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.
*/ staticinlinevoid __dlm_mle_attach_hb_events(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle)
{
assert_spin_locked(&dlm->spinlock);
/* remove from list and free */ staticvoid __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 (!kref_read(&mle->mle_refs)) { /* 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 */ staticvoid dlm_put_mle(struct dlm_master_list_entry *mle)
{ struct dlm_ctxt *dlm;
dlm = mle->dlm;
/* 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));
/* * 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, constchar *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; unsignedint hash; int tries = 0; int bit, wait_on_recovery = 0;
/* * 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) {
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);
spin_unlock(&dlm->track_lock);
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_first_bit(dlm->recovery_map, O2NM_MAX_NODES); 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;
}
spin_lock(&dlm->spinlock);
bit = find_first_bit(dlm->recovery_map, O2NM_MAX_NODES); 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);
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
staticint 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);
/* 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_first_bit(mle->maybe_map, O2NM_MAX_NODES); 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) { unsignedlong timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);
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);
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);
}
}
staticint 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;
}
staticint 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_first_bit(mle->maybe_map,
O2NM_MAX_NODES);
/* 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 */
bitmap_zero(mle->maybe_map, O2NM_MAX_NODES);
bitmap_zero(mle->response_map, O2NM_MAX_NODES); /* reset the vote_map to the current node_map */
bitmap_copy(mle->vote_map, mle->node_map,
O2NM_MAX_NODES); /* 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" *
*/
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();
} elseif (ret == -EINVAL) {
mlog(ML_ERROR, "bad args passed to o2net!\n");
BUG();
} elseif (ret == -ENOMEM) {
mlog(ML_ERROR, "out of memory while trying to send " "network message! retrying\n"); /* this is totally crude */
msleep(50); goto again;
} elseif (!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; unsignedint namelen, hash; int found, ret; int set_maybe; int dispatch_assert = 0; int dispatched = 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);
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;
} elseif (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;
} elseif (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;
}
} elseif (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);
/* 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);
// 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 {
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; elseif (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;
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) {
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;
spin_unlock(&res->spinlock);
dlm_lockres_put(res);
} else {
dispatched = 1;
__dlm_lockres_grab_inflight_worker(dlm, res);
spin_unlock(&res->spinlock);
}
} else { if (res)
dlm_lockres_put(res);
}
if (!dispatched)
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...
*/ staticint 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; constchar *lockname = res->lockname.name; unsignedint namelen = res->lockname.len;
/* note that if this nodemap is empty, it returns 0 */
dlm_node_iter_init(nodemap, &iter); while ((to = dlm_node_iter_next(&iter)) >= 0) { int r = 0; struct dlm_master_list_entry *mle = NULL;
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;
} elseif (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 (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_first_bit(mle->maybe_map, O2NM_MAX_NODES); 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);
} elseif (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);
} elseif (!(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();
}
} elseif (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 = kref_read(&mle->mle_refs); if (mle->inuse > 0) { if (extra_ref && rr < 3)
err = 1; elseif (!extra_ref && rr < 2)
err = 1;
} else { if (extra_ref && rr < 2)
err = 1; elseif (!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);
} elseif (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;
}
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_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);
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);
}
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 heartbeat 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. */ staticint 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;
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; constchar *lockname; unsignedint namelen;
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 = DLM_DEREF_RESPONSE_DONE; goto done;
}
item = kzalloc(sizeof(*item), GFP_NOFS); if (!item) {
ret = -ENOMEM;
mlog_errno(ret); goto done;
}
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 migratable 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.
*/ staticint dlm_is_lockres_migratable(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|
DLM_LOCK_RES_RECOVERY_WAITING)) 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 migratable 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_first_bit(res->refmap, O2NM_MAX_NODES); if (node_ref >= O2NM_MAX_NODES) return 0;
}
mlog(0, "%s: res %.*s, Migratable\n", dlm->name, res->lockname.len,
res->lockname.name);
return 1;
}
/* * DLM_MIGRATE_LOCKRES
*/
staticint 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; constchar *name; unsignedint namelen; int mle_added = 0; int wake = 0;
if (!dlm_grab(dlm)) return -EINVAL;
name = res->lockname.name;
namelen = res->lockname.len;
/* 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); /* get an extra reference on the mle. * otherwise the assert_master from the new * master will destroy this.
*/ if (ret != -EEXIST)
dlm_get_mle_inuse(mle);
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 (ret != -EEXIST && oldmle) { /* master is known, detach if not already detached */
dlm_mle_detach_hb_events(dlm, oldmle);
dlm_put_mle(oldmle);
}
/* * 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);
/* 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);
/* * 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)
__must_hold(&dlm->spinlock)
{ int ret; int lock_dropped = 0;
u8 target = O2NM_MAX_NODES;
assert_spin_locked(&dlm->spinlock);
spin_lock(&res->spinlock); if (dlm_is_lockres_migratable(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;
}
/* 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;
}
staticint 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;
}
staticint 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",
str_yes_no(res->state & DLM_LOCK_RES_DIRTY)); /* 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",
str_yes_no(res->state & DLM_LOCK_RES_MIGRATING),
str_no_yes(test_bit(target, dlm->domain_map)));
} else {
mlog(0, "all is well: migrating? %s, dead? %s\n",
str_yes_no(res->state & DLM_LOCK_RES_MIGRATING),
str_no_yes(test_bit(target, dlm->domain_map)));
} 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 unneeded 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)); else
res->migration_pending = 0;
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. */ staticvoid 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; struct dlm_lock *lock; int noderef;
u8 nodenum = O2NM_MAX_NODES;
/* 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 */ staticint 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;
/* 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;
} elseif (status < 0) {
mlog(0, "migrate request (node %u) returned %d!\n",
nodenum, status);
ret = status;
} elseif (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; constchar *name; unsignedint namelen, hash; int ret = 0;
if (!dlm_grab(dlm)) return 0;
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);
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. */ staticint 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, constchar *name, unsignedint namelen,
u8 new_master, u8 master)
{ int found; int ret = 0;
/* 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);
spin_unlock(&tmp->spinlock); return -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
*/ staticstruct 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);
spin_lock(&mle->spinlock);
bit = find_first_bit(mle->maybe_map, O2NM_MAX_NODES); 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);
}
}
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 (mle->new_master == dead_node && mle->inuse) {
mlog(ML_NOTICE, "%s: target %u died during " "migration from %u, the MLE is " "still keep used, ignore it!\n",
dlm->name, dead_node,
mle->master); 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;
/* 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;
}
bitmap_zero(iter.node_map, O2NM_MAX_NODES);
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;
}
/* * 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);
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