[
https://issues.apache.org/jira/browse/HDFS-1263?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12881801#action_12881801
]
sam rash commented on HDFS-1263:
--------------------------------
so if i follow:
checking that the genstamp of the file is < the one we are trying to update
before doing any mutation of blocks or metadata (ie renaming) should fix this
issue
regarding throwing ioe on concurrent recovery in the same node, that might be
problematic if:
DN A can talk to DN B, not DN C
DN B can talk to DN A and DN C
DN A starts recovery first
DN B starts after
if DN B talks to DN A before DN A times out talking to C, we'll fail a recovery
that could succeed, no?
i like the idea of failing on these as early in the pipe, but i lean towards
fixing the genstamp detection. seems like the whole genstamp process is
designed for this--there's just a tiny bug with the rename
> 0.20: in tryUpdateBlock, the meta file is renamed away before genstamp
> validation is done
> -----------------------------------------------------------------------------------------
>
> Key: HDFS-1263
> URL: https://issues.apache.org/jira/browse/HDFS-1263
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: data-node
> Affects Versions: 0.20-append
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Fix For: 0.20-append
>
>
> Saw an issue where multiple datanodes are trying to recover at the same time,
> and all of them failed. I think the issue is in FSDataset.tryUpdateBlock, we
> do the rename of blk_B_OldGS to blk_B_OldGS_tmpNewGS and *then* check that
> the generation stamp is moving upwards. Because of this, invalid update block
> calls are blocked, but they then cause future updateBlock calls to fail with
> "Meta file not found" errors.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
