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* dlm: implement LSFL_SOFTIRQ_SAFEAlexander Aring2024-06-111-56/+101
| | | | | | | | | When a lockspace user allows it, run callback functions directly from softirq context, instead of queueing callbacks to be run from the dlm_callback workqueue context. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: use LSFL_FS to check for kernel lockspaceAlexander Aring2024-06-111-6/+11
| | | | | | | | | | The existing external lockspace flag DLM_LSFL_FS is now also saved as an internal flag LSFL_FS, so it can be checked from other code locations which want to know if a lockspace is used from the kernel or user space. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: use spin_lock_bh for message processingAlexander Aring2024-04-091-6/+6
| | | | | | | | | | Use spin_lock_bh for all spinlocks involved in message processing, in preparation for softirq message processing. DLM lock requests from user space involve dlm processing in user context, in addition to the standard kernel context, necessitating bh variants. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: remove callback reference countingAlexander Aring2024-04-011-39/+17
| | | | | | | | | | | Get rid of the unnecessary refcounting on callback structs. Copy interesting callback info into the lkb struct rather than maintaining pointers to callback structs from the lkb. This goes back to the way things were done prior to commit 61bed0baa4db ("fs: dlm: use a non-static queue for callbacks"). Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: fix race between final callback and removeAlexander Aring2024-04-011-105/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes the following issue: node 1 is dir node 2 is master node 3 is other 1->2: unlock 2: put final lkb, rsb moved to toss 2->1: unlock_reply 1: queue lkb callback with EUNLOCK 2->1: remove 1: receive_remove ignored (rsb on keep because of queued lkb callback) 1: complete lkb callback, put_lkb, move rsb to toss 3->1: lookup 1->3: lookup_reply master=2 3->2: request 2->3: request_reply EBADR In summary: An unexpected lkb reference causes the rsb to remain on the wrong list. The rsb being on the wrong list causes receive_remove to be ignored. An ignored receive_remove causes inconsistent dir and master state. This sequence requires an unusually long delay in delivering the unlock callback, because the remove message from 2->1 usually happens after some seconds. So, it's not known exactly how frequently this sequence occurs in pratice. It's possible that the same end result could also have another unknown cause. The solution for this issue is to further separate callback state from the lkb, so that an lkb reference (and from that, an rsb ref) are not held while a callback remains queued. Then, within the unlock_reply, the lkb will be freed and the rsb moved to the toss list. So, the receive_remove will not be ignored. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: combine switch case fail and default statementsAlexander Aring2024-04-011-3/+2
| | | | | | | | | This patch combines the failure and default cases for enqueue and dequeue a callback to the lkb callback queue that should end in both cases as it should never happen. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: save callback debug info earlierAlexander Aring2024-04-011-4/+6
| | | | | | | | Save lkb callback info when queueing the callback so that the lkb struct is not needed in the callback workqueue processing. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: remove lkb from callback tracepointsAlexander Aring2024-04-011-2/+7
| | | | | | | | | Stop using lkb structs in the callback tracepoints so that lkb references are not needed. This prepares for separating lkb structs from callbacks. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: fix user space lock decision to copy lvbAlexander Aring2024-04-011-0/+14
| | | | | | | | | | | | | | | This patch fixes the copy lvb decision for user space lock requests. Checking dlm_lvb_operations is done earlier, where granted/requested lock modes are available to use in the matrix. The decision had been moved to the wrong location, where granted mode and requested mode where the same, which causes the dlm_lvb_operations matix to produce the wrong copy decision. For PW or EX requests, the caller could get invalid lvb data. Fixes: 61bed0baa4db ("fs: dlm: use a non-static queue for callbacks") Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: move dlm_purge_lkb_callbacks to user moduleAlexander Aring2023-06-141-17/+0
