zte's code,first commit

Change-Id: I9a04da59e459a9bc0d67f101f700d9d7dc8d681b
diff --git a/ap/os/linux/linux-3.4.x/fs/nfs/pnfs.c b/ap/os/linux/linux-3.4.x/fs/nfs/pnfs.c
new file mode 100644
index 0000000..ae31182
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/fs/nfs/pnfs.c
@@ -0,0 +1,1532 @@
+/*
+ *  pNFS functions to call and manage layout drivers.
+ *
+ *  Copyright (c) 2002 [year of first publication]
+ *  The Regents of the University of Michigan
+ *  All Rights Reserved
+ *
+ *  Dean Hildebrand <dhildebz@umich.edu>
+ *
+ *  Permission is granted to use, copy, create derivative works, and
+ *  redistribute this software and such derivative works for any purpose,
+ *  so long as the name of the University of Michigan is not used in
+ *  any advertising or publicity pertaining to the use or distribution
+ *  of this software without specific, written prior authorization. If
+ *  the above copyright notice or any other identification of the
+ *  University of Michigan is included in any copy of any portion of
+ *  this software, then the disclaimer below must also be included.
+ *
+ *  This software is provided as is, without representation or warranty
+ *  of any kind either express or implied, including without limitation
+ *  the implied warranties of merchantability, fitness for a particular
+ *  purpose, or noninfringement.  The Regents of the University of
+ *  Michigan shall not be liable for any damages, including special,
+ *  indirect, incidental, or consequential damages, with respect to any
+ *  claim arising out of or in connection with the use of the software,
+ *  even if it has been or is hereafter advised of the possibility of
+ *  such damages.
+ */
+
+#include <linux/nfs_fs.h>
+#include <linux/nfs_page.h>
+#include <linux/module.h>
+#include "internal.h"
+#include "pnfs.h"
+#include "iostat.h"
+
+#define NFSDBG_FACILITY		NFSDBG_PNFS
+
+/* Locking:
+ *
+ * pnfs_spinlock:
+ *      protects pnfs_modules_tbl.
+ */
+static DEFINE_SPINLOCK(pnfs_spinlock);
+
+/*
+ * pnfs_modules_tbl holds all pnfs modules
+ */
+static LIST_HEAD(pnfs_modules_tbl);
+
+/* Return the registered pnfs layout driver module matching given id */
+static struct pnfs_layoutdriver_type *
+find_pnfs_driver_locked(u32 id)
+{
+	struct pnfs_layoutdriver_type *local;
+
+	list_for_each_entry(local, &pnfs_modules_tbl, pnfs_tblid)
+		if (local->id == id)
+			goto out;
+	local = NULL;
+out:
+	dprintk("%s: Searching for id %u, found %p\n", __func__, id, local);
+	return local;
+}
+
+static struct pnfs_layoutdriver_type *
+find_pnfs_driver(u32 id)
+{
+	struct pnfs_layoutdriver_type *local;
+
+	spin_lock(&pnfs_spinlock);
+	local = find_pnfs_driver_locked(id);
+	spin_unlock(&pnfs_spinlock);
+	return local;
+}
+
+void
+unset_pnfs_layoutdriver(struct nfs_server *nfss)
+{
+	if (nfss->pnfs_curr_ld) {
+		if (nfss->pnfs_curr_ld->clear_layoutdriver)
+			nfss->pnfs_curr_ld->clear_layoutdriver(nfss);
+		module_put(nfss->pnfs_curr_ld->owner);
+	}
+	nfss->pnfs_curr_ld = NULL;
+}
+
+/*
+ * Try to set the server's pnfs module to the pnfs layout type specified by id.
+ * Currently only one pNFS layout driver per filesystem is supported.
+ *
+ * @id layout type. Zero (illegal layout type) indicates pNFS not in use.
+ */
+void
+set_pnfs_layoutdriver(struct nfs_server *server, const struct nfs_fh *mntfh,
+		      u32 id)
+{
+	struct pnfs_layoutdriver_type *ld_type = NULL;
+
+	if (id == 0)
+		goto out_no_driver;
+	if (!(server->nfs_client->cl_exchange_flags &
+		 (EXCHGID4_FLAG_USE_NON_PNFS | EXCHGID4_FLAG_USE_PNFS_MDS))) {
+		printk(KERN_ERR "NFS: %s: id %u cl_exchange_flags 0x%x\n",
+			__func__, id, server->nfs_client->cl_exchange_flags);
+		goto out_no_driver;
+	}
+	ld_type = find_pnfs_driver(id);
+	if (!ld_type) {
+		request_module("%s-%u", LAYOUT_NFSV4_1_MODULE_PREFIX, id);
+		ld_type = find_pnfs_driver(id);
+		if (!ld_type) {
+			dprintk("%s: No pNFS module found for %u.\n",
+				__func__, id);
+			goto out_no_driver;
+		}
+	}
+	if (!try_module_get(ld_type->owner)) {
+		dprintk("%s: Could not grab reference on module\n", __func__);
+		goto out_no_driver;
+	}
+	server->pnfs_curr_ld = ld_type;
+	if (ld_type->set_layoutdriver
+	    && ld_type->set_layoutdriver(server, mntfh)) {
+		printk(KERN_ERR "NFS: %s: Error initializing pNFS layout "
+			"driver %u.\n", __func__, id);
+		module_put(ld_type->owner);
+		goto out_no_driver;
+	}
+
+	dprintk("%s: pNFS module for %u set\n", __func__, id);
+	return;
+
+out_no_driver:
+	dprintk("%s: Using NFSv4 I/O\n", __func__);
+	server->pnfs_curr_ld = NULL;
+}
+
+int
+pnfs_register_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
+{
+	int status = -EINVAL;
+	struct pnfs_layoutdriver_type *tmp;
+
+	if (ld_type->id == 0) {
+		printk(KERN_ERR "NFS: %s id 0 is reserved\n", __func__);
+		return status;
+	}
+	if (!ld_type->alloc_lseg || !ld_type->free_lseg) {
+		printk(KERN_ERR "NFS: %s Layout driver must provide "
+		       "alloc_lseg and free_lseg.\n", __func__);
+		return status;
+	}
+
+	spin_lock(&pnfs_spinlock);
+	tmp = find_pnfs_driver_locked(ld_type->id);
+	if (!tmp) {
+		list_add(&ld_type->pnfs_tblid, &pnfs_modules_tbl);
+		status = 0;
+		dprintk("%s Registering id:%u name:%s\n", __func__, ld_type->id,
+			ld_type->name);
+	} else {
+		printk(KERN_ERR "NFS: %s Module with id %d already loaded!\n",
+			__func__, ld_type->id);
+	}
+	spin_unlock(&pnfs_spinlock);
+
+	return status;
+}
+EXPORT_SYMBOL_GPL(pnfs_register_layoutdriver);
+
+void
+pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
+{
+	dprintk("%s Deregistering id:%u\n", __func__, ld_type->id);
