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path: root/drivers/block/drbd/drbd_req.c
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2013-03-28drbd: fix drbd epoch write count for ahead/behind modeLars Ellenberg
The sanity check when receiving P_BARRIER_ACK does expect all write requests with a given req->epoch to have been either all replicated, or all not replicated. Because req->epoch was assigned before calling maybe_pull_ahead(), this expectation was not met, leading to an off-by-one in the sanity check, and further to a "Protocol Error". Fix: move the call to maybe_pull_ahead() a few lines up, and assign req->epoch only after that. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-03-28drbd: only fail empty flushes if no good data is reachableLars Ellenberg
We completed empty flushes (blkdev_issue_flush()) with IO error if we lost the local disk, even if we still have an established replication link to a healthy remote disk. Fix this to only report errors to upper layers, if neither local nor remote data is reachable. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-03-22drbd: try hard to max out the updates per AL transactionLars Ellenberg
There may have been more incoming requests while we where preparing the current transaction. Try to consolidate more updates into this transaction until we make no more progres. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-03-22drbd: move start io accounting before activity log transactionLars Ellenberg
The IO accounting of the drbd "queue depth" was misleading. We only started IO accounting once we already wrote the activity log. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-03-22drbd: consolidate as many updates as possible into one AL transactionLars Ellenberg
Depending on current IO depth, try to consolidate as many updates as possible into one activity log transaction. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-03-22drbd: queue writes on submitter thread, unless they pass the activity log ↵Lars Ellenberg
fastpath Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-03-22drbd: prepare to queue write requests on a submit workerLars Ellenberg
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-03-22drbd: split __drbd_make_request in before and after drbd_al_begin_ioLars Ellenberg
This is in preparation to be able to defer requests that need to wait for an activity log transaction to a submitter workqueue. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-03-22drbd: Clarify when activity log I/O is delegated to the worker threadLars Ellenberg
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-01-21drbd: fix potential protocol error and resulting disconnect/reconnectLars Ellenberg
When we notice a disk failure on the receiving side, we stop sending it new incoming writes. Depending on exact timing of various events, the same transfer log epoch could end up containing both replicated (before we noticed the failure) and local-only requests (after we noticed the failure). The sanity checks in tl_release(), called when receiving a P_BARRIER_ACK, check that the ack'ed transfer log epoch matches the expected epoch, and the number of contained writes matches the number of ack'ed writes. In this case, they counted both replicated and local-only writes, but the peer only acknowledges those it has seen. We get a mismatch, resulting in a protocol error and disconnect/reconnect cycle. Messages logged are "BAD! BarrierAck #%u received with n_writes=%u, expected n_writes=%u!\n" A similar issue can also be triggered when starting a resync while having a healthy replication link, by invalidating one side, forcing a full sync, or attaching to a diskless node. Fix this by closing the current epoch if the state changes in a way that would cause the replication intent of the next write. Epochs now contain either only non-replicated, or only replicated writes. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09Merge branch 'drbd-8.4_ed6' into for-3.8-drivers-drbd-8.4_ed6Philipp Reisner
2012-11-09drbd: log request sector offset and size for IO errorsLars Ellenberg
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: always write bitmap on detachLars Ellenberg
If we detach due to local read-error (which sets a bit in the bitmap), stay Primary, and then re-attach (which re-reads the bitmap from disk), we potentially lost the "out-of-sync" (or, "bad block") information in the bitmap. Always (try to) write out the changed bitmap pages before going diskless. That way, we don't lose the bit for the bad block, the next resync will fetch it from the peer, and rewrite it locally, which may result in block reallocation in some lower layer (or the hardware), and thereby "heal" the bad blocks. If the bitmap writeout errors out as well, we will (again: try to) mark the "we need a full sync" bit in our super block, if it was a READ error; writes are covered by the activity log already. If that superblock does not make it to disk either, we are sorry. Maybe we just lost an entire disk or controller (or iSCSI connection), and there actually are no bad blocks at all, so we don't need to re-fetch from the peer, there is no "auto-healing" necessary. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: differentiate early and later "postponing" of requestsLars Ellenberg
