[Ndn-interest] error with build application log

Ishita Dasgupta ishita.dasgupta at gmail.com
Sat Jul 15 12:15:37 PDT 2017

Thanks for sharing that information.
Any possible explanation as to why a company to mount directory would fail
with " cp: cannot create regular file ‘/tmp/ndnfs/file.txt’: No such file
or directory"
Where /tmp/ndnfs is the mount directory?


On Sat, Jul 15, 2017 at 3:03 PM Junxiao Shi <shijunxiao at email.arizona.edu>

> Hi Ishita
> I had an ndnfs-port deployment in 2015-2016, so I'll answer from user's
> perspective.
>> I am trying to debug the error I am receiving while downloading files of
>> different size on ndnfs. In according to do this, when I try to move files
>> of different sizes to the mount directory(/tmp/ndnfs) AND root
>> directory(/tmp/dir), I keep coming across following situations:
>> 1. If I move the new file to mount directory directly, it copies the
>> files to both mount and root directory and I can see DEBUG logs of
>> ndnfs_write and sign_segment logs on the ndnfs build window.
> This is just how FUSE works. The files are physically stored in the root
> directory, but it can be seen from both locations. Only one copy is stored
> on the disk.
> You should modify mount directory only, and never directly modify root
> directory.
>> 2. Sometimes when I try to move a file to mount directory directly, it
>> would give me cp: cannot create regular file ‘/tmp/ndnfs/100KB.txt’: No
>> such file or directory
> In my experience, copying with 'cp' on the terminal always works,
> uploading via sftp or scp never works.
> This may have something to do with how ndnfs-port monitors and reacts to
> file changes.
>> 3. In situations of 2, if I try to copy to root directory instead, it
>> would copy to both mount and root directories, but I can't see DEBUG logs
>> of ndnfs_write and sign_segment logs anymore like in 1 anymore. I need the
>> logs as I am trying to overcome another anomaly where the last segment of a
>> file gets set to 0. So, being able to see the sign_segment logs is
>> necessary.
> You should never modify root directory directly, even when ndnfs is not
> running. It causes inconsistency between file system and ndnfs's database
> which stores the signatures.
>> I do not understand why sometimes copying data directly to mount
>> directory works and sometimes doesn't. Does Anyone has an possible
>> explanation to all of this? It would be great if someone could explain why
>> the application works differently in similar situations.
> Closing words: I wish there's another app that can serve files from
> filesystem directly, without relying on FUSE.
> Yours, Junxiao
>> --
Ishita Dasgupta

*Graduate Student**College of Information and Computer Sciences*
*,UMass Amherst*
*Email*: ishitadg at cs.umass.edu
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