+	spin_lock(&pnfs_spinlock);
+	list_del(&ld_type->pnfs_tblid);
+	spin_unlock(&pnfs_spinlock);
+}
+EXPORT_SYMBOL_GPL(pnfs_unregister_layoutdriver);
+
+/*
+ * pNFS client layout cache
+ */
+
+/* Need to hold i_lock if caller does not already hold reference */
+void
+get_layout_hdr(struct pnfs_layout_hdr *lo)
+{
+	atomic_inc(&lo->plh_refcount);
+}
+
+static struct pnfs_layout_hdr *
+pnfs_alloc_layout_hdr(struct inode *ino, gfp_t gfp_flags)
+{
+	struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
+	return ld->alloc_layout_hdr ? ld->alloc_layout_hdr(ino, gfp_flags) :
+		kzalloc(sizeof(struct pnfs_layout_hdr), gfp_flags);
+}
+
+static void
+pnfs_free_layout_hdr(struct pnfs_layout_hdr *lo)
+{
+	struct pnfs_layoutdriver_type *ld = NFS_SERVER(lo->plh_inode)->pnfs_curr_ld;
+	put_rpccred(lo->plh_lc_cred);
+	return ld->alloc_layout_hdr ? ld->free_layout_hdr(lo) : kfree(lo);
+}
+
+static void
+destroy_layout_hdr(struct pnfs_layout_hdr *lo)
+{
+	dprintk("%s: freeing layout cache %p\n", __func__, lo);
+	BUG_ON(!list_empty(&lo->plh_layouts));
+	NFS_I(lo->plh_inode)->layout = NULL;
+	pnfs_free_layout_hdr(lo);
+}
+
+static void
+put_layout_hdr_locked(struct pnfs_layout_hdr *lo)
+{
+	if (atomic_dec_and_test(&lo->plh_refcount))
+		destroy_layout_hdr(lo);
+}
+
+void
+put_layout_hdr(struct pnfs_layout_hdr *lo)
+{
+	struct inode *inode = lo->plh_inode;
+
+	if (atomic_dec_and_lock(&lo->plh_refcount, &inode->i_lock)) {
+		destroy_layout_hdr(lo);
+		spin_unlock(&inode->i_lock);
+	}
+}
+
+static void
+init_lseg(struct pnfs_layout_hdr *lo, struct pnfs_layout_segment *lseg)
+{
+	INIT_LIST_HEAD(&lseg->pls_list);
+	INIT_LIST_HEAD(&lseg->pls_lc_list);
+	atomic_set(&lseg->pls_refcount, 1);
+	smp_mb();
+	set_bit(NFS_LSEG_VALID, &lseg->pls_flags);
+	lseg->pls_layout = lo;
+}
+
+static void free_lseg(struct pnfs_layout_segment *lseg)
+{
+	struct inode *ino = lseg->pls_layout->plh_inode;
+
+	NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
+	/* Matched by get_layout_hdr in pnfs_insert_layout */
+	put_layout_hdr(NFS_I(ino)->layout);
+}
+
+static void
+put_lseg_common(struct pnfs_layout_segment *lseg)
+{
+	struct inode *inode = lseg->pls_layout->plh_inode;
+
+	WARN_ON(test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
+	list_del_init(&lseg->pls_list);
+	if (list_empty(&lseg->pls_layout->plh_segs)) {
+		set_bit(NFS_LAYOUT_DESTROYED, &lseg->pls_layout->plh_flags);
+		/* Matched by initial refcount set in alloc_init_layout_hdr */
+		put_layout_hdr_locked(lseg->pls_layout);
+	}
+	rpc_wake_up(&NFS_SERVER(inode)->roc_rpcwaitq);
+}
+
+void
+put_lseg(struct pnfs_layout_segment *lseg)
+{
+	struct inode *inode;
+
+	if (!lseg)
+		return;
+
+	dprintk("%s: lseg %p ref %d valid %d\n", __func__, lseg,
+		atomic_read(&lseg->pls_refcount),
+		test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
+	inode = lseg->pls_layout->plh_inode;
+	if (atomic_dec_and_lock(&lseg->pls_refcount, &inode->i_lock)) {
+		LIST_HEAD(free_me);
+
+		put_lseg_common(lseg);
+		list_add(&lseg->pls_list, &free_me);
+		spin_unlock(&inode->i_lock);
+		pnfs_free_lseg_list(&free_me);
+	}
+}
+EXPORT_SYMBOL_GPL(put_lseg);
+
+static inline u64
+end_offset(u64 start, u64 len)
+{
+	u64 end;
+
+	end = start + len;
+	return end >= start ? end : NFS4_MAX_UINT64;
+}
+
+/* last octet in a range */
+static inline u64
+last_byte_offset(u64 start, u64 len)
+{
+	u64 end;
+
+	BUG_ON(!len);
+	end = start + len;
+	return end > start ? end - 1 : NFS4_MAX_UINT64;
+}
+
+/*
+ * is l2 fully contained in l1?
+ *   start1                             end1
+ *   [----------------------------------)
+ *           start2           end2
+ *           [----------------)
+ */
+static inline int
+lo_seg_contained(struct pnfs_layout_range *l1,
+		 struct pnfs_layout_range *l2)
+{
+	u64 start1 = l1->offset;
+	u64 end1 = end_offset(start1, l1->length);
+	u64 start2 = l2->offset;
+	u64 end2 = end_offset(start2, l2->length);
+
+	return (start1 <= start2) && (end1 >= end2);
+}
+
+/*
+ * is l1 and l2 intersecting?
+ *   start1                             end1
+ *   [----------------------------------)
+ *                              start2           end2
+ *                              [----------------)
+ */
+static inline int
+lo_seg_intersecting(struct pnfs_layout_range *l1,
+		    struct pnfs_layout_range *l2)
+{
+	u64 start1 = l1->offset;
+	u64 end1 = end_offset(start1, l1->length);
+	u64 start2 = l2->offset;
+	u64 end2 = end_offset(start2, l2->length);
+
+	return (end1 == NFS4_MAX_UINT64 || end1 > start2) &&
+	       (end2 == NFS4_MAX_UINT64 || end2 > start1);
+}
+
+static bool
+should_free_lseg(struct pnfs_layout_range *lseg_range,
+		 struct pnfs_layout_range *recall_range)
+{
+	return (recall_range->iomode == IOMODE_ANY ||
+		lseg_range->iomode == recall_range->iomode) &&
+	       lo_seg_intersecting(lseg_range, recall_range);
+}
+
+/* Returns 1 if lseg is removed from list, 0 otherwise */
+static int mark_lseg_invalid(struct pnfs_layout_segment *lseg,
+			     struct list_head *tmp_list)
+{
+	int rv = 0;
+
+	if (test_and_clear_bit(NFS_LSEG_VALID, &lseg->pls_flags)) {
+		/* Remove the reference keeping the lseg in the
+		 * list.  It will now be removed when all
+		 * outstanding io is finished.
+		 */
+		dprintk("%s: lseg %p ref %d\n", __func__, lseg,
+			atomic_read(&lseg->pls_refcount));
+		if (atomic_dec_and_test(&lseg->pls_refcount)) {
+			put_lseg_common(lseg);
+			list_add(&lseg->pls_list, tmp_list);
+			rv = 1;
+		}
+	}
+	return rv;
+}
+
+/* Returns count of number of matching invalid lsegs remaining in list
+ * after call.
