[ https://issues.apache.org/jira/browse/HDFS-14285?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Sahil Takiar updated HDFS-14285: -------------------------------- Attachment: HDFS-14285.001.patch > libhdfs hdfsRead copies entire array even if its only partially filled > ---------------------------------------------------------------------- > > Key: HDFS-14285 > URL: https://issues.apache.org/jira/browse/HDFS-14285 > Project: Hadoop HDFS > Issue Type: Bug > Components: hdfs-client, libhdfs, native > Reporter: Sahil Takiar > Priority: Major > Attachments: HDFS-14285.001.patch > > > There is a bug in libhdfs {{hdfsRead}} > {code:java} > jthr = invokeMethod(env, &jVal, INSTANCE, jInputStream, HADOOP_ISTRM, > "read", "([B)I", jbRarray); > if (jthr) { > destroyLocalReference(env, jbRarray); > errno = printExceptionAndFree(env, jthr, PRINT_EXC_ALL, > "hdfsRead: FSDataInputStream#read"); > return -1; > } > if (jVal.i < 0) { > // EOF > destroyLocalReference(env, jbRarray); > return 0; > } else if (jVal.i == 0) { > destroyLocalReference(env, jbRarray); > errno = EINTR; > return -1; > } > (*env)->GetByteArrayRegion(env, jbRarray, 0, noReadBytes, buffer); > {code} > The method makes a call to {{FSInputStream#read(byte[])}} to fill in the Java > byte array, however, {{#read(byte[])}} is not guaranteed to fill up the > entire array, instead it returns the number of bytes written to the array > (which could be less than the size of the array). Yet `{{GetByteArrayRegion}} > decides to copy the entire contents of the {{jbArray}} into the buffer > ({{noReadBytes}} is initialized to the length of the buffer and is never > updated). So if {{FSInputStream#read(byte[])}} decides to read less data than > the size of the byte array, the call to {{GetByteArrayRegion}} will > essentially copy more bytes than necessary. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org