[Gluster-devel] Fail when calling syncop_create

[Anand Avati]

On Sun, Sep 9, 2012 at 10:53 AM, Gustavo Bervian Brand
<gugabrand at gmail.com>wrote:

> Hello,
>
>   I'm implementing a translator and at the moment I'm trying to "cache" at
> the local node's disk the files read from other node.
>   When reading a file from a certain node, at the file open function it's
> added an extended metadata at the original file with info about where this
> file (or part of it) is copied, calling syncop_setxattr to the proper child
> to do it.
>   So, once open is done the readv comes and if this file was not already
> read/cached, at the readv_cbk (before stack unwind) I am trying to create a
> local file with the content got from the original node.
>
>   For that purpose, I am using syncop_create / setattr / write. But the
> syncop_create is always failing with Stale NFS file handle error.
>   I tried to copy the same gfid and pargfid of the loc_t used at open
> function (saved), it didn't work, tried to zero them, nothing... and
> manipulated all the variables used at the syncop_create call... but nothing
> worked to get a success return from syncop_create.
>
>   Is there some requirement to call syncop_create, or a good way to track
> the exact reason for this failure (I could see it's not even reaching the
> client_create() call through gdb)? I am using the code from the master
> branch of 1 week ago. Any comment is welcome.
>
>
> Part of the log:
>
> [2012-09-09 17:04:16.357875] I [gbfs_t.c:361:gbfs_open_cbk] 0-gbfs-test:
> entering gbfs_open_cbk function
> [2012-09-09 17:04:16.358026] I [gbfs_t.c:169:gbfs_readv] 0-gbfs-test:
> entering gbfs_readv function
> [2012-09-09 17:04:16.358156] I [gbfs_t.c:46:gbfs_readv_cbk] 0-gbfs-test:
> entering gbfs_readv_cbk function
> [2012-09-09 17:04:16.358192] I [gbfs_t.c:132:gbfs_readv_cbk] 0-gbfs-test:
> failed to create /35a710dd on examplevol-client-0 (Stale NFS file handle)
>
>
It will be good to put a break-point at gbfs_readv_cbk to inspect the
backtrace to find which layer did the STACK_UNWIND(..,ESTALE...); and
continue debugging from there.

For a create, you are expected to:
- fill loc.pargfid
- fill loc.basename
- fill loc.inode (obtained via inode_new())
- fill "gfid-req" key in xdata dictionary with a GFID to be assigned for
the newly created file.

You can inspect posix_create() and client_create() to double check what the
"dependencies" are. Note that if what you are creating is just a cached
version of the original file, then it might be a good idea to re-use its
gfid too.

Avati
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