+ */
+int
+mark_matching_lsegs_invalid(struct pnfs_layout_hdr *lo,
+			    struct list_head *tmp_list,
+			    struct pnfs_layout_range *recall_range)
+{
+	struct pnfs_layout_segment *lseg, *next;
+	int invalid = 0, removed = 0;
+
+	dprintk("%s:Begin lo %p\n", __func__, lo);
+
+	if (list_empty(&lo->plh_segs)) {
+		if (!test_and_set_bit(NFS_LAYOUT_DESTROYED, &lo->plh_flags))
+			put_layout_hdr_locked(lo);
+		return 0;
+	}
+	list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
+		if (!recall_range ||
+		    should_free_lseg(&lseg->pls_range, recall_range)) {
+			dprintk("%s: freeing lseg %p iomode %d "
+				"offset %llu length %llu\n", __func__,
+				lseg, lseg->pls_range.iomode, lseg->pls_range.offset,
+				lseg->pls_range.length);
+			invalid++;
+			removed += mark_lseg_invalid(lseg, tmp_list);
+		}
+	dprintk("%s:Return %i\n", __func__, invalid - removed);
+	return invalid - removed;
+}
+
+/* note free_me must contain lsegs from a single layout_hdr */
+void
+pnfs_free_lseg_list(struct list_head *free_me)
+{
+	struct pnfs_layout_segment *lseg, *tmp;
+	struct pnfs_layout_hdr *lo;
+
+	if (list_empty(free_me))
+		return;
+
+	lo = list_first_entry(free_me, struct pnfs_layout_segment,
+			      pls_list)->pls_layout;
+
+	if (test_bit(NFS_LAYOUT_DESTROYED, &lo->plh_flags)) {
+		struct nfs_client *clp;
+
+		clp = NFS_SERVER(lo->plh_inode)->nfs_client;
+		spin_lock(&clp->cl_lock);
+		list_del_init(&lo->plh_layouts);
+		spin_unlock(&clp->cl_lock);
+	}
+	list_for_each_entry_safe(lseg, tmp, free_me, pls_list) {
+		list_del(&lseg->pls_list);
+		free_lseg(lseg);
+	}
+}
+
+void
+pnfs_destroy_layout(struct nfs_inode *nfsi)
+{
+	struct pnfs_layout_hdr *lo;
+	LIST_HEAD(tmp_list);
+
+	spin_lock(&nfsi->vfs_inode.i_lock);
+	lo = nfsi->layout;
+	if (lo) {
+		lo->plh_block_lgets++; /* permanently block new LAYOUTGETs */
+		mark_matching_lsegs_invalid(lo, &tmp_list, NULL);
+	}
+	spin_unlock(&nfsi->vfs_inode.i_lock);
+	pnfs_free_lseg_list(&tmp_list);
+}
+
+/*
+ * Called by the state manger to remove all layouts established under an
+ * expired lease.
+ */
+void
+pnfs_destroy_all_layouts(struct nfs_client *clp)
+{
+	struct nfs_server *server;
+	struct pnfs_layout_hdr *lo;
+	LIST_HEAD(tmp_list);
+
+	nfs4_deviceid_mark_client_invalid(clp);
+	nfs4_deviceid_purge_client(clp);
+
+	spin_lock(&clp->cl_lock);
+	rcu_read_lock();
+	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
+		if (!list_empty(&server->layouts))
+			list_splice_init(&server->layouts, &tmp_list);
+	}
+	rcu_read_unlock();
+	spin_unlock(&clp->cl_lock);
+
+	while (!list_empty(&tmp_list)) {
+		lo = list_entry(tmp_list.next, struct pnfs_layout_hdr,
+				plh_layouts);
+		dprintk("%s freeing layout for inode %lu\n", __func__,
+			lo->plh_inode->i_ino);
+		list_del_init(&lo->plh_layouts);
+		pnfs_destroy_layout(NFS_I(lo->plh_inode));
+	}
+}
+
+/* update lo->plh_stateid with new if is more recent */
+void
+pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, const nfs4_stateid *new,
+			bool update_barrier)
+{
+	u32 oldseq, newseq;
+
+	oldseq = be32_to_cpu(lo->plh_stateid.seqid);
+	newseq = be32_to_cpu(new->seqid);
+	if ((int)(newseq - oldseq) > 0) {
+		nfs4_stateid_copy(&lo->plh_stateid, new);
+		if (update_barrier) {
+			u32 new_barrier = be32_to_cpu(new->seqid);
+
+			if ((int)(new_barrier - lo->plh_barrier))
+				lo->plh_barrier = new_barrier;
+		} else {
+			/* Because of wraparound, we want to keep the barrier
+			 * "close" to the current seqids.  It needs to be
+			 * within 2**31 to count as "behind", so if it
+			 * gets too near that limit, give us a litle leeway
+			 * and bring it to within 2**30.
+			 * NOTE - and yes, this is all unsigned arithmetic.
+			 */
+			if (unlikely((newseq - lo->plh_barrier) > (3 << 29)))
+				lo->plh_barrier = newseq - (1 << 30);
+		}
+	}
+}
+
+/* lget is set to 1 if called from inside send_layoutget call chain */
+static bool
+pnfs_layoutgets_blocked(struct pnfs_layout_hdr *lo, nfs4_stateid *stateid,
+			int lget)
+{
+	if ((stateid) &&
+	    (int)(lo->plh_barrier - be32_to_cpu(stateid->seqid)) >= 0)
+		return true;
+	return lo->plh_block_lgets ||
+		test_bit(NFS_LAYOUT_DESTROYED, &lo->plh_flags) ||
+		test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags) ||
+		(list_empty(&lo->plh_segs) &&
+		 (atomic_read(&lo->plh_outstanding) > lget));
+}
+
+int
+pnfs_choose_layoutget_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo,
+			      struct nfs4_state *open_state)
+{
+	int status = 0;
+
+	dprintk("--> %s\n", __func__);
+	spin_lock(&lo->plh_inode->i_lock);
+	if (pnfs_layoutgets_blocked(lo, NULL, 1)) {
+		status = -EAGAIN;
+	} else if (list_empty(&lo->plh_segs)) {
+		int seq;
+
+		do {
+			seq = read_seqbegin(&open_state->seqlock);
+			nfs4_stateid_copy(dst, &open_state->stateid);
+		} while (read_seqretry(&open_state->seqlock, seq));
+	} else
+		nfs4_stateid_copy(dst, &lo->plh_stateid);
+	spin_unlock(&lo->plh_inode->i_lock);
+	dprintk("<-- %s\n", __func__);
+	return status;
+}
+
+/*
+* Get layout from server.
+*    for now, assume that whole file layouts are requested.
