--- /dev/null
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * dlmmod.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/spinlock.h>
+#include <linux/delay.h>
+
+
+#include "cluster/heartbeat.h"
+#include "cluster/nodemanager.h"
+#include "cluster/tcp.h"
+
+#include "dlmapi.h"
+#include "dlmcommon.h"
+#include "dlmdebug.h"
+#include "dlmdomain.h"
+
+#define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_MASTER)
+#include "cluster/masklog.h"
+
+enum dlm_mle_type {
+ DLM_MLE_BLOCK,
+ DLM_MLE_MASTER,
+ DLM_MLE_MIGRATION
+};
+
+struct dlm_lock_name
+{
+ u8 len;
+ u8 name[DLM_LOCKID_NAME_MAX];
+};
+
+struct dlm_master_list_entry
+{
+ struct list_head list;
+ struct list_head hb_events;
+ struct dlm_ctxt *dlm;
+ spinlock_t spinlock;
+ wait_queue_head_t wq;
+ atomic_t woken;
+ struct kref mle_refs;
+ unsigned long maybe_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
+ unsigned long vote_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
+ unsigned long response_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
+ unsigned long node_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
+ u8 master;
+ u8 new_master;
+ enum dlm_mle_type type;
+ struct o2hb_callback_func mle_hb_up;
+ struct o2hb_callback_func mle_hb_down;
+ union {
+ struct dlm_lock_resource *res;
+ struct dlm_lock_name name;
+ } u;
+};
+
+static void dlm_mle_node_down(struct dlm_ctxt *dlm,
+ struct dlm_master_list_entry *mle,
+ struct o2nm_node *node,
+ int idx);
+static void dlm_mle_node_up(struct dlm_ctxt *dlm,
+ struct dlm_master_list_entry *mle,
+ struct o2nm_node *node,
+ int idx);
+
+static void dlm_assert_master_worker(struct dlm_work_item *item, void *data);
+static int dlm_do_assert_master(struct dlm_ctxt *dlm, const char *lockname,
+ unsigned int namelen, void *nodemap,
+ u32 flags);
+
+static inline int dlm_mle_equal(struct dlm_ctxt *dlm,
+ struct dlm_master_list_entry *mle,
+ const char *name,
+ unsigned int namelen)
+{
+ struct dlm_lock_resource *res;
+
+ if (dlm != mle->dlm)
+ return 0;
+
+ if (mle->type == DLM_MLE_BLOCK ||
+ mle->type == DLM_MLE_MIGRATION) {
+ if (namelen != mle->u.name.len ||
+ memcmp(name, mle->u.name.name, namelen)!=0)
+ return 0;
+ } else {
+ res = mle->u.res;
+ if (namelen != res->lockname.len ||
+ memcmp(res->lockname.name, name, namelen) != 0)
+ return 0;
+ }
+ return 1;
+}
+
+#if 0
+/* Code here is included but defined out as it aids debugging */
+
+void dlm_print_one_mle(struct dlm_master_list_entry *mle)
+{
+ int i = 0, refs;
+ char *type;
+ char attached;
+ u8 master;
+ unsigned int namelen;
+ const char *name;
+ struct kref *k;
+
+ k = &mle->mle_refs;
+ if (mle->type == DLM_MLE_BLOCK)
+ type = "BLK";
+ else if (mle->type == DLM_MLE_MASTER)
+ type = "MAS";
+ else
+ type = "MIG";
+ refs = atomic_read(&k->refcount);
+ master = mle->master;
+ attached = (list_empty(&mle->hb_events) ? 'N' : 'Y');
+
+ if (mle->type != DLM_MLE_MASTER) {
+ namelen = mle->u.name.len;
+ name = mle->u.name.name;
+ } else {
+ namelen = mle->u.res->lockname.len;
+ name = mle->u.res->lockname.name;
+ }
+
+ mlog(ML_NOTICE, " #%3d: %3s %3d %3u %3u %c (%d)%.*s\n",
+ i, type, refs, master, mle->new_master, attached,
+ namelen, namelen, name);
+}
+
+static void dlm_dump_mles(struct dlm_ctxt *dlm)
+{
+ struct dlm_master_list_entry *mle;
+ struct list_head *iter;
+
+ mlog(ML_NOTICE, "dumping all mles for domain %s:\n", dlm->name);
+ mlog(ML_NOTICE, " ####: type refs owner new events? lockname nodemap votemap respmap maybemap\n");
+ spin_lock(&dlm->master_lock);
+ list_for_each(iter, &dlm->master_list) {
+ mle = list_entry(iter, struct dlm_master_list_entry, list);
+ dlm_print_one_mle(mle);
+ }
+ spin_unlock(&dlm->master_lock);
+}
+
+int dlm_dump_all_mles(const char __user *data, unsigned int len)
+{
+ struct list_head *iter;
+ struct dlm_ctxt *dlm;
+
+ spin_lock(&dlm_domain_lock);
+ list_for_each(iter, &dlm_domains) {
+ dlm = list_entry (iter, struct dlm_ctxt, list);
+ mlog(ML_NOTICE, "found dlm: %p, name=%s\n", dlm, dlm->name);
+ dlm_dump_mles(dlm);
+ }
+ spin_unlock(&dlm_domain_lock);
+ return len;
+}
+EXPORT_SYMBOL_GPL(dlm_dump_all_mles);
+
+#endif /* 0 */
+
+
+static kmem_cache_t *dlm_mle_cache = NULL;
+
+
+static void dlm_mle_release(struct kref *kref);
+static void dlm_init_mle(struct dlm_master_list_entry *mle,
+ enum dlm_mle_type type,
+ struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res,
+ const char *name,
+ unsigned int namelen);
+static void dlm_put_mle(struct dlm_master_list_entry *mle);
+static void __dlm_put_mle(struct dlm_master_list_entry *mle);
+static int dlm_find_mle(struct dlm_ctxt *dlm,
+ struct dlm_master_list_entry **mle,
+ char *name, unsigned int namelen);
+
+static int dlm_do_master_request(struct dlm_master_list_entry *mle, int to);
+
+
+static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res,
+ struct dlm_master_list_entry *mle,
+ int *blocked);
+static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res,
+ struct dlm_master_list_entry *mle,
+ int blocked);
+static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res,
+ struct dlm_master_list_entry *mle,
+ struct dlm_master_list_entry **oldmle,
+ const char *name, unsigned int namelen,
+ u8 new_master, u8 master);
+
+static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res);
+static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res);
+static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res,
+ u8 target);
+static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res);
+
+
+int dlm_is_host_down(int errno)
+{
+ switch (errno) {
+ case -EBADF:
+ case -ECONNREFUSED:
+ case -ENOTCONN:
+ case -ECONNRESET:
+ case -EPIPE:
+ case -EHOSTDOWN:
+ case -EHOSTUNREACH:
+ case -ETIMEDOUT:
+ case -ECONNABORTED:
+ case -ENETDOWN:
+ case -ENETUNREACH:
+ case -ENETRESET:
+ case -ESHUTDOWN:
+ case -ENOPROTOOPT:
+ case -EINVAL: /* if returned from our tcp code,
+ this means there is no socket */
+ return 1;
+ }
+ return 0;
+}
+
+
+/*
+ * MASTER LIST FUNCTIONS
+ */
+
+
+/*
+ * regarding master list entries and heartbeat callbacks:
+ *
+ * in order to avoid sleeping and allocation that occurs in
+ * heartbeat, master list entries are simply attached to the
+ * dlm's established heartbeat callbacks. the mle is attached
+ * when it is created, and since the dlm->spinlock is held at
+ * that time, any heartbeat event will be properly discovered
+ * by the mle. the mle needs to be detached from the
+ * dlm->mle_hb_events list as soon as heartbeat events are no
+ * longer useful to the mle, and before the mle is freed.
+ *
+ * as a general rule, heartbeat events are no longer needed by
+ * the mle once an "answer" regarding the lock master has been
+ * received.
+ */
+static inline void __dlm_mle_attach_hb_events(struct dlm_ctxt *dlm,
+ struct dlm_master_list_entry *mle)
+{
+ assert_spin_locked(&dlm->spinlock);
+
+ list_add_tail(&mle->hb_events, &dlm->mle_hb_events);
+}
+
+
+static inline void __dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
+ struct dlm_master_list_entry *mle)
+{
+ if (!list_empty(&mle->hb_events))
+ list_del_init(&mle->hb_events);
+}
+
+
+static inline void dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
+ struct dlm_master_list_entry *mle)
+{
+ spin_lock(&dlm->spinlock);
+ __dlm_mle_detach_hb_events(dlm, mle);
+ spin_unlock(&dlm->spinlock);
+}
+
+/* remove from list and free */
+static void __dlm_put_mle(struct dlm_master_list_entry *mle)
+{
+ struct dlm_ctxt *dlm;
+ dlm = mle->dlm;
+
+ assert_spin_locked(&dlm->spinlock);
+ assert_spin_locked(&dlm->master_lock);
+ BUG_ON(!atomic_read(&mle->mle_refs.refcount));
+
+ kref_put(&mle->mle_refs, dlm_mle_release);
+}
+
+
+/* must not have any spinlocks coming in */
+static void dlm_put_mle(struct dlm_master_list_entry *mle)
+{
+ struct dlm_ctxt *dlm;
+ dlm = mle->dlm;
+
+ spin_lock(&dlm->spinlock);
+ spin_lock(&dlm->master_lock);
+ __dlm_put_mle(mle);
+ spin_unlock(&dlm->master_lock);
+ spin_unlock(&dlm->spinlock);
+}
+
+static inline void dlm_get_mle(struct dlm_master_list_entry *mle)
+{
+ kref_get(&mle->mle_refs);
+}
+
+static void dlm_init_mle(struct dlm_master_list_entry *mle,
