Steve Loughran created HDFS-7665:
------------------------------------

             Summary: Add definition of truncate preconditions/postconditions 
to filesystem specification
                 Key: HDFS-7665
                 URL: https://issues.apache.org/jira/browse/HDFS-7665
             Project: Hadoop HDFS
          Issue Type: Sub-task
          Components: documentation
    Affects Versions: 3.0.0
            Reporter: Steve Loughran


With the addition of a major new feature to filesystems, the filesystem 
specification in hadoop-common/site is now out of sync. 

This means that
# there's no strict specification of what it should do
# you can't derive tests from that specification
# other people trying to implement the API will have to infer what to do from 
the HDFS source
# there's no way to decide whether or not the HDFS implementation does what it 
is intended.
# without matching tests against the raw local FS, differences between the HDFS 
impl and the Posix standard one won't be caught until it is potentially too 
late to fix.

The operation should be relatively easy to define (after a truncate, the files 
bytes [0...len-1] must equal the original bytes, length(file)==len, etc)

The truncate tests already written could then be pulled up into contract tests 
which any filesystem implementation can run against.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Reply via email to