/* -*- mode: c; c-basic-offset: 8; -*- * vim: noexpandtab sw=8 ts=8 sts=0: * * dlmthread.c * * standalone DLM module * * Copyright (C) 2004 Oracle. All rights reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public * License along with this program; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 021110-1307, USA. * */ #include <linux/module.h> #include <linux/fs.h> #include <linux/types.h> #include <linux/slab.h> #include <linux/highmem.h> #include <linux/utsname.h> #include <linux/init.h> #include <linux/sysctl.h> #include <linux/random.h> #include <linux/blkdev.h> #include <linux/socket.h> #include <linux/inet.h> #include <linux/timer.h> #include <linux/kthread.h> #include <linux/delay.h> #include "cluster/heartbeat.h" #include "cluster/nodemanager.h" #include "cluster/tcp.h" #include "dlmapi.h" #include "dlmcommon.h" #include "dlmdomain.h" #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_THREAD) #include "cluster/masklog.h" static int dlm_thread(void *data); static void dlm_purge_lockres_now(struct dlm_ctxt *dlm, struct dlm_lock_resource *lockres); static void dlm_flush_asts(struct dlm_ctxt *dlm); #define dlm_lock_is_remote(dlm, lock) ((lock)->ml.node != (dlm)->node_num) /* will exit holding res->spinlock, but may drop in function */ /* waits until flags are cleared on res->state */ void __dlm_wait_on_lockres_flags(struct dlm_lock_resource *res, int flags) { DECLARE_WAITQUEUE(wait, current); assert_spin_locked(&res->spinlock); add_wait_queue(&res->wq, &wait); repeat: set_current_state(TASK_UNINTERRUPTIBLE); if (res->state & flags) { spin_unlock(&res->spinlock); schedule(); spin_lock(&res->spinlock); goto repeat; } remove_wait_queue(&res->wq, &wait); current->state = TASK_RUNNING; } int __dlm_lockres_unused(struct dlm_lock_resource *res) { if (list_empty(&res->granted) && list_empty(&res->converting) && list_empty(&res->blocked) && list_empty(&res->dirty)) return 1; return 0; } /* Call whenever you may have added or deleted something from one of * the lockres queue's. This will figure out whether it belongs on the * unused list or not and does the appropriate thing. */ void __dlm_lockres_calc_usage(struct dlm_ctxt *dlm, struct dlm_lock_resource *res) { mlog_entry("%.*s\n", res->lockname.len, res->lockname.name); assert_spin_locked(&dlm->spinlock); assert_spin_locked(&res->spinlock); if (__dlm_lockres_unused(res)){ /* For now, just keep any resource we master */ if (res->owner == dlm->node_num) { if (!list_empty(&res->purge)) { mlog(0, "we master %s:%.*s, but it is on " "the purge list. Removing\n", dlm->name, res->lockname.len, res->lockname.name); list_del_init(&res->purge); dlm->purge_count--; } return; } if (list_empty(&res->purge)) { mlog(0, "putting lockres %.*s from purge list\n", res->lockname.len, res->lockname.name); res->last_used = jiffies; list_add_tail(&res->purge, &dlm->purge_list); dlm->purge_count++; /* if this node is not the owner, there is * no way to keep track of who the owner could be. * unhash it to avoid serious problems. */ if (res->owner != dlm->node_num) { mlog(0, "%s:%.*s: doing immediate " "purge of lockres owned by %u\n", dlm->name, res->lockname.len, res->lockname.name, res->owner); dlm_purge_lockres_now(dlm, res); } } } else if (!list_empty(&res->purge)) { mlog(0, "removing lockres %.*s from purge list, " "owner=%u\n", res->lockname.len, res->lockname.name, res->owner); list_del_init(&res->purge); dlm->purge_count--; } } void dlm_lockres_calc_usage(struct dlm_ctxt *dlm, struct dlm_lock_resource *res) { mlog_entry("%.