diff options
Diffstat (limited to 'fs/ocfs2/dlm/dlmmaster.c')
| -rw-r--r-- | fs/ocfs2/dlm/dlmmaster.c | 3487 |
1 files changed, 3487 insertions, 0 deletions
diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c new file mode 100644 index 000000000..fdf4b41d0 --- /dev/null +++ b/fs/ocfs2/dlm/dlmmaster.c @@ -0,0 +1,3487 @@ +/* -*- 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/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 "dlmdomain.h" +#include "dlmdebug.h" + +#define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_MASTER) +#include "cluster/masklog.h" + +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, + struct dlm_lock_resource *res, + void *nodemap, u32 flags); +static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data); + +static inline int dlm_mle_equal(struct dlm_ctxt *dlm, + struct dlm_master_list_entry *mle, + const char *name, + unsigned int namelen) +{ + if (dlm != mle->dlm) + return 0; + + if (namelen != mle->mnamelen || + memcmp(name, mle->mname, namelen) != 0) + return 0; + + return 1; +} + +static struct kmem_cache *dlm_lockres_cache; +static struct kmem_cache *dlm_lockname_cache; +static struct kmem_cache *dlm_mle_cache; + +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_lock_resource *res, + struct dlm_master_list_entry *mle, int to); + + +static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res, + struct dlm_master_list_entry *mle, + int *blocked); +static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res, + struct dlm_master_list_entry *mle, + int blocked); +static int dlm_add_migration_mle(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res, + struct dlm_master_list_entry *mle, + struct dlm_master_list_entry **oldmle, + const char *name, unsigned int namelen, + u8 new_master, u8 master); + +static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res); +static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res); +static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res, + u8 target); +static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res); + + +int dlm_is_host_down(int errno) +{ + switch (errno) { + case -EBADF: + case -ECONNREFUSED: + case -ENOTCONN: + case -ECONNRESET: + case -EPIPE: + case -EHOSTDOWN: + case -EHOSTUNREACH: + case -ETIMEDOUT: + case -ECONNABORTED: + case -ENETDOWN: + case -ENETUNREACH: + case -ENETRESET: + case -ESHUTDOWN: + case -ENOPROTOOPT: + case -EINVAL: /* if returned from our tcp code, + this means there is no socket */ + return 1; + } + return 0; +} + + +/* + * MASTER LIST FUNCTIONS + */ + + +/* + * regarding master list entries and heartbeat callbacks: + * + * in order to avoid sleeping and allocation that occurs in + * heartbeat, master list entries are simply attached to the + * dlm's established heartbeat callbacks. the mle is attached + * when it is created, and since the dlm->spinlock is held at + * that time, any heartbeat event will be properly discovered + * by the mle. the mle needs to be detached from the + * dlm->mle_hb_events list as soon as heartbeat events are no + * longer useful to the mle, and before the mle is freed. + * + * as a general rule, heartbeat events are no longer needed by + * the mle once an "answer" regarding the lock master has been + * received. + */ +static inline void __dlm_mle_attach_hb_events(struct dlm_ctxt *dlm, + struct dlm_master_list_entry *mle) +{ + assert_spin_locked(&dlm->spinlock); + + list_add_tail(&mle->hb_events, &dlm->mle_hb_events); +} + + +static inline void __dlm_mle_detach_hb_events(struct dlm_ctxt *dlm, + struct dlm_master_list_entry *mle) +{ + if (!list_empty(&mle->hb_events)) + list_del_init(&mle->hb_events); +} + + +static inline void dlm_mle_detach_hb_events(struct dlm_ctxt *dlm, + struct dlm_master_list_entry *mle) +{ + spin_lock(&dlm->spinlock); + __dlm_mle_detach_hb_events(dlm, mle); + spin_unlock(&dlm->spinlock); +} + +static void dlm_get_mle_inuse(struct dlm_master_list_entry *mle) +{ + struct dlm_ctxt *dlm; + dlm = mle->dlm; + + assert_spin_locked(&dlm->spinlock); + assert_spin_locked(&dlm->master_lock); + mle->inuse++; + kref_get(&mle->mle_refs); +} + +static void dlm_put_mle_inuse(struct dlm_master_list_entry *mle) +{ + struct dlm_ctxt *dlm; + dlm = mle->dlm; + + spin_lock(&dlm->spinlock); + spin_lock(&dlm->master_lock); + mle->inuse--; + __dlm_put_mle(mle); + spin_unlock(&dlm->master_lock); + 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); + if (!atomic_read(&mle->mle_refs.refcount)) { + /* this may or may not crash, but who cares. + * it's a BUG. */ + mlog(ML_ERROR, "bad mle: %p\n", mle); + dlm_print_one_mle(mle); + BUG(); + } else + 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_HLIST_NODE(&mle->master_hash_node); + 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; + mle->inuse = 0; + + BUG_ON(mle->type != DLM_MLE_BLOCK && + mle->type != DLM_MLE_MASTER && + mle->type != DLM_MLE_MIGRATION); + + if (mle->type == DLM_MLE_MASTER) { + BUG_ON(!res); + mle->mleres = res; + memcpy(mle->mname, res->lockname.name, res->lockname.len); + mle->mnamelen = res->lockname.len; + mle->mnamehash = res->lockname.hash; + } else { + BUG_ON(!name); + mle->mleres = NULL; + memcpy(mle->mname, name, namelen); + mle->mnamelen = namelen; + mle->mnamehash = dlm_lockid_hash(name, namelen); + } + + atomic_inc(&dlm->mle_tot_count[mle->type]); + atomic_inc(&dlm->mle_cur_count[mle->type]); + + /* 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); +} + +void __dlm_unlink_mle(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle) +{ + assert_spin_locked(&dlm->spinlock); + assert_spin_locked(&dlm->master_lock); + + if (!hlist_unhashed(&mle->master_hash_node)) + hlist_del_init(&mle->master_hash_node); +} + +void __dlm_insert_mle(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle) +{ + struct hlist_head *bucket; + + assert_spin_locked(&dlm->master_lock); + + bucket = dlm_master_hash(dlm, mle->mnamehash); + hlist_add_head(&mle->master_hash_node, bucket); +} + +/* 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 hlist_head *bucket; + unsigned int hash; + + assert_spin_locked(&dlm->master_lock); + + hash = dlm_lockid_hash(name, namelen); + bucket = dlm_master_hash(dlm, hash); + hlist_for_each_entry(tmpmle, bucket, master_hash_node) { + 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; + + assert_spin_locked(&dlm->spinlock); + + list_for_each_entry(mle, &dlm->mle_hb_events, 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("o2dlm_mle", + sizeof(struct dlm_master_list_entry), + 0, SLAB_HWCACHE_ALIGN, + 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; + + mle = container_of(kref, struct dlm_master_list_entry, mle_refs); + dlm = mle->dlm; + + assert_spin_locked(&dlm->spinlock); + assert_spin_locked(&dlm->master_lock); + + mlog(0, "Releasing mle for %.*s, type %d\n", mle->mnamelen, mle->mname, + mle->type); + + /* remove from list if not already */ + __dlm_unlink_mle(dlm, mle); + + /* detach the mle from the domain node up/down events */ + __dlm_mle_detach_hb_events(dlm, mle); + + atomic_dec(&dlm->mle_cur_count[mle->type]); + + /* 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 + */ + +int dlm_init_master_caches(void) +{ + dlm_lockres_cache = kmem_cache_create("o2dlm_lockres", + sizeof(struct dlm_lock_resource), + 0, SLAB_HWCACHE_ALIGN, NULL); + if (!dlm_lockres_cache) + goto bail; + + dlm_lockname_cache = kmem_cache_create("o2dlm_lockname", + DLM_LOCKID_NAME_MAX, 0, + SLAB_HWCACHE_ALIGN, NULL); + if (!dlm_lockname_cache) + goto bail; + + return 0; +bail: + dlm_destroy_master_caches(); + return -ENOMEM; +} + +void dlm_destroy_master_caches(void) +{ + if (dlm_lockname_cache) { + kmem_cache_destroy(dlm_lockname_cache); + dlm_lockname_cache = NULL; + } + + if (dlm_lockres_cache) { + kmem_cache_destroy(dlm_lockres_cache); + dlm_lockres_cache = NULL; + } +} + +static void dlm_lockres_release(struct kref *kref) +{ + struct dlm_lock_resource *res; + struct dlm_ctxt *dlm; + + res = container_of(kref, struct dlm_lock_resource, refs); + dlm = res->dlm; + + /* 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); + + spin_lock(&dlm->track_lock); + if (!list_empty(&res->tracking)) + list_del_init(&res->tracking); + else { + mlog(ML_ERROR, "Resource %.