+*    arg->offset: 0
+*    arg->length: all ones
+*/
+static struct pnfs_layout_segment *
+send_layoutget(struct pnfs_layout_hdr *lo,
+	   struct nfs_open_context *ctx,
+	   struct pnfs_layout_range *range,
+	   gfp_t gfp_flags)
+{
+	struct inode *ino = lo->plh_inode;
+	struct nfs_server *server = NFS_SERVER(ino);
+	struct nfs4_layoutget *lgp;
+	struct pnfs_layout_segment *lseg = NULL;
+
+	dprintk("--> %s\n", __func__);
+
+	BUG_ON(ctx == NULL);
+	lgp = kzalloc(sizeof(*lgp), gfp_flags);
+	if (lgp == NULL)
+		return NULL;
+
+	lgp->args.minlength = PAGE_CACHE_SIZE;
+	if (lgp->args.minlength > range->length)
+		lgp->args.minlength = range->length;
+	lgp->args.maxcount = PNFS_LAYOUT_MAXSIZE;
+	lgp->args.range = *range;
+	lgp->args.type = server->pnfs_curr_ld->id;
+	lgp->args.inode = ino;
+	lgp->args.ctx = get_nfs_open_context(ctx);
+	lgp->lsegpp = &lseg;
+	lgp->gfp_flags = gfp_flags;
+
+	/* Synchronously retrieve layout information from server and
+	 * store in lseg.
+	 */
+	nfs4_proc_layoutget(lgp, gfp_flags);
+	if (!lseg) {
+		/* remember that LAYOUTGET failed and suspend trying */
+		set_bit(lo_fail_bit(range->iomode), &lo->plh_flags);
+	}
+
+	return lseg;
+}
+
+/* Initiates a LAYOUTRETURN(FILE) */
+int
+_pnfs_return_layout(struct inode *ino)
+{
+	struct pnfs_layout_hdr *lo = NULL;
+	struct nfs_inode *nfsi = NFS_I(ino);
+	LIST_HEAD(tmp_list);
+	struct nfs4_layoutreturn *lrp;
+	nfs4_stateid stateid;
+	int status = 0;
+
+	dprintk("--> %s\n", __func__);
+
+	spin_lock(&ino->i_lock);
+	lo = nfsi->layout;
+	if (!lo) {
+		spin_unlock(&ino->i_lock);
+		dprintk("%s: no layout to return\n", __func__);
+		return status;
+	}
+	stateid = nfsi->layout->plh_stateid;
+	/* Reference matched in nfs4_layoutreturn_release */
+	get_layout_hdr(lo);
+	mark_matching_lsegs_invalid(lo, &tmp_list, NULL);
+	lo->plh_block_lgets++;
+	spin_unlock(&ino->i_lock);
+	pnfs_free_lseg_list(&tmp_list);
+
+	WARN_ON(test_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags));
+
+	lrp = kzalloc(sizeof(*lrp), GFP_KERNEL);
+	if (unlikely(lrp == NULL)) {
+		status = -ENOMEM;
+		set_bit(NFS_LAYOUT_RW_FAILED, &lo->plh_flags);
+		set_bit(NFS_LAYOUT_RO_FAILED, &lo->plh_flags);
+		put_layout_hdr(lo);
+		goto out;
+	}
+
+	lrp->args.stateid = stateid;
+	lrp->args.layout_type = NFS_SERVER(ino)->pnfs_curr_ld->id;
+	lrp->args.inode = ino;
+	lrp->args.layout = lo;
+	lrp->clp = NFS_SERVER(ino)->nfs_client;
+
+	status = nfs4_proc_layoutreturn(lrp);
+out:
+	dprintk("<-- %s status: %d\n", __func__, status);
+	return status;
+}
+
+bool pnfs_roc(struct inode *ino)
+{
+	struct pnfs_layout_hdr *lo;
+	struct pnfs_layout_segment *lseg, *tmp;
+	LIST_HEAD(tmp_list);
+	bool found = false;
+
+	spin_lock(&ino->i_lock);
+	lo = NFS_I(ino)->layout;
+	if (!lo || !test_and_clear_bit(NFS_LAYOUT_ROC, &lo->plh_flags) ||
+	    test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags))
+		goto out_nolayout;
+	list_for_each_entry_safe(lseg, tmp, &lo->plh_segs, pls_list)
+		if (test_bit(NFS_LSEG_ROC, &lseg->pls_flags)) {
+			mark_lseg_invalid(lseg, &tmp_list);
+			found = true;
+		}
+	if (!found)
+		goto out_nolayout;
+	lo->plh_block_lgets++;
+	get_layout_hdr(lo); /* matched in pnfs_roc_release */
+	spin_unlock(&ino->i_lock);
+	pnfs_free_lseg_list(&tmp_list);
+	return true;
+
+out_nolayout:
+	spin_unlock(&ino->i_lock);
+	return false;
+}
+
+void pnfs_roc_release(struct inode *ino)
+{
+	struct pnfs_layout_hdr *lo;
+
+	spin_lock(&ino->i_lock);
+	lo = NFS_I(ino)->layout;
+	lo->plh_block_lgets--;
+	put_layout_hdr_locked(lo);
+	spin_unlock(&ino->i_lock);
+}
+
+void pnfs_roc_set_barrier(struct inode *ino, u32 barrier)
+{
+	struct pnfs_layout_hdr *lo;
+
+	spin_lock(&ino->i_lock);
+	lo = NFS_I(ino)->layout;
+	if ((int)(barrier - lo->plh_barrier) > 0)
+		lo->plh_barrier = barrier;
+	spin_unlock(&ino->i_lock);
+}
+
+bool pnfs_roc_drain(struct inode *ino, u32 *barrier)
+{
+	struct nfs_inode *nfsi = NFS_I(ino);
+	struct pnfs_layout_segment *lseg;
+	bool found = false;
+
+	spin_lock(&ino->i_lock);
+	list_for_each_entry(lseg, &nfsi->layout->plh_segs, pls_list)
+		if (test_bit(NFS_LSEG_ROC, &lseg->pls_flags)) {
+			found = true;
+			break;
+		}
+	if (!found) {
+		struct pnfs_layout_hdr *lo = nfsi->layout;
+		u32 current_seqid = be32_to_cpu(lo->plh_stateid.seqid);
+
+		/* Since close does not return a layout stateid for use as
+		 * a barrier, we choose the worst-case barrier.
+		 */
+		*barrier = current_seqid + atomic_read(&lo->plh_outstanding);
+	}
+	spin_unlock(&ino->i_lock);
+	return found;
+}
+
+/*
+ * Compare two layout segments for sorting into layout cache.
+ * We want to preferentially return RW over RO layouts, so ensure those
+ * are seen first.