We use the RQ_POSTPONED flag to mark a request for several reasons. It may be a conflicting request in a dual-primary setup, where conflict detection and resolution on the peer decided that this request needs to be re-submitted, it needs to re-enter drbd_make_request() to fix the data divergence caused by these conflicting, partially overlapping, quasi-simultaneous requests. In this case we need to mark the corresponding area as out-of-sync, before we call drbd_al_complete_io(). We also use the RQ_POSTPONED flag to just "push back" a request, before even processing it, if IO is suspended for some reason. In this case, as this request was neither submitted nor sent yet, we must not touch the bitmap. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: Fix postponed requestsPhilipp Reisner
A postponed request might has RQ_IN_ACT_LOG already set, but is POSTPONED before it gets something in the RQ_LOCAL_MASK set. Up to now this caused a left-over active extent. Fix that by only testing for the RQ_IN_ACT_LOG bit in drbd_req_destroy() Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: Fix postponed requestsPhilipp Reisner
* Postponed requests should not set or clear out-of-sync marks * When a request gets postponed we need to drop its reference mdev->local_cnt (put_ldev()). Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: Fix completion of requests while the device is suspendedPhilipp Reisner
In various places (E.g. CONNECTION_LOST_WHILE_PENDING) the RQ_COMPLETION_SUSP mask is passed in the clear set to mod_rq_state(). The issue was that it tried to clear the RQ_COMPLETION_SUSP bit out of the state mask first, and eventuelly set it afterwards, in the drbd_req_put_completion_ref() function. Fixed that by moving the reference getting out of drbd_req_put_completion_ref() into the mod_rq_state(), before the place where the extra reference might be put. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: disambiguation, s/P_DISCARD_WRITE/P_SUPERSEDED/Lars Ellenberg
To avoid confusion with REQ_DISCARD aka TRIM, rename our "discard concurrent write acks" from P_DISCARD_WRITE to P_SUPERSEDED. At the same time, rename the drbd request event DISCARD_WRITE to CONFLICT_RESOLVED. It already triggers both successful completion or restart of the request, depending on our RQ_POSTPONED flag. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: NEG_ACK does not imply a barrier-ackLars Ellenberg
Don't drop a request from the transfer log just because it was NEG_ACKED. We need it around to be able to verify P_BARRIER_ACKs against the transver log. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: only start a new epoch, if the current epoch contains writesLars Ellenberg
Almost all code paths calling start_new_tl_epoch() guarded it with if (... current_tle_writes > 0 ... ). Just move that inside start_new_tl_epoch(). Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: Finish requests that completed while IO was frozenPhilipp Reisner
Requests of an acked epoch are stored on the barrier_acked_requests list. In case the private bio of such a request completes while IO on the drbd device is suspended [req_mod(completed_ok)] then the request stays there. When thawing IO because the fence_peer handler returned, then we use tl_clear() to apply the connection_lost_while_pending event to all requests on the transfer-log and the barrier_acked_requests list. Up to now the connection_lost_while_pending event was not applied on requests on the barrier_acked_requests list. Fixed that. I.e. now the connection_lost_while_pending and resend events are applied to requests on the barrier_acked_requests list. For that it is necessary that the resend event finishes (local only) READS correctly. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: fix drbd wire compatibility for empty flushesLars Ellenberg
DRBD has a concept of request epochs or reorder-domains, which are separated on the wire by P_BARRIER packets. Older DRBD is not able to handle zero-sized requests at all, so we need to map empty flushes to these drbd barriers. These are the equivalent of empty flushes, and by default trigger flushes on the receiving side anyways (unless not supported or explicitly disabled), so there is no need to handle this differently in newer drbd either. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: announce FLUSH/FUA capability to upper layersLars Ellenberg
In 8.4, we may have bios spanning two activity log extents. Fixup drbd_al_begin_io() and drbd_al_complete_io() to deal with zero sized bios. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: differentiate between normal and forced detachLars Ellenberg