*s\n", res->lockname.len, res->lockname.name); spin_lock(&dlm->spinlock); spin_lock(&res->spinlock); __dlm_lockres_calc_usage(dlm, res); spin_unlock(&res->spinlock); spin_unlock(&dlm->spinlock); } /* TODO: Eventual API: Called with the dlm spinlock held, may drop it * to do migration, but will re-acquire before exit. */ void dlm_purge_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *lockres) { int master; int ret; spin_lock(&lockres->spinlock); master = lockres->owner == dlm->node_num; spin_unlock(&lockres->spinlock); mlog(0, "purging lockres %.*s, master = %d\n", lockres->lockname.len, lockres->lockname.name, master); /* Non master is the easy case -- no migration required, just * quit. */ if (!master) goto finish; /* Wheee! Migrate lockres here! */ spin_unlock(&dlm->spinlock); again: ret = dlm_migrate_lockres(dlm, lockres, O2NM_MAX_NODES); if (ret == -ENOTEMPTY) { mlog(ML_ERROR, "lockres %.*s still has local locks!\n", lockres->lockname.len, lockres->lockname.name); BUG(); } else if (ret < 0) { mlog(ML_NOTICE, "lockres %.*s: migrate failed, retrying\n", lockres->lockname.len, lockres->lockname.name); msleep(100); goto again; } spin_lock(&dlm->spinlock); finish: if (!list_empty(&lockres->purge)) { list_del_init(&lockres->purge); dlm->purge_count--; } __dlm_unhash_lockres(lockres); } /* make an unused lockres go away immediately. * as soon as the dlm spinlock is dropped, this lockres * will not be found. kfree still happens on last put. */ static void dlm_purge_lockres_now(struct dlm_ctxt *dlm, struct dlm_lock_resource *lockres) { assert_spin_locked(&dlm->spinlock); assert_spin_locked(&lockres->spinlock); BUG_ON(!__dlm_lockres_unused(lockres)); if (!list_empty(&lockres->purge)) { list_del_init(&lockres->purge); dlm->purge_count--; } __dlm_unhash_lockres(lockres); } static void dlm_run_purge_list(struct dlm_ctxt *dlm, int purge_now) { unsigned int run_max, unused; unsigned long purge_jiffies; struct dlm_lock_resource *lockres; spin_lock(&dlm->spinlock); run_max = dlm->purge_count; while(run_max && !list_empty(&dlm->purge_list)) { run_max--; lockres = list_entry(dlm->purge_list.next, struct dlm_lock_resource, purge); /* Status of the lockres *might* change so double * check. If the lockres is unused, holding the dlm * spinlock will prevent people from getting and more * refs on it -- there's no need to keep the lockres * spinlock. */ spin_lock(&lockres->spinlock); unused = __dlm_lockres_unused(lockres); spin_unlock(&lockres->spinlock); if (!unused) continue; purge_jiffies = lockres->last_used + msecs_to_jiffies(DLM_PURGE_INTERVAL_MS); /* Make sure that we want to be processing this guy at * this time. */ if (!purge_now && time_after(purge_jiffies, jiffies)) { /* Since resources are added to the purge list * in tail order, we can stop at the first * unpurgable resource -- anyone added after * him will have a greater last_used value */ break; } list_del_init(&lockres->purge); dlm->purge_count--; /* This may drop and reacquire the dlm spinlock if it * has to do migration. */ mlog(0, "calling dlm_purge_lockres!\n"); dlm_purge_lockres(dlm, lockres); mlog(0, "DONE calling dlm_purge_lockres!\n"); /* Avoid adding any scheduling latencies */ cond_resched_lock(&dlm->spinlock); } spin_unlock(&dlm->spinlock); } static void dlm_shuffle_lists(struct dlm_ctxt *dlm, struct dlm_lock_resource *res) { struct dlm_lock *lock, *target; struct list_head *iter; struct list_head *head; int can_grant = 1; //mlog(0, "res->lockname.len=%d\n", res->lockname.len); //mlog(0, "res->lockname.name=%p\n", res->lockname.name); //mlog(0, "shuffle res %.*s\n", res->lockname.len, // res->lockname.name); /* because this function is called with the lockres * spinlock, and because we know that it is not migrating/ * recovering/in-progress, it is fine to reserve asts and * basts right before queueing them all throughout */ assert_spin_locked(&res->spinlock); BUG_ON((res->state & (DLM_LOCK_RES_MIGRATING| DLM_LOCK_RES_RECOVERING| DLM_LOCK_RES_IN_PROGRESS))); converting: if (list_empty(&res->converting)) goto blocked; mlog(0, "res %.