+ */
+static s64
+cmp_layout(struct pnfs_layout_range *l1,
+	   struct pnfs_layout_range *l2)
+{
+	s64 d;
+
+	/* high offset > low offset */
+	d = l1->offset - l2->offset;
+	if (d)
+		return d;
+
+	/* short length > long length */
+	d = l2->length - l1->length;
+	if (d)
+		return d;
+
+	/* read > read/write */
+	return (int)(l1->iomode == IOMODE_READ) - (int)(l2->iomode == IOMODE_READ);
+}
+
+static void
+pnfs_insert_layout(struct pnfs_layout_hdr *lo,
+		   struct pnfs_layout_segment *lseg)
+{
+	struct pnfs_layout_segment *lp;
+
+	dprintk("%s:Begin\n", __func__);
+
+	assert_spin_locked(&lo->plh_inode->i_lock);
+	list_for_each_entry(lp, &lo->plh_segs, pls_list) {
+		if (cmp_layout(&lseg->pls_range, &lp->pls_range) > 0)
+			continue;
+		list_add_tail(&lseg->pls_list, &lp->pls_list);
+		dprintk("%s: inserted lseg %p "
+			"iomode %d offset %llu length %llu before "
+			"lp %p iomode %d offset %llu length %llu\n",
+			__func__, lseg, lseg->pls_range.iomode,
+			lseg->pls_range.offset, lseg->pls_range.length,
+			lp, lp->pls_range.iomode, lp->pls_range.offset,
+			lp->pls_range.length);
+		goto out;
+	}
+	list_add_tail(&lseg->pls_list, &lo->plh_segs);
+	dprintk("%s: inserted lseg %p "
+		"iomode %d offset %llu length %llu at tail\n",
+		__func__, lseg, lseg->pls_range.iomode,
+		lseg->pls_range.offset, lseg->pls_range.length);
+out:
+	get_layout_hdr(lo);
+
+	dprintk("%s:Return\n", __func__);
+}
+
+static struct pnfs_layout_hdr *
+alloc_init_layout_hdr(struct inode *ino,
+		      struct nfs_open_context *ctx,
+		      gfp_t gfp_flags)
+{
+	struct pnfs_layout_hdr *lo;
+
+	lo = pnfs_alloc_layout_hdr(ino, gfp_flags);
+	if (!lo)
+		return NULL;
+	atomic_set(&lo->plh_refcount, 1);
+	INIT_LIST_HEAD(&lo->plh_layouts);
+	INIT_LIST_HEAD(&lo->plh_segs);
+	INIT_LIST_HEAD(&lo->plh_bulk_recall);
+	lo->plh_inode = ino;
+	lo->plh_lc_cred = get_rpccred(ctx->state->owner->so_cred);
+	return lo;
+}
+
+static struct pnfs_layout_hdr *
+pnfs_find_alloc_layout(struct inode *ino,
+		       struct nfs_open_context *ctx,
+		       gfp_t gfp_flags)
+{
+	struct nfs_inode *nfsi = NFS_I(ino);
+	struct pnfs_layout_hdr *new = NULL;
+
+	dprintk("%s Begin ino=%p layout=%p\n", __func__, ino, nfsi->layout);
+
+	assert_spin_locked(&ino->i_lock);
+	if (nfsi->layout) {
+		if (test_bit(NFS_LAYOUT_DESTROYED, &nfsi->layout->plh_flags))
+			return NULL;
+		else
+			return nfsi->layout;
+	}
+	spin_unlock(&ino->i_lock);
+	new = alloc_init_layout_hdr(ino, ctx, gfp_flags);
+	spin_lock(&ino->i_lock);
+
+	if (likely(nfsi->layout == NULL))	/* Won the race? */
+		nfsi->layout = new;
+	else
+		pnfs_free_layout_hdr(new);
+	return nfsi->layout;
+}
+
+/*
+ * iomode matching rules:
+ * iomode	lseg	match
+ * -----	-----	-----
+ * ANY		READ	true
+ * ANY		RW	true
+ * RW		READ	false
+ * RW		RW	true
+ * READ		READ	true
+ * READ		RW	true
+ */
+static int
+is_matching_lseg(struct pnfs_layout_range *ls_range,
+		 struct pnfs_layout_range *range)
+{
+	struct pnfs_layout_range range1;
+
+	if ((range->iomode == IOMODE_RW &&
+	     ls_range->iomode != IOMODE_RW) ||
+	    !lo_seg_intersecting(ls_range, range))
+		return 0;
+
+	/* range1 covers only the first byte in the range */
+	range1 = *range;
+	range1.length = 1;
+	return lo_seg_contained(ls_range, &range1);
+}
+
+/*
+ * lookup range in layout
+ */
+static struct pnfs_layout_segment *
+pnfs_find_lseg(struct pnfs_layout_hdr *lo,
+		struct pnfs_layout_range *range)
+{
+	struct pnfs_layout_segment *lseg, *ret = NULL;
+
+	dprintk("%s:Begin\n", __func__);
+
+	assert_spin_locked(&lo->plh_inode->i_lock);
+	list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
+		if (test_bit(NFS_LSEG_VALID, &lseg->pls_flags) &&
+		    is_matching_lseg(&lseg->pls_range, range)) {
+			ret = get_lseg(lseg);
+			break;
+		}
+		if (lseg->pls_range.offset > range->offset)
+			break;
+	}
+
+	dprintk("%s:Return lseg %p ref %d\n",
+		__func__, ret, ret ? atomic_read(&ret->pls_refcount) : 0);
+	return ret;
+}
+
+/*
+ * Layout segment is retreived from the server if not cached.
+ * The appropriate layout segment is referenced and returned to the caller.
+ */
+struct pnfs_layout_segment *
+pnfs_update_layout(struct inode *ino,
+		   struct nfs_open_context *ctx,
+		   loff_t pos,
+		   u64 count,
+		   enum pnfs_iomode iomode,
+		   gfp_t gfp_flags)
+{
+	struct pnfs_layout_range arg = {
+		.iomode = iomode,
+		.offset = pos,
+		.length = count,
+	};
+	unsigned pg_offset;
+	struct nfs_inode *nfsi = NFS_I(ino);
+	struct nfs_server *server = NFS_SERVER(ino);
+	struct nfs_client *clp = server->nfs_client;
+	struct pnfs_layout_hdr *lo;
+	struct pnfs_layout_segment *lseg = NULL;
+	bool first = false;
+
+	if (!pnfs_enabled_sb(NFS_SERVER(ino)))
+		return NULL;
+	spin_lock(&ino->i_lock);
+	lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags);
+	if (lo == NULL) {
+		dprintk("%s ERROR: can't get pnfs_layout_hdr\n", __func__);
+		goto out_unlock;
+	}
+
+	/* Do we even need to bother with this? */
+	if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
+		dprintk("%s matches recall, use MDS\n", __func__);
+		goto out_unlock;
+	}
+
+	/* if LAYOUTGET already failed once we don't try again */
+	if (test_bit(lo_fail_bit(iomode), &nfsi->layout->plh_flags))
+		goto out_unlock;
+
+	/* Check to see if the layout for the given range already exists */
+	lseg = pnfs_find_lseg(lo, &arg);
+	if (lseg)
+		goto out_unlock;
+
+	if (pnfs_layoutgets_blocked(lo, NULL, 0))
+		goto out_unlock;
+	atomic_inc(&lo->plh_outstanding);
+
+	get_layout_hdr(lo);
+	if (list_empty(&lo->plh_segs))
+		first = true;
+	spin_unlock(&ino->i_lock);
+	if (first) {
+		/* The lo must be on the clp list if there is any
+		 * chance of a CB_LAYOUTRECALL(FILE) coming in.
