NFS: Fix a commit bug

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@netapp.com>
Cc: Fred Isaman <iisaman@netapp.com>

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

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);
 	}

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 {