| | | | | | | | | | | | | | This patch moves the dlm_purge_lkb_callbacks() function from ast to user dlm module as it is only a function being used by dlm user implementation. I got be hinted to hold specific locks regarding the callback handling for dlm_purge_lkb_callbacks() but it was false positive. It is confusing because ast dlm implementation uses a different locking behaviour as user locks uses as DLM handles kernel and user dlm locks differently. To avoid the confusing we move this function to dlm user implementation. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: clear pending bit when queue was emptyAlexander Aring2023-06-141-3/+5
| | | | | | | | | | | | | This patch clears the DLM_IFL_CB_PENDING_BIT flag which will be set when there is callback work queued when there was no callback to dequeue. It is a buggy case and should never happen, that's why there is a WARN_ON(). However if the case happens we are prepared to somehow recover from it. Cc: stable@vger.kernel.org Fixes: 61bed0baa4db ("fs: dlm: use a non-static queue for callbacks") Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: change dflags to use atomic bitsAlexander Aring2023-03-061-1/+1
| | | | | | | | | | | | | | | | | Currently manipulating lkb_dflags assumes to held the rsb lock assigned to the lkb. This is held by dlm message processing after certain time to lookup the right rsb from the received lkb message id. For user space locks flags, which is currently the only use case for lkb_dflags, flags are also being set during dlm character device handling without holding the rsb lock. To minimize the risk that bit operations are getting corrupted we switch to atomic bit operations. This patch will also introduce helpers to snapshot atomic bit values in an non atomic way. There might be still issues with the flag handling e.g. running in case of manipulating bit ops and snapshot them at the same time, but this patch minimize them and will start to use atomic bit operations. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: store lkb distributed flags into own valueAlexander Aring2023-03-061-1/+1
| | | | | | | | | | | This patch stores lkb distributed flags value in an separate value instead of sharing internal and distributed flags in lkb->lkb_flags value. This has the advantage to not mask/write back flag values in receive_flags() functionality. The dlm debug_fs does not provide the distributed flags anymore, those can be added in future. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: fix DLM_IFL_CB_PENDING gets overwrittenAlexander Aring2023-03-061-5/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch introduce a new internal flag per lkb value to handle internal flags which are handled not on wire. The current lkb internal flags stored as lkb->lkb_flags are split in upper and lower bits, the lower bits are used to share internal flags over wire for other cluster wide lkb copies on other nodes. In commit 61bed0baa4db ("fs: dlm: use a non-static queue for callbacks") we introduced a new internal flag for pending callbacks for the dlm callback queue. This flag is protected by the lkb->lkb_cb_lock lock. This patch overlooked that on dlm receive path and the mentioned upper and lower bits, that dlm will read the flags, mask it and write it back. As example receive_flags() in fs/dlm/lock.c. This flag manipulation is not done atomically and is not protected by lkb->lkb_cb_lock. This has unknown side effects of the current callback handling. In future we should move to set/clear/test bit functionality and avoid read, mask and writing back flag values. In later patches we will move the upper parts to the new introduced internal lkb flags which are not shared between other cluster nodes to the new non shared internal flag field to avoid similar issues. Cc: stable@vger.kernel.org Fixes: 61bed0baa4db ("fs: dlm: use a non-static queue for callbacks") Reported-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: rename DLM_IFL_NEED_SCHED to DLM_IFL_CB_PENDINGAlexander Aring2022-11-211-5/+4
| | | | | | | | | | | | | | This patch renames DLM_IFL_NEED_SCHED to DLM_IFL_CB_PENDING because CB_PENDING is a proper name to describe this flag. This flag is set when callback enqueue will return DLM_ENQUEUE_CALLBACK_NEED_SCHED because the callback worker need to be queued. The flag tells that callbacks are currently pending to be called and will be unset if the callback work for the specific lkb is done. The term need schedule is part of this time but a proper name is to say that there are some callbacks pending to being called. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: ast do WARN_ON_ONCE() on hotpathAlexander Aring2022-11-211-3/+3