+		 */
+		spin_lock(&clp->cl_lock);
+		BUG_ON(!list_empty(&lo->plh_layouts));
+		list_add_tail(&lo->plh_layouts, &server->layouts);
+		spin_unlock(&clp->cl_lock);
+	}
+
+	pg_offset = arg.offset & ~PAGE_CACHE_MASK;
+	if (pg_offset) {
+		arg.offset -= pg_offset;
+		arg.length += pg_offset;
+	}
+	if (arg.length != NFS4_MAX_UINT64)
+		arg.length = PAGE_CACHE_ALIGN(arg.length);
+
+	lseg = send_layoutget(lo, ctx, &arg, gfp_flags);
+	if (!lseg && first) {
+		spin_lock(&clp->cl_lock);
+		list_del_init(&lo->plh_layouts);
+		spin_unlock(&clp->cl_lock);
+	}
+	atomic_dec(&lo->plh_outstanding);
+	put_layout_hdr(lo);
+out:
+	dprintk("%s end, state 0x%lx lseg %p\n", __func__,
+		nfsi->layout ? nfsi->layout->plh_flags : -1, lseg);
+	return lseg;
+out_unlock:
+	spin_unlock(&ino->i_lock);
+	goto out;
+}
+EXPORT_SYMBOL_GPL(pnfs_update_layout);
+
+int
+pnfs_layout_process(struct nfs4_layoutget *lgp)
+{
+	struct pnfs_layout_hdr *lo = NFS_I(lgp->args.inode)->layout;
+	struct nfs4_layoutget_res *res = &lgp->res;
+	struct pnfs_layout_segment *lseg;
+	struct inode *ino = lo->plh_inode;
+	int status = 0;
+
+	/* Inject layout blob into I/O device driver */
+	lseg = NFS_SERVER(ino)->pnfs_curr_ld->alloc_lseg(lo, res, lgp->gfp_flags);
+	if (!lseg || IS_ERR(lseg)) {
+		if (!lseg)
+			status = -ENOMEM;
+		else
+			status = PTR_ERR(lseg);
+		dprintk("%s: Could not allocate layout: error %d\n",
+		       __func__, status);
+		goto out;
+	}
+
+	spin_lock(&ino->i_lock);
+	if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
+		dprintk("%s forget reply due to recall\n", __func__);
+		goto out_forget_reply;
+	}
+
+	if (pnfs_layoutgets_blocked(lo, &res->stateid, 1)) {
+		dprintk("%s forget reply due to state\n", __func__);
+		goto out_forget_reply;
+	}
+	init_lseg(lo, lseg);
+	lseg->pls_range = res->range;
+	*lgp->lsegpp = get_lseg(lseg);
+	pnfs_insert_layout(lo, lseg);
+
+	if (res->return_on_close) {
+		set_bit(NFS_LSEG_ROC, &lseg->pls_flags);
+		set_bit(NFS_LAYOUT_ROC, &lo->plh_flags);
+	}
+
+	/* Done processing layoutget. Set the layout stateid */
+	pnfs_set_layout_stateid(lo, &res->stateid, false);
+	spin_unlock(&ino->i_lock);
+out:
+	return status;
+
+out_forget_reply:
+	spin_unlock(&ino->i_lock);
+	lseg->pls_layout = lo;
+	NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
+	goto out;
+}
+
+void
+pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
+{
+	BUG_ON(pgio->pg_lseg != NULL);
+
+	pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
+					   req->wb_context,
+					   req_offset(req),
+					   req->wb_bytes,
+					   IOMODE_READ,
+					   GFP_KERNEL);
+	/* If no lseg, fall back to read through mds */
+	if (pgio->pg_lseg == NULL)
+		nfs_pageio_reset_read_mds(pgio);
+
+}
+EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_read);
+
+void
+pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
+{
+	BUG_ON(pgio->pg_lseg != NULL);
+
+	pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
+					   req->wb_context,
+					   req_offset(req),
+					   req->wb_bytes,
+					   IOMODE_RW,
+					   GFP_NOFS);
+	/* If no lseg, fall back to write through mds */
+	if (pgio->pg_lseg == NULL)
+		nfs_pageio_reset_write_mds(pgio);
+}
+EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_write);
+
+bool
+pnfs_pageio_init_read(struct nfs_pageio_descriptor *pgio, struct inode *inode)
+{
+	struct nfs_server *server = NFS_SERVER(inode);
+	struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
+
+	if (ld == NULL)
+		return false;
+	nfs_pageio_init(pgio, inode, ld->pg_read_ops, server->rsize, 0);
+	return true;
+}
+
+bool
+pnfs_pageio_init_write(struct nfs_pageio_descriptor *pgio, struct inode *inode, int ioflags)
+{
+	struct nfs_server *server = NFS_SERVER(inode);
+	struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
+
+	if (ld == NULL)
+		return false;
+	nfs_pageio_init(pgio, inode, ld->pg_write_ops, server->wsize, ioflags);
+	return true;
+}
+
+bool
+pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
+		     struct nfs_page *req)
+{
+	if (pgio->pg_lseg == NULL)
+		return nfs_generic_pg_test(pgio, prev, req);
+
+	/*
+	 * Test if a nfs_page is fully contained in the pnfs_layout_range.
+	 * Note that this test makes several assumptions:
+	 * - that the previous nfs_page in the struct nfs_pageio_descriptor
+	 *   is known to lie within the range.
+	 *   - that the nfs_page being tested is known to be contiguous with the
+	 *   previous nfs_page.
+	 *   - Layout ranges are page aligned, so we only have to test the
+	 *   start offset of the request.
+	 *
+	 * Please also note that 'end_offset' is actually the offset of the
+	 * first byte that lies outside the pnfs_layout_range. FIXME?
+	 *
+	 */
+	return req_offset(req) < end_offset(pgio->pg_lseg->pls_range.offset,
+					 pgio->pg_lseg->pls_range.length);
+}
+EXPORT_SYMBOL_GPL(pnfs_generic_pg_test);
+
+static int pnfs_write_done_resend_to_mds(struct inode *inode, struct list_head *head)
+{
+	struct nfs_pageio_descriptor pgio;
+	LIST_HEAD(failed);
+
+	/* Resend all requests through the MDS */
+	nfs_pageio_init_write_mds(&pgio, inode, FLUSH_STABLE);
+	while (!list_empty(head)) {
+		struct nfs_page *req = nfs_list_entry(head->next);
+
+		nfs_list_remove_request(req);
+		if (!nfs_pageio_add_request(&pgio, req))
+			nfs_list_add_request(req, &failed);
+	}
+	nfs_pageio_complete(&pgio);
+
+	if (!list_empty(&failed)) {
+		/* For some reason our attempt to resend pages. Mark the
+		 * overall send request as having failed, and let
+		 * nfs_writeback_release_full deal with the error.
+		 */
+		list_move(&failed, head);
+		return -EIO;
+	}
+	return 0;
+}
+
+/*
+ * Called by non rpc-based layout drivers
+ */
+void pnfs_ld_write_done(struct nfs_write_data *data)
+{
+	if (likely(!data->pnfs_error)) {
+		pnfs_set_layoutcommit(data);
+		data->mds_ops->rpc_call_done(&data->task, data);
+	} else {
+		dprintk("pnfs write error = %d\n", data->pnfs_error);
+		if (NFS_SERVER(data->inode)->pnfs_curr_ld->flags &
+						PNFS_LAYOUTRET_ON_ERROR) {
+			/* Don't lo_commit on error, Server will needs to
+			 * preform a file recovery.
