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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>
This commit is contained in:
Lars Ellenberg 2012-01-24 17:19:42 +01:00 коммит произвёл Philipp Reisner
Родитель b406777e64
Коммит a0d856dfae
4 изменённых файлов: 284 добавлений и 262 удалений
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3
drivers/block/drbd/drbd_int.h
Просмотреть файл

@ -575,13 +575,14 @@ struct drbd_request {
struct list_head tl_requests; /* ring list in the transfer log */
struct bio *master_bio; /* master bio pointer */
unsigned long rq_state; /* see comments above _req_mod() */
unsigned long start_time;
/* once it hits 0, we may complete the master_bio */
atomic_t completion_ref;
/* once it hits 0, we may destroy this drbd_request object */
struct kref kref;
unsigned rq_state; /* see comments above _req_mod() */
};
struct drbd_epoch {

2
drivers/block/drbd/drbd_main.c
Просмотреть файл

@ -210,7 +210,7 @@ void tl_release(struct drbd_tconn *tconn, unsigned int barrier_nr,
/* find latest not yet barrier-acked write request,
* count writes in its epoch. */
list_for_each_entry(r, &tconn->transfer_log, tl_requests) {
const unsigned long s = r->rq_state;
const unsigned s = r->rq_state;
if (!req) {
if (!(s & RQ_WRITE))
continue;

532
drivers/block/drbd/drbd_req.c
Просмотреть файл

@ -85,7 +85,9 @@ static struct drbd_request *drbd_req_new(struct drbd_conf *mdev,
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 @@ static void drbd_req_destroy(struct kref *kref)
{
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 @@ static void drbd_remove_request_interval(struct rb_root *root,
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 @@ void req_may_be_done(struct drbd_request *req)
* 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 @@ void req_may_be_completed(struct drbd_request *req, struct bio_and_error *m)
* 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 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
/* 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 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
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 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
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 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
/* 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 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
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 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
/* 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 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
/* 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 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
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 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
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 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
* 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 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
*/
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 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
* 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 @@ static bool do_remote_read(struct drbd_request *req)
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 @@ static bool do_remote_read(struct drbd_request *req)
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 @@ void __drbd_make_request(struct drbd_conf *mdev, struct bio *bio, unsigned long
/* 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 @@ void __drbd_make_request(struct drbd_conf *mdev, struct bio *bio, unsigned long
/* 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)

9
drivers/block/drbd/drbd_req.h
Просмотреть файл

@ -203,11 +203,18 @@ enum drbd_req_state_bits {
/* The peer has sent a retry ACK */
__RQ_POSTPONED,
/* would have been completed,
* but was not, because of drbd_suspended() */
__RQ_COMPLETION_SUSP,
/* We expect a receive ACK (wire proto B) */
__RQ_EXP_RECEIVE_ACK,
/* We expect a write ACK (wite proto C) */
__RQ_EXP_WRITE_ACK,
/* waiting for a barrier ack, did an extra kref_get */
__RQ_EXP_BARR_ACK,
};
#define RQ_LOCAL_PENDING (1UL << __RQ_LOCAL_PENDING)
@ -230,8 +237,10 @@ enum drbd_req_state_bits {
#define RQ_WRITE (1UL << __RQ_WRITE)
#define RQ_IN_ACT_LOG (1UL << __RQ_IN_ACT_LOG)
#define RQ_POSTPONED (1UL << __RQ_POSTPONED)
#define RQ_COMPLETION_SUSP (1UL << __RQ_COMPLETION_SUSP)
#define RQ_EXP_RECEIVE_ACK (1UL << __RQ_EXP_RECEIVE_ACK)
#define RQ_EXP_WRITE_ACK (1UL << __RQ_EXP_WRITE_ACK)
#define RQ_EXP_BARR_ACK (1UL << __RQ_EXP_BARR_ACK)
/* For waking up the frozen transfer log mod_req() has to return if the request
should be counted in the epoch object*/