pnfs-obj: Fix the comp_index != 0 case

There were bugs in the case of partial layout where olo_comp_index
is not zero. This used to work and was tested but one of the later
cleanup SQUASHMEs broke it and was not tested since.

Also add a dprint that specify those received layout parameters.
Everything else was already printed.

[Needed in v3.0]
CC: Stable Tree <stable@kernel.org>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/objlayout/objio_osd.c

@@ -479,7 +479,6 @@ static int _io_check(struct objio_state *ios, bool is_write)
 	for (i = 0; i <  ios->numdevs; i++) {
 		struct osd_sense_info osi;
 		struct osd_request *or = ios->per_dev[i].or;
-		unsigned dev;
 		int ret;
 
 		if (!or)
@@ -500,9 +499,8 @@ static int _io_check(struct objio_state *ios, bool is_write)
 
 			continue; /* we recovered */
 		}
-		dev = ios->per_dev[i].dev;
-		objlayout_io_set_result(&ios->ol_state, dev,
-					&ios->layout->comps[dev].oc_object_id,
+		objlayout_io_set_result(&ios->ol_state, i,
+					&ios->layout->comps[i].oc_object_id,
 					osd_pri_2_pnfs_err(osi.osd_err_pri),
 					ios->per_dev[i].offset,
 					ios->per_dev[i].length,
@@ -648,7 +646,7 @@ static int _prepare_one_group(struct objio_state *ios, u64 length,
 	int ret = 0;
 
 	while (length) {
-		struct _objio_per_comp *per_dev = &ios->per_dev[dev];
+		struct _objio_per_comp *per_dev = &ios->per_dev[dev - first_dev];
 		unsigned cur_len, page_off = 0;
 
 		if (!per_dev->length) {
@@ -668,8 +666,8 @@ static int _prepare_one_group(struct objio_state *ios, u64 length,
 				cur_len = stripe_unit;
 			}
 
-			if (max_comp < dev)
-				max_comp = dev;
+			if (max_comp < dev - first_dev)
+				max_comp = dev - first_dev;
 		} else {
 			cur_len = stripe_unit;
 		}
@@ -804,7 +802,7 @@ static int _read_mirrors(struct objio_state *ios, unsigned cur_comp)
 	struct _objio_per_comp *per_dev = &ios->per_dev[cur_comp];
 	unsigned dev = per_dev->dev;
 	struct pnfs_osd_object_cred *cred =
-			&ios->layout->comps[dev];
+			&ios->layout->comps[cur_comp];
 	struct osd_obj_id obj = {
 		.partition = cred->oc_object_id.oid_partition_id,
 		.id = cred->oc_object_id.oid_object_id,
@@ -902,7 +900,7 @@ static int _write_mirrors(struct objio_state *ios, unsigned cur_comp)
 	for (; cur_comp < last_comp; ++cur_comp, ++dev) {
 		struct osd_request *or = NULL;
 		struct pnfs_osd_object_cred *cred =
-					&ios->layout->comps[dev];
+					&ios->layout->comps[cur_comp];
 		struct osd_obj_id obj = {
 			.partition = cred->oc_object_id.oid_partition_id,
 			.id = cred->oc_object_id.oid_object_id,

fs/nfs/objlayout/pnfs_osd_xdr_cli.c

@@ -170,6 +170,9 @@ int pnfs_osd_xdr_decode_layout_map(struct pnfs_osd_layout *layout,
 	p = _osd_xdr_decode_data_map(p, &layout->olo_map);
 	layout->olo_comps_index = be32_to_cpup(p++);
 	layout->olo_num_comps = be32_to_cpup(p++);
+	dprintk("%s: olo_comps_index=%d olo_num_comps=%d\n", __func__,
+		layout->olo_comps_index, layout->olo_num_comps);
+
 	iter->total_comps = layout->olo_num_comps;
 	return 0;
 }