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From "Yongjun Zhang (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-6165) "hdfs dfs -rm -r" is slightly different from the Unix "rm -r" for deleting an empty directory
Date Sat, 29 Mar 2014 20:38:16 GMT

    [ https://issues.apache.org/jira/browse/HDFS-6165?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13954431#comment-13954431
] 

Yongjun Zhang commented on HDFS-6165:
-------------------------------------

HI [~daryn],

Thanks a lot for your experiments and comments. The read permission thing is indeed what's
not noticed earlier. It definitely need to be addressed. Several follow-up  questions here:

1. My understanding of your point is, if the empty sub-dir has read permission, then "-rm
<subdir>"  and "-rmdir" would simply go ahead remove the dir, even though all linux
systems we tested so far prompt user (when possible), right? If the answer is yes, then the
userland won't have a choice whether it should prompt to user (as in your summary point #2).
I think this solution works fine for me, but would you please confirm? The folks who commented
earlier may comment on this too.

2. Not to say that we have to do this, for my better understanding, does adding -f support
to the NN protocol as an optional field break compatibility? (my bad in version 002, I did
miss some places to change, the scope seems to be wide because it's an additional API that
I'm adding).

3. Just to clarify, I actually tried to avoid prompting with the patch. At occasions when
linux prompts, the patch I did throws exception like before, however, with improved message
to suggestion user to try -f switch.

BTW, your second to last experiment "Read perms sans -f require a prompt??" didn't really
use "-f" switch,  but sounds like you intended to use "-f" in this test, if so,  would you
please retry this one with "-f"? 

Thanks again.


> "hdfs dfs -rm -r" is slightly different from the Unix "rm -r" for deleting an empty directory
> ---------------------------------------------------------------------------------------------
>
>                 Key: HDFS-6165
>                 URL: https://issues.apache.org/jira/browse/HDFS-6165
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: hdfs-client
>    Affects Versions: 2.3.0
>            Reporter: Yongjun Zhang
>            Assignee: Yongjun Zhang
>            Priority: Minor
>         Attachments: HDFS-6165.001.patch, HDFS-6165.002.patch
>
>
> Given a directory owned by user A with permissions 0700 containing an empty directory
owned by user B, it is not possible to delete user B's directory. This is incorrect. Write
permission on the containing directory should be all that is needed to delete the child directory.
Here's a reproduction:
> {code}
> [root@vm01 ~]# hdfs dfs -ls /user/
> Found 4 items
> drwxr-xr-x   - userabc users               0 2013-05-03 01:55 /user/userabc
> drwxr-xr-x   - hdfs    supergroup          0 2013-05-03 00:28 /user/hdfs
> drwxrwxrwx   - mapred  hadoop              0 2013-05-03 00:13 /user/history
> drwxr-xr-x   - hdfs    supergroup          0 2013-04-14 16:46 /user/hive
> [root@vm01 ~]# hdfs dfs -ls /user/userabc
> Found 8 items
> drwx------   - userabc users          0 2013-05-02 17:00 /user/userabc/.Trash
> drwxr-xr-x   - userabc users          0 2013-05-03 01:34 /user/userabc/.cm
> drwx------   - userabc users          0 2013-05-03 01:06 /user/userabc/.staging
> drwxr-xr-x   - userabc users          0 2013-04-14 18:31 /user/userabc/apps
> drwxr-xr-x   - userabc users          0 2013-04-30 18:05 /user/userabc/ds
> drwxr-xr-x   - hdfs    users          0 2013-05-03 01:54 /user/userabc/foo
> drwxr-xr-x   - userabc users          0 2013-04-30 16:18 /user/userabc/maven_source
> drwxr-xr-x   - hdfs    users          0 2013-05-03 01:40 /user/userabc/test-restore
> [root@vm01 ~]# hdfs dfs -ls /user/userabc/foo/
> [root@vm01 ~]# sudo -u userabc hdfs dfs -rm -r -skipTrash /user/userabc/foo
> rm: Permission denied: user=userabc, access=ALL, inode="/user/userabc/foo":hdfs:users:drwxr-xr-x
> {code}
> The super user can delete the directory.
> {code}
> [root@vm01 ~]# sudo -u hdfs hdfs dfs -rm -r -skipTrash /user/userabc/foo
> Deleted /user/userabc/foo
> {code}
> The same is not true for files, however. They have the correct behavior.
> {code}
> [root@vm01 ~]# sudo -u hdfs hdfs dfs -touchz /user/userabc/foo-file
> [root@vm01 ~]# hdfs dfs -ls /user/userabc/
> Found 8 items
> drwx------   - userabc users          0 2013-05-02 17:00 /user/userabc/.Trash
> drwxr-xr-x   - userabc users          0 2013-05-03 01:34 /user/userabc/.cm
> drwx------   - userabc users          0 2013-05-03 01:06 /user/userabc/.staging
> drwxr-xr-x   - userabc users          0 2013-04-14 18:31 /user/userabc/apps
> drwxr-xr-x   - userabc users          0 2013-04-30 18:05 /user/userabc/ds
> -rw-r--r--   1 hdfs    users          0 2013-05-03 02:11 /user/userabc/foo-file
> drwxr-xr-x   - userabc users          0 2013-04-30 16:18 /user/userabc/maven_source
> drwxr-xr-x   - hdfs    users          0 2013-05-03 01:40 /user/userabc/test-restore
> [root@vm01 ~]# sudo -u userabc hdfs dfs -rm -skipTrash /user/userabc/foo-file
> Deleted /user/userabc/foo-file
> {code}



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