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 000000000000..27e984f7e4cd --- /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); |