+ enum dlm_mle_type type,
+ struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res,
+ const char *name,
+ unsigned int namelen)
+{
+ assert_spin_locked(&dlm->spinlock);
+
+ mle->dlm = dlm;
+ mle->type = type;
+ INIT_LIST_HEAD(&mle->list);
+ INIT_LIST_HEAD(&mle->hb_events);
+ memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
+ spin_lock_init(&mle->spinlock);
+ init_waitqueue_head(&mle->wq);
+ atomic_set(&mle->woken, 0);
+ kref_init(&mle->mle_refs);
+ memset(mle->response_map, 0, sizeof(mle->response_map));
+ mle->master = O2NM_MAX_NODES;
+ mle->new_master = O2NM_MAX_NODES;
+
+ if (mle->type == DLM_MLE_MASTER) {
+ BUG_ON(!res);
+ mle->u.res = res;
+ } else if (mle->type == DLM_MLE_BLOCK) {
+ BUG_ON(!name);
+ memcpy(mle->u.name.name, name, namelen);
+ mle->u.name.len = namelen;
+ } else /* DLM_MLE_MIGRATION */ {
+ BUG_ON(!name);
+ memcpy(mle->u.name.name, name, namelen);
+ mle->u.name.len = namelen;
+ }
+
+ /* copy off the node_map and register hb callbacks on our copy */
+ memcpy(mle->node_map, dlm->domain_map, sizeof(mle->node_map));
+ memcpy(mle->vote_map, dlm->domain_map, sizeof(mle->vote_map));
+ clear_bit(dlm->node_num, mle->vote_map);
+ clear_bit(dlm->node_num, mle->node_map);
+
+ /* attach the mle to the domain node up/down events */
+ __dlm_mle_attach_hb_events(dlm, mle);
+}
+
+
+/* returns 1 if found, 0 if not */
+static int dlm_find_mle(struct dlm_ctxt *dlm,
+ struct dlm_master_list_entry **mle,
+ char *name, unsigned int namelen)
+{
+ struct dlm_master_list_entry *tmpmle;
+ struct list_head *iter;
+
+ assert_spin_locked(&dlm->master_lock);
+
+ list_for_each(iter, &dlm->master_list) {
+ tmpmle = list_entry(iter, struct dlm_master_list_entry, list);
+ if (!dlm_mle_equal(dlm, tmpmle, name, namelen))
+ continue;
+ dlm_get_mle(tmpmle);
+ *mle = tmpmle;
+ return 1;
+ }
+ return 0;
+}
+
+void dlm_hb_event_notify_attached(struct dlm_ctxt *dlm, int idx, int node_up)
+{
+ struct dlm_master_list_entry *mle;
+ struct list_head *iter;
+
+ assert_spin_locked(&dlm->spinlock);
+
+ list_for_each(iter, &dlm->mle_hb_events) {
+ mle = list_entry(iter, struct dlm_master_list_entry,
+ hb_events);
+ if (node_up)
+ dlm_mle_node_up(dlm, mle, NULL, idx);
+ else
+ dlm_mle_node_down(dlm, mle, NULL, idx);
+ }
+}
+
+static void dlm_mle_node_down(struct dlm_ctxt *dlm,
+ struct dlm_master_list_entry *mle,
+ struct o2nm_node *node, int idx)
+{
+ spin_lock(&mle->spinlock);
+
+ if (!test_bit(idx, mle->node_map))
+ mlog(0, "node %u already removed from nodemap!\n", idx);
+ else
+ clear_bit(idx, mle->node_map);
+
+ spin_unlock(&mle->spinlock);
+}
+
+static void dlm_mle_node_up(struct dlm_ctxt *dlm,
+ struct dlm_master_list_entry *mle,
+ struct o2nm_node *node, int idx)
+{
+ spin_lock(&mle->spinlock);
+
+ if (test_bit(idx, mle->node_map))
+ mlog(0, "node %u already in node map!\n", idx);
+ else
+ set_bit(idx, mle->node_map);
+
+ spin_unlock(&mle->spinlock);
+}
+
+
+int dlm_init_mle_cache(void)
+{
+ dlm_mle_cache = kmem_cache_create("dlm_mle_cache",
+ sizeof(struct dlm_master_list_entry),
+ 0, SLAB_HWCACHE_ALIGN,
+ NULL, NULL);
+ if (dlm_mle_cache == NULL)
+ return -ENOMEM;
+ return 0;
+}
+
+void dlm_destroy_mle_cache(void)
+{
+ if (dlm_mle_cache)
+ kmem_cache_destroy(dlm_mle_cache);
+}
+
+static void dlm_mle_release(struct kref *kref)
+{
+ struct dlm_master_list_entry *mle;
+ struct dlm_ctxt *dlm;
+
+ mlog_entry_void();
+
+ mle = container_of(kref, struct dlm_master_list_entry, mle_refs);
+ dlm = mle->dlm;
+
+ if (mle->type != DLM_MLE_MASTER) {
+ mlog(0, "calling mle_release for %.*s, type %d\n",
+ mle->u.name.len, mle->u.name.name, mle->type);
+ } else {
+ mlog(0, "calling mle_release for %.*s, type %d\n",
+ mle->u.res->lockname.len,
+ mle->u.res->lockname.name, mle->type);
+ }
+ assert_spin_locked(&dlm->spinlock);
+ assert_spin_locked(&dlm->master_lock);
+
+ /* remove from list if not already */
+ if (!list_empty(&mle->list))
+ list_del_init(&mle->list);
+
+ /* detach the mle from the domain node up/down events */
+ __dlm_mle_detach_hb_events(dlm, mle);
+
+ /* NOTE: kfree under spinlock here.
+ * if this is bad, we can move this to a freelist. */
+ kmem_cache_free(dlm_mle_cache, mle);
+}
+
+
+/*
+ * LOCK RESOURCE FUNCTIONS
+ */
+
+static void dlm_set_lockres_owner(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res,
+ u8 owner)
+{
+ assert_spin_locked(&res->spinlock);
+
+ mlog_entry("%.*s, %u\n", res->lockname.len, res->lockname.name, owner);
+
+ if (owner == dlm->node_num)
+ atomic_inc(&dlm->local_resources);
+ else if (owner == DLM_LOCK_RES_OWNER_UNKNOWN)
+ atomic_inc(&dlm->unknown_resources);
+ else
+ atomic_inc(&dlm->remote_resources);
+
+ res->owner = owner;
+}
+
+void dlm_change_lockres_owner(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res, u8 owner)
+{
+ assert_spin_locked(&res->spinlock);
+
+ if (owner == res->owner)
+ return;
+
+ if (res->owner == dlm->node_num)
+ atomic_dec(&dlm->local_resources);
+ else if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN)
+ atomic_dec(&dlm->unknown_resources);
+ else
+ atomic_dec(&dlm->remote_resources);
+
+ dlm_set_lockres_owner(dlm, res, owner);
+}
+
+
+static void dlm_lockres_release(struct kref *kref)
+{
+ struct dlm_lock_resource *res;
+
+ res = container_of(kref, struct dlm_lock_resource, refs);
+
+ /* This should not happen -- all lockres' have a name
+ * associated with them at init time. */
+ BUG_ON(!res->lockname.name);
+
+ mlog(0, "destroying lockres %.*s\n", res->lockname.len,
+ res->lockname.name);
+
+ /* By the time we're ready to blow this guy away, we shouldn't
+ * be on any lists. */
+ BUG_ON(!hlist_unhashed(&res->hash_node));
+ BUG_ON(!list_empty(&res->granted));
+ BUG_ON(!list_empty(&res->converting));
+ BUG_ON(!list_empty(&res->blocked));
+ BUG_ON(!list_empty(&res->dirty));
+ BUG_ON(!list_empty(&res->recovering));
+ BUG_ON(!list_empty(&res->purge));
+
+ kfree(res->lockname.name);
+
+ kfree(res);
+}
+
+void dlm_lockres_get(struct dlm_lock_resource *res)
+{
+ kref_get(&res->refs);
+}
+
+void dlm_lockres_put(struct dlm_lock_resource *res)
+{
+ kref_put(&res->refs, dlm_lockres_release);
+}
+
+static void dlm_init_lockres(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res,
+ const char *name, unsigned int namelen)
+{
+ char *qname;
+
+ /* If we memset here, we lose our reference to the kmalloc'd
+ * res->lockname.name, so be sure to init every field
+ * correctly! */
+
+ qname = (char *) res->lockname.name;
+ memcpy(qname, name, namelen);
+
+ res->lockname.len = namelen;
+ res->lockname.hash = full_name_hash(name, namelen);
+
+ init_waitqueue_head(&res->wq);
+ spin_lock_init(&res->spinlock);
+ INIT_HLIST_NODE(&res->hash_node);
+ INIT_LIST_HEAD(&res->granted);
+ INIT_LIST_HEAD(&res->converting);
+ INIT_LIST_HEAD(&res->blocked);
+ INIT_LIST_HEAD(&res->dirty);
+ INIT_LIST_HEAD(&res->recovering);
+ INIT_LIST_HEAD(&res->purge);
+ atomic_set(&res->asts_reserved, 0);
+ res->migration_pending = 0;
+
+ kref_init(&res->refs);
+
+ /* just for consistency */
+ spin_lock(&res->spinlock);
+ dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
+ spin_unlock(&res->spinlock);
+
+ res->state = DLM_LOCK_RES_IN_PROGRESS;
+
+ res->last_used = 0;
+
+ memset(res->lvb, 0, DLM_LVB_LEN);
+}
+
+struct dlm_lock_resource *dlm_new_lockres(struct dlm_ctxt *dlm,
+ const char *name,
+ unsigned int namelen)
+{
+ struct dlm_lock_resource *res;
+
+ res = kmalloc(sizeof(struct dlm_lock_resource), GFP_KERNEL);
+ if (!res)
+ return NULL;
+
+ res->lockname.name = kmalloc(namelen, GFP_KERNEL);
+ if (!res->lockname.name) {
+ kfree(res);
+ return NULL;
+ }
+
+ dlm_init_lockres(dlm, res, name, namelen);
+ return res;
+}
+
+/*
+ * lookup a lock resource by name.
+ * may already exist in the hashtable.
+ * lockid is null terminated
+ *
+ * if not, allocate enough for the lockres and for
+ * the temporary structure used in doing the mastering.
+ *
+ * also, do a lookup in the dlm->master_list to see
+ * if another node has begun mastering the same lock.
+ * if so, there should be a block entry in there
+ * for this name, and we should *not* attempt to master
+ * the lock here. need to wait around for that node
+ * to assert_master (or die).