*s not on the Tracking list\n", + res->lockname.len, res->lockname.name); + dlm_print_one_lock_resource(res); + } + spin_unlock(&dlm->track_lock); + + atomic_dec(&dlm->res_cur_count); + + if (!hlist_unhashed(&res->hash_node) || + !list_empty(&res->granted) || + !list_empty(&res->converting) || + !list_empty(&res->blocked) || + !list_empty(&res->dirty) || + !list_empty(&res->recovering) || + !list_empty(&res->purge)) { + mlog(ML_ERROR, + "Going to BUG for resource %.*s." + " We're on a list! [%c%c%c%c%c%c%c]\n", + res->lockname.len, res->lockname.name, + !hlist_unhashed(&res->hash_node) ? 'H' : ' ', + !list_empty(&res->granted) ? 'G' : ' ', + !list_empty(&res->converting) ? 'C' : ' ', + !list_empty(&res->blocked) ? 'B' : ' ', + !list_empty(&res->dirty) ? 'D' : ' ', + !list_empty(&res->recovering) ? 'R' : ' ', + !list_empty(&res->purge) ? 'P' : ' '); + + dlm_print_one_lock_resource(res); + } + + /* By the time we're ready to blow this guy away, we shouldn't + * be on any lists. */ + BUG_ON(!hlist_unhashed(&res->hash_node)); + BUG_ON(!list_empty(&res->granted)); + BUG_ON(!list_empty(&res->converting)); + BUG_ON(!list_empty(&res->blocked)); + BUG_ON(!list_empty(&res->dirty)); + BUG_ON(!list_empty(&res->recovering)); + BUG_ON(!list_empty(&res->purge)); + + kmem_cache_free(dlm_lockname_cache, (void *)res->lockname.name); + + kmem_cache_free(dlm_lockres_cache, res); +} + +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 = dlm_lockid_hash(name, namelen); + + init_waitqueue_head(&res->wq); + spin_lock_init(&res->spinlock); + INIT_HLIST_NODE(&res->hash_node); + INIT_LIST_HEAD(&res->granted); + INIT_LIST_HEAD(&res->converting); + INIT_LIST_HEAD(&res->blocked); + INIT_LIST_HEAD(&res->dirty); + INIT_LIST_HEAD(&res->recovering); + INIT_LIST_HEAD(&res->purge); + INIT_LIST_HEAD(&res->tracking); + atomic_set(&res->asts_reserved, 0); + res->migration_pending = 0; + res->inflight_locks = 0; + res->inflight_assert_workers = 0; + + res->dlm = dlm; + + kref_init(&res->refs); + + atomic_inc(&dlm->res_tot_count); + atomic_inc(&dlm->res_cur_count); + + /* 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; + + spin_lock(&dlm->spinlock); + list_add_tail(&res->tracking, &dlm->tracking_list); + spin_unlock(&dlm->spinlock); + + memset(res->lvb, 0, DLM_LVB_LEN); + memset(res->refmap, 0, sizeof(res->refmap)); +} + +struct dlm_lock_resource *dlm_new_lockres(struct dlm_ctxt *dlm, + const char *name, + unsigned int namelen) +{ + struct dlm_lock_resource *res = NULL; + + res = kmem_cache_zalloc(dlm_lockres_cache, GFP_NOFS); + if (!res) + goto error; + + res->lockname.name = kmem_cache_zalloc(dlm_lockname_cache, GFP_NOFS); + if (!res->lockname.name) + goto error; + + dlm_init_lockres(dlm, res, name, namelen); + return res; + +error: + if (res) + kmem_cache_free(dlm_lockres_cache, res); + return NULL; +} + +void dlm_lockres_set_refmap_bit(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res, int bit) +{ + assert_spin_locked(&res->spinlock); + + mlog(0, "res %.*s, set node %u, %ps()\n", res->lockname.len, + res->lockname.name, bit, __builtin_return_address(0)); + + set_bit(bit, res->refmap); +} + +void dlm_lockres_clear_refmap_bit(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res, int bit) +{ + assert_spin_locked(&res->spinlock); + + mlog(0, "res %.*s, clr node %u, %ps()\n", res->lockname.len, + res->lockname.name, bit, __builtin_return_address(0)); + + clear_bit(bit, res->refmap); +} + +static void __dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res) +{ + res->inflight_locks++; + + mlog(0, "%s: res %.*s, inflight++: now %u, %ps()\n", dlm->name, + res->lockname.len, res->lockname.name, res->inflight_locks, + __builtin_return_address(0)); +} + +void dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res) +{ + assert_spin_locked(&res->spinlock); + __dlm_lockres_grab_inflight_ref(dlm, res); +} + +void dlm_lockres_drop_inflight_ref(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res) +{ + assert_spin_locked(&res->spinlock); + + BUG_ON(res->inflight_locks == 0); + + res->inflight_locks--; + + mlog(0, "%s: res %.*s, inflight--: now %u, %ps()\n", dlm->name, + res->lockname.len, res->lockname.name, res->inflight_locks, + __builtin_return_address(0)); + + wake_up(&res->wq); +} + +void __dlm_lockres_grab_inflight_worker(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res) +{ + assert_spin_locked(&res->spinlock); + res->inflight_assert_workers++; + mlog(0, "%s:%.*s: inflight assert worker++: now %u\n", + dlm->name, res->lockname.len, res->lockname.name, + res->inflight_assert_workers); +} + +static void __dlm_lockres_drop_inflight_worker(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res) +{ + assert_spin_locked(&res->spinlock); + BUG_ON(res->inflight_assert_workers == 0); + res->inflight_assert_workers--; + mlog(0, "%s:%.*s: inflight assert worker--: now %u\n", + dlm->name, res->lockname.len, res->lockname.name, + res->inflight_assert_workers); +} + +static void dlm_lockres_drop_inflight_worker(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res) +{ + spin_lock(&res->spinlock); + __dlm_lockres_drop_inflight_worker(dlm, res); + spin_unlock(&res->spinlock); +} + +/* + * 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 namelen, + 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 hash; + int tries = 0; + int bit, wait_on_recovery = 0; + + BUG_ON(!lockid); + + hash = dlm_lockid_hash(lockid, namelen); + + mlog(0, "get lockres %s (len %d)\n", lockid, namelen); + +lookup: + spin_lock(&dlm->spinlock); + tmpres = __dlm_lookup_lockres_full(dlm, lockid, namelen, hash); + if (tmpres) { + spin_unlock(&dlm->spinlock); + spin_lock(&tmpres->spinlock); + + /* + * Right after dlm spinlock was released, dlm_thread could have + * purged the lockres. Check if lockres got unhashed. If so + * start over. + */ + if (hlist_unhashed(&tmpres->hash_node)) { + spin_unlock(&tmpres->spinlock); + dlm_lockres_put(tmpres); + tmpres = NULL; + goto lookup; + } + + /* Wait on the thread that is mastering the resource */ + if (tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN) { + __dlm_wait_on_lockres(tmpres); + BUG_ON(tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN); + spin_unlock(&tmpres->spinlock); + dlm_lockres_put(tmpres); + tmpres = NULL; + goto lookup; + } + + /* Wait on the resource purge to complete before continuing */ + if (tmpres->state & DLM_LOCK_RES_DROPPING_REF) { + BUG_ON(tmpres->owner == dlm->node_num); + __dlm_wait_on_lockres_flags(tmpres, + DLM_LOCK_RES_DROPPING_REF); + spin_unlock(&tmpres->spinlock); + dlm_lockres_put(tmpres); + tmpres = NULL; + goto lookup; + } + + /* Grab inflight ref to pin the resource */ + dlm_lockres_grab_inflight_ref(dlm, tmpres); + + spin_unlock(&tmpres->spinlock); + 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 = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS); + 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); + dlm_lockres_grab_inflight_ref(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) { + int mig; + if (mle->type == DLM_MLE_MASTER) { + mlog(ML_ERROR, "master entry for nonexistent lock!\n"); + BUG(); + } + mig = (mle->type == DLM_MLE_MIGRATION); + /* if there is a migration in progress, let the migration + * finish before continuing. we can wait for the absence + * of the MIGRATION mle: either the migrate finished or + * one of the nodes died and the mle was cleaned up. + * if there is a BLOCK here, but it already has a master + * set, we are too late. the master does not have a ref + * for us in the refmap. detach the mle and drop it. + * either way, go back to the top and start over. */ + if (mig || mle->master != O2NM_MAX_NODES) { + BUG_ON(mig && mle->master == dlm->node_num); + /* we arrived too late. the master does not + * have a ref for us. retry. */ + mlog(0, "%s:%.