Return-Path: Date: Tue, 21 Jul 2009 17:47:17 -0400 Message-ID: Subject: nfs4 write delegation status From: "David V. Cloud" To: nfsv4@linux-nfs.org Cc: linux-nfs@vger.kernel.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============0690846410==" Sender: nfsv4-bounces@linux-nfs.org Errors-To: nfsv4-bounces@linux-nfs.org MIME-Version: 1.0 List-ID: --===============0690846410== Content-Type: multipart/alternative; boundary=0016367ed4e1c58789046f3e32b1 --0016367ed4e1c58789046f3e32b1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Hi all, I was playing with nfs4 delegation, finding out that write delegations have never been granted. I am using Benny Halevy's git tree with latest pnfs-block-all branch. With rpcdebug, I found out that the write-delegation grant was rejected due to setlease failure with error code (-11, which is -EAGAIN). I finally figured out that this failure was caused by the following lines in generic_setlease function, if ((arg == F_WRLCK) && ((atomic_read(&dentry->d_count) > 1) || (atomic_read(&inode->i_count) > 1))) goto out; In my nfsd, the i_count, and d_count turn out to be 2 (no conflicts actaully exist in my test case), so write-delegations always failed. I did find some similar posts on nfs4 related mail lists about this problem. One possible hack by Ajay could be found at http://osdir.com/ml/linux.nfsv4/2006-08/msg00063.html I am curious whether there is any progress in awarding write delegation in current linux nfs4 implementation (for example, any git branch with write delegation enabled I can pull?) Or, is write-delegation feature available in other systems like OpenSolaris? Any suggestion if I would like to enable and test write delegation? I think some changes are needed to the setlease interface, right? Thanks, David --0016367ed4e1c58789046f3e32b1 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi all,
I was playing with nfs4 delegation, finding out that write d= elegations have never been granted. I am using Benny Halevy's git tree with= latest pnfs-block-all branch. With rpcdebug, I found out that the wr= ite-delegation grant was rejected due to setlease failure with error code (= -11, which is -EAGAIN). I finally figured out that this failure was caused = by the following lines in generic_setlease function,

        if ((arg =3D=3D F_WRLCK)
= ;           && ((atomic_rea= d(&dentry->d_count) > 1)
       =     || (atomic_read(&inode->i_count) > 1)))
&n= bsp;           goto out;

In = my nfsd, the i_count, and d_count turn out to be 2 (no conflicts actaully e= xist in my test case), so write-delegations always failed. I did find some = similar posts on nfs4 related mail lists about this problem. One possible h= ack by Ajay could be found at
http://os= dir.com/ml/linux.nfsv4/2006-08/msg00063.html

I am curious whethe= r there is any progress in awarding write delegation in current linux nfs4 = implementation (for example, any git branch with write delegation enabled I= can pull?) Or, is write-delegation feature available in other systems like= OpenSolaris?

Any suggestion if I would like to enable and test write delegation? I t= hink some changes are needed to the setlease interface, right?

Thank= s,
David
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