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Hey Jason,
I tried to uncomment the piece of code you suggested, rebuild
everything, umount, mount and here is what happens:
Line: 1092 in fuse-dfs.c:
fuse_dfs: ERROR: hdfs trying to rename
/osg/app/robert/deployment-1.3.x/.svn/tmp/entries to
/osg/app/robert/deployment-1.3.x/.svn/entries
which is due to a call to is_protected() at Line 1018. Both in Hadoop
0.19.1.
Thanks for your help!
Robert
jason hadoop wrote:
> In hadoop 0.19.1, (and 19.0) libhdfs (which is used by the fuse package for
> hdfs access) explicitly denies open requests that pass O_RDWR
>
> If you have binary applications that pass the flag, but would work correctly
> given the limitations of HDFS, you may alter the code in
> src/c++/libhdfs/hdfs.c to allow it, or build a shared library that you
> preload that changes the flags passed to the real open. Hacking hdfs.c is
> much simpler.
>
> Line 407 of hdfs.c
>
> jobject jFS = (jobject)fs;
>
> if (flags & O_RDWR) {
> fprintf(stderr, "ERROR: cannot open an hdfs file in O_RDWR mode\n");
> errno = ENOTSUP;
> return NULL;
> }
>
>
>
>
> On Fri, May 1, 2009 at 6:34 PM, Philip Zeyliger <[email protected]> wrote:
>
>> HDFS does not allow you to overwrite bytes of a file that have already been
>> written. The only operations it supports are read (an existing file),
>> write
>> (a new file), and (in newer versions, not always enabled) append (to an
>> existing file).
>>
>> -- Philip
>>
>> On Fri, May 1, 2009 at 5:56 PM, Robert Engel <[email protected]
>>> wrote:
> Hello,
>
> I am using Hadoop on a small storage cluster (x86_64, CentOS 5.3,
> Hadoop-0.19.1). The hdfs is mounted using fuse and everything seemed
> to work just fine so far. However, I noticed that I cannot:
>
> 1) use svn to check out files on the mounted hdfs partition
> 2) request that stdout and stderr of Globus jobs is written to the
> hdfs partition
>
> In both cases I see following error message in /var/log/messages:
>
> fuse_dfs: ERROR: could not connect open file fuse_dfs.c:1364
>
> When I run fuse_dfs in debugging mode I get:
>
> ERROR: cannot open an hdfs file in O_RDWR mode
> unique: 169, error: -5 (Input/output error), outsize: 16
>
> My question is if this is a general limitation of Hadoop or if this
> operation is just not currently supported? I searched Google and JIRA
> but could not find an answer.
>
> Thanks,
> Robert
>
>>>
>>>
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