*s: late on %s\n", + dlm->name, namelen, lockid, + mig ? "MIGRATION" : "BLOCK"); + spin_unlock(&dlm->master_lock); + spin_unlock(&dlm->spinlock); + + /* master is known, detach */ + if (!mig) + dlm_mle_detach_hb_events(dlm, mle); + dlm_put_mle(mle); + mle = NULL; + /* this is lame, but we can't wait on either + * the mle or lockres waitqueue here */ + if (mig) + msleep(100); + goto lookup; + } + } 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); + __dlm_insert_mle(dlm, mle); + + /* still holding the dlm spinlock, check the recovery map + * to see if there are any nodes that still need to be + * considered. these will not appear in the mle nodemap + * but they might own this lockres. wait on them. */ + bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0); + if (bit < O2NM_MAX_NODES) { + mlog(0, "%s: res %.*s, At least one node (%d) " + "to recover before lock mastery can begin\n", + dlm->name, namelen, (char *)lockid, bit); + wait_on_recovery = 1; + } + } + + /* at this point there is either a DLM_MLE_BLOCK or a + * DLM_MLE_MASTER on the master list, so it's safe to add the + * lockres to the hashtable. anyone who finds the lock will + * still have to wait on the IN_PROGRESS. */ + + /* finally add the lockres to its hash bucket */ + __dlm_insert_lockres(dlm, res); + + /* since this lockres is new it doesn't not require the spinlock */ + __dlm_lockres_grab_inflight_ref(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_inuse(mle); + spin_unlock(&dlm->master_lock); + spin_unlock(&dlm->spinlock); + +redo_request: + while (wait_on_recovery) { + /* any cluster changes that occurred after dropping the + * dlm spinlock would be detectable be a change on the mle, + * so we only need to clear out the recovery map once. */ + if (dlm_is_recovery_lock(lockid, namelen)) { + mlog(0, "%s: Recovery map is not empty, but must " + "master $RECOVERY lock now\n", dlm->name); + if (!dlm_pre_master_reco_lockres(dlm, res)) + wait_on_recovery = 0; + else { + mlog(0, "%s: waiting 500ms for heartbeat state " + "change\n", dlm->name); + msleep(500); + } + continue; + } + + dlm_kick_recovery_thread(dlm); + msleep(1000); + dlm_wait_for_recovery(dlm); + + spin_lock(&dlm->spinlock); + bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0); + if (bit < O2NM_MAX_NODES) { + mlog(0, "%s: res %.*s, At least one node (%d) " + "to recover before lock mastery can begin\n", + dlm->name, namelen, (char *)lockid, bit); + wait_on_recovery = 1; + } else + wait_on_recovery = 0; + spin_unlock(&dlm->spinlock); + + if (wait_on_recovery) + dlm_wait_for_node_recovery(dlm, bit, 10000); + } + + /* must wait for lock to be mastered elsewhere */ + if (blocked) + goto wait; + + ret = -EINVAL; + dlm_node_iter_init(mle->vote_map, &iter); + while ((nodenum = dlm_node_iter_next(&iter)) >= 0) { + ret = dlm_do_master_request(res, mle, nodenum); + if (ret < 0) + mlog_errno(ret); + if (mle->master != O2NM_MAX_NODES) { + /* found a master ! */ + if (mle->master <= nodenum) + break; + /* if our master request has not reached the master + * yet, keep going until it does. this is how the + * master will know that asserts are needed back to + * the lower nodes. */ + mlog(0, "%s: res %.*s, Requests only up to %u but " + "master is %u, keep going\n", dlm->name, namelen, + lockid, nodenum, mle->master); + } + } + +wait: + /* keep going until the response map includes all nodes */ + ret = dlm_wait_for_lock_mastery(dlm, res, mle, &blocked); + if (ret < 0) { + wait_on_recovery = 1; + mlog(0, "%s: res %.*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: res %.*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, "%s: res %.*s, Mastered by %u\n", dlm->name, res->lockname.len, + res->lockname.name, 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_inuse(mle); + +wake_waiters: + spin_lock(&res->spinlock); + res->state &= ~DLM_LOCK_RES_IN_PROGRESS; + spin_unlock(&res->spinlock); + wake_up(&res->wq); + +leave: + /* need to free the unused mle */ + if (alloc_mle) + kmem_cache_free(dlm_mle_cache, alloc_mle); + + return res; +} + + +#define DLM_MASTERY_TIMEOUT_MS 5000 + +static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res, + struct dlm_master_list_entry *mle, + int *blocked) +{ + u8 m; + int ret, bit; + int map_changed, voting_done; + int assert, sleep; + +recheck: + ret = 0; + assert = 0; + + /* check if another node has already become the owner */ + spin_lock(&res->spinlock); + if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) { + mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name, + res->lockname.len, res->lockname.name, res->owner); + spin_unlock(&res->spinlock); + /* this will cause the master to re-assert across + * the whole cluster, freeing up mles */ + if (res->owner != dlm->node_num) { + ret = dlm_do_master_request(res, mle, res->owner); + if (ret < 0) { + /* give recovery a chance to run */ + mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret); + msleep(500); + goto recheck; + } + } + ret = 0; + goto leave; + } + spin_unlock(&res->spinlock); + + spin_lock(&mle->spinlock); + m = mle->master; + map_changed = (memcmp(mle->vote_map, mle->node_map, + sizeof(mle->vote_map)) != 0); + voting_done = (memcmp(mle->vote_map, mle->response_map, + sizeof(mle->vote_map)) == 0); + + /* restart if we hit any errors */ + if (map_changed) { + int b; + mlog(0, "%s: %.*s: node map changed, restarting\n", + dlm->name, res->lockname.len, res->lockname.name); + ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked); + b = (mle->type == DLM_MLE_BLOCK); + if ((*blocked && !b) || (!*blocked && b)) { + mlog(0, "%s:%.*s: status change: old=%d new=%d\n", + dlm->name, res->lockname.len, res->lockname.name, + *blocked, b); + *blocked = b; + } + spin_unlock(&mle->spinlock); + if (ret < 0) { + mlog_errno(ret); + goto leave; + } + mlog(0, "%s:%.*s: restart lock mastery succeeded, " + "rechecking now\n", dlm->name, res->lockname.len, + res->lockname.name); + goto recheck; + } else { + if (!voting_done) { + mlog(0, "map not changed and voting not done " + "for %s:%.*s\n", dlm->name, res->lockname.len, + res->lockname.name); + } + } + + 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; + /* ref was grabbed in get_lock_resource + * will be dropped in dlmlock_master */ + 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, "%s:%.*s: waiting again\n", dlm->name, + res->lockname.len, res->lockname.name); + 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, 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); + /* mastery reference obtained either during + * assert_master_handler or in get_lock_resource */ + dlm_change_lockres_owner(dlm, res, m); + spin_unlock(&res->spinlock); + +leave: + return ret; +} + +struct dlm_bitmap_diff_iter +{ + int curnode; + unsigned long *orig_bm; + unsigned long *cur_bm; + unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)]; +}; + +enum dlm_node_state_change +{ + NODE_DOWN = -1, + NODE_NO_CHANGE = 0, + NODE_UP +}; + +static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter, + unsigned long *orig_bm, + unsigned long *cur_bm) +{ + unsigned long p1, p2; + int i; + + iter->curnode = -1; + iter->orig_bm = orig_bm; + iter->cur_bm = cur_bm; + + for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) { + p1 = *(iter->orig_bm + i); + p2 = *(iter->cur_bm + i); + iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1); + } +} + +static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter, + enum dlm_node_state_change *state) +{ + int bit; + + if (iter->curnode >= O2NM_MAX_NODES) + return -ENOENT; + + bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES, + iter->curnode+1); + if (bit >= O2NM_MAX_NODES) { + iter->curnode = O2NM_MAX_NODES; + return -ENOENT; + } + + /* if it was there in the original then this node died */ + if (test_bit(bit, iter->orig_bm)) + *state = NODE_DOWN; + else + *state = NODE_UP; + + iter->curnode = bit; + return bit; +} + + +static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res, + struct dlm_master_list_entry *mle, + int blocked) +{ + struct dlm_bitmap_diff_iter bdi; + enum dlm_node_state_change sc; + int node; + int ret = 0; + + mlog(0, "something happened such that the " + "master process may need to be restarted!