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2013-03-28drbd: validate resync_after dependency on attach alreadyLars Ellenberg2-3/+18
We validated resync_after dependencies, if changed via disk-options. But we did not validate them when first created via attach. We also did not check or cleanup dependencies that used to be correct, but now point to meanwhile removed minor devices. If the drbd_resync_after_valid() validation in disk-options tried to follow a dependency chain in this way, this could lead to NULL pointer dereference. Validate resync_after settings in drbd_adm_attach() already, as well as in drbd_adm_disk_opts(), and and only reject dependency loops. Depending on non-existing disks is allowed and equivalent to no dependency. 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: fix memory leakLars Ellenberg1-0/+1
We forgot to free the disk_conf, so for each attach/detach cycle we leaked 336 bytes. 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 Ellenberg2-4/+16
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>
2013-03-28drbd: Fix disconnect to keep the peer disk state if connection breaks during operationPhilipp Reisner3-9/+13
The issue was that if the connection broke while we did the gracefull state change to C_DISCONNECTING (C_TEARDOWN), then we returned a success code from the state engine. (SS_CW_NO_NEED) The result of that is that we missed to call the fence-peer script in such a case. Fixed that by introducing a new error code (SS_OUTDATE_WO_CONN). This one should never reach back into user space. 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: fix spurious warning about bitmap being locked from detachPhilipp Reisner1-1/+5
Introduced in drbd: always write bitmap on detach, the bitmap bulk writeout on detach was indicating it expected exclusive bitmap access. Where I meant to say: expect no more modifications, but testing/counting is still allowed. 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: drop now useless duplicate state request from invalidatePhilipp Reisner1-34/+28
Patch best viewed with git diff --ignore-space-change. Now that we attempt the fallback to local bitmap operation only when disconnected, we can safely drop the extra "silent" state request from both invalidate and invalidate-remote. 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: fix effective error returned when refusing an invalidatePhilipp Reisner1-0/+7
Since commit drbd: Disallow the peer_disk_state to be D_OUTDATED while connected trying to invalidate a disconnected Primary returned an error code that did not really match the situation: "Refusing to be Outdated while Connected" Insert two more specific conditions into is_valid_state(), changing that to "Need access to UpToDate data", respectively "Need a connection to start verify or resync". 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: move invalidating the whole bitmap out of after_state ch()Philipp Reisner2-23/+20
To avoid other state change requests, after passing through sanitize_state(), to be mistaken for an invalidate, move the "set all bits as out-of-sync" into the invalidate path. Make invalidate and invalidate-remote behave consistently wrt. current connection state (need either an established replication link, or really be disconnected). Also mention that in the documentation. 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: abort start of resync early, if it raced with connection breakagePhilipp Reisner1-1/+3
We've seen a spurious full resync, because a connection breakage raced with drbd_start_resync(, C_SYNC_TARGET), and the resulting state change request intended to start the resync ended up looking like a local invalidate. Fix: Double check the state inside the lock, and don't even request that state change, if we had connection or IO problems. 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: reset ap_in_flight counter for new connectionsPhilipp Reisner1-0/+1
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: adjust upper limit for activity log extentsLars Ellenberg1-9/+38
Now that the on-disk activity-log ring buffer size is adjustable, the maximum active set can become larger, and is now limited by the use of 16bit "labels". This increases the maximum working set from 6433 to 65534 extents, each of which covers an area of 4MiB. Which means that if you use the maximum, you'd have to resync more than 250 GiB after an unclean Primary shutdown. With capable backend storage and replication links, this is entirely feasible. 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 Ellenberg1-0/+31
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 Ellenberg1-3/+3
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 Ellenberg3-14/+107
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 fastpathLars Ellenberg1-8/+12
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 out some helper functions to drbd_al_begin_ioLars Ellenberg1-21/+28
To make the code easier to follow, use an explicit find_active_resync_extent(), and add a "nonblock" parameter to _al_get(). 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_al_begin_io into fastpath, prepare, and commitLars Ellenberg2-33/+72
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 Ellenberg4-1/+68
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 Ellenberg1-10/+30
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: drbd_al_being_io: short circuit to reduce latencyLars Ellenberg1-2/+12
A request hitting an already "hot" extent should proceed right away, even if some other requests need to wait for pending transactions. Without that short-circuit, several simultaneous make_request contexts race for committing the transaction, possibly penalizing the innocent. 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 Ellenberg5-26/+31
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: read meta data early, base on-disk offsets on super blockLars Ellenberg4-37/+123
