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2014-07-10drbd: debugfs: add per device data_gen_idLars Ellenberg
The data generation identifiers used to be exposed via sysfs at /sys/block/drbdX/drbd/meta_data/data_gen_id (out-of-tree), for advanced policy scripting. Bring that information over to debugfs. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: add per connection oldest requestsLars Ellenberg
Information of former /sys/block/drbdX/drbd/oldest_requests is already with higher detail in these files: debugfs/drbd/resource/$name/in_flight_summary, debugfs/drbd/resource/$name/volumes/$vnr/oldest_requests This patch adds debugfs/drbd/resource/$name/connections/peer/oldest_requests Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: add version tag to debugfs filesLars Ellenberg
Make the first line of debugfs files a version number, starting now with "v: 0". If we change content of presentation, we will bump that. Monitoring or diagnostic scritps that may parse these files can then easily know when they need to be reviewed. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: add per volume oldest_requestsLars Ellenberg
Show oldest requests * pending master bio completion and, * if different, local disk bio completion. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: add callback_historyLars Ellenberg
Add a per-connection worker thread callback_history with timing details, call site and callback function. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: Add in_flight_summaryLars Ellenberg
* Add details about pending meta data operations to in_flight_summary. * Report number of requests waiting for activity log transactions. * timing details of peer_requests to in_flight_summary. * FLUSH details DRBD devides the incoming request stream into "epochs", in which peers are allowed to re-order writes independendly. These epochs are separated by P_BARRIER on the replication link. Such barrier packets, depending on configuration, may cause the receiving side to drain the lower level device request queues and call blkdev_issue_flush(). This is known to be an other major source of latency in DRBD. Track timing details of calls to blkdev_issue_flush(), and add them to in_flight_summary. * data socket stats To be able to diagnose bottlenecks and root causes of "slow" IO on DRBD, it is useful to see network buffer stats along with the timing details of requests, peer requests, and meta data IO. * pending bitmap IO timing details to in_flight_summary. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: deal with destructor racing with open of debugfs fileLars Ellenberg
Try to close the race between open() and debugfs_remove_recursive() from inside an object destructor. Once open succeeds, the object should stay around. Open should not succeed if the object has already reached its destructor. This may be overkill, but to make that happen, we check for existence of a parent directory, "stale-ness" of "this" dentry, and serialize kref_get_unless_zero() on the outermost object relevant for this file with d_delete() on this dentry (using the parent's i_mutex). Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: add in_flight_summary dataLars Ellenberg
To help diagnosing "high latency" or "hung" IO situations on DRBD, present per drbd resource group a summary of operations currently in progress. First item is a list of oldest drbd_request objects waiting for various things: * still being prepared * waiting for activity log transaction * waiting for local disk * waiting to be sent * waiting for peer acknowledgement ("receive ack", "write ack") * waiting for peer epoch acknowledgement ("barrier ack") Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: add basic hierarchyLars Ellenberg
Add new debugfs hierarchy /sys/kernel/debug/ drbd/ resources/ $resource_name/connections/peer/$volume_number/ $resource_name/volumes/$volume_number/ minors/$minor_number -> ../resources/$resource_name/volumes/$volume_number/ Followup commits will populate this hierarchy with files containing statistics, diagnostic information and some attribute data. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: track details of bitmap IOLars Ellenberg
Track start and submit time of bitmap operations, and add pending bitmap IO contexts to a new pending_bitmap_io list. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: register peer requests on read_ee earlyLars Ellenberg
Initialize peer_request with timestamp and proper empty list head. Add peer_request to list early, so debugfs can find this request and report it as "preparing", even if we sleep before we actually submit it. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: track timing details of peer_requestsLars Ellenberg
To be able to present timing details in debugfs, we need to track preparation/submit times of peer requests. Track peer request flags early, before they are put on the epoch_entry lists. Waiting for activity log transactions may be a major latency factor. We want to be able to present the peer_request state accurately in debugfs, and what it is waiting for. Consistently mark/unmark peer requests with EE_CALL_AL_COMPLETE_IO. Set it only *after* calling drbd_al_begin_io(), clear it as soon as we call drbd_al_complete_io(). Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: improve throttling decisions of background resynchronisationLars Ellenberg
Background resynchronisation does some "side-stepping", or throttles itself, if it detects application IO activity, and the current resync rate estimate is above the configured "cmin-rate". What was not detected: if there is no application IO, because it blocks on activity log transactions. Introduce a new atomic_t ap_actlog_cnt, tracking such blocked requests, and count non-zero as application IO activity. This counter is exposed at proc_details level 2 and above. Also make sure to release the currently locked resync extent if we side-step due to such voluntary throttling. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: add caching oldest request pointers for replication stagesLars Ellenberg
