}
@VisibleForTesting
READ3Response read(XDR xdr, SecurityHandler securityHandler,
SocketAddress remoteAddress) {
READ3Response response = new READ3Response(Nfs3Status.NFS3_OK);
final String userName = securityHandler.getUser();
if (!checkAccessPrivilege(remoteAddress, AccessPrivilege.READ_ONLY)) {
response.setStatus(Nfs3Status.NFS3ERR_ACCES);
return response;
}
DFSClient dfsClient = clientCache.getDfsClient(userName);
if (dfsClient == null) {
response.setStatus(Nfs3Status.NFS3ERR_SERVERFAULT);
return response;
}
READ3Request request = null;
try {
request = new READ3Request(xdr);
} catch (IOException e) {
LOG.error("Invalid READ request");
return new READ3Response(Nfs3Status.NFS3ERR_INVAL);
}
long offset = request.getOffset();
int count = request.getCount();
FileHandle handle = request.getHandle();
if (LOG.isDebugEnabled()) {
LOG.debug("NFS READ fileId: " + handle.getFileId() + " offset: " + offset
+ " count: " + count);
}
Nfs3FileAttributes attrs;
boolean eof;
if (count == 0) {
// Only do access check.
try {
// Don't read from cache. Client may not have read permission.
attrs = Nfs3Utils.getFileAttr(dfsClient,
Nfs3Utils.getFileIdPath(handle), iug);
} catch (IOException e) {
if (LOG.isDebugEnabled()) {
LOG.debug("Get error accessing file, fileId:" + handle.getFileId(), e);
}
return new READ3Response(Nfs3Status.NFS3ERR_IO);
}
if (attrs == null) {
if (LOG.isDebugEnabled()) {
LOG.debug("Can't get path for fileId:" + handle.getFileId());
}
return new READ3Response(Nfs3Status.NFS3ERR_NOENT);
}
int access = Nfs3Utils.getAccessRightsForUserGroup(
securityHandler.getUid(), securityHandler.getGid(),
securityHandler.getAuxGids(), attrs);
if ((access & Nfs3Constant.ACCESS3_READ) != 0) {
eof = offset < attrs.getSize() ? false : true;
return new READ3Response(Nfs3Status.NFS3_OK, attrs, 0, eof,
ByteBuffer.wrap(new byte[0]));
} else {
return new READ3Response(Nfs3Status.NFS3ERR_ACCES);
}
}
// In case there is buffered data for the same file, flush it. This can be
// optimized later by reading from the cache.
int ret = writeManager.commitBeforeRead(dfsClient, handle, offset + count);
if (ret != Nfs3Status.NFS3_OK) {
LOG.warn("commitBeforeRead didn't succeed with ret=" + ret
+ ". Read may not get most recent data.");
}
try {
int rtmax = config.getInt(NfsConfigKeys.DFS_NFS_MAX_READ_TRANSFER_SIZE_KEY,
NfsConfigKeys.DFS_NFS_MAX_READ_TRANSFER_SIZE_DEFAULT);
int buffSize = Math.min(rtmax, count);
byte[] readbuffer = new byte[buffSize];
int readCount = 0;
/**
* Retry exactly once because the DFSInputStream can be stale.
*/
for (int i = 0; i < 1; ++i) {
FSDataInputStream fis = clientCache.getDfsInputStream(userName,
Nfs3Utils.getFileIdPath(handle));
try {
readCount = fis.read(offset, readbuffer, 0, count);
} catch (IOException e) {
// TODO: A cleaner way is to throw a new type of exception
// which requires incompatible changes.
if (e.getMessage() == "Stream closed") {
clientCache.invalidateDfsInputStream(userName,
Nfs3Utils.getFileIdPath(handle));
continue;
} else {
throw e;
}
}
}
attrs = Nfs3Utils.getFileAttr(dfsClient, Nfs3Utils.getFileIdPath(handle),
iug);
if (readCount < count) {
LOG.info("Partical read. Asked offset:" + offset + " count:" + count
+ " and read back:" + readCount + "file size:" + attrs.getSize());
}
// HDFS returns -1 for read beyond file size.
if (readCount < 0) {
readCount = 0;
}
eof = (offset + readCount) < attrs.getSize() ? false : true;
return new READ3Response(Nfs3Status.NFS3_OK, attrs, readCount, eof,
ByteBuffer.wrap(readbuffer));
} catch (IOException e) {
LOG.warn("Read error: " + e.getClass() + " offset: " + offset
+ " count: " + count, e);
return new READ3Response(Nfs3Status.NFS3ERR_IO);
}
}