*s has locks on a convert queue\n", res->lockname.len, res->lockname.name); target = list_entry(res->converting.next, struct dlm_lock, list); if (target->ml.convert_type == LKM_IVMODE) { mlog(ML_ERROR, "%.*s: converting a lock with no " "convert_type!\n", res->lockname.len, res->lockname.name); BUG(); } head = &res->granted; list_for_each(iter, head) { lock = list_entry(iter, struct dlm_lock, list); if (lock==target) continue; if (!dlm_lock_compatible(lock->ml.type, target->ml.convert_type)) { can_grant = 0; /* queue the BAST if not already */ if (lock->ml.highest_blocked == LKM_IVMODE) { __dlm_lockres_reserve_ast(res); dlm_queue_bast(dlm, lock); } /* update the highest_blocked if needed */ if (lock->ml.highest_blocked < target->ml.convert_type) lock->ml.highest_blocked = target->ml.convert_type; } } head = &res->converting; list_for_each(iter, head) { lock = list_entry(iter, struct dlm_lock, list); if (lock==target) continue; if (!dlm_lock_compatible(lock->ml.type, target->ml.convert_type)) { can_grant = 0; if (lock->ml.highest_blocked == LKM_IVMODE) { __dlm_lockres_reserve_ast(res); dlm_queue_bast(dlm, lock); } if (lock->ml.highest_blocked < target->ml.convert_type) lock->ml.highest_blocked = target->ml.convert_type; } } /* we can convert the lock */ if (can_grant) { spin_lock(&target->spinlock); BUG_ON(target->ml.highest_blocked != LKM_IVMODE); mlog(0, "calling ast for converting lock: %.*s, have: %d, " "granting: %d, node: %u\n", res->lockname.len, res->lockname.name, target->ml.type, target->ml.convert_type, target->ml.node); target->ml.type = target->ml.convert_type; target->ml.convert_type = LKM_IVMODE; list_move_tail(&target->list, &res->granted); BUG_ON(!target->lksb); target->lksb->status = DLM_NORMAL; spin_unlock(&target->spinlock); __dlm_lockres_reserve_ast(res); dlm_queue_ast(dlm, target); /* go back and check for more */ goto converting; } blocked: if (list_empty(&res->blocked)) goto leave; target = list_entry(res->blocked.next, struct dlm_lock, list); head = &res->granted; list_for_each(iter, head) { lock = list_entry(iter, struct dlm_lock, list); if (lock==target) continue; if (!dlm_lock_compatible(lock->ml.type, target->ml.type)) { can_grant = 0; if (lock->ml.highest_blocked == LKM_IVMODE) { __dlm_lockres_reserve_ast(res); dlm_queue_bast(dlm, lock); } if (lock->ml.highest_blocked < target->ml.type) lock->ml.highest_blocked = target->ml.type; } } head = &res->converting; list_for_each(iter, head) { lock = list_entry(iter, struct dlm_lock, list); if (lock==target) continue; if (!dlm_lock_compatible(lock->ml.type, target->ml.type)) { can_grant = 0; if (lock->ml.highest_blocked == LKM_IVMODE) { __dlm_lockres_reserve_ast(res); dlm_queue_bast(dlm, lock); } if (lock->ml.highest_blocked < target->ml.type) lock->ml.highest_blocked = target->ml.type; } } /* we can grant the blocked lock (only * possible if converting list empty) */ if (can_grant) { spin_lock(&target->spinlock); BUG_ON(target->ml.highest_blocked != LKM_IVMODE); mlog(0, "calling ast for blocked lock: %.*s, granting: %d, " "node: %u\n", res->lockname.len, res->lockname.name, target->ml.type, target->ml.node); // target->ml.type is already correct list_move_tail(&target->list, &res->granted); BUG_ON(!target->lksb); target->lksb->status = DLM_NORMAL; spin_unlock(&target->spinlock); __dlm_lockres_reserve_ast(res); dlm_queue_ast(dlm, target); /* go back and check for more */ goto converting; } leave: return; } /* must have NO locks when calling this with res !