diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index e56564d2ef95a37608106fb439723ff3e3c1e90d..9561c8fc8bdb6d7fed807d94f6cb5c2e3bb52276 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -36,6 +36,7 @@
 #include <linux/namei.h>
 #include <linux/bio.h>		/* struct bio */
 #include <linux/buffer_head.h>	/* various write calls */
+#include <linux/prefetch.h>
 
 #include "blocklayout.h"
 
diff --git a/fs/nfs/callback.h b/fs/nfs/callback.h
index b257383bb565a1331a68197a53d45545d436225e..07df5f1d85e5188b16d51f13049dd925870b5238 100644
--- a/fs/nfs/callback.h
+++ b/fs/nfs/callback.h
@@ -38,6 +38,7 @@ enum nfs4_callback_opnum {
 struct cb_process_state {
 	__be32			drc_status;
 	struct nfs_client	*clp;
+	int			slotid;
 };
 
 struct cb_compound_hdr_arg {
@@ -166,7 +167,6 @@ extern unsigned nfs4_callback_layoutrecall(
 	void *dummy, struct cb_process_state *cps);
 
 extern void nfs4_check_drain_bc_complete(struct nfs4_session *ses);
-extern void nfs4_cb_take_slot(struct nfs_client *clp);
 
 struct cb_devicenotifyitem {
 	uint32_t		cbd_notify_type;
diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 74780f9f852c6d3c5a01d71c3e2461ace4322963..43926add945b0a4a88625b23062e1cdd393a743d 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -348,7 +348,7 @@ validate_seqid(struct nfs4_slot_table *tbl, struct cb_sequenceargs * args)
 	/* Normal */
 	if (likely(args->csa_sequenceid == slot->seq_nr + 1)) {
 		slot->seq_nr++;
-		return htonl(NFS4_OK);
+		goto out_ok;
 	}
 
 	/* Replay */
@@ -367,11 +367,14 @@ validate_seqid(struct nfs4_slot_table *tbl, struct cb_sequenceargs * args)
 	/* Wraparound */
 	if (args->csa_sequenceid == 1 && (slot->seq_nr + 1) == 0) {
 		slot->seq_nr = 1;
-		return htonl(NFS4_OK);
+		goto out_ok;
 	}
 
 	/* Misordered request */
 	return htonl(NFS4ERR_SEQ_MISORDERED);
+out_ok:
+	tbl->highest_used_slotid = args->csa_slotid;
+	return htonl(NFS4_OK);
 }
 
 /*
@@ -433,26 +436,37 @@ __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
 			      struct cb_sequenceres *res,
 			      struct cb_process_state *cps)
 {
+	struct nfs4_slot_table *tbl;
 	struct nfs_client *clp;
 	int i;
 	__be32 status = htonl(NFS4ERR_BADSESSION);
 
-	cps->clp = NULL;
-
 	clp = nfs4_find_client_sessionid(args->csa_addr, &args->csa_sessionid);
 	if (clp == NULL)
 		goto out;
 
+	tbl = &clp->cl_session->bc_slot_table;
+
+	spin_lock(&tbl->slot_tbl_lock);
 	/* state manager is resetting the session */
 	if (test_bit(NFS4_SESSION_DRAINING, &clp->cl_session->session_state)) {
-		status = NFS4ERR_DELAY;
+		spin_unlock(&tbl->slot_tbl_lock);
+		status = htonl(NFS4ERR_DELAY);
+		/* Return NFS4ERR_BADSESSION if we're draining the session
+		 * in order to reset it.
+		 */
+		if (test_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state))
+			status = htonl(NFS4ERR_BADSESSION);
 		goto out;
 	}
 
 	status = validate_seqid(&clp->cl_session->bc_slot_table, args);
+	spin_unlock(&tbl->slot_tbl_lock);
 	if (status)
 		goto out;
 
+	cps->slotid = args->csa_slotid;
+
 	/*
 	 * Check for pending referring calls.  If a match is found, a
 	 * related callback was received before the response to the original
@@ -469,7 +483,6 @@ __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
 	res->csr_slotid = args->csa_slotid;
 	res->csr_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
 	res->csr_target_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
-	nfs4_cb_take_slot(clp);
 
 out:
 	cps->clp = clp; /* put in nfs4_callback_compound */
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index c6c86a77e043fe938c40df750314116b8a3fcbb0..918ad647afeaf4fe62840ea8d3146bb6ed87f406 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -754,26 +754,15 @@ static void nfs4_callback_free_slot(struct nfs4_session *session)
 	 * Let the state manager know callback processing done.
 	 * A single slot, so highest used slotid is either 0 or -1
 	 */
-	tbl->highest_used_slotid--;
+	tbl->highest_used_slotid = -1;
 	nfs4_check_drain_bc_complete(session);
 	spin_unlock(&tbl->slot_tbl_lock);
 }
 
