From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Thu, 12 Feb 2015 21:50:21 +0000 (-0800)
Subject: Merge branch 'for-3.20/bdi' of git://git.kernel.dk/linux-block
X-Git-Tag: drm-fsl-dcu-for-next~3784
X-Git-Url: http://git.agner.ch/gitweb/?p=linux-drm-fsl-dcu.git;a=commitdiff_plain;h=6bec0035286119eefc32a5b1102127e6a4032cb2

Merge branch 'for-3.20/bdi' of git://git.kernel.dk/linux-block

Pull backing device changes from Jens Axboe:
 "This contains a cleanup of how the backing device is handled, in
  preparation for a rework of the life time rules.  In this part, the
  most important change is to split the unrelated nommu mmap flags from
  it, but also removing a backing_dev_info pointer from the
  address_space (and inode), and a cleanup of other various minor bits.

  Christoph did all the work here, I just fixed an oops with pages that
  have a swap backing.  Arnd fixed a missing export, and Oleg killed the
  lustre backing_dev_info from staging.  Last patch was from Al,
  unexporting parts that are now no longer needed outside"

* 'for-3.20/bdi' of git://git.kernel.dk/linux-block:
  Make super_blocks and sb_lock static
  mtd: export new mtd_mmap_capabilities
  fs: make inode_to_bdi() handle NULL inode
  staging/lustre/llite: get rid of backing_dev_info
  fs: remove default_backing_dev_info
  fs: don't reassign dirty inodes to default_backing_dev_info
  nfs: don't call bdi_unregister
  ceph: remove call to bdi_unregister
  fs: remove mapping->backing_dev_info
  fs: export inode_to_bdi and use it in favor of mapping->backing_dev_info
  nilfs2: set up s_bdi like the generic mount_bdev code
  block_dev: get bdev inode bdi directly from the block device
  block_dev: only write bdev inode on close
  fs: introduce f_op->mmap_capabilities for nommu mmap support
  fs: kill BDI_CAP_SWAP_BACKED
  fs: deduplicate noop_backing_dev_info
---