We used to calculate all on-disk meta data offsets, and then compare the stored offsets, basically treating them as magic numbers. Now with the activity log striping, the activity log size is no longer fixed. We need to first read the super block, then base the activity log and bitmap offsets on the stored offsets/al stripe settings. 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: mechanically rename la_size to la_size_sectLars Ellenberg3-12/+12
Make it obvious that this value is in units of 512 Byte sectors. 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: use the cached meta_dev_idxLars Ellenberg2-33/+6
Now we have the cached meta_dev_idx member, we can get rid of a few rcu_read_lock() sections and rcu_dereference(). 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 for new striped layout of activity logLars Ellenberg4-40/+94
Introduce two new on-disk meta data fields: al_stripes and al_stripe_size_4k The intended use case is activity log on RAID 0 or similar. Logically consecutive transactions will advance their on-disk position by al_stripe_size_4k 4kB (transaction sized) blocks. Right now, these are still asserted to be the backward compatible values al_stripes = 1, al_stripe_size_4k = 8 (which amounts to 32kB). Also introduce a caching member for meta_dev_idx in the in-core structure: even though it is initially passed in in the rcu-protected disk_conf structure, it cannot change without a detach/attach cycle. 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: cleanup ondisk meta data layout calculations and definesLars Ellenberg5-57/+123
Add a comment about our meta data layout variants, and rename a few defines (e.g. MD_RESERVED_SECT -> MD_128MB_SECT) to make it clear that they are short hand for fixed constants, and not arbitrarily to be redefined as one may see fit. Properly pad struct meta_data_on_disk to 4kB, and initialize to zero not only the first 512 Byte, but all of it in drbd_md_sync(). 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: cleanup bogus assert messageLars Ellenberg2-10/+4
This fixes ASSERT( mdev->state.disk == D_FAILED ) in drivers/block/drbd/drbd_main.c When we detach from local disk, we let the local refcount hit zero twice. First, we transition to D_FAILED, so we won't give out new references to incoming requests; we still may give out *internal* references, though. Once the refcount hits zero [1] while in D_FAILED, we queue a transition to D_DISKLESS to our worker. We need to queue it, because we may be in atomic context when putting the reference. Once the transition to D_DISKLESS actually happened [2] from worker context, we don't give out new internal references either. Between hitting zero the first time [1] and actually transition to D_DISKLESS [2], there may be a few very short lived internal get/put, so we may hit zero more than once while being in D_FAILED, or even see a race where a an internal get_ldev() happened while D_FAILED, but the corresponding put_ldev() happens just after the transition to D_DISKLESS. That's why we have the additional test_and_set_bit(GO_DISKLESS,); and that's why the assert was placed wrong. Since there was exactly one code path left to drbd_go_diskless(), and that checks already for D_FAILED, drop that assert, and fold in the drbd_queue_work(). 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>
2013-02-27drbd: convert to idr_alloc()Tejun Heo1-16/+13
Convert to the much saner new idr interface. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-01-21drbd: fix potential protocol error and resulting disconnect/reconnectLars Ellenberg3-1/+9
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>
2012-12-06drbd: update Kconfig to match current dependenciesLars Ellenberg1-4/+6
We no longer need the connector. But we need libcrc32c. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-12-06drbd: Fix drbdsetup wait-connect, wait-sync etc... commandsPhilipp Reisner1-5/+6
This was introduces when moving the code over from the 8.3 codebase with commit 328e0f125bf41f4f33f684db22015f92cb44fe56 Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-12-06drbd: close race between drbd_set_role and drbd_connectPhilipp Reisner1-0/+10
drbd_set_role(, R_PRIMARY, ) does the state change to Primary, some more housekeeping, and possibly generates a new UUID set. All of this holding the "state_mutex". The connection handshake involves sending of various state information, including the current data generation UUID set, and two connection state changes from C_WF_CONNECTION to C_WF_REPORT_PARAMS further to a number of different outcomes, resync being one of them. If the connection handshake happens between the state change to Primary and the generation of the new UUIDs, the resync decision based on the old UUID set may be confused, depending on circumstances. Make sure that, before we do the handshake, any promotion to Primary role will either be complete (including the housekeeping stuff), or can see, and serialize with, the ongoing handshake, based on the "STATE_SENT" bit, which is set when we start the handshake, and cleared only when we leave C_WF_REPORT_PARAMS again. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-12-06drbd: respect no-md-barriers setting also when changed online via disk-optionsLars Ellenberg1-0/+5
We need to propagate the configuration into the flag bits, or it won't be effective. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-12-06drbd: Remove obsolete checkPhilipp Reisner1-1/+1
Smatch complained about it this redundanct check. The check was introduced in 2006-09-13. On 2007-07-24 the body of the function was enclosed by get_ldev()/put_ldev() reference counting. Since then the check is useless and miss leading. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-30drbd: fixup after wait_even_lock_irq() addition to generic codeJens Axboe2-29/+1