-static void nfs4_cb_free_slot(struct nfs_client *clp)
+static void nfs4_cb_free_slot(struct cb_process_state *cps)
 {
-	if (clp && clp->cl_session)
-		nfs4_callback_free_slot(clp->cl_session);
-}
-
-/* A single slot, so highest used slotid is either 0 or -1 */
-void nfs4_cb_take_slot(struct nfs_client *clp)
-{
-	struct nfs4_slot_table *tbl = &clp->cl_session->bc_slot_table;
-
-	spin_lock(&tbl->slot_tbl_lock);
-	tbl->highest_used_slotid++;
-	BUG_ON(tbl->highest_used_slotid != 0);
-	spin_unlock(&tbl->slot_tbl_lock);
+	if (cps->slotid != -1)
+		nfs4_callback_free_slot(cps->clp->cl_session);
 }
 
 #else /* CONFIG_NFS_V4_1 */
@@ -784,7 +773,7 @@ preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
 	return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
 }
 
-static void nfs4_cb_free_slot(struct nfs_client *clp)
+static void nfs4_cb_free_slot(struct cb_process_state *cps)
 {
 }
 #endif /* CONFIG_NFS_V4_1 */
@@ -866,6 +855,7 @@ static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *r
 	struct cb_process_state cps = {
 		.drc_status = 0,
 		.clp = NULL,
+		.slotid = -1,
 	};
 	unsigned int nops = 0;
 
@@ -906,7 +896,7 @@ static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *r
 
 	*hdr_res.status = status;
 	*hdr_res.nops = htonl(nops);
-	nfs4_cb_free_slot(cps.clp);
+	nfs4_cb_free_slot(&cps);
 	nfs_put_client(cps.clp);
 	dprintk("%s: done, status = %u\n", __func__, ntohl(status));
 	return rpc_success;
diff --git a/fs/nfs/objlayout/objio_osd.c b/fs/nfs/objlayout/objio_osd.c
index 9383ca7245bc7f3ef5a5eeeb9a3b64248f933079..d0cda12fddc325c104ff643455ebae50afbb1ac9 100644
--- a/fs/nfs/objlayout/objio_osd.c
+++ b/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,
@@ -589,22 +587,19 @@ static void _calc_stripe_info(struct objio_state *ios, u64 file_offset,
 }
 
 static int _add_stripe_unit(struct objio_state *ios,  unsigned *cur_pg,
-		unsigned pgbase, struct _objio_per_comp *per_dev, int cur_len,
+		unsigned pgbase, struct _objio_per_comp *per_dev, int len,
 		gfp_t gfp_flags)
 {
 	unsigned pg = *cur_pg;
+	int cur_len = len;
 	struct request_queue *q =
 			osd_request_queue(_io_od(ios, per_dev->dev));
 
-	per_dev->length += cur_len;
-
 	if (per_dev->bio == NULL) {
-		unsigned stripes = ios->layout->num_comps /
-						     ios->layout->mirrors_p1;
-		unsigned pages_in_stripe = stripes *
+		unsigned pages_in_stripe = ios->layout->group_width *
 				      (ios->layout->stripe_unit / PAGE_SIZE);
 		unsigned bio_size = (ios->ol_state.nr_pages + pages_in_stripe) /
-				    stripes;
+				    ios->layout->group_width;
 
 		if (BIO_MAX_PAGES_KMALLOC < bio_size)
 			bio_size = BIO_MAX_PAGES_KMALLOC;
@@ -632,6 +627,7 @@ static int _add_stripe_unit(struct objio_state *ios,  unsigned *cur_pg,
 	}
 	BUG_ON(cur_len);
 
+	per_dev->length += len;
 	*cur_pg = pg;
 	return 0;
 }
@@ -650,7 +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) {
@@ -670,8 +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;
 		}
@@ -806,7 +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,
@@ -904,7 +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,
diff --git a/fs/nfs/objlayout/pnfs_osd_xdr_cli.c b/fs/nfs/objlayout/pnfs_osd_xdr_cli.c
index 16fc758e91233a7c931cdda1d05148ad8dc5ae44..b3918f7ac34d0eaa0f778fa0bb170fe5dedddcfe 100644
--- a/fs/nfs/objlayout/pnfs_osd_xdr_cli.c
+++ b/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;
 }