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Yiqun Lin edited comment on HDFS-14172 at 1/31/19 9:32 AM: ----------------------------------------------------------- {quote}Regarding the behavior against an unknown section, I would prefer logging a warn/error to throwing a descriptive IOException and aborting the program. {quote} Re-looking into this, as HDFS-7076 is not merged, I think a descriptive IOException and aborting the program will be a more appropriate way. I mean that, it's safe for NN that it loads an unknown section and it should aborts the program. So a descriptive IOException throwing should be enough, can we revert additional change and make this JIRA more clear, [~water]? {code:java} SectionName sectionName = SectionName.fromString(n); if (sectionName == null) { throw new IOException("Unrecognized section " + n); } switch (sectionName) { case NS_INFO: loadNameSystemSection(in); break; ... {code} was (Author: linyiqun): {quote}Regarding the behavior against an unknown section, I would prefer logging a warn/error to throwing a descriptive IOException and aborting the program. {quote} Re-looking into this, as HDFS-7076 is not merged, I think a descriptive IOException and aborting the program will be a more appropriate way. I mean that, it's safe for NN that it loads an unknown section and it should aborts the program. So a descriptive IOException throwing should be enough, can we revert additional change and make this JIRA more clear, [~water]? {code:java} SectionName sectionName = SectionName.fromString(n); if (sectionName == null) { throw new IOException("Unrecognized section {}" + n); } switch (sectionName) { case NS_INFO: loadNameSystemSection(in); break; ... {code} > Avoid NPE when SectionName#fromString() returns null > ---------------------------------------------------- > > Key: HDFS-14172 > URL: https://issues.apache.org/jira/browse/HDFS-14172 > Project: Hadoop HDFS > Issue Type: Improvement > Reporter: Xiang Li > Assignee: Xiang Li > Priority: Minor > Attachments: HADOOP-14172.000.patch, HADOOP-14172.001.patch, > HADOOP-14172.002.patch > > > In FSImageFormatProtobuf.SectionName#fromString(), as follows: > {code:java} > public static SectionName fromString(String name) { > for (SectionName n : values) { > if (n.name.equals(name)) > return n; > } > return null; > } > {code} > When the code meets an unknown section from the fsimage, the function will > return null. Callers always operates the return value with a "switch" clause, > like FSImageFormatProtobuf.Loader#loadInternal(), as: > {code:java} > switch (SectionName.fromString(n)) > {code} > NPE will be thrown here. > For self-protection, shall we add a default section name in the enum of > SectionName, like "UNKNOWN", to steer clear of NPE? -- 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