kernel/drivers/block/drbd/drbd_state.c, branch linux-5.1.y

drbd: Change drbd_request_detach_interruptible's return type to int

2018-12-20T16:51:31Z

Clang warns when an implicit conversion is done between enumerated types: drivers/block/drbd/drbd_state.c:708:8: warning: implicit conversion from enumeration type 'enum drbd_ret_code' to different enumeration type 'enum drbd_state_rv' [-Wenum-conversion] rv = ERR_INTR; ~ ^~~~~~~~ drbd_request_detach_interruptible's only call site is in the return statement of adm_detach, which returns an int. Change the return type of drbd_request_detach_interruptible to match, silencing Clang's warning. Reported-by: Nick Desaulniers Reviewed-by: Nick Desaulniers Signed-off-by: Nathan Chancellor Signed-off-by: Jens Axboe

drbd: fix comment typos

2018-12-20T16:51:30Z

Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe

drbd: must not use connection after kref_put(&connection->kref)

2018-12-20T16:51:29Z

Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe

drbd: fix potential deadlock when trying to detach during handshake

2017-08-29T21:34:45Z

When requesting a detach, we first suspend IO, and also inhibit meta-data IO by means of drbd_md_get_buffer(), because we don't want to "fail" the disk while there is IO in-flight: the transition into D_FAILED for detach purposes may get misinterpreted as actual IO error in a confused endio function. We wrap it all into wait_event(), to retry in case the drbd_req_state() returns SS_IN_TRANSIENT_STATE, as it does for example during an ongoing connection handshake. In that example, the receiver thread may need to grab drbd_md_get_buffer() during the handshake to make progress. To avoid potential deadlock with detach, detach needs to grab and release the meta data buffer inside of that wait_event retry loop. To avoid lock inversion between mutex_lock(&device->state_mutex) and drbd_md_get_buffer(device), introduce a new enum chg_state_flag CS_INHIBIT_MD_IO, and move the call to drbd_md_get_buffer() inside the state_mutex grabbed in drbd_req_state(). Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe

drbd: Fix resource role for newly created resources in events2

2017-08-29T21:34:44Z

The conn_higest_role() (a terribly misnamed function) returns the role of the resource. It returned R_UNKNOWN as long as the resource has not a single device. Resources without devices are short living objects. But it matters for the NOTIFY_CREATE netwlink message. It makes a lot more sense to report R_SECONDARY for the newly created resource than R_UNKNOWN. I reviewd all call sites of conn_highest_role(), that change does not matter for the other call sites. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe

drbd: get rid of empty statement in is_valid_state

2016-06-14T03:43:07Z

This should silence a warning about an empty statement. Thanks to Fabian Frederick who sent a patch I modified to be smaller and avoids an additional indent level. Signed-off-by: Roland Kammerer Signed-off-by: Philipp Reisner Signed-off-by: Jens Axboe

drbd: code cleanups without semantic changes

2016-06-14T03:43:07Z

This contains various cosmetic fixes ranging from simple typos to const-ifying, and using booleans properly. Original commit messages from Fabian's patch set: drbd: debugfs: constify drbd_version_fops drbd: use seq_put instead of seq_print where possible drbd: include linux/uaccess.h instead of asm/uaccess.h drbd: use const char * const for drbd strings drbd: kerneldoc warning fix in w_e_end_data_req() drbd: use unsigned for one bit fields drbd: use bool for peer is_ states drbd: fix typo drbd: use | for bitmask combination drbd: use true/false for bool drbd: fix drbd_bm_init() comments drbd: introduce peer state union drbd: fix maybe_pull_ahead() locking comments drbd: use bool for growing drbd: remove redundant declarations drbd: replace if/BUG by BUG_ON Signed-off-by: Fabian Frederick Signed-off-by: Roland Kammerer Signed-off-by: Jens Axboe

