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  1. Hadoop HDFS
  2. HDFS-12862

CacheDirective becomes invalid when NN restart or failover

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    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 2.7.1
    • Fix Version/s: 3.3.0, 3.2.2
    • Component/s: caching, hdfs
    • Labels:
    • Target Version/s:

      Description

      The logic in FSNDNCacheOp#modifyCacheDirective is not correct. when modify cacheDirective,the expiration in directive may be a relative expiryTime, and EditLog will serial a relative expiry time.

      // Some comments here
      static void modifyCacheDirective(
            FSNamesystem fsn, CacheManager cacheManager, CacheDirectiveInfo directive,
            EnumSet<CacheFlag> flags, boolean logRetryCache) throws IOException {
          final FSPermissionChecker pc = getFsPermissionChecker(fsn);
      
          cacheManager.modifyDirective(directive, pc, flags);
          fsn.getEditLog().logModifyCacheDirectiveInfo(directive, logRetryCache);
        }
      

      But when SBN replay the log ,it will invoke FSImageSerialization#readCacheDirectiveInfo as a absolute expiryTime.It will result in the inconsistency .

        public static CacheDirectiveInfo readCacheDirectiveInfo(DataInput in)
            throws IOException {
          CacheDirectiveInfo.Builder builder =
              new CacheDirectiveInfo.Builder();
          builder.setId(readLong(in));
          int flags = in.readInt();
          if ((flags & 0x1) != 0) {
            builder.setPath(new Path(readString(in)));
          }
          if ((flags & 0x2) != 0) {
            builder.setReplication(readShort(in));
          }
          if ((flags & 0x4) != 0) {
            builder.setPool(readString(in));
          }
          if ((flags & 0x8) != 0) {
            builder.setExpiration(
                CacheDirectiveInfo.Expiration.newAbsolute(readLong(in)));
          }
          if ((flags & ~0xF) != 0) {
            throw new IOException("unknown flags set in " +
                "ModifyCacheDirectiveInfoOp: " + flags);
          }
          return builder.build();
        }
      

      In other words´╝î fsn.getEditLog().logModifyCacheDirectiveInfo(directive, logRetryCache) may serial a relative expiry time,But builder.setExpiration(CacheDirectiveInfo.Expiration.newAbsolute(readLong(in))) read it as a absolute expiryTime.

        Attachments

        1. HDFS-12862-branch-2.7.1.001.patch
          7 kB
          Wang XL
        2. HDFS-12862-trunk.002.patch
          6 kB
          Wang XL
        3. HDFS-12862-trunk.003.patch
          6 kB
          Wang XL
        4. HDFS-12862-trunk.004.patch
          6 kB
          Wei-Chiu Chuang
        5. HDFS-12862.005.patch
          6 kB
          Wang XL
        6. HDFS-12862.006.patch
          5 kB
          Wang XL
        7. HDFS-12862.007.patch
          5 kB
          Wang XL
        8. HDFS-12862.branch-3.1.patch
          5 kB
          Wei-Chiu Chuang

          Activity

            People

            • Assignee:
              Wang XL Wang XL
              Reporter:
              Wang XL Wang XL
            • Votes:
              1 Vote for this issue
              Watchers:
              9 Start watching this issue

              Dates

              • Created:
                Updated:
                Resolved: