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mds: locking. Keep trap of neighbors and coalesce them

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This commit is contained in:
Greg Farnum 2010-05-11 13:01:32 -07:00
parent df813369d3
commit b443f1300b
1 changed files with 55 additions and 7 deletions
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62
src/mds/mdstypes.h
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@ -358,9 +358,10 @@ struct ceph_lock_state_t {
*/
bool add_lock(ceph_filelock& new_lock, bool wait_on_fail) {
bool ret = false;
list<ceph_filelock*> overlapping_locks, self_overlapping_locks;
list<ceph_filelock*> overlapping_locks, self_overlapping_locks,
neighbor_locks;
// first, get any overlapping locks and split them into owned-by-us and not
if(get_overlapping_locks(new_lock, overlapping_locks)) {
if(get_overlapping_locks(new_lock, overlapping_locks, &neighbor_locks)) {
split_by_owner(new_lock, overlapping_locks, self_overlapping_locks);
}
if (!overlapping_locks.empty()) { //overlapping locks owned by others :(
@ -380,14 +381,14 @@ struct ceph_lock_state_t {
ret = false;
} else {
//yay, we can insert a shared lock
adjust_locks(self_overlapping_locks, new_lock);
adjust_locks(self_overlapping_locks, new_lock, neighbor_locks);
held_locks.
insert(pair<__u64, ceph_filelock>(new_lock.start, new_lock));
ret = true;
}
}
} else { //no overlapping locks except our own
adjust_locks(self_overlapping_locks, new_lock);
adjust_locks(self_overlapping_locks, new_lock, neighbor_locks);
held_locks.insert(pair<__u64, ceph_filelock>(new_lock.start, new_lock));
ret = true;
}
@ -539,7 +540,8 @@ private:
* old_locks: list of all locks currently held by same
* client/process that overlap new_lock.
*/
void adjust_locks(list<ceph_filelock*> old_locks, ceph_filelock& new_lock) {
void adjust_locks(list<ceph_filelock*> old_locks, ceph_filelock& new_lock,
list<ceph_filelock*> neighbor_locks) {
bool new_lock_to_end = (0 == new_lock.length);
bool old_lock_to_end;
__u64 new_lock_start = new_lock.start;
@ -617,6 +619,35 @@ private:
client_held_lock_counts.erase(old_lock->client);
}
}
//make sure to coalesce neighboring locks
for (list<ceph_filelock*>::iterator iter = neighbor_locks.begin();
iter != neighbor_locks.end();
++iter) {
old_lock = *iter;
/* because if it's a neibhoring lock there can't be any self-overlapping
locks that covered it */
if (old_lock->type == new_lock.type) { //merge them
if (0 == new_lock.length) {
if (old_lock->start + old_lock->length == new_lock.start) {
new_lock.start = old_lock->start;
} else assert(0); /* if there's no end to new_lock, the neighbor
HAS TO be to left side */
} else if (0 == old_lock->length) {
if (new_lock.start + new_lock.length == old_lock->start) {
new_lock.length = 0;
} else assert(0); //same as before, but reversed
} else {
if (old_lock->start + old_lock->length == new_lock.start) {
new_lock.start = old_lock->start;
new_lock.length += old_lock->length;
} else if (new_lock.start + new_lock.length == old_lock->start) {
new_lock.length += old_lock->length;
}
}
held_locks.erase(find_specific_elem(old_lock, held_locks));
}
}
}
//this won't reset the counter map value, do that yourself
@ -698,14 +729,26 @@ private:
* Returns: true if at least one lock overlaps.
*/
bool get_overlapping_locks(ceph_filelock& lock,
list<ceph_filelock*>& overlaps) {
list<ceph_filelock*>& overlaps,
list<ceph_filelock*>* self_neighbors) {
dout(0) << "get_overlapping_locks" << dendl;
// create a lock starting one earlier and ending one later
// to check for neighbors
ceph_filelock neighbor_check_lock = lock;
--neighbor_check_lock.start;
if (neighbor_check_lock.length) neighbor_check_lock.length += 2;
//find the last held lock starting at the point after lock
multimap<__u64, ceph_filelock>::iterator iter =
get_last_before(lock.start + lock.length - 1, held_locks);
get_last_before(lock.start + lock.length, held_locks);
bool cont = iter != held_locks.end();
while(cont) {
if (share_space(iter, lock)) {
overlaps.push_front(&iter->second);
} else if (self_neighbors &&
(neighbor_check_lock.client == iter->second.client) &&
(neighbor_check_lock.pid == iter->second.pid) &&
share_space(iter, neighbor_check_lock)) {
self_neighbors->push_front(&iter->second);
}
if ((iter->first < lock.start) && (CEPH_LOCK_EXCL == iter->second.type)) {
//can't be any more overlapping locks or they'd interfere with this one
@ -716,6 +759,11 @@ private:
return !overlaps.empty();
}
bool get_overlapping_locks(ceph_filelock& lock,
list<ceph_filelock*>& overlaps) {
return get_overlapping_locks(lock, overlaps, NULL);
}
/**
* Get a list of all waiting locks that overlap with the given lock's range.
* lock: specifies the range to compare with