A request that is to be shipped to the peer goes through a few stages: - queued - sent, waiting for ack - ack received, waiting for "barrier ack", which is re-order epoch being closed on the peer by acknowledging a "cache flush" equivalent on the lower level device. In the later two stages, depending on protocol, we may have already completed this request to the upper layers, so it won't be found anymore on device->pending_master_completion[] lists. Track the oldest request yet to be sent (req_next), the oldest not yet acknowledged (req_ack_pending) and the oldest "still waiting for something from the peer" (req_not_net_done), doing short list walks on the transfer log to find the next pending one whenever such a request makes progress. Now we have a fast way to look up the oldest requests, don't do a transfer log walk every time. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: add lists to find oldest pending requestsLars Ellenberg
Adding requests to per-device fifo lists as soon as possible after allocating them leaves a simple list_first_entry_or_null() to find the oldest request, regardless what it is still waiting for. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: gather detailed timing statistics for drbd_requestsLars Ellenberg
Record (in jiffies) how much time a request spends in which stages. Followup commits will use and present this additional timing information so we can better locate and tackle the root causes of latency spikes, or present the backlog for asynchronous replication. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: track meta data IO intent, start and submit timeLars Ellenberg
For diagnostic purposes, track intent, start time and latest submit time of meta data IO. Move separate members from struct drbd_device into the embeded struct drbd_md_io. s/md_io_(page|in_use)/md_io.\1/ Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: fix drbd_destroy_device reference count updatesLars Ellenberg
drbd_destroy_device means to give up reference counts on the connection(s) reachable via the peer_device(s). It must not do that by iterating via device->resource->connections, resource and connections may have already been disassociated by drbd_free_resource, and we'd leak connection refs. Instead, iterate via device->peer_devices->connection. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: poison free'd device, resource and connection structsLars Ellenberg
Now that we have additional asynchronous kref_get/kref_put via debugfs, make sure we catch access after free. Poison struct drbd_device, drbd_connection and drbd_resource before kfree() with 0xfd, 0xfc, and 0xf2, respectively. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: also keep track of trim -> zero-out fallback peer_requestsLars Ellenberg
To be able to find and present such zero-out fallback peer_requests in debugfs, we add those to "active_ee", once that list drained. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: consistently use list_add_tail for peer_request trackingLars Ellenberg
Keep the epoch entry lists (active_ee, read_ee, sync_ee, ...) consistently "oldest first". That way finding the oldest not yet successfully processed request is simply list_first_entry_or_null. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: drop drbd_md_flushLars Ellenberg
The only user of drbd_md_flush was bm_rw(), and it is always followed by either a drbd_md_sync(), or an al_write_transaction(), which, if so configured, both end up submiting a FLUSH|FUA request anyways. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: add drbd_queue_work_if_unqueued helperLars Ellenberg
We sometimes do if (list_empty(&w.list)) drbd_queue_work(&q, &w.list); Removal (list_del_init) may happen outside all locks, after all pending work entries have been moved to an on-stack local work list. For not dynamically allocated, but embeded, work structs, we must avoid to re-add until it really was removed. Move that list_empty check inside the spin_lock(&q->q_lock) within the helper function, and change to list_empty_careful(). This may have been the reason for a list_add corruption inside drbd_queue_work(). Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: drbd_rs_number_requests: fix unit mismatch in comparisonLars Ellenberg
We try to limit the number of "in-flight" resync requests. One condition for that is the amount of requested data should not exceed half of what can be covered by our "max-buffers" setting. However we compared number of 4k pages with number of in-flight 512 Byte sectors, and this extra throttle triggered much earlier than intended. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: cosmetic: change all printk(level, ...) to pr_<level>(...)Lars Ellenberg
Cosmetic change only. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: clear CRASHED_PRIMARY only after successful resyncLars Ellenberg
If we lost a disk during the first resync after primary crash, we could have prematurely cleared the CRASHED_PRIMARY flag. Testing on C_CONNECTED is not what we meant there, but testing for both peers to become D_UP_TO_DATE. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: improve resync request throttling due to sendbuf sizeLars Ellenberg
If we throttle resync because the socket sendbuffer is filling up, tell TCP about it, so it may expand the sendbuffer for us. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10block: Convert last uses of __FUNCTION__ to __func__Joe Perches