Compiling drbd yields: drivers/block/drbd/drbd_state.c: In function ‘_conn_request_state’: drivers/block/drbd/drbd_state.c:1804:5: error: macro "wait_event_lock_irq" passed 4 arguments, but takes just 3 drivers/block/drbd/drbd_state.c:1801:3: error: ‘wait_event_lock_irq’ undeclared (first use in this function) drivers/block/drbd/drbd_state.c:1801:3: note: each undeclared identifier is reported only once for each function it appears in drivers/block/drbd/drbd_state.c: At top level: drivers/block/drbd/drbd_state.c:1734:1: warning: ‘_conn_rq_cond’ defined but not used [-Wunused-function] Due to drbd having copied the MD definition for wait_event_lock_irq() as well. Kill them. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-11-09drbd: use copy_highpageAkinobu Mita1-7/+1
Use copy_highpage() to copy from one page to another. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: if the replication link breaks during handshake, keep retryingLars Ellenberg1-1/+1
The 8.3.12 commit drbd: Bugfix for the connection behavior fixes a "wasted established connection", if a former connection attempt failed during its early stages. However it opened a window for a regression, if a connection attempt fails during its last stages. The result was a terminated receiver thread, that left behind the supposedly transient "C_UNCONNECTED" state. Any later requests to change the connection state fail, as they wait for the connection state to "stabilize". Fix: short circuit and keep retrying to restablish a new connection, if we don't reach C_WF_REPORT_PARAMS. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: check return of kmalloc in receive_uuidsJing Wang1-0/+4
Signed-off-by: Jing Wang <windsdaemon@gmail.com> 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 Reisner19-8024/+10449
2012-11-09drbd: Broadcast sync progress no more often than once per secondPhilipp Reisner3-0/+11
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: don't try to clear bits once the disk has failedPhilipp Reisner1-5/+10
If the disk has failed already, there is no point trying to change the bitmap. drbd_set_out_of_sync() already had this safeguard, time to add it to drbd_set_in_sync() as well. This also prevents some warning messages, like FIXME asender in bm_change_bits_to, bitmap locked for 'detach' by worker if our disk fails during resync, while there are some resync acks queued up. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: fix regression: potential NULL pointer dereferencePhilipp Reisner2-2/+11
recent commit drbd: always write bitmap on detach introduced a bitmap writeout during detach, which obviously needs some meta data device to write to. Unfortunately, that same error path may be taken if we fail to attach, e.g. due to UUID mismatch, after we changed state to D_ATTACHING, but before the lower level device pointer is even assigned. We need to test for presence of mdev->ldev. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: Fix clearing of MDF_AL_DISABLEDPhilipp Reisner1-2/+2
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: log request sector offset and size for IO errorsLars Ellenberg1-1/+18
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 Ellenberg5-11/+63
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: wait for meta data IO completion even with failed disk, unless force-detachedLars Ellenberg3-16/+13
The intention of force-detach is to be able to deal with a completely unresponsive lower level IO stack, which does not even deliver error completions anymore, but no completion at all. In all other cases, we must still wait for the meta data IO completion. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: a few more GFP_KERNEL -> GFP_NOIOLars Ellenberg2-2/+2
This has not yet been observed, but conceivably, when using GFP_KERNEL allocations from drbd_md_sync(), drbd_flush_after_epoch() or receive_SyncParam(), we could trigger additional IO to our own device, or an other device in a criss-cross setup, and end up in a local deadlock, or potentially a distributed deadlock in a criss-cross setup involving the peer blocked in a similar way waiting for us to make progress. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: fix potential deadlock during bitmap (re-)allocationLars Ellenberg1-7/+9
The former comment arguing that GFP_KERNEL was good enough was wrong: it did not take resize into account at all, and assumed the only path leading here was the normal attach on a still secondary device, so no deadlock would be possible. Both resize on a Primary, or attach on a diskless Primary, could potentially deadlock. drbd_bm_resize() is called while IO to the respective device is suspended, so we must use GFP_NOIO to avoid potential deadlock. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: use list_move_tail instead of list_del/list_add_tailLars Ellenberg1-2/+1
Using list_move_tail() instead of list_del() + list_add_tail(). spatch with a semantic match is used to found this problem. (http://coccinelle.lip6.fr/) Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: panic on delayed completion of aborted requestsPhilipp Reisner1-0/+37
"aborting" requests, or force-detaching the disk, is intended for completely blocked/hung local backing devices which do no longer complete requests at all, not even do error completions. In this situation, usually a hard-reset and failover is the only way out. By "aborting", basically faking a local error-completion, we allow for a more graceful swichover by cleanly migrating services. Still the affected node has to be rebooted "soon". By completing these requests, we allow the upper layers to re-use the associated data pages. If later the local backing device "recovers", and now DMAs some data from disk into the original request pages, in the best case it will just put random data into unused pages; but typically it will corrupt meanwhile completely unrelated data, causing all sorts of damage. Which means delayed successful completion, especially for READ requests, is a reason to panic(). We assume that a delayed *error* completion is OK, though we still will complain noisily about it. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
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