| | | | | | | | | | This patch changes the ast hotpath functionality in very unlikely cases that we do WARN_ON_ONCE() instead of WARN_ON() to not spamming the console output if we run into states that it would occur over and over again. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: drop lkb ref in bug caseAlexander Aring2022-11-211-1/+2
| | | | | | | | | This patch will drop the lkb reference in an very unlikely case which should in practice not happened. However if it happens we cleanup the reference just in case. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: use a non-static queue for callbacksAlexander Aring2022-11-081-170/+124
| | | | | | | | | | | | | | | | | | | | | | | | This patch will introducde a queue implementation for callbacks by using the Linux lists. The current callback queue handling is implemented by a static limit of 6 entries, see DLM_CALLBACKS_SIZE. The sequence number inside the callback structure was used to see if the entries inside the static entry is valid or not. We don't need any sequence numbers anymore with a dynamic datastructure with grows and shrinks during runtime to offer such functionality. We assume that every callback will be delivered to the DLM user if once queued. Therefore the callback flag DLM_CB_SKIP was dropped and the check for skipping bast was moved before worker handling and not skip while the callback worker executes. This will reduce unnecessary queues of the callback worker. All last callback saves are pointers now and don't need to copied over. There is a reference counter for callback structures which will care about to free the callback structures at the right time if they are not referenced anymore. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: move last cast bast time to function callAlexander Aring2022-11-081-6/+4
| | | | | | | | This patch moves the debugging information of the last cast and bast time when calling the last and bast function call. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: use spin lock instead of mutexAlexander Aring2022-11-081-4/+4
| | | | | | | | | There is no need to use a mutex in those hot path sections. We change it to spin lock to serve callbacks more faster by not allowing schedule. The locked sections will not be locked for a long time. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: convert ls_cb_mutex mutex to spinlockAlexander Aring2022-11-081-6/+6
| | | | | | | | This patch converts the ls_cb_mutex mutex to a spinlock, there is no sleepable context when this lock is held. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: let dlm_add_cb queue work after resume onlyAlexander Aring2022-11-081-2/+2
| | | | | | | | | We should allow dlm_add_cb() to call queue_work() only after the recovery queued pending for delayed lkbs. This patch will move the switch LSFL_CB_DELAY after the delayed lkb work was processed. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: LSFL_CB_DELAY only for kernel lockspacesAlexander Aring2022-08-231-6/+7
| | | | | | | | | This patch only set/clear the LSFL_CB_DELAY bit when it's actually a kernel lockspace signaled by if ls->ls_callback_wq is set or not set in this case. User lockspaces will never evaluate this flag. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: fix race between test_bit() and queue_work()Alexander Aring2022-08-231-2/+4
| | | | | | | | | | | | | | This patch fixes a race by using ls_cb_mutex around the bit operations and conditional code blocks for LSFL_CB_DELAY. The function dlm_callback_stop() expects to stop all callbacks and flush all currently queued onces. The set_bit() is not enough because there can still be queue_work() after the workqueue was flushed. To avoid queue_work() after set_bit(), surround both by ls_cb_mutex. Cc: stable@vger.kernel.org Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: remove additional dereference of lksbAlexander Aring2022-06-241-1/+1
| | | | | | | | | | This patch removes a dereference of lksb of lkb when calling ast tracepoint. First it reduces additional overhead, even if traces are not active. Second we can deference it in TP_fast_assign from the existing lkb parameter. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: change ast and bast trace orderAlexander Aring2022-06-241-2/+2
| | | | | | | | This patch moves the trace calls for ast and bast to before the ast and bast callback functions are called rather than after. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: use list_empty() to check last iterationAlexander Aring2021-12-071-1/+3