\n"); + + assert_spin_locked(&mle->spinlock); + + dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map); + node = dlm_bitmap_diff_iter_next(&bdi, &sc); + while (node >= 0) { + if (sc == NODE_UP) { + /* a node came up. clear any old vote from + * the response map and set it in the vote map + * then restart the mastery. */ + mlog(ML_NOTICE, "node %d up while restarting\n", node); + + /* redo the master request, but only for the new node */ + mlog(0, "sending request to new node\n"); + clear_bit(node, mle->response_map); + set_bit(node, mle->vote_map); + } else { + mlog(ML_ERROR, "node down! %d\n", node); + if (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) { + mlog(0, "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, "%s:%.*s:still " + "blocked. waiting on %u " + "now\n", dlm->name, + res->lockname.len, + res->lockname.name, + lowest); + } else { + /* 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, "%s:%.*s: no " + "longer blocking. try to " + "master this here\n", + dlm->name, + res->lockname.len, + res->lockname.name); + mle->type = DLM_MLE_MASTER; + mle->mleres = res; + } + } + } + + /* now blank out everything, as if we had never + * contacted anyone */ + memset(mle->maybe_map, 0, sizeof(mle->maybe_map)); + memset(mle->response_map, 0, sizeof(mle->response_map)); + /* reset the vote_map to the current node_map */ + memcpy(mle->vote_map, mle->node_map, + sizeof(mle->node_map)); + /* put myself into the maybe map */ + if (mle->type != DLM_MLE_BLOCK) + set_bit(dlm->node_num, mle->maybe_map); + } + ret = -EAGAIN; + 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_lock_resource *res, + 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); + + request.namelen = (u8)mle->mnamelen; + memcpy(request.name, mle->mname, 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); + mlog(0, "%s:%.*s: master node %u now knows I have a " + "reference\n", dlm->name, res->lockname.len, + res->lockname.name, 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, + void **ret_data) +{ + u8 response = DLM_MASTER_RESP_MAYBE; + struct dlm_ctxt *dlm = data; + struct dlm_lock_resource *res = NULL; + struct dlm_master_request *request = (struct dlm_master_request *) msg->buf; + struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL; + char *name; + unsigned int namelen, hash; + int found, ret; + int set_maybe; + int dispatch_assert = 0; + + if (!dlm_grab(dlm)) + return DLM_MASTER_RESP_NO; + + if (!dlm_domain_fully_joined(dlm)) { + response = DLM_MASTER_RESP_NO; + goto send_response; + } + + name = request->name; + namelen = request->namelen; + hash = dlm_lockid_hash(name, 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, hash); + if (res) { + spin_unlock(&dlm->spinlock); + + /* take care of the easy cases up front */ + spin_lock(&res->spinlock); + + /* + * Right after dlm spinlock was released, dlm_thread could have + * purged the lockres. Check if lockres got unhashed. If so + * start over. + */ + if (hlist_unhashed(&res->hash_node)) { + spin_unlock(&res->spinlock); + dlm_lockres_put(res); + goto way_up_top; + } + + if (res->state & (DLM_LOCK_RES_RECOVERING| + DLM_LOCK_RES_MIGRATING)) { + spin_unlock(&res->spinlock); + mlog(0, "returning DLM_MASTER_RESP_ERROR since res is " + "being recovered/migrated\n"); + response = DLM_MASTER_RESP_ERROR; + if (mle) + kmem_cache_free(dlm_mle_cache, mle); + goto send_response; + } + + if (res->owner == dlm->node_num) { + dlm_lockres_set_refmap_bit(dlm, res, request->node_idx); + spin_unlock(&res->spinlock); + response = DLM_MASTER_RESP_YES; + if (mle) + kmem_cache_free(dlm_mle_cache, mle); + + /* this node is the owner. + * there is some extra work that needs to + * happen now. the requesting node has + * caused all nodes up to this one to + * create mles. this node now needs to + * go back and clean those up. */ + dispatch_assert = 1; + goto send_response; + } else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) { + spin_unlock(&res->spinlock); + // mlog(0, "node %u is the master\n", res->owner); + response = DLM_MASTER_RESP_NO; + if (mle) + kmem_cache_free(dlm_mle_cache, mle); + goto send_response; + } + + /* ok, there is no owner. either this node is + * being blocked, or it is actively trying to + * master this lock. */ + if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) { + mlog(ML_ERROR, "lock with no owner should be " + "in-progress!\n"); + BUG(); + } + + // mlog(0, "lockres is in progress...\n"); + spin_lock(&dlm->master_lock); + found = dlm_find_mle(dlm, &tmpmle, name, namelen); + if (!found) { + mlog(ML_ERROR, "no mle found for this lock!\n"); + BUG(); + } + set_maybe = 1; + spin_lock(&tmpmle->spinlock); + if (tmpmle->type == DLM_MLE_BLOCK) { + // mlog(0, "this node is waiting for " + // "lockres to be mastered\n"); + response = DLM_MASTER_RESP_NO; + } else if (tmpmle->type == DLM_MLE_MIGRATION) { + mlog(0, "node %u is master, but trying to migrate to " + "node %u.\n", tmpmle->master, tmpmle->new_master); + if (tmpmle->master == dlm->node_num) { + mlog(ML_ERROR, "no owner on lockres, but this " + "node is trying to migrate it to %u?!\n", + tmpmle->new_master); + BUG(); + } else { + /* the real master can respond on its own */ + response = DLM_MASTER_RESP_NO; + } + } else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) { + set_maybe = 0; + if (tmpmle->master == dlm->node_num) { + response = DLM_MASTER_RESP_YES; + /* this node will be the owner. + * go back and clean the mles on any + * other nodes */ + dispatch_assert = 1; + dlm_lockres_set_refmap_bit(dlm, res, + request->node_idx); + } 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 = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS); + if (!mle) { + response = DLM_MASTER_RESP_ERROR; + mlog_errno(-ENOMEM); + goto send_response; + } + goto way_up_top; + } + + // mlog(0, "this is second time thru, already allocated, " + // "add the block.\n"); + dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL, name, namelen); + set_bit(request->node_idx, mle->maybe_map); + __dlm_insert_mle(dlm, mle); + response = DLM_MASTER_RESP_NO; + } else { + // mlog(0, "mle was found\n"); + set_maybe = 1; + spin_lock(&tmpmle->spinlock); + if (tmpmle->master == dlm->node_num) { + mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n"); + BUG(); + } + if (tmpmle->type == DLM_MLE_BLOCK) + response = DLM_MASTER_RESP_NO; + else if (tmpmle->type == DLM_MLE_MIGRATION) { + mlog(0, "migration mle was found (%u->%u)\n", + tmpmle->master, tmpmle->new_master); + /* real master can respond on its own */ + response = DLM_MASTER_RESP_NO; + } else + response = DLM_MASTER_RESP_MAYBE; + if (set_maybe) + set_bit(request->node_idx, tmpmle->maybe_map); + spin_unlock(&tmpmle->spinlock); + } + spin_unlock(&dlm->master_lock); + spin_unlock(&dlm->spinlock); + + if (found) { + /* keep the mle attached to heartbeat events */ + dlm_put_mle(tmpmle); + } +send_response: + /* + * __dlm_lookup_lockres() grabbed a reference to this lockres. + * The reference is released by dlm_assert_master_worker() under + * the call to dlm_dispatch_assert_master(). If + * dlm_assert_master_worker() isn't called, we drop it here. + */ + if (dispatch_assert) { + if (response != DLM_MASTER_RESP_YES) + mlog(ML_ERROR, "invalid response %d\n", response); + if (!res) { + mlog(ML_ERROR, "bad lockres while trying to assert!\n"); + BUG(); + } + mlog(0, "%u is the owner of %.