Date: Wed, 29 Apr 2015 15:11:48 +0200
From: Christoph Hellwig <hch@lst.de>
To: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Christoph Hellwig <hch@lst.de>, linux-nfs@vger.kernel.org
Subject: Re: [PATCH 5/6] nfsd: take struct file setup fully into
	nfs4_preprocess_stateid_op
Message-ID: <20150429131148.GA3381@lst.de>
References: <1430228480-7656-1-git-send-email-hch@lst.de> <1430228480-7656-6-git-send-email-hch@lst.de> <20150428204455.GC16090@fieldses.org>
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Sender: linux-nfs-owner@vger.kernel.org

On Tue, Apr 28, 2015 at 04:44:55PM -0400, J. Bruce Fields wrote:
> This causes a failure on pynfs OPEN23b.

I've once again tried to run pynfs, but I'm still errors out with weird
python backtraces for any of the examples from the readme I copy
and pasted, e.g.:

root@vm:~/pynfs/nfs4.0# ./testserver.py 127.0.0.1:/mnt/test --maketree all
Initialization failed, no tests run.
Traceback (most recent call last):
  File "./testserver.py", line 379, in <module>
    main()
  File "./testserver.py", line 342, in main
    env.init()
  File "/root/pynfs/nfs4.0/servertests/environment.py", line 140, in init
    self._maketree()
  File "/root/pynfs/nfs4.0/servertests/environment.py", line 159, in _maketree
    "Could not LOOKUP /%s," % '/'.join(path))
  File "/root/pynfs/nfs4.0/servertests/environment.py", line 274, in checklist
    raise testmod.FailureException(msg)
testmod.FailureException: Could not LOOKUP /mnt, should return NFS4_OK or NFS4ERR_NOENT, instead got NFS4ERR_PERM


root@vm:~/pynfs/nfs4.1# ./testserver.py 127.0.0.1:/mnt/test --maketree all
Could not find gssapi module, proceeding without
INFO   :rpc.poll:got connection from ('127.0.0.1', 37715), assigned to fd=5
INFO   :rpc.thread:Called connect(('127.0.0.1', 2049))
INFO   :rpc.poll:Adding 6 generated by another thread
INFO   :test.env:Created client to 127.0.0.1, 2049
INFO   :nfs.client.cb:********************
INFO   :nfs.client.cb:Handling CB_NULL
Initialization failed, no tests run.
Traceback (most recent call last):
  File "./testserver.py", line 359, in <module>
    main()
  File "./testserver.py", line 322, in main
    env.init()
  File "/root/pynfs/nfs4.1/server41tests/environment.py", line 150, in init
    self._maketree(sess)
  File "/root/pynfs/nfs4.1/server41tests/environment.py", line 166, in _maketree
    "LOOKUP /%s," % '/'.join(path))
  File "/root/pynfs/nfs4.1/server41tests/environment.py", line 304, in checklist
    raise testmod.FailureException(msg)
testmod.FailureException: LOOKUP /mnt, should return NFS4_OK or NFS4ERR_NOENT, instead got NFS4ERR_PERM


> It's doing a READ using a stateid from a write open.  We previously
> returned NFS_OK, taking the "may" option from:
> 
> 	http://tools.ietf.org/html/rfc7530#page-111
> 
> 	In the case of READ, the server may perform the corresponding
> 	check on the access mode, or it may choose to allow READ on
> 	opens for WRITE only, to accommodate clients whose write
> 	implementation may unavoidably do reads (e.g., due to buffer
> 	cache constraints).
> 
> OPENMODE might also have been OK, but we're returning SERVERFAULT.  I
> guess the old code was passing preprocess_stateid_op without returning a
> file, then relying on a temporary open for the read?  Ugh.

Looks like it.  I can change it to return an OPENMODE, or we could
make it fall back to a temp read open.