=NULL * */ void dlm_kick_thread(struct dlm_ctxt *dlm, struct dlm_lock_resource *res) { mlog_entry("dlm=%p, res=%p\n", dlm, res); if (res) { spin_lock(&dlm->spinlock); spin_lock(&res->spinlock); __dlm_dirty_lockres(dlm, res); spin_unlock(&res->spinlock); spin_unlock(&dlm->spinlock); } wake_up(&dlm->dlm_thread_wq); } void __dlm_dirty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res) { mlog_entry("dlm=%p, res=%p\n", dlm, res); assert_spin_locked(&dlm->spinlock); assert_spin_locked(&res->spinlock); /* don't shuffle secondary queues */ if ((res->owner == dlm->node_num) && !(res->state & DLM_LOCK_RES_DIRTY)) { /* ref for dirty_list */ dlm_lockres_get(res); list_add_tail(&res->dirty, &dlm->dirty_list); res->state |= DLM_LOCK_RES_DIRTY; } } /* Launch the NM thread for the mounted volume */ int dlm_launch_thread(struct dlm_ctxt *dlm) { mlog(0, "starting dlm thread...\n"); dlm->dlm_thread_task = kthread_run(dlm_thread, dlm, "dlm_thread"); if (IS_ERR(dlm->dlm_thread_task)) { mlog_errno(PTR_ERR(dlm->dlm_thread_task)); dlm->dlm_thread_task = NULL; return -EINVAL; } return 0; } void dlm_complete_thread(struct dlm_ctxt *dlm) { if (dlm->dlm_thread_task) { mlog(ML_KTHREAD, "waiting for dlm thread to exit\n"); kthread_stop(dlm->dlm_thread_task); dlm->dlm_thread_task = NULL; } } static int dlm_dirty_list_empty(struct dlm_ctxt *dlm) { int empty; spin_lock(&dlm->spinlock); empty = list_empty(&dlm->dirty_list); spin_unlock(&dlm->spinlock); return empty; } static void dlm_flush_asts(struct dlm_ctxt *dlm) { int ret; struct dlm_lock *lock; struct dlm_lock_resource *res; u8 hi; spin_lock(&dlm->ast_lock); while (!list_empty(&dlm->pending_asts)) { lock = list_entry(dlm->pending_asts.next, struct dlm_lock, ast_list); /* get an extra ref on lock */ dlm_lock_get(lock); res = lock->lockres; mlog(0, "delivering an ast for this lockres\n"); BUG_ON(!lock->ast_pending); /* remove from list (including ref) */ list_del_init(&lock->ast_list); dlm_lock_put(lock); spin_unlock(&dlm->ast_lock); if (lock->ml.node != dlm->node_num) { ret = dlm_do_remote_ast(dlm, res, lock); if (ret < 0) mlog_errno(ret); } else dlm_do_local_ast(dlm, res, lock); spin_lock(&dlm->ast_lock); /* possible that another ast was queued while * we were delivering the last one */ if (!list_empty(&lock->ast_list)) { mlog(0, "aha another ast got queued while " "we were finishing the last one. will " "keep the ast_pending flag set.\n"); } else lock->ast_pending = 0; /* drop the extra ref. * this may drop it completely. */ dlm_lock_put(lock); dlm_lockres_release_ast(dlm, res); } while (!list_empty(&dlm->pending_basts)) { lock = list_entry(dlm->pending_basts.next, struct dlm_lock, bast_list); /* get an extra ref on lock */ dlm_lock_get(lock); res = lock->lockres; BUG_ON(!lock->bast_pending); /* get the highest blocked lock, and reset */ spin_lock(&lock->spinlock); BUG_ON(lock->ml.highest_blocked <= LKM_IVMODE); hi = lock->ml.highest_blocked; lock->ml.highest_blocked = LKM_IVMODE; spin_unlock(&lock->spinlock); /* remove from list (including ref) */ list_del_init(&lock->bast_list); dlm_lock_put(lock); spin_unlock(&dlm->ast_lock); mlog(0, "delivering a bast for this lockres " "(blocked = %d\n", hi); if (lock->ml.node != dlm->node_num) { ret = dlm_send_proxy_bast(dlm, res, lock, hi); if (ret < 0) mlog_errno(ret); } else dlm_do_local_bast(dlm, res, lock, hi); spin_lock(&dlm->ast_lock); /* possible that another bast was queued while * we were delivering the last one */ if (!list_empty(&lock->bast_list)) { mlog(0, "aha another bast got queued while " "we were finishing the last one. will " "keep the bast_pending flag set.