+ *
+ */
+struct dlm_lock_resource * dlm_get_lock_resource(struct dlm_ctxt *dlm,
+ const char *lockid,
+ int flags)
+{
+ struct dlm_lock_resource *tmpres=NULL, *res=NULL;
+ struct dlm_master_list_entry *mle = NULL;
+ struct dlm_master_list_entry *alloc_mle = NULL;
+ int blocked = 0;
+ int ret, nodenum;
+ struct dlm_node_iter iter;
+ unsigned int namelen;
+ int tries = 0;
+ int bit, wait_on_recovery = 0;
+
+ BUG_ON(!lockid);
+
+ namelen = strlen(lockid);
+
+ mlog(0, "get lockres %s (len %d)\n", lockid, namelen);
+
+lookup:
+ spin_lock(&dlm->spinlock);
+ tmpres = __dlm_lookup_lockres(dlm, lockid, namelen);
+ if (tmpres) {
+ spin_unlock(&dlm->spinlock);
+ mlog(0, "found in hash!\n");
+ if (res)
+ dlm_lockres_put(res);
+ res = tmpres;
+ goto leave;
+ }
+
+ if (!res) {
+ spin_unlock(&dlm->spinlock);
+ mlog(0, "allocating a new resource\n");
+ /* nothing found and we need to allocate one. */
+ alloc_mle = (struct dlm_master_list_entry *)
+ kmem_cache_alloc(dlm_mle_cache, GFP_KERNEL);
+ if (!alloc_mle)
+ goto leave;
+ res = dlm_new_lockres(dlm, lockid, namelen);
+ if (!res)
+ goto leave;
+ goto lookup;
+ }
+
+ mlog(0, "no lockres found, allocated our own: %p\n", res);
+
+ if (flags & LKM_LOCAL) {
+ /* caller knows it's safe to assume it's not mastered elsewhere
+ * DONE! return right away */
+ spin_lock(&res->spinlock);
+ dlm_change_lockres_owner(dlm, res, dlm->node_num);
+ __dlm_insert_lockres(dlm, res);
+ spin_unlock(&res->spinlock);
+ spin_unlock(&dlm->spinlock);
+ /* lockres still marked IN_PROGRESS */
+ goto wake_waiters;
+ }
+
+ /* check master list to see if another node has started mastering it */
+ spin_lock(&dlm->master_lock);
+
+ /* if we found a block, wait for lock to be mastered by another node */
+ blocked = dlm_find_mle(dlm, &mle, (char *)lockid, namelen);
+ if (blocked) {
+ if (mle->type == DLM_MLE_MASTER) {
+ mlog(ML_ERROR, "master entry for nonexistent lock!\n");
+ BUG();
+ } else if (mle->type == DLM_MLE_MIGRATION) {
+ /* migration is in progress! */
+ /* the good news is that we now know the
+ * "current" master (mle->master). */
+
+ spin_unlock(&dlm->master_lock);
+ assert_spin_locked(&dlm->spinlock);
+
+ /* set the lockres owner and hash it */
+ spin_lock(&res->spinlock);
+ dlm_set_lockres_owner(dlm, res, mle->master);
+ __dlm_insert_lockres(dlm, res);
+ spin_unlock(&res->spinlock);
+ spin_unlock(&dlm->spinlock);
+
+ /* master is known, detach */
+ dlm_mle_detach_hb_events(dlm, mle);
+ dlm_put_mle(mle);
+ mle = NULL;
+ goto wake_waiters;
+ }
+ } else {
+ /* go ahead and try to master lock on this node */
+ mle = alloc_mle;
+ /* make sure this does not get freed below */
+ alloc_mle = NULL;
+ dlm_init_mle(mle, DLM_MLE_MASTER, dlm, res, NULL, 0);
+ set_bit(dlm->node_num, mle->maybe_map);
+ list_add(&mle->list, &dlm->master_list);
+
+ /* still holding the dlm spinlock, check the recovery map
+ * to see if there are any nodes that still need to be
+ * considered. these will not appear in the mle nodemap
+ * but they might own this lockres. wait on them. */
+ bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
+ if (bit < O2NM_MAX_NODES) {
+ mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to"
+ "recover before lock mastery can begin\n",
+ dlm->name, namelen, (char *)lockid, bit);
+ wait_on_recovery = 1;
+ }
+ }
+
+ /* at this point there is either a DLM_MLE_BLOCK or a
+ * DLM_MLE_MASTER on the master list, so it's safe to add the
+ * lockres to the hashtable. anyone who finds the lock will
+ * still have to wait on the IN_PROGRESS. */
+
+ /* finally add the lockres to its hash bucket */
+ __dlm_insert_lockres(dlm, res);
+ /* get an extra ref on the mle in case this is a BLOCK
+ * if so, the creator of the BLOCK may try to put the last
+ * ref at this time in the assert master handler, so we
+ * need an extra one to keep from a bad ptr deref. */
+ dlm_get_mle(mle);
+ spin_unlock(&dlm->master_lock);
+ spin_unlock(&dlm->spinlock);
+
+ while (wait_on_recovery) {
+ /* any cluster changes that occurred after dropping the
+ * dlm spinlock would be detectable be a change on the mle,
+ * so we only need to clear out the recovery map once. */
+ if (dlm_is_recovery_lock(lockid, namelen)) {
+ mlog(ML_NOTICE, "%s: recovery map is not empty, but "
+ "must master $RECOVERY lock now\n", dlm->name);
+ if (!dlm_pre_master_reco_lockres(dlm, res))
+ wait_on_recovery = 0;
+ else {
+ mlog(0, "%s: waiting 500ms for heartbeat state "
+ "change\n", dlm->name);
+ msleep(500);
+ }
+ continue;
+ }
+
+ dlm_kick_recovery_thread(dlm);
+ msleep(100);
+ dlm_wait_for_recovery(dlm);
+
+ spin_lock(&dlm->spinlock);
+ bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
+ if (bit < O2NM_MAX_NODES) {
+ mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to"
+ "recover before lock mastery can begin\n",
+ dlm->name, namelen, (char *)lockid, bit);
+ wait_on_recovery = 1;
+ } else
+ wait_on_recovery = 0;
+ spin_unlock(&dlm->spinlock);
+ }
+
+ /* must wait for lock to be mastered elsewhere */
+ if (blocked)
+ goto wait;
+
+redo_request:
+ ret = -EINVAL;
+ dlm_node_iter_init(mle->vote_map, &iter);
+ while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
+ ret = dlm_do_master_request(mle, nodenum);
+ if (ret < 0)
+ mlog_errno(ret);
+ if (mle->master != O2NM_MAX_NODES) {
+ /* found a master ! */
+ if (mle->master <= nodenum)
+ break;
+ /* if our master request has not reached the master
+ * yet, keep going until it does. this is how the
+ * master will know that asserts are needed back to
+ * the lower nodes. */
+ mlog(0, "%s:%.*s: requests only up to %u but master "
+ "is %u, keep going\n", dlm->name, namelen,
+ lockid, nodenum, mle->master);
+ }
+ }
+
+wait:
+ /* keep going until the response map includes all nodes */
+ ret = dlm_wait_for_lock_mastery(dlm, res, mle, &blocked);
+ if (ret < 0) {
+ mlog(0, "%s:%.*s: node map changed, redo the "
+ "master request now, blocked=%d\n",
+ dlm->name, res->lockname.len,
+ res->lockname.name, blocked);
+ if (++tries > 20) {
+ mlog(ML_ERROR, "%s:%.*s: spinning on "
+ "dlm_wait_for_lock_mastery, blocked=%d\n",
+ dlm->name, res->lockname.len,
+ res->lockname.name, blocked);
+ dlm_print_one_lock_resource(res);
+ /* dlm_print_one_mle(mle); */
+ tries = 0;
+ }
+ goto redo_request;
+ }
+
+ mlog(0, "lockres mastered by %u\n", res->owner);
+ /* make sure we never continue without this */
+ BUG_ON(res->owner == O2NM_MAX_NODES);
+
+ /* master is known, detach if not already detached */
+ dlm_mle_detach_hb_events(dlm, mle);
+ dlm_put_mle(mle);
+ /* put the extra ref */
+ dlm_put_mle(mle);
+
+wake_waiters:
+ spin_lock(&res->spinlock);
+ res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
+ spin_unlock(&res->spinlock);
+ wake_up(&res->wq);
+
+leave:
+ /* need to free the unused mle */
+ if (alloc_mle)
+ kmem_cache_free(dlm_mle_cache, alloc_mle);
+
+ return res;
+}
+
+
+#define DLM_MASTERY_TIMEOUT_MS 5000
+
+static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res,
+ struct dlm_master_list_entry *mle,
+ int *blocked)
+{
+ u8 m;
+ int ret, bit;
+ int map_changed, voting_done;
+ int assert, sleep;
+
+recheck:
+ ret = 0;
+ assert = 0;
+
+ /* check if another node has already become the owner */
+ spin_lock(&res->spinlock);
+ if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
+ mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name,
+ res->lockname.len, res->lockname.name, res->owner);
+ spin_unlock(&res->spinlock);
+ /* this will cause the master to re-assert across
+ * the whole cluster, freeing up mles */
+ ret = dlm_do_master_request(mle, res->owner);
+ if (ret < 0) {
+ /* give recovery a chance to run */
+ mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret);
+ msleep(500);
+ goto recheck;
+ }
+ ret = 0;
+ goto leave;
+ }
+ spin_unlock(&res->spinlock);
+
+ spin_lock(&mle->spinlock);
+ m = mle->master;
+ map_changed = (memcmp(mle->vote_map, mle->node_map,
+ sizeof(mle->vote_map)) != 0);
+ voting_done = (memcmp(mle->vote_map, mle->response_map,
+ sizeof(mle->vote_map)) == 0);
+
+ /* restart if we hit any errors */
+ if (map_changed) {
+ int b;
+ mlog(0, "%s: %.*s: node map changed, restarting\n",
+ dlm->name, res->lockname.len, res->lockname.name);
+ ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked);
+ b = (mle->type == DLM_MLE_BLOCK);
+ if ((*blocked && !b) || (!*blocked && b)) {
+ mlog(0, "%s:%.*s: status change: old=%d new=%d\n",
+ dlm->name, res->lockname.len, res->lockname.name,
+ *blocked, b);
+ *blocked = b;
+ }
+ spin_unlock(&mle->spinlock);
+ if (ret < 0) {
+ mlog_errno(ret);
+ goto leave;
+ }
+ mlog(0, "%s:%.*s: restart lock mastery succeeded, "
+ "rechecking now\n", dlm->name, res->lockname.len,
+ res->lockname.name);
+ goto recheck;
+ }
+
+ if (m != O2NM_MAX_NODES) {
+ /* another node has done an assert!
+ * all done! */
+ sleep = 0;
+ } else {
+ sleep = 1;
+ /* have all nodes responded? */
+ if (voting_done && !*blocked) {
+ bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
+ if (dlm->node_num <= bit) {
+ /* my node number is lowest.
+ * now tell other nodes that I am
+ * mastering this. */
+ mle->master = dlm->node_num;
+ assert = 1;
+ sleep = 0;
+ }
+ /* if voting is done, but we have not received
+ * an assert master yet, we must sleep */
+ }
+ }
+
+ spin_unlock(&mle->spinlock);
+
+ /* sleep if we haven't finished voting yet */
+ if (sleep) {
+ unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);
+
+ /*
+ if (atomic_read(&mle->mle_refs.refcount) < 2)
+ mlog(ML_ERROR, "mle (%p) refs=%d, name=%.*s\n", mle,
+ atomic_read(&mle->mle_refs.refcount),
+ res->lockname.len, res->lockname.name);
+ */
+ atomic_set(&mle->woken, 0);
+ (void)wait_event_timeout(mle->wq,
+ (atomic_read(&mle->woken) == 1),
+ timeo);
+ if (res->owner == O2NM_MAX_NODES) {
+ mlog(0, "waiting again\n");
+ goto recheck;
+ }
+ mlog(0, "done waiting, master is %u\n", res->owner);
+ ret = 0;
+ goto leave;
+ }
+
+ ret = 0; /* done */
+ if (assert) {
+ m = dlm->node_num;
+ mlog(0, "about to master %.*s here, this=%u\n",
+ res->lockname.len, res->lockname.name, m);
+ ret = dlm_do_assert_master(dlm, res->lockname.name,
+ res->lockname.len, mle->vote_map, 0);
+ if (ret) {
+ /* This is a failure in the network path,
+ * not in the response to the assert_master
+ * (any nonzero response is a BUG on this node).
+ * Most likely a socket just got disconnected
+ * due to node death. */
+ mlog_errno(ret);
+ }
+ /* no longer need to restart lock mastery.
