diff options
Diffstat (limited to 'src/mongo/s/catalog/legacy/distlock.cpp')
| -rw-r--r-- | src/mongo/s/catalog/legacy/distlock.cpp | 74 |
1 files changed, 43 insertions, 31 deletions
diff --git a/src/mongo/s/catalog/legacy/distlock.cpp b/src/mongo/s/catalog/legacy/distlock.cpp index b0d30b28967..fa9c7a90fde 100644 --- a/src/mongo/s/catalog/legacy/distlock.cpp +++ b/src/mongo/s/catalog/legacy/distlock.cpp @@ -106,8 +106,8 @@ DistLockHandle LockException::getMustUnlockID() const { } /** - * Create a new distributed lock, potentially with a custom sleep and takeover time. If a custom sleep time is - * specified (time between pings) + * Create a new distributed lock, potentially with a custom sleep and takeover time. If a custom + * sleep time is specified (time between pings) */ DistributedLock::DistributedLock(const ConnectionString& conn, const string& name, @@ -155,8 +155,9 @@ const string& DistributedLock::getProcessId() const { } /** - * Returns the remote time as reported by the cluster or server. The maximum difference between the reported time - * and the actual time on the remote server (at the completion of the function) is the maxNetSkew + * Returns the remote time as reported by the cluster or server. The maximum difference between the + * reported time and the actual time on the remote server (at the completion of the function) is the + * maxNetSkew */ Date_t DistributedLock::remoteTime(const ConnectionString& cluster, unsigned long long maxNetSkew) { ConnectionString server(*cluster.getServers().begin()); @@ -197,8 +198,8 @@ Date_t DistributedLock::remoteTime(const ConnectionString& cluster, unsigned lon 13647); } - // Make sure that our delay is not more than 2x our maximum network skew, since this is the max our remote - // time value can be off by if we assume a response in the middle of the delay. + // Make sure that our delay is not more than 2x our maximum network skew, since this is the max + // our remote time value can be off by if we assume a response in the middle of the delay. if (delay > Milliseconds(maxNetSkew * 2)) { throw TimeNotFoundException( str::stream() << "server " << server.toString() << " in cluster " << cluster.toString() @@ -227,7 +228,8 @@ bool DistributedLock::checkSkew(const ConnectionString& cluster, if (i == 0) avgSkews.push_back(0); - // Could check if this is self, but shouldn't matter since local network connection should be fast. + // Could check if this is self, but shouldn't matter since local network connection + // should be fast. ConnectionString server(*si); vector<long long> skew; @@ -375,7 +377,8 @@ bool DistributedLock::lock_try(const string& why, BSONObj* other, double timeout LockpingsType::ConfigNS, o[LocksType::process()].wrap(LockpingsType::process())); if (lastPing.isEmpty()) { LOG(logLvl) << "empty ping found for process in lock '" << lockName << "'" << endl; - // TODO: Using 0 as a "no time found" value Will fail if dates roll over, but then, so will a lot. + // TODO: Using 0 as a "no time found" value Will fail if dates roll over, but then, + // so will a lot. lastPing = BSON(LockpingsType::process(o[LocksType::process()].String()) << LockpingsType::ping(Date_t())); } @@ -420,7 +423,8 @@ bool DistributedLock::lock_try(const string& why, BSONObj* other, double timeout } catch (LockException& e) { // Remote server cannot be found / is not responsive warning() << "Could not get remote time from " << _conn << causedBy(e); - // If our config server is having issues, forget all the pings until we can see it again + // If our config server is having issues, forget all the pings until we can see it + // again resetLastPing(); } @@ -438,8 +442,8 @@ bool DistributedLock::lock_try(const string& why, BSONObj* other, double timeout if (elapsed > takeover) { // Lock may forced, reset our timer if succeeds or fails - // Ensures that another timeout must happen if something borks up here, and resets our pristine - // ping state if acquired. + // Ensures that another timeout must happen if something borks up here, and resets + // our pristine ping state if acquired. resetLastPing(); try { @@ -464,7 +468,8 @@ bool DistributedLock::lock_try(const string& why, BSONObj* other, double timeout BSONObj err = conn->getLastErrorDetailed(); string errMsg = DBClientWithCommands::getLastErrorString(err); - // TODO: Clean up all the extra code to exit this method, probably with a refactor + // TODO: Clean up all the extra code to exit this method, probably with a + // refactor if (!errMsg.empty() || !err["n"].type() || err["n"].numberInt() < 1) { logErrMsgOrWarn( "Could not force lock", lockName, errMsg, "(another force won"); @@ -475,8 +480,8 @@ bool DistributedLock::lock_try(const string& why, BSONObj* other, double timeout } } catch (UpdateNotTheSame&) { - // Ok to continue since we know we forced at least one lock document, and all lock docs - // are required for a lock to be held. + // Ok to continue since we know we forced at least one lock document, and all + // lock docs are required for a lock to be held. warning() << "lock forcing " << lockName << " inconsistent" << endl; } catch (const LockException&) { // Let the exception go up and don't repackage the exception. @@ -495,8 +500,9 @@ bool DistributedLock::lock_try(const string& why, BSONObj* other, double timeout // are acquired. resetLastPing(); - // Test that the lock is held by trying to update the finalized state of the lock to the same state - // if it does not update or does not update on all servers, we can't re-enter. + // Test that the lock is held by trying to update the finalized state of the lock to + // the same state if it does not update or does not update on all servers, we can't + // re-enter. try { // Test the lock with the correct "ts" (OID) value conn->update(LocksType::ConfigNS, @@ -508,7 +514,8 @@ bool DistributedLock::lock_try(const string& why, BSONObj* other, double timeout BSONObj err = conn->getLastErrorDetailed(); string errMsg = DBClientWithCommands::getLastErrorString(err); - // TODO: Clean up all the extra code to exit this method, probably with a refactor + // TODO: Clean up all the extra code to exit this method, probably with a + // refactor if (!errMsg.empty() || !err["n"].type() || err["n"].numberInt() < 1) { logErrMsgOrWarn( "Could not re-enter lock", lockName, errMsg, "(not sure lock is held"); @@ -541,7 +548,8 @@ bool DistributedLock::lock_try(const string& why, BSONObj* other, double timeout LOG(logLvl - 1) << "lock '" << lockName << "' successfully forced" << endl; - // We don't need the ts value in the query, since we will only ever replace locks with state=0. + // We don't need the ts value in the query, since we will only ever replace locks with + // state=0. } // Case 3: We have an expired lock else if (o[LocksType::lockID()].type()) { @@ -549,8 +557,9 @@ bool DistributedLock::lock_try(const string& why, BSONObj* other, double timeout } } - // Always reset our ping if we're trying to get a lock, since getting a lock implies the lock state is open - // and no locks need to be forced. If anything goes wrong, we don't want to remember an old lock. + // Always reset our ping if we're trying to get a lock, since getting a lock implies the lock + // state is open and no locks need to be forced. If anything goes wrong, we don't want to + // remember an old lock. resetLastPing(); bool gotLock = false; @@ -607,10 +616,11 @@ bool DistributedLock::lock_try(const string& why, BSONObj* other, double timeout indUpdate = indDB->findOne(LocksType::ConfigNS, BSON(LocksType::name(_name))); // If we override this lock in any way, grab and protect it. - // We assume/ensure that if a process does not have all lock documents, it is no longer - // holding the lock. - // Note - finalized locks may compete too, but we know they've won already if competing - // in this round. Cleanup of crashes during finalizing may take a few tries. + // We assume/ensure that if a process does not have all lock documents, it is no + // longer holding the lock. + // Note - finalized locks may compete too, but we know they've won already if + // competing in this round. Cleanup of crashes during finalizing may take a few + // tries. if (indUpdate[LocksType::lockID()] < lockDetails[LocksType::lockID()] || indUpdate[LocksType::state()].numberInt() == 0) { BSONObj grabQuery = @@ -622,8 +632,9 @@ bool DistributedLock::lock_try(const string& why, BSONObj* other, double timeout BSON(LocksType::lockID(lockDetails[LocksType::lockID()].OID()) << LocksType::state(1)); - // Either our update will succeed, and we'll grab the lock, or it will fail b/c some other - // process grabbed the lock (which will change the ts), but the lock will be set until forcing + // Either our update will succeed, and we'll grab the lock, or it will fail b/c + // some other process grabbed the lock (which will change the ts), but the lock + // will be set until forcing indDB->update(LocksType::ConfigNS, grabQuery, BSON("$set" << grabChanges)); indUpdate = indDB->findOne(LocksType::ConfigNS, BSON(LocksType::name(_name))); @@ -687,11 +698,12 @@ bool DistributedLock::lock_try(const string& why, BSONObj* other, double timeout // Complete lock propagation if (gotLock) { - // This is now safe, since we know that no new locks will be placed on top of the ones we've checked for at - // least 15 minutes. Sets the state = 2, so that future clients can determine that the lock is truly set. - // The invariant for rollbacks is that we will never force locks with state = 2 and active pings, since that - // indicates the lock is active, but this means the process creating/destroying them must explicitly poll - // when something goes wrong. + // This is now safe, since we know that no new locks will be placed on top of the ones we've + // checked for at least 15 minutes. Sets the state = 2, so that future clients can + // determine that the lock is truly set. The invariant for rollbacks is that we will never + // force locks with state = 2 and active pings, since that indicates the lock is active, but + // this means the process creating/destroying them must explicitly poll when something goes + // wrong. try { BSONObjBuilder finalLockDetails; BSONObjIterator bi(lockDetails); |