Just about all of these have been converted to __func__, so convert the last uses. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drivers/block: Use RCU_INIT_POINTER(x, NULL) in drbd/drbd_state.cMonam Agarwal
This patch replaces rcu_assign_pointer(x, NULL) with RCU_INIT_POINTER(x, NULL) The rcu_assign_pointer() ensures that the initialization of a structure is carried out before storing a pointer to that structure. And in the case of the NULL pointer, there is no structure to initialize. So, rcu_assign_pointer(p, NULL) can be safely converted to RCU_INIT_POINTER(p, NULL) Signed-off-by: Monam Agarwal <monamagarwal123@gmail.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: short-circuit in maybe_pull_aheadLars Ellenberg
If we already "pulled ahead", we can short-circuit, and avoid logging the same messages over and over again. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: application writes may set-in-sync in protocol != CLars Ellenberg
If "dirty" blocks are written to during resync, that brings them in-sync. By explicitly requesting write-acks during resync even in protocol != C, we now can actually respect this. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: New net configuration option socket-check-timeoutPhilipp Reisner
In setups involving a DRBD-proxy and connections that experience a lot of buffer-bloat it might be necessary to set ping-timeout to an unusual high value. By default DRBD uses the same value to wait if a newly established TCP-connection is stable. Since the DRBD-proxy is usually located in the same data center such a long wait time may hinder DRBD's connect process. In such setups socket-check-timeout should be set to at least to the round trip time between DRBD and DRBD-proxy. I.e. in most cases to 1. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: Limit the time we are waiting for the first packet on an accepted socketPhilipp Reisner
Before the patch 'drbd: Keep the listening socket open while trying to connect to the peer' the newly created socket inherited the receive timeout from the listen socket. The listen socket had a receive timeout of connect-intervall +- 30% random jitter. The real issue is that after the mentioned patch we had no timeout at all. Now use 4 times the ping-timeout. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: implement csums-after-crash-onlyLars Ellenberg
Checksum based resync trades CPU cycles for network bandwidth, in situations where we expect much of the to-be-resynced blocks to be actually identical on both sides already. In a "network hickup" scenario, it won't help: all to-be-resynced blocks will typically be different. The use case is for the resync of *potentially* different blocks after crash recovery -- the crash recovery had marked larger areas (those covered by the activity log) as need-to-be-resynced, just in case. Most of those blocks will be identical. This option makes it possible to configure checksum based resync, but only actually use it for the first resync after primary crash. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: don't implicitly resize Diskless node beyond end of deviceLars Ellenberg
During handshake, we compare backend sizes, and user set limits, and agree on what device size we are going to expose. We remember that last-agreed-size in our meta data. But if we come up diskless, we have to accept what the peer presents us with. We used to accept the peers maximum potential capacity (backend size), which is wrong, and could lead to IO errors due to access beyond end of device. Instead, we need to accept the peer's current size. Unless that is communicated as 0, in which case we accept the backend size, or the user set limit, if set. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: fix bogus resync stats in /proc/drbdLars Ellenberg
We intentionally do not serialize /proc/drbd access with internal state changes or statistic updates. Because of that, cat /proc/drbd may race with resync just being finished, still see the sync state, and find information about number of blocks still to go, but then find the total number of blocks within this resync has just been reset to 0 when accessing it. This now produces bogus numbers in the resync speed estimates. Fix by accessing all relevant data only once, and fixing it up if "still to go" happens to be more than "total". Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: Remove unnecessary/unused codeAndreas Gruenbacher
Get rid of dump_stack() debug statements. There is no point whatsoever in registering and unregistering a reboot notifier that doesn't do anything. The intention was to switch to an "emergency read-only" mode, so we won't have to resync the full activity log just because we had been Primary before the reboot. Once we have that implemented, we may re-introduce the reboot notifier. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: silence -Wmissing-prototypes warningsLars Ellenberg
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: drop wrong debugging aidLars Ellenberg
The textual representation of resync extents in /proc/drbd presented with proc_details >= 3 was wrong, it used bitnumbers as bitmasks. It was not particularly useful either, and I doubt anyone has even tried to look at it in the last few years. Drop it. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: get rid of drbd_queue_work_frontLars Ellenberg
The last user was al_write_transaction, if called with "delegate", and the last user to call it with "delegate = true" was the receiver thread, which has no need to delegate, but can call it himself. Finally drop the delegate parameter, drop the extra w_al_write_transaction callback, and drop drbd_queue_work_front. Do not (yet) change dequeue_work_item to dequeue_work_batch, though. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: use drbd_device_post_work() in more placesLars Ellenberg
