, m);
- /* else: done by HANDED_OVER_TO_NETWORK */
+ mod_rq_state(req, m, RQ_NET_OK|RQ_NET_PENDING, RQ_NET_DONE);
break;
case FAIL_FROZEN_DISK_IO:
if (!(req->rq_state & RQ_LOCAL_COMPLETED))
break;
-
- req_may_be_completed(req, m); /* Allowed while state.susp */
+ mod_rq_state(req, m, RQ_COMPLETION_SUSP, 0);
break;
case RESTART_FROZEN_DISK_IO:
if (!(req->rq_state & RQ_LOCAL_COMPLETED))
break;
- req->rq_state &= ~RQ_LOCAL_COMPLETED;
+ mod_rq_state(req, m,
+ RQ_COMPLETION_SUSP|RQ_LOCAL_COMPLETED,
+ RQ_LOCAL_PENDING);
rv = MR_READ;
if (bio_data_dir(req->master_bio) == WRITE)
rv = MR_WRITE;
- get_ldev(mdev);
+ get_ldev(mdev); /* always succeeds in this call path */
req->w.cb = w_restart_disk_io;
drbd_queue_work(&mdev->tconn->sender_work, &req->w);
break;
case RESEND:
/* If RQ_NET_OK is already set, we got a P_WRITE_ACK or P_RECV_ACK
- before the connection loss (B&C only); only P_BARRIER_ACK was missing.
+ before the connection loss (B&C only); only P_BARRIER_ACK
+ (or the local completion?) was missing when we suspended.
Throwing them out of the TL here by pretending we got a BARRIER_ACK.
During connection handshake, we ensure that the peer was not rebooted. */
if (!(req->rq_state & RQ_NET_OK)) {
+ /* FIXME could this possibly be a req->w.cb == w_send_out_of_sync?
+ * in that case we must not set RQ_NET_PENDING. */
+
+ mod_rq_state(req, m, RQ_COMPLETION_SUSP, RQ_NET_QUEUED|RQ_NET_PENDING);
if (req->w.cb) {
- /* w.cb expected to be w_send_dblock, or w_send_read_req */
drbd_queue_work(&mdev->tconn->sender_work, &req->w);
rv = req->rq_state & RQ_WRITE ? MR_WRITE : MR_READ;
- }
+ } /* else: FIXME can this happen? */
break;
}
/* else, fall through to BARRIER_ACKED */
case BARRIER_ACKED:
+ /* barrier ack for READ requests does not make sense */
if (!(req->rq_state & RQ_WRITE))
break;
@@ -689,20 +705,17 @@
* we won't be able to clean them up... */
dev_err(DEV, "FIXME (BARRIER_ACKED but pending)\n");
}
- if ((req->rq_state & RQ_NET_MASK) != 0) {
- req->rq_state |= RQ_NET_DONE;
- if (!(req->rq_state & (RQ_EXP_RECEIVE_ACK | RQ_EXP_WRITE_ACK)))
- atomic_sub(req->i.size>>9, &mdev->ap_in_flight);
- }
- req_may_be_done(req); /* Allowed while state.susp */
+ /* Allowed to complete requests, even while suspended.
+ * As this is called for all requests within a matching epoch,
+ * we need to filter, and only set RQ_NET_DONE for those that
+ * have actually been on the wire. */
+ mod_rq_state(req, m, RQ_COMPLETION_SUSP,
+ (req->rq_state & RQ_NET_MASK) ? RQ_NET_DONE : 0);
break;
case DATA_RECEIVED:
D_ASSERT(req->rq_state & RQ_NET_PENDING);
- dec_ap_pending(mdev);
- req->rq_state &= ~RQ_NET_PENDING;
- req->rq_state |= (RQ_NET_OK|RQ_NET_DONE);
- req_may_be_completed_not_susp(req, m);
+ mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK|RQ_NET_DONE);
break;
};
@@ -867,6 +880,9 @@
if (mdev->state.pdsk != D_UP_TO_DATE)
return false;
+ if (req->private_bio == NULL)
+ return true;
+
/* TODO: improve read balancing decisions, take into account drbd
* protocol, pending requests etc. */
@@ -877,9 +893,6 @@
if (rbm == RB_PREFER_LOCAL && req->private_bio)
return false; /* submit locally */
- if (req->private_bio == NULL)
- return true;
-
if (remote_due_to_read_balancing(mdev, req->i.sector, rbm)) {
if (req->private_bio) {
bio_put(req->private_bio);
@@ -1010,7 +1023,7 @@
/* We fail READ/READA early, if we can not serve it.
* We must do this before req is registered on any lists.
- * Otherwise, req_may_be_completed() will queue failed READ for retry. */
+ * Otherwise, drbd_req_complete() will queue failed READ for retry. */
if (rw != WRITE) {
if (!do_remote_read(req) && !req->private_bio)
goto nodata;
@@ -1042,19 +1055,18 @@
/* but we need to give up the spinlock to submit */
spin_unlock_irq(&mdev->tconn->req_lock);
drbd_submit_req_private_bio(req);
- /* once we have submitted, we must no longer look at req,
- * it may already be destroyed. */
- return;
+ spin_lock_irq(&mdev->tconn->req_lock);
} else if (no_remote) {
nodata:
if (__ratelimit(&drbd_ratelimit_state))
dev_err(DEV, "IO ERROR: neither local nor remote disk\n");
/* A write may have been queued for send_oos, however.
- * So we can not simply free it, we must go through req_may_be_completed() */
+ * So we can not simply free it, we must go through drbd_req_put_completion_ref() */
}
out:
- req_may_be_completed(req, &m);
+ if (drbd_req_put_completion_ref(req, &m, 1))
+ kref_put(&req->kref, drbd_req_destroy);
spin_unlock_irq(&mdev->tconn->req_lock);
if (m.bio)