*s, cleaning everyone else\n", + dlm->node_num, res->lockname.len, res->lockname.name); + spin_lock(&res->spinlock); + ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx, + DLM_ASSERT_MASTER_MLE_CLEANUP); + if (ret < 0) { + mlog(ML_ERROR, "failed to dispatch assert master work\n"); + response = DLM_MASTER_RESP_ERROR; + dlm_lockres_put(res); + } else + __dlm_lockres_grab_inflight_worker(dlm, res); + spin_unlock(&res->spinlock); + } else { + if (res) + dlm_lockres_put(res); + } + + 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, + struct dlm_lock_resource *res, + void *nodemap, u32 flags) +{ + struct dlm_assert_master assert; + int to, tmpret; + struct dlm_node_iter iter; + int ret = 0; + int reassert; + const char *lockname = res->lockname.name; + unsigned int namelen = res->lockname.len; + + BUG_ON(namelen > O2NM_MAX_NAME_LEN); + + spin_lock(&res->spinlock); + res->state |= DLM_LOCK_RES_SETREF_INPROG; + spin_unlock(&res->spinlock); + +again: + reassert = 0; + + /* note that if this nodemap is empty, it returns 0 */ + dlm_node_iter_init(nodemap, &iter); + while ((to = dlm_node_iter_next(&iter)) >= 0) { + int r = 0; + struct dlm_master_list_entry *mle = NULL; + + 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, "Error %d when sending message %u (key " + "0x%x) to node %u\n", tmpret, + DLM_ASSERT_MASTER_MSG, dlm->key, to); + if (!dlm_is_host_down(tmpret)) { + mlog(ML_ERROR, "unhandled error=%d!\n", tmpret); + BUG(); + } + /* a node died. finish out the rest of the nodes. */ + mlog(0, "link to %d went down!\n", to); + /* any nonzero status return will do */ + ret = tmpret; + r = 0; + } 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); + spin_lock(&dlm->spinlock); + spin_lock(&dlm->master_lock); + if (dlm_find_mle(dlm, &mle, (char *)lockname, + namelen)) { + dlm_print_one_mle(mle); + __dlm_put_mle(mle); + } + spin_unlock(&dlm->master_lock); + spin_unlock(&dlm->spinlock); + BUG(); + } + + if (r & DLM_ASSERT_RESPONSE_REASSERT && + !(r & DLM_ASSERT_RESPONSE_MASTERY_REF)) { + mlog(ML_ERROR, "%.*s: very strange, " + "master MLE but no lockres on %u\n", + namelen, lockname, to); + } + + if (r & DLM_ASSERT_RESPONSE_REASSERT) { + mlog(0, "%.*s: node %u create mles on other " + "nodes and requests a re-assert\n", + namelen, lockname, to); + reassert = 1; + } + if (r & DLM_ASSERT_RESPONSE_MASTERY_REF) { + mlog(0, "%.*s: node %u has a reference to this " + "lockres, set the bit in the refmap\n", + namelen, lockname, to); + spin_lock(&res->spinlock); + dlm_lockres_set_refmap_bit(dlm, res, to); + spin_unlock(&res->spinlock); + } + } + + if (reassert) + goto again; + + spin_lock(&res->spinlock); + res->state &= ~DLM_LOCK_RES_SETREF_INPROG; + spin_unlock(&res->spinlock); + wake_up(&res->wq); + + 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, + void **ret_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, hash; + u32 flags; + int master_request = 0, have_lockres_ref = 0; + int ret = 0; + + if (!dlm_grab(dlm)) + return 0; + + name = assert->name; + namelen = assert->namelen; + hash = dlm_lockid_hash(name, 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(0, "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(0, "%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); + } + } + if (mle->type == DLM_MLE_MIGRATION) { + if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) { + mlog(0, "%s:%.*s: got cleanup assert" + " from %u for migration\n", + dlm->name, namelen, name, + assert->node_idx); + } else if (!(flags & DLM_ASSERT_MASTER_FINISH_MIGRATION)) { + mlog(0, "%s:%.*s: got unrelated assert" + " from %u for migration, ignoring\n", + dlm->name, namelen, name, + assert->node_idx); + __dlm_put_mle(mle); + spin_unlock(&dlm->master_lock); + spin_unlock(&dlm->spinlock); + goto done; + } + } + } + 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, hash); + 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 != DLM_LOCK_RES_OWNER_UNKNOWN && + res->owner != assert->node_idx) { + mlog(ML_ERROR, "DIE! Mastery assert from %u, " + "but current owner is %u! (%.*s)\n", + assert->node_idx, res->owner, namelen, + name); + __dlm_print_one_lock_resource(res); + BUG(); + } + } 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); + } + + // mlog(0, "woo! got an assert_master from node %u!\n", + // assert->node_idx); + if (mle) { + int extra_ref = 0; + int nn = -1; + int rr, err = 0; + + spin_lock(&mle->spinlock); + if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION) + extra_ref = 1; + else { + /* MASTER mle: if any bits set in the response map + * then the calling node needs to re-assert to clear + * up nodes that this node contacted */ + while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES, + nn+1)) < O2NM_MAX_NODES) { + if (nn != dlm->node_num && nn != assert->node_idx) { + master_request = 1; + break; + } + } + } + mle->master = assert->node_idx; + atomic_set(&mle->woken, 1); + wake_up(&mle->wq); + spin_unlock(&mle->spinlock); + + if (res) { + int wake = 0; + spin_lock(&res->spinlock); + if (mle->type == DLM_MLE_MIGRATION) { + 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); + res->state &= ~DLM_LOCK_RES_MIGRATING; + wake = 1; + dlm_change_lockres_owner(dlm, res, mle->new_master); + BUG_ON(res->state & DLM_LOCK_RES_DIRTY); + } else { + dlm_change_lockres_owner(dlm, res, mle->master); + } + spin_unlock(&res->spinlock); + have_lockres_ref = 1; + if (wake) + wake_up(&res->wq); + } + + /* master is known, detach if not already detached. + * ensures that only one assert_master call will happen + * on this mle. */ + spin_lock(&dlm->master_lock); + + rr = atomic_read(&mle->mle_refs.refcount); + if (mle->inuse > 0) { + if (extra_ref && rr < 3) + err = 1; + else if (!extra_ref && rr < 2) + err = 1; + } else { + if (extra_ref && rr < 2) + err = 1; + else if (!extra_ref && rr < 1) + err = 1; + } + if (err) { + mlog(ML_ERROR, "%s:%.*s: got assert master from %u " + "that will mess up this node, refs=%d, extra=%d, " + "inuse=%d\n", dlm->name, namelen, name, + assert->node_idx, rr, extra_ref, mle->inuse); + dlm_print_one_mle(mle); + } + __dlm_unlink_mle(dlm, mle); + __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); + } + spin_unlock(&dlm->master_lock); + } else if (res) { + if (res->owner != assert->node_idx) { + mlog(0, "assert_master from %u, but current " + "owner is %u (%.*s), no mle\n", assert->node_idx, + res->owner, namelen, name); + } + } + spin_unlock(&dlm->spinlock); + +done: + ret = 0; + if (res) { + spin_lock(&res->spinlock); + res->state |= DLM_LOCK_RES_SETREF_INPROG; + spin_unlock(&res->spinlock); + *ret_data = (void *)res; + } + dlm_put(dlm); + if (master_request) { + mlog(0, "need to tell master to reassert\n"); + /* positive. negative would shoot down the node. */ + ret |= DLM_ASSERT_RESPONSE_REASSERT; + if (!have_lockres_ref) { + mlog(ML_ERROR, "strange, got assert from %u, MASTER " + "mle present here for %s:%.*s, but no lockres!\n", + assert->node_idx, dlm->name, namelen, name); + } + } + if (have_lockres_ref) { + /* let the master know we have a reference to the lockres */ + ret |= DLM_ASSERT_RESPONSE_MASTERY_REF; + mlog(0, "%s:%.