This replaces the md_sync_work member of struct drbd_device by a new MD_SYNC "work bit" in device->flags. This replaces the resync_start_work member of struct drbd_device by a new RS_START "work bit" in device->flags. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: make sure disk cleanup happens in worker contextLars Ellenberg
The recent fix to put_ldev() (correct ordering of access to local_cnt and state.disk; memory barrier in __drbd_set_state) guarantees that the cleanup happens exactly once. However it does not yet guarantee that the cleanup happens from worker context, the last put_ldev() may still happen from atomic context, which must not happen: blkdev_put() may sleep. Fix this by scheduling the cleanup to the worker instead, using a couple more bits in device->flags and a new helper, drbd_device_post_work(). Generalized the "resync progress" work to cover these new work bits. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: close race when detaching from diskLars Ellenberg
BUG: unable to handle kernel NULL pointer dereference at 0000000000000058 IP: bd_release+0x21/0x70 Process drbd_w_t7146 Call Trace: close_bdev_exclusive drbd_free_ldev [drbd] drbd_ldev_destroy [drbd] w_after_state_ch [drbd] Race probably went like this: state.disk = D_FAILED ... first one to hit zero during D_FAILED: put_ldev() /* ----------------> 0 */ i = atomic_dec_return() if (i == 0) if (state.disk == D_FAILED) schedule_work(go_diskless) /* 1 <------ */ get_ldev_if_state() go_diskless() do_some_pre_cleanup() corresponding put_ldev(): force_state(D_DISKLESS) /* 0 <------ */ i = atomic_dec_return() if (i == 0) atomic_inc() /* ---------> 1 */ state.disk = D_DISKLESS schedule_work(after_state_ch) /* execution pre-empted by IRQ ? */ after_state_ch() put_ldev() i = atomic_dec_return() /* 0 */ if (i == 0) if (state.disk == D_DISKLESS) if (state.disk == D_DISKLESS) drbd_ldev_destroy() drbd_ldev_destroy(); Trying to fix this by checking the disk state *before* the atomic_dec_return(), which implies memory barriers, and by inserting extra memory barriers around the state assignment in __drbd_set_state(). Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: explicitly submit meta data requests with REQ_NOIDLELars Ellenberg
For some reason we have assumed NOIDLE was implied by one of the other flags we set. It is not (anymore?). Explicitly set REQ_NOIDLE for synchronous meta data updates, or we can seriously starve random writes when using CFQ. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: move set_disk_ro() to after we persisted the new roleLars Ellenberg
This probably does not have any real life impact, but we should first persist any potentially new UUID and other meta data flags, as well as our new role, before we allow/disallow write access. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: trigger tcp_push_pending_frames() for PING and PING_ACKLars Ellenberg
This should reduce latency for such in-DRBD-protocol "pings", and may help reduce spurious disconnect/reconnect cycles due to "PingAck did not arrive in time." Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: re-add lost conf_mutex protection in drbd_set_roleLars Ellenberg
The conf_update mutex used to be held while clearing the net_conf->discard_my_data flag inside drbd_set_role. It was moved into drbd_adm_set_role with drbd: allow parallel promote/demote actions but then replaced at that location by the newly introduced adm_mutex with drbd: Fix a potential deadlock in drbdsetup, introduce resource->adm_mutex And I simply forgot to put it back in at the original location. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: stop the meta data sync timer before open coded meta data syncLars Ellenberg
If we re-write all meta data due to resize, we have open-coded write-out of our meta data super block. Stop the md_sync_timer, it would just trigger scary but in this case spurious "timer expired" messages. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: fix resync finished detectionLars Ellenberg
This fixes one recent regresion, and one long existing bug. The bug: drbd_try_clear_on_disk_bm() assumed that all "count" bits have to be accounted in the resync extent corresponding to the start sector. Since we allow application requests to cross our "extent" boundaries, this assumption is no longer true, resulting in possible misaccounting, scary messages ("BAD! sector=12345s enr=6 rs_left=-7 rs_failed=0 count=58 cstate=..."), and potentially, if the last bit to be cleared during resync would reside in previously misaccounted resync extent, the resync would never be recognized as finished, but would be "stalled" forever, even though all blocks are in sync again and all bits have been cleared... The regression was introduced by drbd: get rid of atomic update on disk bitmap works For an "empty" resync (rs_total == 0), we must not "finish" the resync on the SyncSource before the SyncTarget knows all relevant information (sync uuid). We need to wait for the full round-trip, the SyncTarget will then explicitly notify us. Also for normal, non-empty resyncs (rs_total > 0), the resync-finished condition needs to be tested before the schedule() in wait_for_work, or it is likely to be missed. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: fix a race stopping the worker threadLars Ellenberg
We may implicitly call drbd_send() from inside wait_for_work(), via maybe_send_barrier(). If the "stop" signal was send just before that, drbd_send() would call flush_signals(), and we would run an unbounded schedule() afterwards. Fix: check for thread_state == RUNNING before we schedule() Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>