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Date: Thu, 4 Apr 2013 22:58:16 +0000 (UTC)
From: "Suresh Srinivas (JIRA)" <jira@apache.org>
To: hdfs-issues@hadoop.apache.org
Message-ID: <JIRA.12628980.1358987003125.111288.1365116296739@arcas>
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Subject: [jira] [Comment Edited] (HDFS-4434) Provide a mapping from INodeId
 to INode
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    [ https://issues.apache.org/jira/browse/HDFS-4434?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13622920#comment-13622920 ] 

Suresh Srinivas edited comment on HDFS-4434 at 4/4/13 10:57 PM:
----------------------------------------------------------------

Description of changes so far in the patch:
A unique id for each of the inodes in HDFS was added in HDFS-4334. This patch builds on top of it and is based on the design posted in HDFS-4489. See https://issues.apache.org/jira/browse/HDFS-4489?focusedCommentId=13603642&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13603642.

The patch covers the following functionality:
# Changes the reserved inode ID from 1000 to 1023. Also uses 1024 as root inode ID.
# Adds a LightWeightGSet to map an inode ID to corresponding Inode. When inode is created and deleted, an entry is added/deleted from this map.
# Adds the support for path of format "/.reserved/.inodes/inodeID". This can be used in existing methods to identify a file/directory instead of adding a new variant of APIs and protocol methods to use Inode ID for identifying files and directories.
# Disallows creating a directory or file with the name /.reserved. For existing installs that might have such directory or file, during fsimage loading, prints an error indicating such file needs to be removed prior to upgrades.
# Lot of unit tests for all the functionality added.

With this change, each {{INode}} will have close to 16 bytes cost. 8 bytes for the next field in INode and < 8 bytes for the GSet.

                
      was (Author: sureshms):
    Description of changes so far in the patch:
A unique id for each of the inodes in HDFS was added in HDFS-4334. This patch builds on top of it and is based on the design posted in HDFS-4489. See https://issues.apache.org/jira/browse/HDFS-4489?focusedCommentId=13603642&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13603642.

The patch covers the following functionality:
# Changes the reserved inode ID from 1000 to 1023. Also uses 1024 as root inode ID.
# Adds a LightWeightGSet to map an inode ID to corresponding Inode. When inode is created and deleted, an entry is added/deleted from this map.
# Adds the support for path of format "/.reserved/.inodes/inodeID". This can be used in existing methods to identify a file/directory instead of adding a new variant of APIs and protocol methods to use Inode ID for identifying files and directories.
# Disallows creating a directory or file with the name /.reserved. For existing installs that might have such directory or file, during fsimage loading, prints an error indicating such file needs to be removed prior to upgrades.
# Lot of unit tests for all the functionality added.

With this change, each {{INode}} will have additional 16 bytes cost (less than 16 bytes). 8 bytes for the next field in INode and < 8 bytes for the GSet.

                  
> Provide a mapping from INodeId to INode
> ---------------------------------------
>
>                 Key: HDFS-4434
>                 URL: https://issues.apache.org/jira/browse/HDFS-4434
>             Project: Hadoop HDFS
>          Issue Type: Sub-task
>          Components: namenode
>    Affects Versions: 3.0.0
>            Reporter: Brandon Li
>            Assignee: Suresh Srinivas
>         Attachments: HDFS-4434.patch, HDFS-4434.patch, HDFS-4434.patch, HDFS-4434.patch, HDFS-4434.patch, HDFS-4434.patch, HDFS-4434.patch, HDFS-4434.patch, HDFS-4434.patch, HDFS-4434.patch, HDFS-4434.patch
>
>
> This JIRA is to provide a way to access the INode via its id. The proposed solution is to have an in-memory mapping from INodeId to INode. 

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