| | | | | | | | | | This patch will use list_empty(&ls->ls_cb_delay) to check for last list iteration. In case of a multiply count of MAX_CB_QUEUE and the list is empty we do a extra goto more which we can avoid by checking on list_empty(). Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: initial support for tracepointsAlexander Aring2021-11-021-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds initial support for dlm tracepoints. It will introduce tracepoints to dlm main functionality dlm_lock()/dlm_unlock() and their complete ast() callback or blocking bast() callback. The lock/unlock functionality has a start and end tracepoint, this is because there exists a race in case if would have a tracepoint at the end position only the complete/blocking callbacks could occur before. To work with eBPF tracing and using their lookup hash functionality there could be problems that an entry was not inserted yet. However use the start functionality for hash insert and check again in end functionality if there was an dlm internal error so there is no ast callback. In further it might also that locks with local masters will occur those callbacks immediately so we must have such functionality. I did not make everything accessible yet, although it seems eBPF can be used to access a lot of internal datastructures if it's aware of the struct definitions of the running kernel instance. We still can change it, if you do eBPF experiments e.g. time measurements between lock and callback functionality you can simple use the local lkb_id field as hash value in combination with the lockspace id if you have multiple lockspaces. Otherwise you can simple use trace-cmd for some functionality, e.g. `trace-cmd record -e dlm` and `trace-cmd report` afterwards. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* fs: dlm: make dlm_callback_resume quiteAlexander Aring2021-11-021-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | This patch makes dlm_callback_resume info printout less noisy by accumulate all callback queues into one printout not in 25 times steps. It seems this printout became lately quite noisy in relationship with gfs2. Before: [241767.849302] dlm: bin: dlm_callback_resume 25 [241767.854846] dlm: bin: dlm_callback_resume 25 [241767.860373] dlm: bin: dlm_callback_resume 25 ... [241767.865920] dlm: bin: dlm_callback_resume 25 [241767.871352] dlm: bin: dlm_callback_resume 25 [241767.876733] dlm: bin: dlm_callback_resume 25 After the patch: [ 385.485728] dlm: gfs2: dlm_callback_resume 175 if zero it will not be printed out. Reported-by: Barry Marson <bmarson@redhat.com> Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 193Thomas Gleixner2019-05-301-3/+1
| | | | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this copyrighted material is made available to anyone wishing to use modify copy or redistribute it subject to the terms and conditions of the gnu general public license v 2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 45 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Steve Winslow <swinslow@gmail.com> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190528170027.342746075@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* dlm: Don't swamp the CPU with callbacks queued during recoveryBob Peterson2018-11-081-0/+10
| | | | | | | | | | | Before this patch, recovery would cause all callbacks to be delayed, put on a queue, and afterward they were all queued to the callback work queue. This patch does the same thing, but occasionally takes a break after 25 of them so it won't swamp the CPU at the expense of other RT processes like corosync. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* DLM: fix overflow dlm_cb_seqtsutomu.owa@toshiba.co.jp2017-09-251-0/+2
| | | | | | | | | dlm_cb_seq is 64 bits. If dlm_cb_seq overflows and returns to 0, dlm_rem_lkb_callback() will not work properly. Signed-off-by: Tadashi Miyauchi <miyauchi@toshiba-tops.co.jp> Signed-off-by: Tsutomu Owa <tsutomu.owa@toshiba.co.jp> Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: don't specify WQ_UNBOUND for the ast callback workqueueBob Peterson2016-10-191-1/+1
| | | | | | | | | | This patch removes the WQ_UNBOUND flag (which implies WQ_HIGHPRI) from the DLM's ast work queue, in favor of just WQ_HIGHPRI. This has been shown to cause a 19 percent performance increase for simultaneous inode creates on GFS2 with fs_mark. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: use INFO for recovery messagesDavid Teigland2014-02-141-1/+1
