pnfs: pass ds_commit_idx through the commit path

Pass ds_commit_idx through the nfs commit path. It's used to select
the commit bucket when using pnfs and is ignored when not using pnfs.
Several functions had to be changed: nfs_retry_commit,
nfs_mark_request_commit, pnfs_mark_request_commit and the pnfs layout
driver .mark_request_commit functions.

Signed-off-by: Tom Haynes <loghyr@primarydata.com>
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index e997457..2bee165 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -847,9 +847,9 @@
  */
 void
 nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
-			struct nfs_commit_info *cinfo)
+			struct nfs_commit_info *cinfo, u32 ds_commit_idx)
 {
-	if (pnfs_mark_request_commit(req, lseg, cinfo))
+	if (pnfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx))
 		return;
 	nfs_request_add_commit_list(req, &cinfo->mds->list, cinfo);
 }
@@ -905,7 +905,8 @@
 		}
 		if (nfs_write_need_commit(hdr)) {
 			memcpy(&req->wb_verf, &hdr->verf.verifier, sizeof(req->wb_verf));
-			nfs_mark_request_commit(req, hdr->lseg, &cinfo);
+			nfs_mark_request_commit(req, hdr->lseg, &cinfo,
+				0);
 			goto next;
 		}
 remove_req:
@@ -1560,14 +1561,15 @@
 
 void nfs_retry_commit(struct list_head *page_list,
 		      struct pnfs_layout_segment *lseg,
-		      struct nfs_commit_info *cinfo)
+		      struct nfs_commit_info *cinfo,
+		      u32 ds_commit_idx)
 {
 	struct nfs_page *req;
 
 	while (!list_empty(page_list)) {
 		req = nfs_list_entry(page_list->next);
 		nfs_list_remove_request(req);
-		nfs_mark_request_commit(req, lseg, cinfo);
+		nfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx);
 		if (!cinfo->dreq) {
 			dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
 			dec_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info,
@@ -1598,7 +1600,7 @@
 	return nfs_initiate_commit(NFS_CLIENT(inode), data, NFS_PROTO(inode),
 				   data->mds_ops, how, 0);
  out_bad:
-	nfs_retry_commit(head, NULL, cinfo);
+	nfs_retry_commit(head, NULL, cinfo, 0);
 	cinfo->completion_ops->error_cleanup(NFS_I(inode));
 	return -ENOMEM;
 }