+			 */
+			clear_bit(NFS_INO_LAYOUTCOMMIT,
+				  &NFS_I(data->inode)->flags);
+			pnfs_return_layout(data->inode);
+		}
+		data->task.tk_status = pnfs_write_done_resend_to_mds(data->inode, &data->pages);
+	}
+	put_lseg(data->lseg);
+	data->mds_ops->rpc_release(data);
+}
+EXPORT_SYMBOL_GPL(pnfs_ld_write_done);
+
+static void
+pnfs_write_through_mds(struct nfs_pageio_descriptor *desc,
+		struct nfs_write_data *data)
+{
+	list_splice_tail_init(&data->pages, &desc->pg_list);
+	if (data->req && list_empty(&data->req->wb_list))
+		nfs_list_add_request(data->req, &desc->pg_list);
+	nfs_pageio_reset_write_mds(desc);
+	desc->pg_recoalesce = 1;
+	put_lseg(data->lseg);
+	nfs_writedata_release(data);
+}
+
+static enum pnfs_try_status
+pnfs_try_to_write_data(struct nfs_write_data *wdata,
+			const struct rpc_call_ops *call_ops,
+			struct pnfs_layout_segment *lseg,
+			int how)
+{
+	struct inode *inode = wdata->inode;
+	enum pnfs_try_status trypnfs;
+	struct nfs_server *nfss = NFS_SERVER(inode);
+
+	wdata->mds_ops = call_ops;
+	wdata->lseg = get_lseg(lseg);
+
+	dprintk("%s: Writing ino:%lu %u@%llu (how %d)\n", __func__,
+		inode->i_ino, wdata->args.count, wdata->args.offset, how);
+
+	trypnfs = nfss->pnfs_curr_ld->write_pagelist(wdata, how);
+	if (trypnfs == PNFS_NOT_ATTEMPTED) {
+		put_lseg(wdata->lseg);
+		wdata->lseg = NULL;
+	} else
+		nfs_inc_stats(inode, NFSIOS_PNFS_WRITE);
+
+	dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
+	return trypnfs;
+}
+
+static void
+pnfs_do_multiple_writes(struct nfs_pageio_descriptor *desc, struct list_head *head, int how)
+{
+	struct nfs_write_data *data;
+	const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
+	struct pnfs_layout_segment *lseg = desc->pg_lseg;
+
+	desc->pg_lseg = NULL;
+	while (!list_empty(head)) {
+		enum pnfs_try_status trypnfs;
+
+		data = list_entry(head->next, struct nfs_write_data, list);
+		list_del_init(&data->list);
+
+		trypnfs = pnfs_try_to_write_data(data, call_ops, lseg, how);
+		if (trypnfs == PNFS_NOT_ATTEMPTED)
+			pnfs_write_through_mds(desc, data);
+	}
+	put_lseg(lseg);
+}
+
+int
+pnfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
+{
+	LIST_HEAD(head);
+	int ret;
+
+	ret = nfs_generic_flush(desc, &head);
+	if (ret != 0) {
+		put_lseg(desc->pg_lseg);
+		desc->pg_lseg = NULL;
+		return ret;
+	}
+	pnfs_do_multiple_writes(desc, &head, desc->pg_ioflags);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pnfs_generic_pg_writepages);
+
+static void pnfs_ld_handle_read_error(struct nfs_read_data *data)
+{
+	struct nfs_pageio_descriptor pgio;
+
+	put_lseg(data->lseg);
+	data->lseg = NULL;
+	dprintk("pnfs write error = %d\n", data->pnfs_error);
+	if (NFS_SERVER(data->inode)->pnfs_curr_ld->flags &
+						PNFS_LAYOUTRET_ON_ERROR)
+		pnfs_return_layout(data->inode);
+
+	nfs_pageio_init_read_mds(&pgio, data->inode);
+
+	while (!list_empty(&data->pages)) {
+		struct nfs_page *req = nfs_list_entry(data->pages.next);
+
+		nfs_list_remove_request(req);
+		nfs_pageio_add_request(&pgio, req);
+	}
+	nfs_pageio_complete(&pgio);
+}
+
+/*
+ * Called by non rpc-based layout drivers
+ */
+void pnfs_ld_read_done(struct nfs_read_data *data)
+{
+	if (likely(!data->pnfs_error)) {
+		__nfs4_read_done_cb(data);
+		data->mds_ops->rpc_call_done(&data->task, data);
+	} else
+		pnfs_ld_handle_read_error(data);
+	put_lseg(data->lseg);
+	data->mds_ops->rpc_release(data);
+}
+EXPORT_SYMBOL_GPL(pnfs_ld_read_done);
+
+static void
+pnfs_read_through_mds(struct nfs_pageio_descriptor *desc,
+		struct nfs_read_data *data)
+{
+	list_splice_tail_init(&data->pages, &desc->pg_list);
+	if (data->req && list_empty(&data->req->wb_list))
+		nfs_list_add_request(data->req, &desc->pg_list);
+	nfs_pageio_reset_read_mds(desc);
+	desc->pg_recoalesce = 1;
+	nfs_readdata_release(data);
+}
+
+/*
+ * Call the appropriate parallel I/O subsystem read function.
+ */
+static enum pnfs_try_status
+pnfs_try_to_read_data(struct nfs_read_data *rdata,
+		       const struct rpc_call_ops *call_ops,
+		       struct pnfs_layout_segment *lseg)
+{
+	struct inode *inode = rdata->inode;
+	struct nfs_server *nfss = NFS_SERVER(inode);
+	enum pnfs_try_status trypnfs;
+
+	rdata->mds_ops = call_ops;
+	rdata->lseg = get_lseg(lseg);
+
+	dprintk("%s: Reading ino:%lu %u@%llu\n",
+		__func__, inode->i_ino, rdata->args.count, rdata->args.offset);
+
+	trypnfs = nfss->pnfs_curr_ld->read_pagelist(rdata);
+	if (trypnfs == PNFS_NOT_ATTEMPTED) {
+		put_lseg(rdata->lseg);
+		rdata->lseg = NULL;
+	} else {
+		nfs_inc_stats(inode, NFSIOS_PNFS_READ);
+	}
+	dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
+	return trypnfs;
+}
+
+static void
+pnfs_do_multiple_reads(struct nfs_pageio_descriptor *desc, struct list_head *head)
+{
+	struct nfs_read_data *data;
+	const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
+	struct pnfs_layout_segment *lseg = desc->pg_lseg;
+
+	desc->pg_lseg = NULL;
+	while (!list_empty(head)) {
+		enum pnfs_try_status trypnfs;
+
+		data = list_entry(head->next, struct nfs_read_data, list);
+		list_del_init(&data->list);
+
+		trypnfs = pnfs_try_to_read_data(data, call_ops, lseg);
+		if (trypnfs == PNFS_NOT_ATTEMPTED)
+			pnfs_read_through_mds(desc, data);
+	}
+	put_lseg(lseg);
+}
+
+int
+pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
+{
+	LIST_HEAD(head);
+	int ret;
+
+	ret = nfs_generic_pagein(desc, &head);
+	if (ret != 0) {
+		put_lseg(desc->pg_lseg);
+		desc->pg_lseg = NULL;
+		return ret;
+	}
+	pnfs_do_multiple_reads(desc, &head);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pnfs_generic_pg_readpages);
+
+/*
+ * There can be multiple RW segments.