*s: got assert from %u, need a ref\n", + dlm->name, namelen, name, assert->node_idx); + } + return ret; + +kill: + /* kill the caller! */ + 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_print_one_lock_resource(res); + spin_unlock(&res->spinlock); + spin_lock(&dlm->master_lock); + if (mle) + __dlm_put_mle(mle); + spin_unlock(&dlm->master_lock); + spin_unlock(&dlm->spinlock); + *ret_data = (void *)res; + dlm_put(dlm); + return -EINVAL; +} + +void dlm_assert_master_post_handler(int status, void *data, void *ret_data) +{ + struct dlm_lock_resource *res = (struct dlm_lock_resource *)ret_data; + + if (ret_data) { + spin_lock(&res->spinlock); + res->state &= ~DLM_LOCK_RES_SETREF_INPROG; + spin_unlock(&res->spinlock); + wake_up(&res->wq); + dlm_lockres_put(res); + } + return; +} + +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 = kzalloc(sizeof(*item), GFP_ATOMIC); + if (!item) + return -ENOMEM; + + + /* queue up work for dlm_assert_master_worker */ + dlm_grab(dlm); /* get an extra ref for the work item */ + dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL); + item->u.am.lockres = res; /* already have a ref */ + /* can optionally ignore node numbers higher than this node */ + item->u.am.ignore_higher = ignore_higher; + item->u.am.request_from = request_from; + item->u.am.flags = flags; + + if (ignore_higher) + mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len, + res->lockname.name); + + spin_lock(&dlm->work_lock); + list_add_tail(&item->list, &dlm->work_list); + spin_unlock(&dlm->work_lock); + + queue_work(dlm->dlm_worker, &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); + } + } + + /* + * If we're migrating this lock to someone else, we are no + * longer allowed to assert out own mastery. OTOH, we need to + * prevent migration from starting while we're still asserting + * our dominance. The reserved ast delays migration. + */ + spin_lock(&res->spinlock); + if (res->state & DLM_LOCK_RES_MIGRATING) { + mlog(0, "Someone asked us to assert mastery, but we're " + "in the middle of migration. Skipping assert, " + "the new master will handle that.\n"); + spin_unlock(&res->spinlock); + goto put; + } else + __dlm_lockres_reserve_ast(res); + spin_unlock(&res->spinlock); + + /* 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, nodemap, flags); + if (ret < 0) { + /* no need to restart, we are done */ + if (!dlm_is_host_down(ret)) + mlog_errno(ret); + } + + /* Ok, we've asserted ourselves. Let's let migration start. */ + dlm_lockres_release_ast(dlm, res); + +put: + dlm_lockres_drop_inflight_worker(dlm, res); + + dlm_lockres_put(res); + + mlog(0, "finished with dlm_assert_master_worker\n"); +} + +/* SPECIAL CASE for the $RECOVERY lock used by the recovery thread. + * We cannot wait for node recovery to complete to begin mastering this + * lockres because this lockres is used to kick off recovery! ;-) + * So, do a pre-check on all living nodes to see if any of those nodes + * think that $RECOVERY is currently mastered by a dead node. If so, + * we wait a short time to allow that node to get notified by its own + * heartbeat stack, then check again. All $RECOVERY lock resources + * mastered by dead nodes are purged when the hearbeat callback is + * fired, so we can know for sure that it is safe to continue once + * the node returns a live node or no node. */ +static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res) +{ + struct dlm_node_iter iter; + int nodenum; + int ret = 0; + u8 master = DLM_LOCK_RES_OWNER_UNKNOWN; + + spin_lock(&dlm->spinlock); + dlm_node_iter_init(dlm->domain_map, &iter); + spin_unlock(&dlm->spinlock); + + while ((nodenum = dlm_node_iter_next(&iter)) >= 0) { + /* do not send to self */ + if (nodenum == dlm->node_num) + continue; + ret = dlm_do_master_requery(dlm, res, nodenum, &master); + if (ret < 0) { + mlog_errno(ret); + if (!dlm_is_host_down(ret)) + BUG(); + /* host is down, so answer for that node would be + * DLM_LOCK_RES_OWNER_UNKNOWN. continue. */ + ret = 0; + } + + if (master != DLM_LOCK_RES_OWNER_UNKNOWN) { + /* check to see if this master is in the recovery map */ + spin_lock(&dlm->spinlock); + if (test_bit(master, dlm->recovery_map)) { + mlog(ML_NOTICE, "%s: node %u has not seen " + "node %u go down yet, and thinks the " + "dead node is mastering the recovery " + "lock. must wait.\n", dlm->name, + nodenum, master); + ret = -EAGAIN; + } + spin_unlock(&dlm->spinlock); + mlog(0, "%s: reco lock master is %u\n", dlm->name, + master); + break; + } + } + return ret; +} + +/* + * DLM_DEREF_LOCKRES_MSG + */ + +int dlm_drop_lockres_ref(struct dlm_ctxt *dlm, struct dlm_lock_resource *res) +{ + struct dlm_deref_lockres deref; + int ret = 0, r; + const char *lockname; + unsigned int namelen; + + lockname = res->lockname.name; + namelen = res->lockname.len; + BUG_ON(namelen > O2NM_MAX_NAME_LEN); + + memset(&deref, 0, sizeof(deref)); + deref.node_idx = dlm->node_num; + deref.namelen = namelen; + memcpy(deref.name, lockname, namelen); + + ret = o2net_send_message(DLM_DEREF_LOCKRES_MSG, dlm->key, + &deref, sizeof(deref), res->owner, &r); + if (ret < 0) + mlog(ML_ERROR, "%s: res %.*s, error %d send DEREF to node %u\n", + dlm->name, namelen, lockname, ret, res->owner); + else if (r < 0) { + /* BAD. other node says I did not have a ref. */ + mlog(ML_ERROR, "%s: res %.*s, DEREF to node %u got %d\n", + dlm->name, namelen, lockname, res->owner, r); + dlm_print_one_lock_resource(res); + BUG(); + } + return ret; +} + +int dlm_deref_lockres_handler(struct o2net_msg *msg, u32 len, void *data, + void **ret_data) +{ + struct dlm_ctxt *dlm = data; + struct dlm_deref_lockres *deref = (struct dlm_deref_lockres *)msg->buf; + struct dlm_lock_resource *res = NULL; + char *name; + unsigned int namelen; + int ret = -EINVAL; + u8 node; + unsigned int hash; + struct dlm_work_item *item; + int cleared = 0; + int dispatch = 0; + + if (!dlm_grab(dlm)) + return 0; + + name = deref->name; + namelen = deref->namelen; + node = deref->node_idx; + + if (namelen > DLM_LOCKID_NAME_MAX) { + mlog(ML_ERROR, "Invalid name length!"); + goto done; + } + if (deref->node_idx >= O2NM_MAX_NODES) { + mlog(ML_ERROR, "Invalid node number: %u\n", node); + goto done; + } + + hash = dlm_lockid_hash(name, namelen); + + spin_lock(&dlm->spinlock); + res = __dlm_lookup_lockres_full(dlm, name, namelen, hash); + if (!res) { + spin_unlock(&dlm->spinlock); + mlog(ML_ERROR, "%s:%.*s: bad lockres name\n", + dlm->name, namelen, name); + goto done; + } + spin_unlock(&dlm->spinlock); + + spin_lock(&res->spinlock); + if (res->state & DLM_LOCK_RES_SETREF_INPROG) + dispatch = 1; + else { + BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF); + if (test_bit(node, res->refmap)) { + dlm_lockres_clear_refmap_bit(dlm, res, node); + cleared = 1; + } + } + spin_unlock(&res->spinlock); + + if (!dispatch) { + if (cleared) + dlm_lockres_calc_usage(dlm, res); + else { + mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref " + "but it is already dropped!\n", dlm->name, + res->lockname.len, res->lockname.name, node); + dlm_print_one_lock_resource(res); + } + ret = 0; + goto done; + } + + item = kzalloc(sizeof(*item), GFP_NOFS); + if (!item) { + ret = -ENOMEM; + mlog_errno(ret); + goto done; + } + + dlm_init_work_item(dlm, item, dlm_deref_lockres_worker, NULL); + item->u.dl.deref_res = res; + item->u.dl.deref_node = node; + + spin_lock(&dlm->work_lock); + list_add_tail(&item->list, &dlm->work_list); + spin_unlock(&dlm->work_lock); + + queue_work(dlm->dlm_worker, &dlm->dispatched_work); + return 0; + +done: + if (res) + dlm_lockres_put(res); + dlm_put(dlm); + + return ret; +} + +static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data) +{ + struct dlm_ctxt *dlm; + struct dlm_lock_resource *res; + u8 node; + u8 cleared = 0; + + dlm = item->dlm; + res = item->u.dl.deref_res; + node = item->u.dl.deref_node; + + spin_lock(&res->spinlock); + BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF); + if (test_bit(node, res->refmap)) { + __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG); + dlm_lockres_clear_refmap_bit(dlm, res, node); + cleared = 1; + } + spin_unlock(&res->spinlock); + + if (cleared) { + mlog(0, "%s:%.*s node %u ref dropped in dispatch\n", + dlm->name, res->lockname.len, res->lockname.name, node); + dlm_lockres_calc_usage(dlm, res); + } else { + mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref " + "but it is already dropped!\n", dlm->name, + res->lockname.len, res->lockname.name, node); + dlm_print_one_lock_resource(res); + } + + dlm_lockres_put(res); +} + +/* + * A migrateable resource is one that is : + * 1. locally mastered, and, + * 2. zero local locks, and, + * 3. one or more non-local locks, or, one or more references + * Returns 1 if yes, 0 if not. + */ +static int dlm_is_lockres_migrateable(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res) +{ + enum dlm_lockres_list idx; + int nonlocal = 0, node_ref; + struct list_head *queue; + struct dlm_lock *lock; + u64 cookie; + + assert_spin_locked(&res->spinlock); + + /* delay migration when the lockres is in MIGRATING state */ + if (res->state & DLM_LOCK_RES_MIGRATING) + return 0; + + /* delay migration when the lockres is in RECOCERING state */ + if (res->state & DLM_LOCK_RES_RECOVERING) + return 0; + + if (res->owner != dlm->node_num) + return 0; + + for (idx = DLM_GRANTED_LIST; idx <= DLM_BLOCKED_LIST; idx++) { + queue = dlm_list_idx_to_ptr(res, idx); + list_for_each_entry(lock, queue, list) { + if (lock->ml.node != dlm->node_num) { + nonlocal++; + continue; + } + cookie = be64_to_cpu(lock->ml.cookie); + mlog(0, "%s: Not migrateable res %.