[HDFS-1792] Add code to detect valid length of an edits file

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Edit log branch (HDFS-1073)
• Fix Version/s: Edit log branch (HDFS-1073)
• Hadoop Flags: Reviewed
• Assignee: Todd Lipcon
• Reporter: Todd Lipcon
• Created: 29/Mar/11 06:30
• Updated: 07/Jul/11 05:57
• Resolved: 31/Mar/11 01:54

Description

In some edit log corruption situations, it's useful to be able to determine the "valid" length of an edit log. For this JIRA we define "valid" as the length of the file excluding any trailing 0x00 bytes, usually left there by the preallocation done while writing. In the future this API can be extended to look at edit checksums, etc.