Re: [PATCH] NFS: Fix a commit bug

[Chuck Lever <chuck.lever@xxxxxxxxxx>]

On 06/07/2012 11:08 AM, Adamson, Dros wrote:
> On Jun 7, 2012, at 11:05 AM, Chuck Lever wrote:
>
> > This does not appear to fix the problem I'm seeing.
> >
> > With this patch applied, the client is silly renaming the file, deleting it, then writing it again and failing with NFS4ERR_STALE.
> What command(s) are you running?

Connectathon basic test 5.


> -dros
>
> > I had to apply the change by hand, so I could have missed something.  I'll go back and check.
> >
> > On Jun 6, 2012, at 9:59 AM, Adamson, Dros wrote:
> >
> > > ACK - This fixes the problem I was seeing!
> > >
> > > For the list, we were seeing duplicate writes sent to unstable servers even though the COMMIT succeeds (with matching verf):
> > >
> > > - mount a server that returns writes with committed = UNSTABLE4
> > > - run "dd if=/dev/zero of=/mnt/foo bs=1024 count=10240"
> > > - umount
> > > - in wireshark, you'll see the COMMIT succeed, but after a short pause there will be a flurry of FILE_SYNC4 writes that are duplicates (same ranges, data) of the writes associated with the COMMIT.
> > >
> > > -dros
> > >
> > > On Jun 5, 2012, at 6:43 PM, Trond Myklebust wrote:
> > >
> > > > The new commit code fails to copy the verifier into the wb_verf field
> > > > of _all_ the nfs_page structures; it only copies it into the first entry.
> > > > The consequence is that most requests end up failing to match in
> > > > nfs_commit_release.
> > > >
> > > > Fix is to copy the verifier into the req->wb_verf field in
> > > > nfs_write_completion.
> > > >
> > > > Signed-off-by: Trond Myklebust<Trond.Myklebust@xxxxxxxxxx>
> > > > Cc: Fred Isaman<iisaman@xxxxxxxxxx>
> > > > ---
> > > > fs/nfs/direct.c         |    4 ++--
> > > > fs/nfs/write.c          |    7 ++++---
> > > > include/linux/nfs_xdr.h |    2 ++
> > > > 3 files changed, 8 insertions(+), 5 deletions(-)
> > > >
> > > > diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
> > > > index 23d170b..b5385a7 100644
> > > > --- a/fs/nfs/direct.c
> > > > +++ b/fs/nfs/direct.c
> > > > @@ -710,12 +710,12 @@ static void nfs_direct_write_completion(struct nfs_pgio_header *hdr)
> > > > 			if (dreq->flags == NFS_ODIRECT_RESCHED_WRITES)
> > > > 				bit = NFS_IOHDR_NEED_RESCHED;
> > > > 			else if (dreq->flags == 0) {
> > > > -				memcpy(&dreq->verf,&req->wb_verf,
> > > > +				memcpy(&dreq->verf, hdr->verf,
> > > > 				       sizeof(dreq->verf));
> > > > 				bit = NFS_IOHDR_NEED_COMMIT;
> > > > 				dreq->flags = NFS_ODIRECT_DO_COMMIT;
> > > > 			} else if (dreq->flags == NFS_ODIRECT_DO_COMMIT) {
> > > > -				if (memcmp(&dreq->verf,&req->wb_verf, sizeof(dreq->verf))) {
> > > > +				if (memcmp(&dreq->verf, hdr->verf, sizeof(dreq->verf))) {
> > > > 					dreq->flags = NFS_ODIRECT_RESCHED_WRITES;
> > > > 					bit = NFS_IOHDR_NEED_RESCHED;
> > > > 				} else
> > > > diff --git a/fs/nfs/write.c b/fs/nfs/write.c
> > > > index e6fe3d6..4d6861c 100644
> > > > --- a/fs/nfs/write.c
> > > > +++ b/fs/nfs/write.c
> > > > @@ -80,6 +80,7 @@ struct nfs_write_header *nfs_writehdr_alloc(void)
> > > > 		INIT_LIST_HEAD(&hdr->rpc_list);
> > > > 		spin_lock_init(&hdr->lock);
> > > > 		atomic_set(&hdr->refcnt, 0);
> > > > +		hdr->verf =&p->verf;
> > > > 	}
> > > > 	return p;
> > > > }
> > > > @@ -619,6 +620,7 @@ static void nfs_write_completion(struct nfs_pgio_header *hdr)
> > > > 			goto next;
> > > > 		}
> > > > 		if (test_bit(NFS_IOHDR_NEED_COMMIT,&hdr->flags)) {
> > > > +			memcpy(&req->wb_verf, hdr->verf, sizeof(req->wb_verf));
> > > > 			nfs_mark_request_commit(req, hdr->lseg,&cinfo);
> > > > 			goto next;
> > > > 		}
> > > > @@ -1255,15 +1257,14 @@ static void nfs_writeback_release_common(void *calldata)
> > > > 	struct nfs_write_data	*data = calldata;
> > > > 	struct nfs_pgio_header *hdr = data->header;
> > > > 	int status = data->task.tk_status;
> > > > -	struct nfs_page *req = hdr->req;
> > > >
> > > > 	if ((status>= 0)&&  nfs_write_need_commit(data)) {
> > > > 		spin_lock(&hdr->lock);
> > > > 		if (test_bit(NFS_IOHDR_NEED_RESCHED,&hdr->flags))
> > > > 			; /* Do nothing */
> > > > 		else if (!test_and_set_bit(NFS_IOHDR_NEED_COMMIT,&hdr->flags))
> > > > -			memcpy(&req->wb_verf,&data->verf, sizeof(req->wb_verf));
> > > > -		else if (memcmp(&req->wb_verf,&data->verf, sizeof(req->wb_verf)))
> > > > +			memcpy(hdr->verf,&data->verf, sizeof(*hdr->verf));
> > > > +		else if (memcmp(hdr->verf,&data->verf, sizeof(*hdr->verf)))
> > > > 			set_bit(NFS_IOHDR_NEED_RESCHED,&hdr->flags);
> > > > 		spin_unlock(&hdr->lock);
> > > > 	}
> > > > diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
> > > > index 7519bae..8aadd90 100644
> > > > --- a/include/linux/nfs_xdr.h
> > > > +++ b/include/linux/nfs_xdr.h
> > > > @@ -1237,6 +1237,7 @@ struct nfs_pgio_header {
> > > > 	struct list_head	rpc_list;
> > > > 	atomic_t		refcnt;
> > > > 	struct nfs_page		*req;
> > > > +	struct nfs_writeverf	*verf;
> > > > 	struct pnfs_layout_segment *lseg;
> > > > 	loff_t			io_start;
> > > > 	const struct rpc_call_ops *mds_ops;
> > > > @@ -1274,6 +1275,7 @@ struct nfs_write_data {
> > > > struct nfs_write_header {
> > > > 	struct nfs_pgio_header	header;
> > > > 	struct nfs_write_data	rpc_data;
> > > > +	struct nfs_writeverf	verf;
> > > > };
> > > >
> > > > struct nfs_mds_commit_info {
> > > > --
> > > > 1.7.10.2
> > ---
> > Chuck Lever
> > chuck [dot] lever [at] oracle [dot] com

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