+ * all living nodes have been contacted. */
+ ret = 0;
+ }
+
+ /* set the lockres owner */
+ spin_lock(&res->spinlock);
+ dlm_change_lockres_owner(dlm, res, m);
+ spin_unlock(&res->spinlock);
+
+leave:
+ return ret;
+}
+
+struct dlm_bitmap_diff_iter
+{
+ int curnode;
+ unsigned long *orig_bm;
+ unsigned long *cur_bm;
+ unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)];
+};
+
+enum dlm_node_state_change
+{
+ NODE_DOWN = -1,
+ NODE_NO_CHANGE = 0,
+ NODE_UP
+};
+
+static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter,
+ unsigned long *orig_bm,
+ unsigned long *cur_bm)
+{
+ unsigned long p1, p2;
+ int i;
+
+ iter->curnode = -1;
+ iter->orig_bm = orig_bm;
+ iter->cur_bm = cur_bm;
+
+ for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) {
+ p1 = *(iter->orig_bm + i);
+ p2 = *(iter->cur_bm + i);
+ iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1);
+ }
+}
+
+static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter,
+ enum dlm_node_state_change *state)
+{
+ int bit;
+
+ if (iter->curnode >= O2NM_MAX_NODES)
+ return -ENOENT;
+
+ bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES,
+ iter->curnode+1);
+ if (bit >= O2NM_MAX_NODES) {
+ iter->curnode = O2NM_MAX_NODES;
+ return -ENOENT;
+ }
+
+ /* if it was there in the original then this node died */
+ if (test_bit(bit, iter->orig_bm))
+ *state = NODE_DOWN;
+ else
+ *state = NODE_UP;
+
+ iter->curnode = bit;
+ return bit;
+}
+
+
+static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res,
+ struct dlm_master_list_entry *mle,
+ int blocked)
+{
+ struct dlm_bitmap_diff_iter bdi;
+ enum dlm_node_state_change sc;
+ int node;
+ int ret = 0;
+
+ mlog(0, "something happened such that the "
+ "master process may need to be restarted!\n");
+
+ assert_spin_locked(&mle->spinlock);
+
+ dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map);
+ node = dlm_bitmap_diff_iter_next(&bdi, &sc);
+ while (node >= 0) {
+ if (sc == NODE_UP) {
+ /* a node came up. clear any old vote from
+ * the response map and set it in the vote map
+ * then restart the mastery. */
+ mlog(ML_NOTICE, "node %d up while restarting\n", node);
+
+ /* redo the master request, but only for the new node */
+ mlog(0, "sending request to new node\n");
+ clear_bit(node, mle->response_map);
+ set_bit(node, mle->vote_map);
+ } else {
+ mlog(ML_ERROR, "node down! %d\n", node);
+
+ /* if the node wasn't involved in mastery skip it,
+ * but clear it out from the maps so that it will
+ * not affect mastery of this lockres */
+ clear_bit(node, mle->response_map);
+ clear_bit(node, mle->vote_map);
+ if (!test_bit(node, mle->maybe_map))
+ goto next;
+
+ /* if we're already blocked on lock mastery, and the
+ * dead node wasn't the expected master, or there is
+ * another node in the maybe_map, keep waiting */
+ if (blocked) {
+ int lowest = find_next_bit(mle->maybe_map,
+ O2NM_MAX_NODES, 0);
+
+ /* act like it was never there */
+ clear_bit(node, mle->maybe_map);
+
+ if (node != lowest)
+ goto next;
+
+ mlog(ML_ERROR, "expected master %u died while "
+ "this node was blocked waiting on it!\n",
+ node);
+ lowest = find_next_bit(mle->maybe_map,
+ O2NM_MAX_NODES,
+ lowest+1);
+ if (lowest < O2NM_MAX_NODES) {
+ mlog(0, "still blocked. waiting "
+ "on %u now\n", lowest);
+ goto next;
+ }
+
+ /* mle is an MLE_BLOCK, but there is now
+ * nothing left to block on. we need to return
+ * all the way back out and try again with
+ * an MLE_MASTER. dlm_do_local_recovery_cleanup
+ * has already run, so the mle refcount is ok */
+ mlog(0, "no longer blocking. we can "
+ "try to master this here\n");
+ mle->type = DLM_MLE_MASTER;
+ memset(mle->maybe_map, 0,
+ sizeof(mle->maybe_map));
+ memset(mle->response_map, 0,
+ sizeof(mle->maybe_map));
+ memcpy(mle->vote_map, mle->node_map,
+ sizeof(mle->node_map));
+ mle->u.res = res;
+ set_bit(dlm->node_num, mle->maybe_map);
+
+ ret = -EAGAIN;
+ goto next;
+ }
+
+ clear_bit(node, mle->maybe_map);
+ if (node > dlm->node_num)
+ goto next;
+
+ mlog(0, "dead node in map!\n");
+ /* yuck. go back and re-contact all nodes
+ * in the vote_map, removing this node. */
+ memset(mle->response_map, 0,
+ sizeof(mle->response_map));
+ }
+ ret = -EAGAIN;
+next:
+ node = dlm_bitmap_diff_iter_next(&bdi, &sc);
+ }
+ return ret;
+}
+
+
+/*
+ * DLM_MASTER_REQUEST_MSG
+ *
+ * returns: 0 on success,
+ * -errno on a network error
+ *
+ * on error, the caller should assume the target node is "dead"
+ *
+ */
+
+static int dlm_do_master_request(struct dlm_master_list_entry *mle, int to)
+{
+ struct dlm_ctxt *dlm = mle->dlm;
+ struct dlm_master_request request;
+ int ret, response=0, resend;
+
+ memset(&request, 0, sizeof(request));
+ request.node_idx = dlm->node_num;
+
+ BUG_ON(mle->type == DLM_MLE_MIGRATION);
+
+ if (mle->type != DLM_MLE_MASTER) {
+ request.namelen = mle->u.name.len;
+ memcpy(request.name, mle->u.name.name, request.namelen);
+ } else {
+ request.namelen = mle->u.res->lockname.len;
+ memcpy(request.name, mle->u.res->lockname.name,
+ request.namelen);
+ }
+
+again:
+ ret = o2net_send_message(DLM_MASTER_REQUEST_MSG, dlm->key, &request,
+ sizeof(request), to, &response);
+ if (ret < 0) {
+ if (ret == -ESRCH) {
+ /* should never happen */
+ mlog(ML_ERROR, "TCP stack not ready!\n");
+ BUG();
+ } else if (ret == -EINVAL) {
+ mlog(ML_ERROR, "bad args passed to o2net!\n");
+ BUG();
+ } else if (ret == -ENOMEM) {
+ mlog(ML_ERROR, "out of memory while trying to send "
+ "network message! retrying\n");
+ /* this is totally crude */
+ msleep(50);
+ goto again;
+ } else if (!dlm_is_host_down(ret)) {
+ /* not a network error. bad. */
+ mlog_errno(ret);
+ mlog(ML_ERROR, "unhandled error!");
+ BUG();
+ }
+ /* all other errors should be network errors,
+ * and likely indicate node death */
+ mlog(ML_ERROR, "link to %d went down!\n", to);
+ goto out;
+ }
+
+ ret = 0;
+ resend = 0;
+ spin_lock(&mle->spinlock);
+ switch (response) {
+ case DLM_MASTER_RESP_YES:
+ set_bit(to, mle->response_map);
+ mlog(0, "node %u is the master, response=YES\n", to);
+ mle->master = to;
+ break;
+ case DLM_MASTER_RESP_NO:
+ mlog(0, "node %u not master, response=NO\n", to);
+ set_bit(to, mle->response_map);
+ break;
+ case DLM_MASTER_RESP_MAYBE:
+ mlog(0, "node %u not master, response=MAYBE\n", to);
+ set_bit(to, mle->response_map);
+ set_bit(to, mle->maybe_map);
+ break;
+ case DLM_MASTER_RESP_ERROR:
+ mlog(0, "node %u hit an error, resending\n", to);
+ resend = 1;
+ response = 0;
+ break;
+ default:
+ mlog(ML_ERROR, "bad response! %u\n", response);
+ BUG();
+ }
+ spin_unlock(&mle->spinlock);
+ if (resend) {
+ /* this is also totally crude */
+ msleep(50);
+ goto again;
+ }
+
+out:
+ return ret;
+}
+
+/*
+ * locks that can be taken here:
+ * dlm->spinlock
+ * res->spinlock
+ * mle->spinlock
+ * dlm->master_list
+ *
+ * if possible, TRIM THIS DOWN!!!
+ */
+int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data)
+{
+ u8 response = DLM_MASTER_RESP_MAYBE;
+ struct dlm_ctxt *dlm = data;
+ struct dlm_lock_resource *res = NULL;
+ struct dlm_master_request *request = (struct dlm_master_request *) msg->buf;
+ struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL;
+ char *name;
+ unsigned int namelen;
+ int found, ret;
+ int set_maybe;
+ int dispatch_assert = 0;
+
+ if (!dlm_grab(dlm))
+ return DLM_MASTER_RESP_NO;
+
+ if (!dlm_domain_fully_joined(dlm)) {
+ response = DLM_MASTER_RESP_NO;
+ goto send_response;
+ }
+
+ name = request->name;
+ namelen = request->namelen;
+
+ if (namelen > DLM_LOCKID_NAME_MAX) {
+ response = DLM_IVBUFLEN;
+ goto send_response;
+ }
+
+way_up_top:
+ spin_lock(&dlm->spinlock);
+ res = __dlm_lookup_lockres(dlm, name, namelen);
+ if (res) {
+ spin_unlock(&dlm->spinlock);
+
+ /* take care of the easy cases up front */
+ spin_lock(&res->spinlock);
+ if (res->state & DLM_LOCK_RES_RECOVERING) {
+ spin_unlock(&res->spinlock);
+ mlog(0, "returning DLM_MASTER_RESP_ERROR since res is "
+ "being recovered\n");
+ response = DLM_MASTER_RESP_ERROR;
+ if (mle)
+ kmem_cache_free(dlm_mle_cache, mle);
+ goto send_response;
+ }
+
+ if (res->owner == dlm->node_num) {
+ spin_unlock(&res->spinlock);
+ // mlog(0, "this node is the master\n");
+ response = DLM_MASTER_RESP_YES;
+ if (mle)
+ kmem_cache_free(dlm_mle_cache, mle);
+
+ /* this node is the owner.
+ * there is some extra work that needs to
+ * happen now. the requesting node has
+ * caused all nodes up to this one to
+ * create mles. this node now needs to
+ * go back and clean those up. */
+ dispatch_assert = 1;
+ goto send_response;
+ } else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
+ spin_unlock(&res->spinlock);
+ // mlog(0, "node %u is the master\n", res->owner);
+ response = DLM_MASTER_RESP_NO;
+ if (mle)
+ kmem_cache_free(dlm_mle_cache, mle);
+ goto send_response;
+ }
+
+ /* ok, there is no owner. either this node is
+ * being blocked, or it is actively trying to
+ * master this lock. */
+ if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
+ mlog(ML_ERROR, "lock with no owner should be "
+ "in-progress!\n");
+ BUG();
+ }
+
+ // mlog(0, "lockres is in progress...\n");
+ spin_lock(&dlm->master_lock);
+ found = dlm_find_mle(dlm, &tmpmle, name, namelen);
+ if (!found) {
+ mlog(ML_ERROR, "no mle found for this lock!\n");
+ BUG();
+ }
+ set_maybe = 1;
+ spin_lock(&tmpmle->spinlock);
+ if (tmpmle->type == DLM_MLE_BLOCK) {
+ // mlog(0, "this node is waiting for "
+ // "lockres to be mastered\n");
+ response = DLM_MASTER_RESP_NO;
+ } else if (tmpmle->type == DLM_MLE_MIGRATION) {
+ mlog(0, "node %u is master, but trying to migrate to "
+ "node %u.\n", tmpmle->master, tmpmle->new_master);
+ if (tmpmle->master == dlm->node_num) {
+ response = DLM_MASTER_RESP_YES;
+ mlog(ML_ERROR, "no owner on lockres, but this "
+ "node is trying to migrate it to %u?!\n",
+ tmpmle->new_master);
+ BUG();
+ } else {
+ /* the real master can respond on its own */
+ response = DLM_MASTER_RESP_NO;
+ }
+ } else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) {
+ set_maybe = 0;
+ if (tmpmle->master == dlm->node_num) {
+ response = DLM_MASTER_RESP_YES;
+ /* this node will be the owner.