\n"); } else lock->bast_pending = 0; /* drop the extra ref. * this may drop it completely. */ dlm_lock_put(lock); dlm_lockres_release_ast(dlm, res); } wake_up(&dlm->ast_wq); spin_unlock(&dlm->ast_lock); } #define DLM_THREAD_TIMEOUT_MS (4 * 1000) #define DLM_THREAD_MAX_DIRTY 100 #define DLM_THREAD_MAX_ASTS 10 static int dlm_thread(void *data) { struct dlm_lock_resource *res; struct dlm_ctxt *dlm = data; unsigned long timeout = msecs_to_jiffies(DLM_THREAD_TIMEOUT_MS); mlog(0, "dlm thread running for %s...\n", dlm->name); while (!kthread_should_stop()) { int n = DLM_THREAD_MAX_DIRTY; /* dlm_shutting_down is very point-in-time, but that * doesn't matter as we'll just loop back around if we * get false on the leading edge of a state * transition. */ dlm_run_purge_list(dlm, dlm_shutting_down(dlm)); /* We really don't want to hold dlm->spinlock while * calling dlm_shuffle_lists on each lockres that * needs to have its queues adjusted and AST/BASTs * run. So let's pull each entry off the dirty_list * and drop dlm->spinlock ASAP. Once off the list, * res->spinlock needs to be taken again to protect * the queues while calling dlm_shuffle_lists. */ spin_lock(&dlm->spinlock); while (!list_empty(&dlm->dirty_list)) { int delay = 0; res = list_entry(dlm->dirty_list.next, struct dlm_lock_resource, dirty); /* peel a lockres off, remove it from the list, * unset the dirty flag and drop the dlm lock */ BUG_ON(!res); dlm_lockres_get(res); spin_lock(&res->spinlock); res->state &= ~DLM_LOCK_RES_DIRTY; list_del_init(&res->dirty); spin_unlock(&res->spinlock); spin_unlock(&dlm->spinlock); /* Drop dirty_list ref */ dlm_lockres_put(res); /* lockres can be re-dirtied/re-added to the * dirty_list in this gap, but that is ok */ spin_lock(&res->spinlock); if (res->owner != dlm->node_num) { __dlm_print_one_lock_resource(res); mlog(ML_ERROR, "inprog:%s, mig:%s, reco:%s, dirty:%s\n", res->state & DLM_LOCK_RES_IN_PROGRESS ? "yes" : "no", res->state & DLM_LOCK_RES_MIGRATING ? "yes" : "no", res->state & DLM_LOCK_RES_RECOVERING ? "yes" : "no", res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no"); } BUG_ON(res->owner != dlm->node_num); /* it is now ok to move lockreses in these states * to the dirty list, assuming that they will only be * dirty for a short while. */ if (res->state & (DLM_LOCK_RES_IN_PROGRESS | DLM_LOCK_RES_MIGRATING | DLM_LOCK_RES_RECOVERING)) { /* move it to the tail and keep going */ spin_unlock(&res->spinlock); mlog(0, "delaying list shuffling for in-" "progress lockres %.*s, state=%d\n", res->lockname.len, res->lockname.name, res->state); delay = 1; goto in_progress; } /* at this point the lockres is not migrating/ * recovering/in-progress. we have the lockres * spinlock and do NOT have the dlm lock. * safe to reserve/queue asts and run the lists. */ mlog(0, "calling dlm_shuffle_lists with dlm=%s, " "res=%.*s\n", dlm->name, res->lockname.len, res->lockname.name); /* called while holding lockres lock */ dlm_shuffle_lists(dlm, res); spin_unlock(&res->spinlock); dlm_lockres_calc_usage(dlm, res); in_progress: spin_lock(&dlm->spinlock); /* if the lock was in-progress, stick * it on the back of the list */ if (delay) { /* ref for dirty_list */ dlm_lockres_get(res); spin_lock(&res->spinlock); list_add_tail(&res->dirty, &dlm->dirty_list); res->state |= DLM_LOCK_RES_DIRTY; spin_unlock(&res->spinlock); } dlm_lockres_put(res); /* unlikely, but we may need to give time to * other tasks */ if (!--n) { mlog(0, "throttling dlm_thread\n"); break; } } spin_unlock(&dlm->spinlock); dlm_flush_asts(dlm); /* yield and continue right away if there is more work to do */ if (!n) { cond_resched(); continue; } wait_event_interruptible_timeout(dlm->dlm_thread_wq, !dlm_dirty_list_empty(dlm) || kthread_should_stop(), timeout); } mlog(0, "quitting DLM thread\n"); return 0; }