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https://issues.apache.org/jira/browse/HADOOP-9972?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13773584#comment-13773584
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Binglin Chang commented on HADOOP-9972:
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bq. Hmm. We could have a convenience method called listLinkStatus which just
called into listStatus with the correct PathOptions. I sort of lean towards
fewer APIs rather than more, but maybe it makes sense.
I mean listStatus(Path, PathOption) should call into listLinkStatus(it is
HDFS::listStatus which is a primitive RPC call), not the other way around. I
wonder how can we implement listStatus(Path, PathOption) without the primitive
of listLinkStatus(Path)?
bq. Shell globbing doesn't ignore all errors
What I say of globbing is just shell wildcard substitution, it indeed ignore
all errors, glob just substitute a string with wildcard to some string.
http://www.linuxjournal.com/content/bash-extended-globbing
http://tldp.org/LDP/abs/html/globbingref.html
{code}
drwxr-xr-x 2 decster staff 68 Sep 19 17:09 aa
drwxr-xr-x 2 decster staff 68 Sep 19 17:12 bb
decster:~/projects/test> echo *
aa bb
decster:~/projects/test> echo */cc
*/cc
{code}
In your example:
{code}
cmccabe@keter:~/mydir> ls b/c
ls: cannot access b/c: Permission denied
# this error is thrown by ls, not globbing
cmccabe@keter:~/mydir> ls *
a:
c
ls: cannot open directory b: Permission denied
# "ls *" first become "ls a c"
# then ls throw the error when process c
{code}
> new APIs for listStatus and globStatus to deal with symlinks
> ------------------------------------------------------------
>
> Key: HADOOP-9972
> URL: https://issues.apache.org/jira/browse/HADOOP-9972
> Project: Hadoop Common
> Issue Type: Improvement
> Components: fs
> Affects Versions: 2.1.1-beta
> Reporter: Colin Patrick McCabe
> Assignee: Colin Patrick McCabe
>
> Based on the discussion in HADOOP-9912, we need new APIs for FileSystem to
> deal with symlinks. The issue is that code has been written which is
> incompatible with the existence of things which are not files or directories.
> For example,
> there is a lot of code out there that looks at FileStatus#isFile, and
> if it returns false, assumes that what it is looking at is a
> directory. In the case of a symlink, this assumption is incorrect.
> It seems reasonable to make the default behavior of {{FileSystem#listStatus}}
> and {{FileSystem#globStatus}} be fully resolving symlinks, and ignoring
> dangling ones. This will prevent incompatibility with existing MR jobs and
> other HDFS users. We should also add new versions of listStatus and
> globStatus that allow new, symlink-aware code to deal with symlinks as
> symlinks.
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