| | | | | | | | The log messages relating to the progress of recovery are minimal and very often useful. Change these to the KERN_INFO level so they are always available. Signed-off-by: David Teigland <teigland@redhat.com>
* fs: Include appropriate header file in dlm/ast.cRashika Kheria2014-02-121-0/+1
| | | | | | | | | | | | | | | | | | | Include appropriate header file fs/dlm/ast.h in fs/dlm/ast.c because it contains function prototypes of some functions defined in fs/dlm/ast.c. This also eliminates the following warning in fs/dlm/ast: fs/dlm/ast.c:52:5: warning: no previous prototype for ‘dlm_add_lkb_callback’ [-Wmissing-prototypes] fs/dlm/ast.c:113:5: warning: no previous prototype for ‘dlm_rem_lkb_callback’ [-Wmissing-prototypes] fs/dlm/ast.c:174:6: warning: no previous prototype for ‘dlm_add_cb’ [-Wmissing-prototypes] fs/dlm/ast.c:212:6: warning: no previous prototype for ‘dlm_callback_work’ [-Wmissing-prototypes] fs/dlm/ast.c:267:5: warning: no previous prototype for ‘dlm_callback_start’ [-Wmissing-prototypes] fs/dlm/ast.c:278:6: warning: no previous prototype for ‘dlm_callback_stop’ [-Wmissing-prototypes] fs/dlm/ast.c:284:6: warning: no previous prototype for ‘dlm_callback_suspend’ [-Wmissing-prototypes] fs/dlm/ast.c:292:6: warning: no previous prototype for ‘dlm_callback_resume’ [-Wmissing-prototypes] Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: WQ_NON_REENTRANT is meaningless and going awayTejun Heo2013-07-301-4/+1
| | | | | | | | | | dbf2576e37 ("workqueue: make all workqueues non-reentrant") made WQ_NON_REENTRANT no-op and the flag is going away. Remove its usages. This patch doesn't introduce any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: fix uninitialized spinlockDavid Teigland2012-08-081-2/+2
| | | | | | Use DEFINE_SPINLOCK for global dlm_cb_seq_spin. Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: fixes for nodir modeDavid Teigland2012-05-021-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The "nodir" mode (statically assign master nodes instead of using the resource directory) has always been highly experimental, and never seriously used. This commit fixes a number of problems, making nodir much more usable. - Major change to recovery: recover all locks and restart all in-progress operations after recovery. In some cases it's not possible to know which in-progess locks to recover, so recover all. (Most require recovery in nodir mode anyway since rehashing changes most master nodes.) - Change the way nodir mode is enabled, from a command line mount arg passed through gfs2, into a sysfs file managed by dlm_controld, consistent with the other config settings. - Allow recovering MSTCPY locks on an rsb that has not yet been turned into a master copy. - Ignore RCOM_LOCK and RCOM_LOCK_REPLY recovery messages from a previous, aborted recovery cycle. Base this on the local recovery status not being in the state where any nodes should be sending LOCK messages for the current recovery cycle. - Hold rsb lock around dlm_purge_mstcpy_locks() because it may run concurrently with dlm_recover_master_copy(). - Maintain highbast on process-copy lkb's (in addition to the master as is usual), because the lkb can switch back and forth between being a master and being a process copy as the master node changes in recovery. - When recovering MSTCPY locks, flag rsb's that have non-empty convert or waiting queues for granting at the end of recovery. (Rename flag from LOCKS_PURGED to RECOVER_GRANT and similar for the recovery function, because it's not only resources with purged locks that need grant a grant attempt.) - Replace a couple of unnecessary assertion panics with error messages. Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: don't limit active work itemsDavid Teigland2011-07-191-1/+4
| | | | | | | | Allow multiple workqueue items (locks with callbacks) to be processed concurrently. There should be no reason not to take advantage of this workqueue feature. Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: use workqueue for callbacksDavid Teigland2011-07-151-148/+114
| | | | | | | | | Instead of creating our own kthread (dlm_astd) to deliver callbacks for all lockspaces, use a per-lockspace workqueue to deliver the callbacks. This eliminates complications and slowdowns from many lockspaces sharing the same thread. Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: record full callback stateDavid Teigland2011-03-101-59/+198