+ * go back and clean the mles on any
+ * other nodes */
+ dispatch_assert = 1;
+ } else
+ response = DLM_MASTER_RESP_NO;
+ } else {
+ // mlog(0, "this node is attempting to "
+ // "master lockres\n");
+ response = DLM_MASTER_RESP_MAYBE;
+ }
+ if (set_maybe)
+ set_bit(request->node_idx, tmpmle->maybe_map);
+ spin_unlock(&tmpmle->spinlock);
+
+ spin_unlock(&dlm->master_lock);
+ spin_unlock(&res->spinlock);
+
+ /* keep the mle attached to heartbeat events */
+ dlm_put_mle(tmpmle);
+ if (mle)
+ kmem_cache_free(dlm_mle_cache, mle);
+ goto send_response;
+ }
+
+ /*
+ * lockres doesn't exist on this node
+ * if there is an MLE_BLOCK, return NO
+ * if there is an MLE_MASTER, return MAYBE
+ * otherwise, add an MLE_BLOCK, return NO
+ */
+ spin_lock(&dlm->master_lock);
+ found = dlm_find_mle(dlm, &tmpmle, name, namelen);
+ if (!found) {
+ /* this lockid has never been seen on this node yet */
+ // mlog(0, "no mle found\n");
+ if (!mle) {
+ spin_unlock(&dlm->master_lock);
+ spin_unlock(&dlm->spinlock);
+
+ mle = (struct dlm_master_list_entry *)
+ kmem_cache_alloc(dlm_mle_cache, GFP_KERNEL);
+ if (!mle) {
+ response = DLM_MASTER_RESP_ERROR;
+ mlog_errno(-ENOMEM);
+ goto send_response;
+ }
+ spin_lock(&dlm->spinlock);
+ dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL,
+ name, namelen);
+ spin_unlock(&dlm->spinlock);
+ goto way_up_top;
+ }
+
+ // mlog(0, "this is second time thru, already allocated, "
+ // "add the block.\n");
+ set_bit(request->node_idx, mle->maybe_map);
+ list_add(&mle->list, &dlm->master_list);
+ response = DLM_MASTER_RESP_NO;
+ } else {
+ // mlog(0, "mle was found\n");
+ set_maybe = 1;
+ spin_lock(&tmpmle->spinlock);
+ if (tmpmle->master == dlm->node_num) {
+ mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n");
+ BUG();
+ }
+ if (tmpmle->type == DLM_MLE_BLOCK)
+ response = DLM_MASTER_RESP_NO;
+ else if (tmpmle->type == DLM_MLE_MIGRATION) {
+ mlog(0, "migration mle was found (%u->%u)\n",
+ tmpmle->master, tmpmle->new_master);
+ /* real master can respond on its own */
+ response = DLM_MASTER_RESP_NO;
+ } else
+ response = DLM_MASTER_RESP_MAYBE;
+ if (set_maybe)
+ set_bit(request->node_idx, tmpmle->maybe_map);
+ spin_unlock(&tmpmle->spinlock);
+ }
+ spin_unlock(&dlm->master_lock);
+ spin_unlock(&dlm->spinlock);
+
+ if (found) {
+ /* keep the mle attached to heartbeat events */
+ dlm_put_mle(tmpmle);
+ }
+send_response:
+
+ if (dispatch_assert) {
+ if (response != DLM_MASTER_RESP_YES)
+ mlog(ML_ERROR, "invalid response %d\n", response);
+ if (!res) {
+ mlog(ML_ERROR, "bad lockres while trying to assert!\n");
+ BUG();
+ }
+ mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
+ dlm->node_num, res->lockname.len, res->lockname.name);
+ ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx,
+ DLM_ASSERT_MASTER_MLE_CLEANUP);
+ if (ret < 0) {
+ mlog(ML_ERROR, "failed to dispatch assert master work\n");
+ response = DLM_MASTER_RESP_ERROR;
+ }
+ }
+
+ dlm_put(dlm);
+ return response;
+}
+
+/*
+ * DLM_ASSERT_MASTER_MSG
+ */
+
+
+/*
+ * NOTE: this can be used for debugging
+ * can periodically run all locks owned by this node
+ * and re-assert across the cluster...
+ */
+static int dlm_do_assert_master(struct dlm_ctxt *dlm, const char *lockname,
+ unsigned int namelen, void *nodemap,
+ u32 flags)
+{
+ struct dlm_assert_master assert;
+ int to, tmpret;
+ struct dlm_node_iter iter;
+ int ret = 0;
+ int reassert;
+
+ BUG_ON(namelen > O2NM_MAX_NAME_LEN);
+again:
+ reassert = 0;
+
+ /* note that if this nodemap is empty, it returns 0 */
+ dlm_node_iter_init(nodemap, &iter);
+ while ((to = dlm_node_iter_next(&iter)) >= 0) {
+ int r = 0;
+ mlog(0, "sending assert master to %d (%.*s)\n", to,
+ namelen, lockname);
+ memset(&assert, 0, sizeof(assert));
+ assert.node_idx = dlm->node_num;
+ assert.namelen = namelen;
+ memcpy(assert.name, lockname, namelen);
+ assert.flags = cpu_to_be32(flags);
+
+ tmpret = o2net_send_message(DLM_ASSERT_MASTER_MSG, dlm->key,
+ &assert, sizeof(assert), to, &r);
+ if (tmpret < 0) {
+ mlog(ML_ERROR, "assert_master returned %d!\n", tmpret);
+ if (!dlm_is_host_down(tmpret)) {
+ mlog(ML_ERROR, "unhandled error!\n");
+ BUG();
+ }
+ /* a node died. finish out the rest of the nodes. */
+ mlog(ML_ERROR, "link to %d went down!\n", to);
+ /* any nonzero status return will do */
+ ret = tmpret;
+ } else if (r < 0) {
+ /* ok, something horribly messed. kill thyself. */
+ mlog(ML_ERROR,"during assert master of %.*s to %u, "
+ "got %d.\n", namelen, lockname, to, r);
+ dlm_dump_lock_resources(dlm);
+ BUG();
+ } else if (r == EAGAIN) {
+ mlog(0, "%.*s: node %u create mles on other "
+ "nodes and requests a re-assert\n",
+ namelen, lockname, to);
+ reassert = 1;
+ }
+ }
+
+ if (reassert)
+ goto again;
+
+ return ret;
+}
+
+/*
+ * locks that can be taken here:
+ * dlm->spinlock
+ * res->spinlock
+ * mle->spinlock
+ * dlm->master_list
+ *
+ * if possible, TRIM THIS DOWN!!!
+ */
+int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data)
+{
+ struct dlm_ctxt *dlm = data;
+ struct dlm_master_list_entry *mle = NULL;
+ struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf;
+ struct dlm_lock_resource *res = NULL;
+ char *name;
+ unsigned int namelen;
+ u32 flags;
+ int master_request = 0;
+ int ret = 0;
+
+ if (!dlm_grab(dlm))
+ return 0;
+
+ name = assert->name;
+ namelen = assert->namelen;
+ flags = be32_to_cpu(assert->flags);
+
+ if (namelen > DLM_LOCKID_NAME_MAX) {
+ mlog(ML_ERROR, "Invalid name length!");
+ goto done;
+ }
+
+ spin_lock(&dlm->spinlock);
+
+ if (flags)
+ mlog(0, "assert_master with flags: %u\n", flags);
+
+ /* find the MLE */
+ spin_lock(&dlm->master_lock);
+ if (!dlm_find_mle(dlm, &mle, name, namelen)) {
+ /* not an error, could be master just re-asserting */
+ mlog(0, "just got an assert_master from %u, but no "
+ "MLE for it! (%.*s)\n", assert->node_idx,
+ namelen, name);
+ } else {
+ int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
+ if (bit >= O2NM_MAX_NODES) {
+ /* not necessarily an error, though less likely.
+ * could be master just re-asserting. */
+ mlog(ML_ERROR, "no bits set in the maybe_map, but %u "
+ "is asserting! (%.*s)\n", assert->node_idx,
+ namelen, name);
+ } else if (bit != assert->node_idx) {
+ if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
+ mlog(0, "master %u was found, %u should "
+ "back off\n", assert->node_idx, bit);
+ } else {
+ /* with the fix for bug 569, a higher node
+ * number winning the mastery will respond
+ * YES to mastery requests, but this node
+ * had no way of knowing. let it pass. */
+ mlog(ML_ERROR, "%u is the lowest node, "
+ "%u is asserting. (%.*s) %u must "
+ "have begun after %u won.\n", bit,
+ assert->node_idx, namelen, name, bit,
+ assert->node_idx);
+ }
+ }
+ }
+ spin_unlock(&dlm->master_lock);
+
+ /* ok everything checks out with the MLE
+ * now check to see if there is a lockres */
+ res = __dlm_lookup_lockres(dlm, name, namelen);
+ if (res) {
+ spin_lock(&res->spinlock);
+ if (res->state & DLM_LOCK_RES_RECOVERING) {
+ mlog(ML_ERROR, "%u asserting but %.*s is "
+ "RECOVERING!\n", assert->node_idx, namelen, name);
+ goto kill;
+ }
+ if (!mle) {
+ if (res->owner != assert->node_idx) {
+ mlog(ML_ERROR, "assert_master from "
+ "%u, but current owner is "
+ "%u! (%.*s)\n",
+ assert->node_idx, res->owner,
+ namelen, name);
+ goto kill;
+ }
+ } else if (mle->type != DLM_MLE_MIGRATION) {
+ if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
+ /* owner is just re-asserting */
+ if (res->owner == assert->node_idx) {
+ mlog(0, "owner %u re-asserting on "
+ "lock %.*s\n", assert->node_idx,
+ namelen, name);
+ goto ok;
+ }
+ mlog(ML_ERROR, "got assert_master from "
+ "node %u, but %u is the owner! "
+ "(%.*s)\n", assert->node_idx,
+ res->owner, namelen, name);
+ goto kill;
+ }
+ if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
+ mlog(ML_ERROR, "got assert from %u, but lock "
+ "with no owner should be "
+ "in-progress! (%.*s)\n",
+ assert->node_idx,
+ namelen, name);
+ goto kill;
+ }
+ } else /* mle->type == DLM_MLE_MIGRATION */ {
+ /* should only be getting an assert from new master */
+ if (assert->node_idx != mle->new_master) {
+ mlog(ML_ERROR, "got assert from %u, but "
+ "new master is %u, and old master "
+ "was %u (%.*s)\n",
+ assert->node_idx, mle->new_master,
+ mle->master, namelen, name);
+ goto kill;
+ }
+
+ }
+ok:
+ spin_unlock(&res->spinlock);
+ }
+ spin_unlock(&dlm->spinlock);
+
+ // mlog(0, "woo! got an assert_master from node %u!\n",
+ // assert->node_idx);
+ if (mle) {
+ int extra_ref = 0;
+ int nn = -1;
+
+ spin_lock(&mle->spinlock);
+ if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION)
+ extra_ref = 1;
+ else {
+ /* MASTER mle: if any bits set in the response map
+ * then the calling node needs to re-assert to clear
+ * up nodes that this node contacted */
+ while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES,
+ nn+1)) < O2NM_MAX_NODES) {
+ if (nn != dlm->node_num && nn != assert->node_idx)
+ master_request = 1;
+ }
+ }
+ mle->master = assert->node_idx;
+ atomic_set(&mle->woken, 1);
+ wake_up(&mle->wq);
+ spin_unlock(&mle->spinlock);
+
+ if (mle->type == DLM_MLE_MIGRATION && res) {
+ mlog(0, "finishing off migration of lockres %.*s, "
+ "from %u to %u\n",
+ res->lockname.len, res->lockname.name,
+ dlm->node_num, mle->new_master);
+ spin_lock(&res->spinlock);
+ res->state &= ~DLM_LOCK_RES_MIGRATING;
+ dlm_change_lockres_owner(dlm, res, mle->new_master);
+ BUG_ON(res->state & DLM_LOCK_RES_DIRTY);
+ spin_unlock(&res->spinlock);
+ }
+ /* master is known, detach if not already detached */
+ dlm_mle_detach_hb_events(dlm, mle);
+ dlm_put_mle(mle);
+
+ if (extra_ref) {
+ /* the assert master message now balances the extra
+ * ref given by the master / migration request message.
