// transitionToActive RPC takes the write lock before calling
// tailer.stop() -- so if we're not interruptible, it will
// deadlock.
namesystem.writeLockInterruptibly();
try {
FSImage image = namesystem.getFSImage();
long lastTxnId = image.getLastAppliedTxId();
if (LOG.isDebugEnabled()) {
LOG.debug("lastTxnId: " + lastTxnId);
}
Collection<EditLogInputStream> streams;
try {
streams = editLog.selectInputStreams(lastTxnId + 1, 0, false);
} catch (IOException ioe) {
// This is acceptable. If we try to tail edits in the middle of an edits
// log roll, i.e. the last one has been finalized but the new inprogress
// edits file hasn't been started yet.
LOG.warn("Edits tailer failed to find any streams. Will try again " +
"later.", ioe);
return;
}
if (LOG.isDebugEnabled()) {
LOG.debug("edit streams to load from: " + streams.size());
}
// Once we have streams to load, errors encountered are legitimate cause
// for concern, so we don't catch them here. Simple errors reading from
// disk are ignored.
long editsLoaded = 0;
try {
editsLoaded = image.loadEdits(streams, namesystem, null);
} catch (EditLogInputException elie) {
editsLoaded = elie.getNumEditsLoaded();
throw elie;
} finally {
if (editsLoaded > 0 || LOG.isDebugEnabled()) {
LOG.info(String.format("Loaded %d edits starting from txid %d ",
editsLoaded, lastTxnId));
}
}
if (editsLoaded > 0) {
lastLoadTimestamp = now();
}
lastLoadedTxnId = image.getLastAppliedTxId();
} finally {
namesystem.writeUnlock();
}
}