*s, lock %u:%llu on " + "%s list\n", dlm->name, res->lockname.len, + res->lockname.name, + dlm_get_lock_cookie_node(cookie), + dlm_get_lock_cookie_seq(cookie), + dlm_list_in_text(idx)); + return 0; + } + } + + if (!nonlocal) { + node_ref = find_next_bit(res->refmap, O2NM_MAX_NODES, 0); + if (node_ref >= O2NM_MAX_NODES) + return 0; + } + + mlog(0, "%s: res %.*s, Migrateable\n", dlm->name, res->lockname.len, + res->lockname.name); + + return 1; +} + +/* + * DLM_MIGRATE_LOCKRES + */ + + +static 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 = 0; + const char *name; + unsigned int namelen; + int mle_added = 0; + int wake = 0; + + if (!dlm_grab(dlm)) + return -EINVAL; + + BUG_ON(target == O2NM_MAX_NODES); + + name = res->lockname.name; + namelen = res->lockname.len; + + mlog(0, "%s: Migrating %.*s to node %u\n", dlm->name, namelen, name, + target); + + /* preallocate up front. if this fails, abort */ + ret = -ENOMEM; + mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_NOFS); + if (!mres) { + mlog_errno(ret); + goto leave; + } + + mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS); + if (!mle) { + mlog_errno(ret); + goto leave; + } + ret = 0; + + /* + * clear any existing master requests and + * add the migration mle to the list + */ + spin_lock(&dlm->spinlock); + 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; + wake = 1; + 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); + mle = NULL; + } + goto leave; + } + + /* + * at this point, we have a migration target, an mle + * in the master list, and the MIGRATING flag set on + * the lockres + */ + + /* now that remote nodes are spinning on the MIGRATING flag, + * ensure that all assert_master work is flushed. */ + flush_workqueue(dlm->dlm_worker); + + /* 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_inuse(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_inuse(mle); + spin_lock(&res->spinlock); + res->state &= ~DLM_LOCK_RES_MIGRATING; + wake = 1; + spin_unlock(&res->spinlock); + if (dlm_is_host_down(ret)) + dlm_wait_for_node_death(dlm, target, + DLM_NODE_DEATH_WAIT_MAX); + 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 UNKNOWN. */ + + + /* 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, "%s:%.*s: timed out during migration\n", + dlm->name, res->lockname.len, res->lockname.name); + /* avoid hang during shutdown when migrating lockres + * to a node which also goes down */ + if (dlm_is_node_dead(dlm, target)) { + mlog(0, "%s:%.*s: expected migration " + "target %u is no longer up, restarting\n", + dlm->name, res->lockname.len, + res->lockname.name, target); + ret = -EINVAL; + /* migration failed, detach and clean up mle */ + dlm_mle_detach_hb_events(dlm, mle); + dlm_put_mle(mle); + dlm_put_mle_inuse(mle); + spin_lock(&res->spinlock); + res->state &= ~DLM_LOCK_RES_MIGRATING; + wake = 1; + spin_unlock(&res->spinlock); + goto leave; + } + } else + mlog(0, "%s:%.*s: caught signal during migration\n", + dlm->name, res->lockname.len, res->lockname.name); + } + + /* 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_inuse(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); + + /* wake up waiters if the MIGRATING flag got set + * but migration failed */ + if (wake) + wake_up(&res->wq); + + if (mres) + free_page((unsigned long)mres); + + dlm_put(dlm); + + mlog(0, "%s: Migrating %.*s to %u, returns %d\n", dlm->name, namelen, + name, target, ret); + return ret; +} + +#define DLM_MIGRATION_RETRY_MS 100 + +/* + * Should be called only after beginning the domain leave process. + * There should not be any remaining locks on nonlocal lock resources, + * and there should be no local locks left on locally mastered resources. + * + * Called with the dlm spinlock held, may drop it to do migration, but + * will re-acquire before exit. + * + * Returns: 1 if dlm->spinlock was dropped/retaken, 0 if never dropped + */ +int dlm_empty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res) +{ + int ret; + int lock_dropped = 0; + u8 target = O2NM_MAX_NODES; + + assert_spin_locked(&dlm->spinlock); + + spin_lock(&res->spinlock); + if (dlm_is_lockres_migrateable(dlm, res)) + target = dlm_pick_migration_target(dlm, res); + spin_unlock(&res->spinlock); + + if (target == O2NM_MAX_NODES) + goto leave; + + /* Wheee! Migrate lockres here! Will sleep so drop spinlock. */ + spin_unlock(&dlm->spinlock); + lock_dropped = 1; + ret = dlm_migrate_lockres(dlm, res, target); + if (ret) + mlog(0, "%s: res %.*s, Migrate to node %u failed with %d\n", + dlm->name, res->lockname.len, res->lockname.name, + target, ret); + spin_lock(&dlm->spinlock); +leave: + return lock_dropped; +} + +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; +} + +static 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 */ + dlm_kick_thread(dlm, res); + /* before waiting on DIRTY, block processes which may + * try to dirty the lockres before MIGRATING is set */ + spin_lock(&res->spinlock); + BUG_ON(res->state & DLM_LOCK_RES_BLOCK_DIRTY); + res->state |= DLM_LOCK_RES_BLOCK_DIRTY; + spin_unlock(&res->spinlock); + /* now wait on any pending asts and the DIRTY state */ + 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; + } + + ret = 0; + /* 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); + + /* + * if target is down, we need to clear DLM_LOCK_RES_BLOCK_DIRTY for + * another try; otherwise, we are sure the MIGRATING state is there, + * drop the unneded state which blocked threads trying to DIRTY + */ + spin_lock(&res->spinlock); + BUG_ON(!(res->state & DLM_LOCK_RES_BLOCK_DIRTY)); + res->state &= ~DLM_LOCK_RES_BLOCK_DIRTY; + if (!ret) + BUG_ON(!(res->state & DLM_LOCK_RES_MIGRATING)); + spin_unlock(&res->spinlock); + + /* + * at this point: + * + * o the DLM_LOCK_RES_MIGRATING flag is set if target not down + * 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 *queue = &res->granted; + int i, bit; + struct dlm_lock *lock, *next; + + assert_spin_locked(&res->spinlock); + + BUG_ON(res->owner == dlm->node_num); + + for (i=0; i<3; i++) { + list_for_each_entry_safe(lock, next, queue, 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); + dlm_lockres_clear_refmap_bit(dlm, res, + lock->ml.node); + list_del_init(&lock->list); + dlm_lock_put(lock); + /* In a normal unlock, we would have added a + * DLM_UNLOCK_FREE_LOCK action. Force it. */ + dlm_lock_put(lock); + } + } + queue++; + } + bit = 0; + while (1) { + bit = find_next_bit(res->refmap, O2NM_MAX_NODES, bit); + if (bit >= O2NM_MAX_NODES) + break; + /* do not clear the local node reference, if there is a + * process holding this, let it drop the ref itself */ + if (bit != dlm->node_num) { + mlog(0, "%s:%.