+ * if this is the last put, it will be removed
+ * from the list. */
+ dlm_put_mle(mle);
+ }
+ }
+
+done:
+ ret = 0;
+ if (res)
+ dlm_lockres_put(res);
+ dlm_put(dlm);
+ if (master_request) {
+ mlog(0, "need to tell master to reassert\n");
+ ret = EAGAIN; // positive. negative would shoot down the node.
+ }
+ return ret;
+
+kill:
+ /* kill the caller! */
+ spin_unlock(&res->spinlock);
+ spin_unlock(&dlm->spinlock);
+ dlm_lockres_put(res);
+ mlog(ML_ERROR, "Bad message received from another node. Dumping state "
+ "and killing the other node now! This node is OK and can continue.\n");
+ dlm_dump_lock_resources(dlm);
+ dlm_put(dlm);
+ return -EINVAL;
+}
+
+int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res,
+ int ignore_higher, u8 request_from, u32 flags)
+{
+ struct dlm_work_item *item;
+ item = kcalloc(1, sizeof(*item), GFP_KERNEL);
+ if (!item)
+ return -ENOMEM;
+
+
+ /* queue up work for dlm_assert_master_worker */
+ dlm_grab(dlm); /* get an extra ref for the work item */
+ dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL);
+ item->u.am.lockres = res; /* already have a ref */
+ /* can optionally ignore node numbers higher than this node */
+ item->u.am.ignore_higher = ignore_higher;
+ item->u.am.request_from = request_from;
+ item->u.am.flags = flags;
+
+ if (ignore_higher)
+ mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len,
+ res->lockname.name);
+
+ spin_lock(&dlm->work_lock);
+ list_add_tail(&item->list, &dlm->work_list);
+ spin_unlock(&dlm->work_lock);
+
+ schedule_work(&dlm->dispatched_work);
+ return 0;
+}
+
+static void dlm_assert_master_worker(struct dlm_work_item *item, void *data)
+{
+ struct dlm_ctxt *dlm = data;
+ int ret = 0;
+ struct dlm_lock_resource *res;
+ unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)];
+ int ignore_higher;
+ int bit;
+ u8 request_from;
+ u32 flags;
+
+ dlm = item->dlm;
+ res = item->u.am.lockres;
+ ignore_higher = item->u.am.ignore_higher;
+ request_from = item->u.am.request_from;
+ flags = item->u.am.flags;
+
+ spin_lock(&dlm->spinlock);
+ memcpy(nodemap, dlm->domain_map, sizeof(nodemap));
+ spin_unlock(&dlm->spinlock);
+
+ clear_bit(dlm->node_num, nodemap);
+ if (ignore_higher) {
+ /* if is this just to clear up mles for nodes below
+ * this node, do not send the message to the original
+ * caller or any node number higher than this */
+ clear_bit(request_from, nodemap);
+ bit = dlm->node_num;
+ while (1) {
+ bit = find_next_bit(nodemap, O2NM_MAX_NODES,
+ bit+1);
+ if (bit >= O2NM_MAX_NODES)
+ break;
+ clear_bit(bit, nodemap);
+ }
+ }
+
+ /* this call now finishes out the nodemap
+ * even if one or more nodes die */
+ mlog(0, "worker about to master %.*s here, this=%u\n",
+ res->lockname.len, res->lockname.name, dlm->node_num);
+ ret = dlm_do_assert_master(dlm, res->lockname.name,
+ res->lockname.len,
+ nodemap, flags);
+ if (ret < 0) {
+ /* no need to restart, we are done */
+ mlog_errno(ret);
+ }
+
+ dlm_lockres_put(res);
+
+ mlog(0, "finished with dlm_assert_master_worker\n");
+}
+
+/* SPECIAL CASE for the $RECOVERY lock used by the recovery thread.
+ * We cannot wait for node recovery to complete to begin mastering this
+ * lockres because this lockres is used to kick off recovery! ;-)
+ * So, do a pre-check on all living nodes to see if any of those nodes
+ * think that $RECOVERY is currently mastered by a dead node. If so,
+ * we wait a short time to allow that node to get notified by its own
+ * heartbeat stack, then check again. All $RECOVERY lock resources
+ * mastered by dead nodes are purged when the hearbeat callback is
+ * fired, so we can know for sure that it is safe to continue once
+ * the node returns a live node or no node. */
+static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res)
+{
+ struct dlm_node_iter iter;
+ int nodenum;
+ int ret = 0;
+ u8 master = DLM_LOCK_RES_OWNER_UNKNOWN;
+
+ spin_lock(&dlm->spinlock);
+ dlm_node_iter_init(dlm->domain_map, &iter);
+ spin_unlock(&dlm->spinlock);
+
+ while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
+ /* do not send to self */
+ if (nodenum == dlm->node_num)
+ continue;
+ ret = dlm_do_master_requery(dlm, res, nodenum, &master);
+ if (ret < 0) {
+ mlog_errno(ret);
+ if (!dlm_is_host_down(ret))
+ BUG();
+ /* host is down, so answer for that node would be
+ * DLM_LOCK_RES_OWNER_UNKNOWN. continue. */
+ }
+
+ if (master != DLM_LOCK_RES_OWNER_UNKNOWN) {
+ /* check to see if this master is in the recovery map */
+ spin_lock(&dlm->spinlock);
+ if (test_bit(master, dlm->recovery_map)) {
+ mlog(ML_NOTICE, "%s: node %u has not seen "
+ "node %u go down yet, and thinks the "
+ "dead node is mastering the recovery "
+ "lock. must wait.\n", dlm->name,
+ nodenum, master);
+ ret = -EAGAIN;
+ }
+ spin_unlock(&dlm->spinlock);
+ mlog(0, "%s: reco lock master is %u\n", dlm->name,
+ master);
+ break;
+ }
+ }
+ return ret;
+}
+
+
+/*
+ * DLM_MIGRATE_LOCKRES
+ */
+
+
+int dlm_migrate_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
+ u8 target)
+{
+ struct dlm_master_list_entry *mle = NULL;
+ struct dlm_master_list_entry *oldmle = NULL;
+ struct dlm_migratable_lockres *mres = NULL;
+ int ret = -EINVAL;
+ const char *name;
+ unsigned int namelen;
+ int mle_added = 0;
+ struct list_head *queue, *iter;
+ int i;
+ struct dlm_lock *lock;
+ int empty = 1;
+
+ if (!dlm_grab(dlm))
+ return -EINVAL;
+
+ name = res->lockname.name;
+ namelen = res->lockname.len;
+
+ mlog(0, "migrating %.*s to %u\n", namelen, name, target);
+
+ /*
+ * ensure this lockres is a proper candidate for migration
+ */
+ spin_lock(&res->spinlock);
+ if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
+ mlog(0, "cannot migrate lockres with unknown owner!\n");
+ spin_unlock(&res->spinlock);
+ goto leave;
+ }
+ if (res->owner != dlm->node_num) {
+ mlog(0, "cannot migrate lockres this node doesn't own!\n");
+ spin_unlock(&res->spinlock);
+ goto leave;
+ }
+ mlog(0, "checking queues...\n");
+ queue = &res->granted;
+ for (i=0; i<3; i++) {
+ list_for_each(iter, queue) {
+ lock = list_entry (iter, struct dlm_lock, list);
+ empty = 0;
+ if (lock->ml.node == dlm->node_num) {
+ mlog(0, "found a lock owned by this node "
+ "still on the %s queue! will not "
+ "migrate this lockres\n",
+ i==0 ? "granted" :
+ (i==1 ? "converting" : "blocked"));
+ spin_unlock(&res->spinlock);
+ ret = -ENOTEMPTY;
+ goto leave;
+ }
+ }
+ queue++;
+ }
+ mlog(0, "all locks on this lockres are nonlocal. continuing\n");
+ spin_unlock(&res->spinlock);
+
+ /* no work to do */
+ if (empty) {
+ mlog(0, "no locks were found on this lockres! done!\n");
+ ret = 0;
+ goto leave;
+ }
+
+ /*
+ * preallocate up front
+ * if this fails, abort
+ */
+
+ ret = -ENOMEM;
+ mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_KERNEL);
+ if (!mres) {
+ mlog_errno(ret);
+ goto leave;
+ }
+
+ mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
+ GFP_KERNEL);
+ if (!mle) {
+ mlog_errno(ret);
+ goto leave;
+ }
+ ret = 0;
+
+ /*
+ * find a node to migrate the lockres to
+ */
+
+ mlog(0, "picking a migration node\n");
+ spin_lock(&dlm->spinlock);
+ /* pick a new node */
+ if (!test_bit(target, dlm->domain_map) ||
+ target >= O2NM_MAX_NODES) {
+ target = dlm_pick_migration_target(dlm, res);
+ }
+ mlog(0, "node %u chosen for migration\n", target);
+
+ if (target >= O2NM_MAX_NODES ||
+ !test_bit(target, dlm->domain_map)) {
+ /* target chosen is not alive */
+ ret = -EINVAL;
+ }
+
+ if (ret) {
+ spin_unlock(&dlm->spinlock);
+ goto fail;
+ }
+
+ mlog(0, "continuing with target = %u\n", target);
+
+ /*
+ * clear any existing master requests and
+ * add the migration mle to the list
+ */
+ spin_lock(&dlm->master_lock);
+ ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
+ namelen, target, dlm->node_num);
+ spin_unlock(&dlm->master_lock);
+ spin_unlock(&dlm->spinlock);
+
+ if (ret == -EEXIST) {
+ mlog(0, "another process is already migrating it\n");
+ goto fail;
+ }
+ mle_added = 1;
+
+ /*
+ * set the MIGRATING flag and flush asts
+ * if we fail after this we need to re-dirty the lockres
+ */
+ if (dlm_mark_lockres_migrating(dlm, res, target) < 0) {
+ mlog(ML_ERROR, "tried to migrate %.*s to %u, but "
+ "the target went down.\n", res->lockname.len,
+ res->lockname.name, target);
+ spin_lock(&res->spinlock);
+ res->state &= ~DLM_LOCK_RES_MIGRATING;
+ spin_unlock(&res->spinlock);
+ ret = -EINVAL;
+ }
+
+fail:
+ if (oldmle) {
+ /* master is known, detach if not already detached */
+ dlm_mle_detach_hb_events(dlm, oldmle);
+ dlm_put_mle(oldmle);
+ }
+
+ if (ret < 0) {
+ if (mle_added) {
+ dlm_mle_detach_hb_events(dlm, mle);
+ dlm_put_mle(mle);
+ } else if (mle) {
+ kmem_cache_free(dlm_mle_cache, mle);
+ }
+ goto leave;
+ }
+
+ /*
+ * at this point, we have a migration target, an mle
+ * in the master list, and the MIGRATING flag set on
+ * the lockres
+ */
+
+
+ /* get an extra reference on the mle.
+ * otherwise the assert_master from the new
+ * master will destroy this.
+ * also, make sure that all callers of dlm_get_mle
+ * take both dlm->spinlock and dlm->master_lock */
+ spin_lock(&dlm->spinlock);
+ spin_lock(&dlm->master_lock);
+ dlm_get_mle(mle);
+ spin_unlock(&dlm->master_lock);
+ spin_unlock(&dlm->spinlock);
+
+ /* notify new node and send all lock state */
+ /* call send_one_lockres with migration flag.