6bec0035286119eefc32a5b1102127e6a4032cb2
diff --cc fs/nfs/flexfilelayout/flexfilelayout.c
index f29fb7d7e8f8,000000000000..c22ecaa86c1c
mode 100644,000000..100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@@ -1,1574 -1,0 +1,1574 @@@
 +/*
 + * Module for pnfs flexfile layout driver.
 + *
 + * Copyright (c) 2014, Primary Data, Inc. All rights reserved.
 + *
 + * Tao Peng <bergwolf@primarydata.com>
 + */
 +
 +#include <linux/nfs_fs.h>
 +#include <linux/nfs_page.h>
 +#include <linux/module.h>
 +
 +#include <linux/sunrpc/metrics.h>
 +#include <linux/nfs_idmap.h>
 +
 +#include "flexfilelayout.h"
 +#include "../nfs4session.h"
 +#include "../internal.h"
 +#include "../delegation.h"
 +#include "../nfs4trace.h"
 +#include "../iostat.h"
 +#include "../nfs.h"
 +
 +#define NFSDBG_FACILITY         NFSDBG_PNFS_LD
 +
 +#define FF_LAYOUT_POLL_RETRY_MAX     (15*HZ)
 +
 +static struct pnfs_layout_hdr *
 +ff_layout_alloc_layout_hdr(struct inode *inode, gfp_t gfp_flags)
 +{
 +	struct nfs4_flexfile_layout *ffl;
 +
 +	ffl = kzalloc(sizeof(*ffl), gfp_flags);
 +	if (ffl) {
 +		INIT_LIST_HEAD(&ffl->error_list);
 +		return &ffl->generic_hdr;
 +	} else
 +		return NULL;
 +}
 +
 +static void
 +ff_layout_free_layout_hdr(struct pnfs_layout_hdr *lo)
 +{
 +	struct nfs4_ff_layout_ds_err *err, *n;
 +
 +	list_for_each_entry_safe(err, n, &FF_LAYOUT_FROM_HDR(lo)->error_list,
 +				 list) {
 +		list_del(&err->list);
 +		kfree(err);
 +	}
 +	kfree(FF_LAYOUT_FROM_HDR(lo));
 +}
 +
 +static int decode_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
 +{
 +	__be32 *p;
 +
 +	p = xdr_inline_decode(xdr, NFS4_STATEID_SIZE);
 +	if (unlikely(p == NULL))
 +		return -ENOBUFS;
 +	memcpy(stateid, p, NFS4_STATEID_SIZE);
 +	dprintk("%s: stateid id= [%x%x%x%x]\n", __func__,
 +		p[0], p[1], p[2], p[3]);
 +	return 0;
 +}
 +
 +static int decode_deviceid(struct xdr_stream *xdr, struct nfs4_deviceid *devid)
 +{
 +	__be32 *p;
 +
 +	p = xdr_inline_decode(xdr, NFS4_DEVICEID4_SIZE);
 +	if (unlikely(!p))
 +		return -ENOBUFS;
 +	memcpy(devid, p, NFS4_DEVICEID4_SIZE);
 +	nfs4_print_deviceid(devid);
 +	return 0;
 +}
 +
 +static int decode_nfs_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
 +{
 +	__be32 *p;
 +
 +	p = xdr_inline_decode(xdr, 4);
 +	if (unlikely(!p))
 +		return -ENOBUFS;
 +	fh->size = be32_to_cpup(p++);
 +	if (fh->size > sizeof(struct nfs_fh)) {
 +		printk(KERN_ERR "NFS flexfiles: Too big fh received %d\n",
 +		       fh->size);
 +		return -EOVERFLOW;
 +	}
 +	/* fh.data */
 +	p = xdr_inline_decode(xdr, fh->size);
 +	if (unlikely(!p))
 +		return -ENOBUFS;
 +	memcpy(&fh->data, p, fh->size);
 +	dprintk("%s: fh len %d\n", __func__, fh->size);
 +
 +	return 0;
 +}
 +
 +/*
 + * Currently only stringified uids and gids are accepted.
 + * I.e., kerberos is not supported to the DSes, so no pricipals.
 + *
 + * That means that one common function will suffice, but when
 + * principals are added, this should be split to accomodate
 + * calls to both nfs_map_name_to_uid() and nfs_map_group_to_gid().
 + */
 +static int
 +decode_name(struct xdr_stream *xdr, u32 *id)
 +{
 +	__be32 *p;
 +	int len;
 +
 +	/* opaque_length(4)*/
 +	p = xdr_inline_decode(xdr, 4);
 +	if (unlikely(!p))
 +		return -ENOBUFS;
 +	len = be32_to_cpup(p++);
 +	if (len < 0)
 +		return -EINVAL;
 +
 +	dprintk("%s: len %u\n", __func__, len);
 +
 +	/* opaque body */
 +	p = xdr_inline_decode(xdr, len);
 +	if (unlikely(!p))
 +		return -ENOBUFS;
 +
 +	if (!nfs_map_string_to_numeric((char *)p, len, id))
 +		return -EINVAL;
 +
 +	return 0;
 +}
 +
 +static void ff_layout_free_mirror_array(struct nfs4_ff_layout_segment *fls)
 +{
 +	int i;
 +
 +	if (fls->mirror_array) {
 +		for (i = 0; i < fls->mirror_array_cnt; i++) {