+ */
+static void pnfs_list_write_lseg(struct inode *inode, struct list_head *listp)
+{
+	struct pnfs_layout_segment *lseg;
+
+	list_for_each_entry(lseg, &NFS_I(inode)->layout->plh_segs, pls_list) {
+		if (lseg->pls_range.iomode == IOMODE_RW &&
+		    test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
+			list_add(&lseg->pls_lc_list, listp);
+	}
+}
+
+static void pnfs_list_write_lseg_done(struct inode *inode, struct list_head *listp)
+{
+	struct pnfs_layout_segment *lseg, *tmp;
+	unsigned long *bitlock = &NFS_I(inode)->flags;
+
+	/* Matched by references in pnfs_set_layoutcommit */
+	list_for_each_entry_safe(lseg, tmp, listp, pls_lc_list) {
+		list_del_init(&lseg->pls_lc_list);
+		put_lseg(lseg);
+	}
+
+	clear_bit_unlock(NFS_INO_LAYOUTCOMMITTING, bitlock);
+	smp_mb__after_clear_bit();
+	wake_up_bit(bitlock, NFS_INO_LAYOUTCOMMITTING);
+}
+
+void pnfs_set_lo_fail(struct pnfs_layout_segment *lseg)
+{
+	if (lseg->pls_range.iomode == IOMODE_RW) {
+		dprintk("%s Setting layout IOMODE_RW fail bit\n", __func__);
+		set_bit(lo_fail_bit(IOMODE_RW), &lseg->pls_layout->plh_flags);
+	} else {
+		dprintk("%s Setting layout IOMODE_READ fail bit\n", __func__);
+		set_bit(lo_fail_bit(IOMODE_READ), &lseg->pls_layout->plh_flags);
+	}
+}
+EXPORT_SYMBOL_GPL(pnfs_set_lo_fail);
+
+void
+pnfs_set_layoutcommit(struct nfs_write_data *wdata)
+{
+	struct nfs_inode *nfsi = NFS_I(wdata->inode);
+	loff_t end_pos = wdata->mds_offset + wdata->res.count;
+	bool mark_as_dirty = false;
+
+	spin_lock(&nfsi->vfs_inode.i_lock);
+	if (!test_and_set_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags)) {
+		mark_as_dirty = true;
+		dprintk("%s: Set layoutcommit for inode %lu ",
+			__func__, wdata->inode->i_ino);
+	}
+	if (!test_and_set_bit(NFS_LSEG_LAYOUTCOMMIT, &wdata->lseg->pls_flags)) {
+		/* references matched in nfs4_layoutcommit_release */
+		get_lseg(wdata->lseg);
+	}
+	if (end_pos > nfsi->layout->plh_lwb)
+		nfsi->layout->plh_lwb = end_pos;
+	spin_unlock(&nfsi->vfs_inode.i_lock);
+	dprintk("%s: lseg %p end_pos %llu\n",
+		__func__, wdata->lseg, nfsi->layout->plh_lwb);
+
+	/* if pnfs_layoutcommit_inode() runs between inode locks, the next one
+	 * will be a noop because NFS_INO_LAYOUTCOMMIT will not be set */
+	if (mark_as_dirty)
+		mark_inode_dirty_sync(wdata->inode);
+}
+EXPORT_SYMBOL_GPL(pnfs_set_layoutcommit);
+
+void pnfs_cleanup_layoutcommit(struct nfs4_layoutcommit_data *data)
+{
+	struct nfs_server *nfss = NFS_SERVER(data->args.inode);
+
+	if (nfss->pnfs_curr_ld->cleanup_layoutcommit)
+		nfss->pnfs_curr_ld->cleanup_layoutcommit(data);
+	pnfs_list_write_lseg_done(data->args.inode, &data->lseg_list);
+}
+
+/*
+ * For the LAYOUT4_NFSV4_1_FILES layout type, NFS_DATA_SYNC WRITEs and
+ * NFS_UNSTABLE WRITEs with a COMMIT to data servers must store enough
+ * data to disk to allow the server to recover the data if it crashes.
+ * LAYOUTCOMMIT is only needed when the NFL4_UFLG_COMMIT_THRU_MDS flag
+ * is off, and a COMMIT is sent to a data server, or
+ * if WRITEs to a data server return NFS_DATA_SYNC.
+ */
+int
+pnfs_layoutcommit_inode(struct inode *inode, bool sync)
+{
+	struct nfs4_layoutcommit_data *data;
+	struct nfs_inode *nfsi = NFS_I(inode);
+	loff_t end_pos;
+	int status = 0;
+
+	dprintk("--> %s inode %lu\n", __func__, inode->i_ino);
+
+	if (!test_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
+		return 0;
+
+	/* Note kzalloc ensures data->res.seq_res.sr_slot == NULL */
+	data = kzalloc(sizeof(*data), GFP_NOFS);
+	if (!data) {
+		status = -ENOMEM;
+		goto out;
+	}
+
+	if (!test_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
+		goto out_free;
+
+	if (test_and_set_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags)) {
+		if (!sync) {
+			status = -EAGAIN;
+			goto out_free;
+		}
+		status = wait_on_bit_lock(&nfsi->flags, NFS_INO_LAYOUTCOMMITTING,
+					nfs_wait_bit_killable, TASK_KILLABLE);
+		if (status)
+			goto out_free;
+	}
+
+	INIT_LIST_HEAD(&data->lseg_list);
+	spin_lock(&inode->i_lock);
+	if (!test_and_clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags)) {
+		clear_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags);
+		spin_unlock(&inode->i_lock);
+		wake_up_bit(&nfsi->flags, NFS_INO_LAYOUTCOMMITTING);
+		goto out_free;
+	}
+
+	pnfs_list_write_lseg(inode, &data->lseg_list);
+
+	end_pos = nfsi->layout->plh_lwb;
+	nfsi->layout->plh_lwb = 0;
+
+	nfs4_stateid_copy(&data->args.stateid, &nfsi->layout->plh_stateid);
+	spin_unlock(&inode->i_lock);
+
+	data->args.inode = inode;
+	data->cred = get_rpccred(nfsi->layout->plh_lc_cred);
+	nfs_fattr_init(&data->fattr);
+	data->args.bitmask = NFS_SERVER(inode)->cache_consistency_bitmask;
+	data->res.fattr = &data->fattr;
+	data->args.lastbytewritten = end_pos - 1;
+	data->res.server = NFS_SERVER(inode);
+
+	status = nfs4_proc_layoutcommit(data, sync);
+out:
+	if (status)
+		mark_inode_dirty_sync(inode);
+	dprintk("<-- %s status %d\n", __func__, status);
+	return status;
+out_free:
+	kfree(data);
+	goto out;
+}