drbd: bump current uuid when resuming IO with diskless peer

2016-06-14T03:43:07Z

Scenario, starting with normal operation Connected Primary/Secondary UpToDate/UpToDate NetworkFailure Primary/Unknown UpToDate/DUnknown (frozen) ... more failures happen, secondary loses it's disk, but eventually is able to re-establish the replication link ... Connected Primary/Secondary UpToDate/Diskless (resumed; needs to bump uuid!) We used to just resume/resent suspended requests, without bumping the UUID. Which will lead to problems later, when we want to re-attach the disk on the peer, without first disconnecting, or if we experience additional failures, because we now have diverging data without being able to recognize it. Make sure we also bump the current data generation UUID, if we notice "peer disk unknown" -> "peer disk known bad". Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe

drbd: disallow promotion during resync handshake, avoid deadlock and hard reset

2016-06-14T03:43:07Z

We already serialize connection state changes, and other, non-connection state changes (role changes) while we are establishing a connection. But if we have an established connection, then trigger a resync handshake (by primary --force or similar), until now we just had to be "lucky". Consider this sequence (e.g. deployment scenario): create-md; up; -> Connected Secondary/Secondary Inconsistent/Inconsistent then do a racy primary --force on both peers. block drbd0: drbd_sync_handshake: block drbd0: self 0000000000000004:0000000000000000:0000000000000000:0000000000000000 bits:25590 flags:0 block drbd0: peer 0000000000000004:0000000000000000:0000000000000000:0000000000000000 bits:25590 flags:0 block drbd0: peer( Unknown -> Secondary ) conn( WFReportParams -> Connected ) pdsk( DUnknown -> Inconsistent ) block drbd0: peer( Secondary -> Primary ) pdsk( Inconsistent -> UpToDate ) *** HERE things go wrong. *** block drbd0: role( Secondary -> Primary ) block drbd0: drbd_sync_handshake: block drbd0: self 0000000000000005:0000000000000000:0000000000000000:0000000000000000 bits:25590 flags:0 block drbd0: peer C90D2FC716D232AB:0000000000000004:0000000000000000:0000000000000000 bits:25590 flags:0 block drbd0: Becoming sync target due to disk states. block drbd0: Writing the whole bitmap, full sync required after drbd_sync_handshake. block drbd0: Remote failed to finish a request within 6007ms > ko-count (2) * timeout (30 * 0.1s) drbd s0: peer( Primary -> Unknown ) conn( Connected -> Timeout ) pdsk( UpToDate -> DUnknown ) The problem here is that the local promotion happens before the sync handshake triggered by the remote promotion was completed. Some assumptions elsewhere become wrong, and when the expected resync handshake is then received and processed, we get stuck in a deadlock, which can only be recovered by reboot :-( Fix: if we know the peer has good data, and our own disk is present, but NOT good, and there is no resync going on yet, we expect a sync handshake to happen "soon". So reject a racy promotion with SS_IN_TRANSIENT_STATE. Result: ... as above ... block drbd0: peer( Secondary -> Primary ) pdsk( Inconsistent -> UpToDate ) *** local promotion being postponed until ... *** block drbd0: drbd_sync_handshake: block drbd0: self 0000000000000004:0000000000000000:0000000000000000:0000000000000000 bits:25590 flags:0 block drbd0: peer 77868BDA836E12A5:0000000000000004:0000000000000000:0000000000000000 bits:25590 flags:0 ... block drbd0: conn( WFBitMapT -> WFSyncUUID ) block drbd0: updated sync uuid 85D06D0E8887AD44:0000000000000000:0000000000000000:0000000000000000 block drbd0: conn( WFSyncUUID -> SyncTarget ) *** ... after the resync handshake *** block drbd0: role( Secondary -> Primary ) Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe

drbd: only restart frozen disk io when D_UP_TO_DATE

2016-06-14T03:43:06Z

When re-attaching the local backend device to a C_STANDALONE D_DISKLESS R_PRIMARY with OND_SUSPEND_IO, we may only resume IO if we recognize the backend that is being attached as D_UP_TO_DATE. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe