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ASF GitHub Bot commented on HDFS-16785: --------------------------------------- tomscut commented on PR #4945: URL: https://github.com/apache/hadoop/pull/4945#issuecomment-1295157989 > ``` > final FsVolumeImpl fsVolume = > createFsVolume(sd.getStorageUuid(), sd, location); > // no need to add lock > final ReplicaMap tempVolumeMap = new ReplicaMap(); > ArrayList<IOException> exceptions = Lists.newArrayList(); > > for (final NamespaceInfo nsInfo : nsInfos) { > String bpid = nsInfo.getBlockPoolID(); > try (AutoCloseDataSetLock l = lockManager.writeLock(LockLevel.BLOCK_POOl, bpid)) { > fsVolume.addBlockPool(bpid, this.conf, this.timer); > fsVolume.getVolumeMap(bpid, tempVolumeMap, ramDiskReplicaTracker); > } catch (IOException e) { > LOG.warn("Caught exception when adding " + fsVolume + > ". Will throw later.", e); > exceptions.add(e); > } > } > ``` > > The `fsVolume` here is a local temporary variable and still not be added into the `volumes`, and add/remove bp operations just use the volume in `volumes`, so there is no conflicts. So here doesn't need the lock for `BlockPoolSlice`. > > @Hexiaoqiao Sir, can check it again? I agree with @ZanderXu here. +1 from my side. > DataNode hold BP write lock to scan disk > ---------------------------------------- > > Key: HDFS-16785 > URL: https://issues.apache.org/jira/browse/HDFS-16785 > Project: Hadoop HDFS > Issue Type: Improvement > Reporter: ZanderXu > Assignee: ZanderXu > Priority: Major > Labels: pull-request-available > > When patching the fine-grained locking of datanode, I found that `addVolume` > will hold the write block of the BP lock to scan the new volume to get the > blocks. If we try to add one full volume that was fixed offline before, i > will hold the write lock for a long time. > The related code as bellows: > {code:java} > for (final NamespaceInfo nsInfo : nsInfos) { > String bpid = nsInfo.getBlockPoolID(); > try (AutoCloseDataSetLock l = lockManager.writeLock(LockLevel.BLOCK_POOl, > bpid)) { > fsVolume.addBlockPool(bpid, this.conf, this.timer); > fsVolume.getVolumeMap(bpid, tempVolumeMap, ramDiskReplicaTracker); > } catch (IOException e) { > LOG.warn("Caught exception when adding " + fsVolume + > ". Will throw later.", e); > exceptions.add(e); > } > } {code} > And I noticed that this lock is added by HDFS-15382, means that this logic is > not in lock before. -- This message was sent by Atlassian Jira (v8.20.10#820010) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org