bulkLoadHFiles failed because write lock on HRegion

[Frank Chow]

Hi guys,

Do bulkload Hfiles sometimes failed on my cluster because rpc time out.
I found that when doing bulkload hfiles, it require wirtelock on the region 
when there are multi-families. But the compact operation also require read lock 
on the region. When the compacting files are big, it need more time to finish 
(some times cost half an hour or more). So when the region is compacting, the 
bulkloadHfiles operation will not be able to get the writelock, and causing the 
bulkloading hfiles timeout.

Code is below:
HRegion:
public boolean bulkLoadHFiles(List<Pair<byte[], String>> familyPaths,
      BulkLoadListener bulkLoadListener) throws IOException {
    Preconditions.checkNotNull(familyPaths);
    // we need writeLock for multi-family bulk load
    startBulkRegionOperation(hasMultipleColumnFamilies(familyPaths));

private void startBulkRegionOperation(boolean writeLockNeeded)
      throws NotServingRegionException, RegionTooBusyException, 
InterruptedIOException {
    if (this.closing.get()) {
      throw new NotServingRegionException(regionInfo.getRegionNameAsString() +
          " is closing");
    }
    if (writeLockNeeded) lock(lock.writeLock());
    else lock(lock.readLock());

My question is: why write lock is needed when there is multi-families ? Can 
readlock also work? If it only need a readlock, there will be no conflict and 
loading hfiles will not timeout.

Thanks.