+ * this serves as notice to the target node that a
+ * migration is starting. */
+ ret = dlm_send_one_lockres(dlm, res, mres, target,
+ DLM_MRES_MIGRATION);
+
+ if (ret < 0) {
+ mlog(0, "migration to node %u failed with %d\n",
+ target, ret);
+ /* migration failed, detach and clean up mle */
+ dlm_mle_detach_hb_events(dlm, mle);
+ dlm_put_mle(mle);
+ dlm_put_mle(mle);
+ goto leave;
+ }
+
+ /* at this point, the target sends a message to all nodes,
+ * (using dlm_do_migrate_request). this node is skipped since
+ * we had to put an mle in the list to begin the process. this
+ * node now waits for target to do an assert master. this node
+ * will be the last one notified, ensuring that the migration
+ * is complete everywhere. if the target dies while this is
+ * going on, some nodes could potentially see the target as the
+ * master, so it is important that my recovery finds the migration
+ * mle and sets the master to UNKNONWN. */
+
+
+ /* wait for new node to assert master */
+ while (1) {
+ ret = wait_event_interruptible_timeout(mle->wq,
+ (atomic_read(&mle->woken) == 1),
+ msecs_to_jiffies(5000));
+
+ if (ret >= 0) {
+ if (atomic_read(&mle->woken) == 1 ||
+ res->owner == target)
+ break;
+
+ mlog(0, "timed out during migration\n");
+ /* avoid hang during shutdown when migrating lockres
+ * to a node which also goes down */
+ if (dlm_is_node_dead(dlm, target)) {
+ mlog(0, "%s:%.*s: expected migration target %u "
+ "is no longer up. restarting.\n",
+ dlm->name, res->lockname.len,
+ res->lockname.name, target);
+ ret = -ERESTARTSYS;
+ }
+ }
+ if (ret == -ERESTARTSYS) {
+ /* migration failed, detach and clean up mle */
+ dlm_mle_detach_hb_events(dlm, mle);
+ dlm_put_mle(mle);
+ dlm_put_mle(mle);
+ goto leave;
+ }
+ /* TODO: if node died: stop, clean up, return error */
+ }
+
+ /* all done, set the owner, clear the flag */
+ spin_lock(&res->spinlock);
+ dlm_set_lockres_owner(dlm, res, target);
+ res->state &= ~DLM_LOCK_RES_MIGRATING;
+ dlm_remove_nonlocal_locks(dlm, res);
+ spin_unlock(&res->spinlock);
+ wake_up(&res->wq);
+
+ /* master is known, detach if not already detached */
+ dlm_mle_detach_hb_events(dlm, mle);
+ dlm_put_mle(mle);
+ ret = 0;
+
+ dlm_lockres_calc_usage(dlm, res);
+
+leave:
+ /* re-dirty the lockres if we failed */
+ if (ret < 0)
+ dlm_kick_thread(dlm, res);
+
+ /* TODO: cleanup */
+ if (mres)
+ free_page((unsigned long)mres);
+
+ dlm_put(dlm);
+
+ mlog(0, "returning %d\n", ret);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(dlm_migrate_lockres);
+
+int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock)
+{
+ int ret;
+ spin_lock(&dlm->ast_lock);
+ spin_lock(&lock->spinlock);
+ ret = (list_empty(&lock->bast_list) && !lock->bast_pending);
+ spin_unlock(&lock->spinlock);
+ spin_unlock(&dlm->ast_lock);
+ return ret;
+}
+
+static int dlm_migration_can_proceed(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res,
+ u8 mig_target)
+{
+ int can_proceed;
+ spin_lock(&res->spinlock);
+ can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING);
+ spin_unlock(&res->spinlock);
+
+ /* target has died, so make the caller break out of the
+ * wait_event, but caller must recheck the domain_map */
+ spin_lock(&dlm->spinlock);
+ if (!test_bit(mig_target, dlm->domain_map))
+ can_proceed = 1;
+ spin_unlock(&dlm->spinlock);
+ return can_proceed;
+}
+
+int dlm_lockres_is_dirty(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
+{
+ int ret;
+ spin_lock(&res->spinlock);
+ ret = !!(res->state & DLM_LOCK_RES_DIRTY);
+ spin_unlock(&res->spinlock);
+ return ret;
+}
+
+
+static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res,
+ u8 target)
+{
+ int ret = 0;
+
+ mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n",
+ res->lockname.len, res->lockname.name, dlm->node_num,
+ target);
+ /* need to set MIGRATING flag on lockres. this is done by
+ * ensuring that all asts have been flushed for this lockres. */
+ spin_lock(&res->spinlock);
+ BUG_ON(res->migration_pending);
+ res->migration_pending = 1;
+ /* strategy is to reserve an extra ast then release
+ * it below, letting the release do all of the work */
+ __dlm_lockres_reserve_ast(res);
+ spin_unlock(&res->spinlock);
+
+ /* now flush all the pending asts.. hang out for a bit */
+ dlm_kick_thread(dlm, res);
+ wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
+ dlm_lockres_release_ast(dlm, res);
+
+ mlog(0, "about to wait on migration_wq, dirty=%s\n",
+ res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
+ /* if the extra ref we just put was the final one, this
+ * will pass thru immediately. otherwise, we need to wait
+ * for the last ast to finish. */
+again:
+ ret = wait_event_interruptible_timeout(dlm->migration_wq,
+ dlm_migration_can_proceed(dlm, res, target),
+ msecs_to_jiffies(1000));
+ if (ret < 0) {
+ mlog(0, "woken again: migrating? %s, dead? %s\n",
+ res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
+ test_bit(target, dlm->domain_map) ? "no":"yes");
+ } else {
+ mlog(0, "all is well: migrating? %s, dead? %s\n",
+ res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
+ test_bit(target, dlm->domain_map) ? "no":"yes");
+ }
+ if (!dlm_migration_can_proceed(dlm, res, target)) {
+ mlog(0, "trying again...\n");
+ goto again;
+ }
+
+ /* did the target go down or die? */
+ spin_lock(&dlm->spinlock);
+ if (!test_bit(target, dlm->domain_map)) {
+ mlog(ML_ERROR, "aha. migration target %u just went down\n",
+ target);
+ ret = -EHOSTDOWN;
+ }
+ spin_unlock(&dlm->spinlock);
+
+ /*
+ * at this point:
+ *
+ * o the DLM_LOCK_RES_MIGRATING flag is set
+ * o there are no pending asts on this lockres
+ * o all processes trying to reserve an ast on this
+ * lockres must wait for the MIGRATING flag to clear
+ */
+ return ret;
+}
+
+/* last step in the migration process.
+ * original master calls this to free all of the dlm_lock
+ * structures that used to be for other nodes. */
+static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res)
+{
+ struct list_head *iter, *iter2;
+ struct list_head *queue = &res->granted;
+ int i;
+ struct dlm_lock *lock;
+
+ assert_spin_locked(&res->spinlock);
+
+ BUG_ON(res->owner == dlm->node_num);
+
+ for (i=0; i<3; i++) {
+ list_for_each_safe(iter, iter2, queue) {
+ lock = list_entry (iter, struct dlm_lock, list);
+ if (lock->ml.node != dlm->node_num) {
+ mlog(0, "putting lock for node %u\n",
+ lock->ml.node);
+ /* be extra careful */
+ BUG_ON(!list_empty(&lock->ast_list));
+ BUG_ON(!list_empty(&lock->bast_list));
+ BUG_ON(lock->ast_pending);
+ BUG_ON(lock->bast_pending);
+ list_del_init(&lock->list);
+ dlm_lock_put(lock);
+ }
+ }
+ queue++;
+ }
+}
+
+/* for now this is not too intelligent. we will
+ * need stats to make this do the right thing.
+ * this just finds the first lock on one of the
+ * queues and uses that node as the target. */
+static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res)
+{
+ int i;
+ struct list_head *queue = &res->granted;
+ struct list_head *iter;
+ struct dlm_lock *lock;
+ int nodenum;
+
+ assert_spin_locked(&dlm->spinlock);
+
+ spin_lock(&res->spinlock);
+ for (i=0; i<3; i++) {
+ list_for_each(iter, queue) {
+ /* up to the caller to make sure this node
+ * is alive */
+ lock = list_entry (iter, struct dlm_lock, list);
+ if (lock->ml.node != dlm->node_num) {
+ spin_unlock(&res->spinlock);
+ return lock->ml.node;
+ }
+ }
+ queue++;
+ }
+ spin_unlock(&res->spinlock);
+ mlog(0, "have not found a suitable target yet! checking domain map\n");
+
+ /* ok now we're getting desperate. pick anyone alive. */
+ nodenum = -1;
+ while (1) {
+ nodenum = find_next_bit(dlm->domain_map,
+ O2NM_MAX_NODES, nodenum+1);
+ mlog(0, "found %d in domain map\n", nodenum);
+ if (nodenum >= O2NM_MAX_NODES)
+ break;
+ if (nodenum != dlm->node_num) {
+ mlog(0, "picking %d\n", nodenum);
+ return nodenum;
+ }
+ }
+
+ mlog(0, "giving up. no master to migrate to\n");
+ return DLM_LOCK_RES_OWNER_UNKNOWN;
+}
+
+
+
+/* this is called by the new master once all lockres
+ * data has been received */
+static int dlm_do_migrate_request(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res,
+ u8 master, u8 new_master,
+ struct dlm_node_iter *iter)
+{
+ struct dlm_migrate_request migrate;
+ int ret, status = 0;
+ int nodenum;
+
+ memset(&migrate, 0, sizeof(migrate));
+ migrate.namelen = res->lockname.len;
+ memcpy(migrate.name, res->lockname.name, migrate.namelen);
+ migrate.new_master = new_master;
+ migrate.master = master;
+
+ ret = 0;
+
+ /* send message to all nodes, except the master and myself */
+ while ((nodenum = dlm_node_iter_next(iter)) >= 0) {
+ if (nodenum == master ||
+ nodenum == new_master)
+ continue;
+
+ ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key,
+ &migrate, sizeof(migrate), nodenum,
+ &status);
+ if (ret < 0)
+ mlog_errno(ret);
+ else if (status < 0) {
+ mlog(0, "migrate request (node %u) returned %d!\n",
+ nodenum, status);
+ ret = status;
+ }
+ }
+
+ if (ret < 0)
+ mlog_errno(ret);
+
+ mlog(0, "returning ret=%d\n", ret);
+ return ret;
+}
+
+
+/* if there is an existing mle for this lockres, we now know who the master is.
+ * (the one who sent us *this* message) we can clear it up right away.