Aborting local requests (not waiting for completion from the lower level disk) is dangerous: if the master bio has been completed to upper layers, data pages may be re-used for other things already. If local IO is still pending and later completes, this may cause crashes or corrupt unrelated data. Only abort local IO if explicitly requested. Intended use case is a lower level device that turned into a tarpit, not completing io requests, not even doing error completion. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: fix null pointer dereference with on-congestion policy when disklessLars Ellenberg
We must not look at mdev->actlog, unless we have a get_ldev() reference. It also does not make much sense to try to disconnect or pull-ahead of the peer, if we don't have good local data. Only even consider congestion policies, if our local disk is D_UP_TO_DATE. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: allow read requests to be retried after force-detachLars Ellenberg
Sometimes, a lower level block device turns into a tar-pit, not completing requests at all, not even doing error completion. We can force-detach from such a tar-pit block device, either by disk-timeout, or by drbdadm detach --force. Queueing for retry only from the request destruction path (kref hit 0) makes it impossible to retry affected read requests from the peer, until the local IO completion happened, as the locally submitted bio holds a reference on the drbd request object. If we can only complete READs when the local completion finally happens, we would not need to force-detach in the first place. Instead, queue for retry where we otherwise had done the error completion. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: __req_mod: make DISCARD_WRITE and independend caseLars Ellenberg
cherry-picked and adapted from drbd 9 devel branch This looks cleaner to me, and also gets rid of the other ugly if-inside-case-fall-through. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: base completion and destruction of requests on ref countsLars Ellenberg
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>
2012-11-08drbd: introduce completion_ref and kref to struct drbd_requestLars Ellenberg
cherry-picked and adapted from drbd 9 devel branch completion_ref will count pending events necessary for completion. kref is for destruction. This only introduces these new members of struct drbd_request, a followup patch will make actual use of them. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: __drbd_make_request() is now voidLars Ellenberg
The previous commit causes __drbd_make_request() to always return 0. Change it to void. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: better separate WRITE and READ code paths in drbd_make_requestLars Ellenberg
cherry-picked and adapted from drbd 9 devel branch READs will be interesting to at most one connection, WRITEs should be interesting for all established connections. Introduce some helper functions to hopefully make this easier to follow. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: remove struct drbd_tl_epoch objects (barrier works)Lars Ellenberg
cherry-picked and adapted from drbd 9 devel branch DRBD requests (struct drbd_request) are already on the per resource transfer log list, and carry their epoch number. We do not need to additionally link them on other ring lists in other structs. The drbd sender thread can recognize itself when to send a P_BARRIER, by tracking the currently processed epoch, and how many writes have been processed for that epoch. If the epoch of the request to be processed does not match the currently processed epoch, any writes have been processed in it, a P_BARRIER for this last processed epoch is send out first. The new epoch then becomes the currently processed epoch. To not get stuck in drbd_al_begin_io() waiting for P_BARRIER_ACK, the sender thread also needs to handle the case when the current epoch was closed already, but no new requests are queued yet, and send out P_BARRIER as soon as possible. This is done by comparing the per resource "current transfer log epoch" (tconn->current_tle_nr) with the per connection "currently processed epoch number" (tconn->send.current_epoch_nr), while waiting for new requests to be processed in wait_for_work(). Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: move the drbd_work_queue from drbd_socket to drbd_connectionLars Ellenberg
cherry-picked and adapted from drbd 9 devel branch In 8.4, we don't distinguish between "resource work" and "connection work" yet, we have one worker for both, as we still have only one connection. We only ever used the "data.work", no need to keep the "meta.work" around. Move tconn->data.work to tconn->sender_work. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: transfer log epoch numbers are now per resourceLars Ellenberg