*s: node %u had a ref to this " + "migrating lockres, clearing\n", dlm->name, + res->lockname.len, res->lockname.name, bit); + dlm_lockres_clear_refmap_bit(dlm, res, bit); + } + bit++; + } +} + +/* + * Pick a node to migrate the lock resource to. This function selects a + * potential target based first on the locks and then on refmap. It skips + * nodes that are in the process of exiting the domain. + */ +static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res) +{ + enum dlm_lockres_list idx; + struct list_head *queue = &res->granted; + struct dlm_lock *lock; + int noderef; + u8 nodenum = O2NM_MAX_NODES; + + assert_spin_locked(&dlm->spinlock); + assert_spin_locked(&res->spinlock); + + /* Go through all the locks */ + for (idx = DLM_GRANTED_LIST; idx <= DLM_BLOCKED_LIST; idx++) { + queue = dlm_list_idx_to_ptr(res, idx); + list_for_each_entry(lock, queue, list) { + if (lock->ml.node == dlm->node_num) + continue; + if (test_bit(lock->ml.node, dlm->exit_domain_map)) + continue; + nodenum = lock->ml.node; + goto bail; + } + } + + /* Go thru the refmap */ + noderef = -1; + while (1) { + noderef = find_next_bit(res->refmap, O2NM_MAX_NODES, + noderef + 1); + if (noderef >= O2NM_MAX_NODES) + break; + if (noderef == dlm->node_num) + continue; + if (test_bit(noderef, dlm->exit_domain_map)) + continue; + nodenum = noderef; + goto bail; + } + +bail: + return nodenum; +} + +/* 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, skip, 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; + + /* We could race exit domain. If exited, skip. */ + spin_lock(&dlm->spinlock); + skip = (!test_bit(nodenum, dlm->domain_map)); + spin_unlock(&dlm->spinlock); + if (skip) { + clear_bit(nodenum, iter->node_map); + continue; + } + + ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key, + &migrate, sizeof(migrate), nodenum, + &status); + if (ret < 0) { + mlog(ML_ERROR, "%s: res %.*s, Error %d send " + "MIGRATE_REQUEST to node %u\n", dlm->name, + migrate.namelen, migrate.name, ret, nodenum); + if (!dlm_is_host_down(ret)) { + mlog(ML_ERROR, "unhandled error=%d!\n", ret); + BUG(); + } + clear_bit(nodenum, iter->node_map); + ret = 0; + } else if (status < 0) { + mlog(0, "migrate request (node %u) returned %d!\n", + nodenum, status); + ret = status; + } else if (status == DLM_MIGRATE_RESPONSE_MASTERY_REF) { + /* during the migration request we short-circuited + * the mastery of the lockres. make sure we have + * a mastery ref for nodenum */ + mlog(0, "%s:%.*s: need ref for node %u\n", + dlm->name, res->lockname.len, res->lockname.name, + nodenum); + spin_lock(&res->spinlock); + dlm_lockres_set_refmap_bit(dlm, res, nodenum); + spin_unlock(&res->spinlock); + } + } + + 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, + void **ret_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, hash; + int ret = 0; + + if (!dlm_grab(dlm)) + return -EINVAL; + + name = migrate->name; + namelen = migrate->namelen; + hash = dlm_lockid_hash(name, namelen); + + /* preallocate.. if this fails, abort */ + mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS); + + if (!mle) { + ret = -ENOMEM; + goto leave; + } + + /* check for pre-existing lock */ + spin_lock(&dlm->spinlock); + res = __dlm_lookup_lockres(dlm, name, namelen, hash); + 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); + } + + spin_lock(&dlm->master_lock); + /* ignore status. only nonzero status would BUG. */ + ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, + name, namelen, + migrate->new_master, + migrate->master); + + spin_unlock(&dlm->master_lock); +unlock: + 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; + + 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 so that only one mle will be found */ + __dlm_unlink_mle(dlm, tmp); + __dlm_mle_detach_hb_events(dlm, tmp); + if (tmp->type == DLM_MLE_MASTER) { + ret = DLM_MIGRATE_RESPONSE_MASTERY_REF; + mlog(0, "%s:%.*s: master=%u, newmaster=%u, " + "telling master to get ref " + "for cleared out mle during " + "migration\n", dlm->name, + namelen, name, master, + new_master); + } + } + 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; + /* the new master will be sending an assert master for this. + * at that point we will get the refmap reference */ + mle->master = master; + /* do this for consistency with other mle types */ + set_bit(new_master, mle->maybe_map); + __dlm_insert_mle(dlm, mle); + + return ret; +} + +/* + * Sets the owner of the lockres, associated to the mle, to UNKNOWN + */ +static struct dlm_lock_resource *dlm_reset_mleres_owner(struct dlm_ctxt *dlm, + struct dlm_master_list_entry *mle) +{ + struct dlm_lock_resource *res; + + /* Find the lockres associated to the mle and set its owner to UNK */ + res = __dlm_lookup_lockres(dlm, mle->mname, mle->mnamelen, + mle->mnamehash); + if (res) { + spin_unlock(&dlm->master_lock); + + /* move lockres onto recovery list */ + spin_lock(&res->spinlock); + dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN); + dlm_move_lockres_to_recovery_list(dlm, res); + spin_unlock(&res->spinlock); + dlm_lockres_put(res); + + /* about to get rid of mle, detach from heartbeat */ + __dlm_mle_detach_hb_events(dlm, mle); + + /* dump the mle */ + spin_lock(&dlm->master_lock); + __dlm_put_mle(mle); + spin_unlock(&dlm->master_lock); + } + + return res; +} + +static void dlm_clean_migration_mle(struct dlm_ctxt *dlm, + struct dlm_master_list_entry *mle) +{ + __dlm_mle_detach_hb_events(dlm, mle); + + spin_lock(&mle->spinlock); + __dlm_unlink_mle(dlm, mle); + atomic_set(&mle->woken, 1); + spin_unlock(&mle->spinlock); + + wake_up(&mle->wq); +} + +static void dlm_clean_block_mle(struct dlm_ctxt *dlm, + struct dlm_master_list_entry *mle, u8 dead_node) +{ + int bit; + + BUG_ON(mle->type != DLM_MLE_BLOCK); + + 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(0, "node %u was expected master\n", dead_node); + atomic_set(&mle->woken, 1); + spin_unlock(&mle->spinlock); + wake_up(&mle->wq); + + /* Do not need events any longer, so detach from heartbeat */ + __dlm_mle_detach_hb_events(dlm, mle); + __dlm_put_mle(mle); + } +} + +void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node) +{ + struct dlm_master_list_entry *mle; + struct dlm_lock_resource *res; + struct hlist_head *bucket; + struct hlist_node *tmp; + unsigned int i; + + mlog(0, "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); + for (i = 0; i < DLM_HASH_BUCKETS; i++) { + bucket = dlm_master_hash(dlm, i); + hlist_for_each_entry_safe(mle, tmp, bucket, master_hash_node) { + 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) { + dlm_clean_block_mle(dlm, mle, dead_node); + 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 lockres' 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. */ + dlm_clean_migration_mle(dlm, mle); + + mlog(0, "%s: node %u died during migration from " + "%u to %u!\n", dlm->name, dead_node, mle->master, + mle->new_master); + + /* If we find a lockres associated with the mle, we've + * hit this rare case that messes up our lock ordering. + * If so, 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. */ + res = dlm_reset_mleres_owner(dlm, mle); + if (res) + /* 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); + + /* ownership of the lockres is changing. account for the + * mastery reference here since old_master will briefly have + * a reference after the migration completes */ + spin_lock(&res->spinlock); + dlm_lockres_set_refmap_bit(dlm, res, old_master); + spin_unlock(&res->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, 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, 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); +} + +void dlm_force_free_mles(struct dlm_ctxt *dlm) +{ + int i; + struct hlist_head *bucket; + struct dlm_master_list_entry *mle; + struct hlist_node *tmp; + + /* + * We notified all other nodes that we are exiting the domain and + * marked the dlm state to DLM_CTXT_LEAVING. If any mles are still + * around we force free them and wake any processes that are waiting + * on the mles + */ + spin_lock(&dlm->spinlock); + spin_lock(&dlm->master_lock); + + BUG_ON(dlm->dlm_state != DLM_CTXT_LEAVING); + BUG_ON((find_next_bit(dlm->domain_map, O2NM_MAX_NODES, 0) < O2NM_MAX_NODES)); + + for (i = 0; i < DLM_HASH_BUCKETS; i++) { + bucket = dlm_master_hash(dlm, i); + hlist_for_each_entry_safe(mle, tmp, bucket, master_hash_node) { + if (mle->type != DLM_MLE_BLOCK) { + mlog(ML_ERROR, "bad mle: %p\n", mle); + dlm_print_one_mle(mle); + } + atomic_set(&mle->woken, 1); + wake_up(&mle->wq); + + __dlm_unlink_mle(dlm, mle); + __dlm_mle_detach_hb_events(dlm, mle); + __dlm_put_mle(mle); + } + } + spin_unlock(&dlm->master_lock); + spin_unlock(&dlm->spinlock); +} |