diff options
Diffstat (limited to 'fs/ocfs2/dlm/dlmmaster.c')
| -rw-r--r-- | fs/ocfs2/dlm/dlmmaster.c | 2664 |
1 files changed, 2664 insertions, 0 deletions
diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c new file mode 100644 index 0000000000000..27e984f7e4cdb --- /dev/null +++ b/fs/ocfs2/dlm/dlmmaster.c @@ -0,0 +1,2664 @@ +/* -*- 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); + + +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(!list_empty(&res->list)); + 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_LIST_HEAD(&res->list); + 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; + + 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); + } + + /* 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); + + /* 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 ! */ + break; + } + } + +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) { + spin_unlock(&res->spinlock); + 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. easy. might not even need + * to talk to it if its node number is higher + * or if we are already blocked. */ + mlog(0, "node up! %d\n", node); + if (blocked) + goto next; + + if (node > dlm->node_num) { + mlog(0, "node > this node. skipping.\n"); + goto next; + } + + /* 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; + 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; + + 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) { + u32 flags = DLM_ASSERT_MASTER_MLE_CLEANUP; + 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. */ + 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, 1, + request->node_idx, + flags); + if (ret < 0) { + mlog(ML_ERROR, "failed to dispatch assert " + "master work\n"); + response = DLM_MASTER_RESP_ERROR; + } + 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; + 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) { + // bad bad bad... this sucks. + response = DLM_MASTER_RESP_ERROR; + 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->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); + if (tmpmle->master == dlm->node_num) { + mlog(ML_ERROR, "no lockres, but migration mle " + "says that this node is master!\n"); + BUG(); + } + /* real master can respond on its own */ + response = DLM_MASTER_RESP_NO; + } else { + if (tmpmle->master == dlm->node_num) { + response = DLM_MASTER_RESP_YES; + set_maybe = 0; + } 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: + 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; + + BUG_ON(namelen > O2NM_MAX_NAME_LEN); + + /* 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(); + } + } + + 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; + + 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; + + spin_lock(&mle->spinlock); + extra_ref = !!(mle->type == DLM_MLE_BLOCK + || mle->type == DLM_MLE_MIGRATION); + 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: + if (res) + dlm_lockres_put(res); + dlm_put(dlm); + return 0; + +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; + + 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"); +} + + +/* + * 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"); + } + 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); + /* final put will take care of list removal */ + __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); + + /* 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); +} |