cherry-picked from drbd 9 devel branch. In preparation of multiple connections, the "barrier number" or "epoch number" needs to be tracked per-resource, not per connection. The sequence number space will not be reset anymore. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: rename drbd_restart_write to drbd_restart_requestLars Ellenberg
Meanwhile, this is used to restart failed READ requests as well. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: fix wrong assert in completion/retry path of failed local readsLars Ellenberg
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: fix local read error hung foreverLars Ellenberg
The commit drbd: simplify retry path of failed READ requests simplified it too much: it just did not do anything for local read errors. Add the missing req_may_be_completed_not_susp() to the READ_COMPLETED_WITH_ERROR case. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: fix resend/resubmit of frozen IOLars Ellenberg
DRBD can freeze IO, due to fencing policy (fencing resource-and-stonith), or because we lost access to data (on-no-data-accessible suspend-io). Resuming from there (re-connect, or re-attach, or explicit admin intervention) should "just work". Unfortunately, if the re-attach/re-connect did not happen within the timeout, since the commit drbd: Implemented real timeout checking for request processing time if so configured, the request_timer_fn() would timeout and detach/disconnect virtually immediately. This change tracks the most recent attach and connect, and does not timeout within <configured timeout interval> after attach/connect. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: complete_conflicting_writes() should not care about connectionsLars Ellenberg
complete_conflicting_writes() should not cause -EIO. It should not timeout either, or care for connection states. Connection timeout is detected elsewhere, and it's cleanup path is supposed to remove any pending requests or peer_requests from the write_requests tree. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: simplify retry path of failed READ requestsLars Ellenberg
If a local or remote READ request fails, just push it back to the retry workqueue. 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. This obsoletes w_read_retry_remote(), and eliminates two goto...retry blocks in __req_mod() Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: move put_ldev from __req_mod() to the endio callbackLars Ellenberg
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: factor out master_bio completion and drbd_request destruction pathsLars Ellenberg
In preparation for multiple connections and reference counting, separate the code paths for completion of the master bio and destruction of the request object. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: conflicting writes: make wake_up of waiting peer_requests explicitLars Ellenberg
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: fix WRITE_ACKED_BY_PEER_AND_SIS to not set RQ_NET_DONELars Ellenberg
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: fix READ_RETRY_REMOTE_CANCELED to not complete if device is suspendedLars Ellenberg
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: make OOS_HANDED_TO_NETWORK its own caseLars Ellenberg
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: fix potential deadlock during "restart" of conflicting writesLars Ellenberg
w_restart_write(), run from worker context, calls __drbd_make_request() and further drbd_al_begin_io(, delegate=true), which then potentially deadlocks. The previous patch moved a BUG_ON to expose such call paths, which would now be triggered. Also, if we call __drbd_make_request() from resource worker context, like w_restart_write() did, and that should block for whatever reason (!drbd_state_is_stable(), resource suspended, ...), we potentially deadlock the whole resource, as the worker is needed for state changes and other things. Create a dedicated retry workqueue for this instead. Also make sure that inc_ap_bio()/dec_ap_bio() are properly paired, even if do_retry() needs to retry itself, in case __drbd_make_request() returns != 0. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: Fix a potential race that could case data inconsistencyLars Ellenberg
When we have a write request and a state change C_WF_BITMAP_S -> C_SYNC_SOURCE at the same time, and it happens that the line remote = remote && drbd_should_do_remote(s); stills sees C_WF_BITMAP_S, and send_oos = rw == WRITE && drbd_should_send_oos(s); already sees C_SYNC_SOURCE both are 0. This causes the write to not be mirrored, but marked as out-of-sync on the Sync_Source node. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: Consider that bio->bi_bdev might be modified below DRBDPhilipp Reisner
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: add missing part_round_stats to _drbd_start_io_acctPhilipp Reisner
Without this, iostat frequently sees bogus svctime and >= 100% "utilization". Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>