| | | | | | | | | | | | | Change how callbacks are recorded for locks. Previously, information about multiple callbacks was combined into a couple of variables that indicated what the end result should be. In some situations, we could not tell from this combined state what the exact sequence of callbacks were, and would end up either delivering the callbacks in the wrong order, or suppress redundant callbacks incorrectly. This new approach records all the data for each callback, leaving no uncertainty about what needs to be delivered. Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: fix ordering of bast and castDavid Teigland2010-02-241-16/+58
| | | | | | | | | | | | | | | | | | | When both blocking and completion callbacks are queued for lock, the dlm would always deliver the completion callback (cast) first. In some cases the blocking callback (bast) is queued before the cast, though, and should be delivered first. This patch keeps track of the order in which they were queued and delivers them in that order. This patch also keeps track of the granted mode in the last cast and eliminates the following bast if the bast mode is compatible with the preceding cast mode. This happens when a remotely mastered lock is demoted, e.g. EX->NL, in which case the local node queues a cast immediately after sending the demote message. In this way a cast can be queued for a mode, e.g. NL, that makes an in-transit bast extraneous. Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: fs/dlm/ast.c: fix warningAndrew Morton2008-12-231-22/+17
| | | | | | | | | | fs/dlm/ast.c: In function 'dlm_astd': fs/dlm/ast.c:64: warning: 'bastmode' may be used uninitialized in this function Cleans code up. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: improve how bast mode handlingDavid Teigland2008-12-231-6/+8
| | | | | | | | | | | The lkb bastmode value is set in the context of processing the lock, and read by the dlm_astd thread. Because it's accessed in these two separate contexts, the writing/reading ought to be done under a lock. This is simple to do by setting it and reading it when the lkb is added to and removed from dlm_astd's callback list which is properly locked. Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: remove extra blocking callback checkDavid Teigland2008-12-231-6/+1
| | | | | | | | | | | | | | | | | Just before delivering a blocking callback (bast), the dlm_astd thread checks again that the granted mode of the lkb actually blocks the mode requested by the bast. The idea behind this was originally that the granted mode may have changed since the bast was queued, making the callback now unnecessary. Reasons for removing this extra check are: - dlm_astd doesn't lock the rsb before reading the lkb grmode, so it's not technically safe (this removes the long standing FIXME) - after running some tests, it doesn't appear the check ever actually eliminates a bast - delivering an unnecessary blocking callback isn't a bad thing and can happen anyway Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: replace schedule with cond_reschedSteven Whitehouse2008-12-231-1/+1
| | | | | | | | | | This is a one-liner to use cond_resched() rather than schedule() in the ast delivery loop. It should not be necessary to schedule every time, so this will save some cpu time while continuing to allow scheduling when required. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
* dlm: proper types for asts and bastsDavid Teigland2008-02-061-5/+4
| | | | | | | Use proper types for ast and bast functions, and use consistent type for ast param. Signed-off-by: David Teigland <teigland@redhat.com>
* [DLM] fs/dlm/ast.c should #include "ast.h"Adrian Bunk2007-05-011-0/+1
| | | | | | | | | Every file should include the headers containing the prototypes for it's global functions. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
* [DLM] down conversion clearing flagsDavid Teigland2006-08-231-0/+1
| | | | | | | | | | | The down-conversion optimization was resulting in the lkb flags being cleared because the stub message reply had no flags value set. Copy the current flags into the stub message so they'll be copied back into the lkb as part of processing the fake reply. Also add an assertion to catch this error more directly if it exists elsewhere. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
* [DLM] dlm: user locksDavid Teigland2006-07-131-1/+6
| | | | | | | | | | | | This changes the way the dlm handles user locks. The core dlm is now aware of user locks so they can be dealt with more efficiently. There is no more dlm_device module which previously managed its own duplicate copy of every user lock. Signed-off-by: Patrick Caulfield <pcaulfie@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
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