+ * since the process that put the mle on the list still has a reference to it,
+ * we can unhash it now, set the master and wake the process. as a result,
+ * we will have no mle in the list to start with. now we can add an mle for
+ * the migration and this should be the only one found for those scanning the
+ * list. */
+int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data)
+{
+ struct dlm_ctxt *dlm = data;
+ struct dlm_lock_resource *res = NULL;
+ struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf;
+ struct dlm_master_list_entry *mle = NULL, *oldmle = NULL;
+ const char *name;
+ unsigned int namelen;
+ int ret = 0;
+
+ if (!dlm_grab(dlm))
+ return -EINVAL;
+
+ name = migrate->name;
+ namelen = migrate->namelen;
+
+ /* preallocate.. if this fails, abort */
+ mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
+ GFP_KERNEL);
+
+ if (!mle) {
+ ret = -ENOMEM;
+ goto leave;
+ }
+
+ /* check for pre-existing lock */
+ spin_lock(&dlm->spinlock);
+ res = __dlm_lookup_lockres(dlm, name, namelen);
+ spin_lock(&dlm->master_lock);
+
+ if (res) {
+ spin_lock(&res->spinlock);
+ if (res->state & DLM_LOCK_RES_RECOVERING) {
+ /* if all is working ok, this can only mean that we got
+ * a migrate request from a node that we now see as
+ * dead. what can we do here? drop it to the floor? */
+ spin_unlock(&res->spinlock);
+ mlog(ML_ERROR, "Got a migrate request, but the "
+ "lockres is marked as recovering!");
+ kmem_cache_free(dlm_mle_cache, mle);
+ ret = -EINVAL; /* need a better solution */
+ goto unlock;
+ }
+ res->state |= DLM_LOCK_RES_MIGRATING;
+ spin_unlock(&res->spinlock);
+ }
+
+ /* ignore status. only nonzero status would BUG. */
+ ret = dlm_add_migration_mle(dlm, res, mle, &oldmle,
+ name, namelen,
+ migrate->new_master,
+ migrate->master);
+
+unlock:
+ spin_unlock(&dlm->master_lock);
+ spin_unlock(&dlm->spinlock);
+
+ if (oldmle) {
+ /* master is known, detach if not already detached */
+ dlm_mle_detach_hb_events(dlm, oldmle);
+ dlm_put_mle(oldmle);
+ }
+
+ if (res)
+ dlm_lockres_put(res);
+leave:
+ dlm_put(dlm);
+ return ret;
+}
+
+/* must be holding dlm->spinlock and dlm->master_lock
+ * when adding a migration mle, we can clear any other mles
+ * in the master list because we know with certainty that
+ * the master is "master". so we remove any old mle from
+ * the list after setting it's master field, and then add
+ * the new migration mle. this way we can hold with the rule
+ * of having only one mle for a given lock name at all times. */
+static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res,
+ struct dlm_master_list_entry *mle,
+ struct dlm_master_list_entry **oldmle,
+ const char *name, unsigned int namelen,
+ u8 new_master, u8 master)
+{
+ int found;
+ int ret = 0;
+
+ *oldmle = NULL;
+
+ mlog_entry_void();
+
+ assert_spin_locked(&dlm->spinlock);
+ assert_spin_locked(&dlm->master_lock);
+
+ /* caller is responsible for any ref taken here on oldmle */
+ found = dlm_find_mle(dlm, oldmle, (char *)name, namelen);
+ if (found) {
+ struct dlm_master_list_entry *tmp = *oldmle;
+ spin_lock(&tmp->spinlock);
+ if (tmp->type == DLM_MLE_MIGRATION) {
+ if (master == dlm->node_num) {
+ /* ah another process raced me to it */
+ mlog(0, "tried to migrate %.*s, but some "
+ "process beat me to it\n",
+ namelen, name);
+ ret = -EEXIST;
+ } else {
+ /* bad. 2 NODES are trying to migrate! */
+ mlog(ML_ERROR, "migration error mle: "
+ "master=%u new_master=%u // request: "
+ "master=%u new_master=%u // "
+ "lockres=%.*s\n",
+ tmp->master, tmp->new_master,
+ master, new_master,
+ namelen, name);
+ BUG();
+ }
+ } else {
+ /* this is essentially what assert_master does */
+ tmp->master = master;
+ atomic_set(&tmp->woken, 1);
+ wake_up(&tmp->wq);
+ /* remove it from the list so that only one
+ * mle will be found */
+ list_del_init(&tmp->list);
+ }
+ spin_unlock(&tmp->spinlock);
+ }
+
+ /* now add a migration mle to the tail of the list */
+ dlm_init_mle(mle, DLM_MLE_MIGRATION, dlm, res, name, namelen);
+ mle->new_master = new_master;
+ mle->master = master;
+ /* do this for consistency with other mle types */
+ set_bit(new_master, mle->maybe_map);
+ list_add(&mle->list, &dlm->master_list);
+
+ return ret;
+}
+
+
+void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
+{
+ struct list_head *iter, *iter2;
+ struct dlm_master_list_entry *mle;
+ struct dlm_lock_resource *res;
+
+ mlog_entry("dlm=%s, dead node=%u\n", dlm->name, dead_node);
+top:
+ assert_spin_locked(&dlm->spinlock);
+
+ /* clean the master list */
+ spin_lock(&dlm->master_lock);
+ list_for_each_safe(iter, iter2, &dlm->master_list) {
+ mle = list_entry(iter, struct dlm_master_list_entry, list);
+
+ BUG_ON(mle->type != DLM_MLE_BLOCK &&
+ mle->type != DLM_MLE_MASTER &&
+ mle->type != DLM_MLE_MIGRATION);
+
+ /* MASTER mles are initiated locally. the waiting
+ * process will notice the node map change
+ * shortly. let that happen as normal. */
+ if (mle->type == DLM_MLE_MASTER)
+ continue;
+
+
+ /* BLOCK mles are initiated by other nodes.
+ * need to clean up if the dead node would have
+ * been the master. */
+ if (mle->type == DLM_MLE_BLOCK) {
+ int bit;
+
+ spin_lock(&mle->spinlock);
+ bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
+ if (bit != dead_node) {
+ mlog(0, "mle found, but dead node %u would "
+ "not have been master\n", dead_node);
+ spin_unlock(&mle->spinlock);
+ } else {
+ /* must drop the refcount by one since the
+ * assert_master will never arrive. this
+ * may result in the mle being unlinked and
+ * freed, but there may still be a process
+ * waiting in the dlmlock path which is fine. */
+ mlog(ML_ERROR, "node %u was expected master\n",
+ dead_node);
+ atomic_set(&mle->woken, 1);
+ spin_unlock(&mle->spinlock);
+ wake_up(&mle->wq);
+ /* do not need events any longer, so detach
+ * from heartbeat */
+ __dlm_mle_detach_hb_events(dlm, mle);
+ __dlm_put_mle(mle);
+ }
+ continue;
+ }
+
+ /* everything else is a MIGRATION mle */
+
+ /* the rule for MIGRATION mles is that the master
+ * becomes UNKNOWN if *either* the original or
+ * the new master dies. all UNKNOWN lockreses
+ * are sent to whichever node becomes the recovery
+ * master. the new master is responsible for
+ * determining if there is still a master for
+ * this lockres, or if he needs to take over
+ * mastery. either way, this node should expect
+ * another message to resolve this. */
+ if (mle->master != dead_node &&
+ mle->new_master != dead_node)
+ continue;
+
+ /* if we have reached this point, this mle needs to
+ * be removed from the list and freed. */
+
+ /* remove from the list early. NOTE: unlinking
+ * list_head while in list_for_each_safe */
+ spin_lock(&mle->spinlock);
+ list_del_init(&mle->list);
+ atomic_set(&mle->woken, 1);
+ spin_unlock(&mle->spinlock);
+ wake_up(&mle->wq);
+
+ mlog(0, "node %u died during migration from "
+ "%u to %u!\n", dead_node,
+ mle->master, mle->new_master);
+ /* if there is a lockres associated with this
+ * mle, find it and set its owner to UNKNOWN */
+ res = __dlm_lookup_lockres(dlm, mle->u.name.name,
+ mle->u.name.len);
+ if (res) {
+ /* unfortunately if we hit this rare case, our
+ * lock ordering is messed. we need to drop
+ * the master lock so that we can take the
+ * lockres lock, meaning that we will have to
+ * restart from the head of list. */
+ spin_unlock(&dlm->master_lock);
+
+ /* move lockres onto recovery list */
+ spin_lock(&res->spinlock);
+ dlm_set_lockres_owner(dlm, res,
+ DLM_LOCK_RES_OWNER_UNKNOWN);
+ dlm_move_lockres_to_recovery_list(dlm, res);
+ spin_unlock(&res->spinlock);
+ dlm_lockres_put(res);
+
+ /* about to get rid of mle, detach from heartbeat */
+ __dlm_mle_detach_hb_events(dlm, mle);
+
+ /* dump the mle */
+ spin_lock(&dlm->master_lock);
+ __dlm_put_mle(mle);
+ spin_unlock(&dlm->master_lock);
+
+ /* restart */
+ goto top;
+ }
+
+ /* this may be the last reference */
+ __dlm_put_mle(mle);
+ }
+ spin_unlock(&dlm->master_lock);
+}
+
+
+int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
+ u8 old_master)
+{
+ struct dlm_node_iter iter;
+ int ret = 0;
+
+ spin_lock(&dlm->spinlock);
+ dlm_node_iter_init(dlm->domain_map, &iter);
+ clear_bit(old_master, iter.node_map);
+ clear_bit(dlm->node_num, iter.node_map);
+ spin_unlock(&dlm->spinlock);
+
+ mlog(0, "now time to do a migrate request to other nodes\n");
+ ret = dlm_do_migrate_request(dlm, res, old_master,
+ dlm->node_num, &iter);
+ if (ret < 0) {
+ mlog_errno(ret);
+ goto leave;
+ }
+
+ mlog(0, "doing assert master of %.*s to all except the original node\n",
+ res->lockname.len, res->lockname.name);
+ /* this call now finishes out the nodemap
+ * even if one or more nodes die */
+ ret = dlm_do_assert_master(dlm, res->lockname.name,
+ res->lockname.len, iter.node_map,
+ DLM_ASSERT_MASTER_FINISH_MIGRATION);
+ if (ret < 0) {
+ /* no longer need to retry. all living nodes contacted. */
+ mlog_errno(ret);
+ ret = 0;
+ }
+
+ memset(iter.node_map, 0, sizeof(iter.node_map));
+ set_bit(old_master, iter.node_map);
+ mlog(0, "doing assert master of %.*s back to %u\n",
+ res->lockname.len, res->lockname.name, old_master);
+ ret = dlm_do_assert_master(dlm, res->lockname.name,
+ res->lockname.len, iter.node_map,
+ DLM_ASSERT_MASTER_FINISH_MIGRATION);
+ if (ret < 0) {
+ mlog(0, "assert master to original master failed "
+ "with %d.\n", ret);
+ /* the only nonzero status here would be because of
+ * a dead original node. we're done. */
+ ret = 0;
+ }
+
+ /* all done, set the owner, clear the flag */
+ spin_lock(&res->spinlock);
+ dlm_set_lockres_owner(dlm, res, dlm->node_num);
+ res->state &= ~DLM_LOCK_RES_MIGRATING;
+ spin_unlock(&res->spinlock);
+ /* re-dirty it on the new master */
+ dlm_kick_thread(dlm, res);
+ wake_up(&res->wq);
+leave:
+ return ret;
+}
+
+/*
+ * LOCKRES AST REFCOUNT
+ * this is integral to migration
+ */
+
+/* for future intent to call an ast, reserve one ahead of time.
+ * this should be called only after waiting on the lockres
+ * with dlm_wait_on_lockres, and while still holding the
+ * spinlock after the call. */
+void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res)
+{
+ assert_spin_locked(&res->spinlock);
+ if (res->state & DLM_LOCK_RES_MIGRATING) {
+ __dlm_print_one_lock_resource(res);
+ }
+ BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
+
+ atomic_inc(&res->asts_reserved);
+}
+
+/*
+ * used to drop the reserved ast, either because it went unused,
+ * or because the ast/bast was actually called.
+ *
+ * also, if there is a pending migration on this lockres,
+ * and this was the last pending ast on the lockres,
+ * atomically set the MIGRATING flag before we drop the lock.
+ * this is how we ensure that migration can proceed with no
+ * asts in progress. note that it is ok if the state of the
+ * queues is such that a lock should be granted in the future
+ * or that a bast should be fired, because the new master will
+ * shuffle the lists on this lockres as soon as it is migrated.
+ */
+void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res)
+{
+ if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
+ return;
+
+ if (!res->migration_pending) {
+ spin_unlock(&res->spinlock);
+ return;
+ }
+
+ BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
+ res->migration_pending = 0;
+ res->state |= DLM_LOCK_RES_MIGRATING;
+ spin_unlock(&res->spinlock);
+ wake_up(&res->wq);
+ wake_up(&dlm->migration_wq);
+}
git://git.onelab.eu / linux-2.6.git / blobdiff