 +			/* normally mirror_ds is freed in
 +			 * .free_deviceid_node but we still do it here
 +			 * for .alloc_lseg error path */
 +			if (fls->mirror_array[i]) {
 +				kfree(fls->mirror_array[i]->fh_versions);
 +				nfs4_ff_layout_put_deviceid(fls->mirror_array[i]->mirror_ds);
 +				kfree(fls->mirror_array[i]);
 +			}
 +		}
 +		kfree(fls->mirror_array);
 +		fls->mirror_array = NULL;
 +	}
 +}
 +
 +static int ff_layout_check_layout(struct nfs4_layoutget_res *lgr)
 +{
 +	int ret = 0;
 +
 +	dprintk("--> %s\n", __func__);
 +
 +	/* FIXME: remove this check when layout segment support is added */
 +	if (lgr->range.offset != 0 ||
 +	    lgr->range.length != NFS4_MAX_UINT64) {
 +		dprintk("%s Only whole file layouts supported. Use MDS i/o\n",
 +			__func__);
 +		ret = -EINVAL;
 +	}
 +
 +	dprintk("--> %s returns %d\n", __func__, ret);
 +	return ret;
 +}
 +
 +static void _ff_layout_free_lseg(struct nfs4_ff_layout_segment *fls)
 +{
 +	if (fls) {
 +		ff_layout_free_mirror_array(fls);
 +		kfree(fls);
 +	}
 +}
 +
 +static void ff_layout_sort_mirrors(struct nfs4_ff_layout_segment *fls)
 +{
 +	struct nfs4_ff_layout_mirror *tmp;
 +	int i, j;
 +
 +	for (i = 0; i < fls->mirror_array_cnt - 1; i++) {
 +		for (j = i + 1; j < fls->mirror_array_cnt; j++)
 +			if (fls->mirror_array[i]->efficiency <
 +			    fls->mirror_array[j]->efficiency) {
 +				tmp = fls->mirror_array[i];
 +				fls->mirror_array[i] = fls->mirror_array[j];
 +				fls->mirror_array[j] = tmp;
 +			}
 +	}
 +}
 +
 +static struct pnfs_layout_segment *
 +ff_layout_alloc_lseg(struct pnfs_layout_hdr *lh,
 +		     struct nfs4_layoutget_res *lgr,
 +		     gfp_t gfp_flags)
 +{
 +	struct pnfs_layout_segment *ret;
 +	struct nfs4_ff_layout_segment *fls = NULL;
 +	struct xdr_stream stream;
 +	struct xdr_buf buf;
 +	struct page *scratch;
 +	u64 stripe_unit;
 +	u32 mirror_array_cnt;
 +	__be32 *p;
 +	int i, rc;
 +
 +	dprintk("--> %s\n", __func__);
 +	scratch = alloc_page(gfp_flags);
 +	if (!scratch)
 +		return ERR_PTR(-ENOMEM);
 +
 +	xdr_init_decode_pages(&stream, &buf, lgr->layoutp->pages,
 +			      lgr->layoutp->len);
 +	xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
 +
 +	/* stripe unit and mirror_array_cnt */
 +	rc = -EIO;
 +	p = xdr_inline_decode(&stream, 8 + 4);
 +	if (!p)
 +		goto out_err_free;
 +
 +	p = xdr_decode_hyper(p, &stripe_unit);
 +	mirror_array_cnt = be32_to_cpup(p++);
 +	dprintk("%s: stripe_unit=%llu mirror_array_cnt=%u\n", __func__,
 +		stripe_unit, mirror_array_cnt);
 +
 +	if (mirror_array_cnt > NFS4_FLEXFILE_LAYOUT_MAX_MIRROR_CNT ||
 +	    mirror_array_cnt == 0)
 +		goto out_err_free;
 +
 +	rc = -ENOMEM;
 +	fls = kzalloc(sizeof(*fls), gfp_flags);
 +	if (!fls)
 +		goto out_err_free;
 +
 +	fls->mirror_array_cnt = mirror_array_cnt;
 +	fls->stripe_unit = stripe_unit;
 +	fls->mirror_array = kcalloc(fls->mirror_array_cnt,
 +				    sizeof(fls->mirror_array[0]), gfp_flags);
 +	if (fls->mirror_array == NULL)
 +		goto out_err_free;
 +
 +	for (i = 0; i < fls->mirror_array_cnt; i++) {
 +		struct nfs4_deviceid devid;
 +		struct nfs4_deviceid_node *idnode;
 +		u32 ds_count;
 +		u32 fh_count;
 +		int j;
 +
 +		rc = -EIO;
 +		p = xdr_inline_decode(&stream, 4);
 +		if (!p)
 +			goto out_err_free;
 +		ds_count = be32_to_cpup(p);
 +
 +		/* FIXME: allow for striping? */
 +		if (ds_count != 1)
 +			goto out_err_free;
 +
 +		fls->mirror_array[i] =
 +			kzalloc(sizeof(struct nfs4_ff_layout_mirror),
 +				gfp_flags);
 +		if (fls->mirror_array[i] == NULL) {
 +			rc = -ENOMEM;
 +			goto out_err_free;
 +		}
 +
 +		spin_lock_init(&fls->mirror_array[i]->lock);
 +		fls->mirror_array[i]->ds_count = ds_count;
 +
 +		/* deviceid */
 +		rc = decode_deviceid(&stream, &devid);
 +		if (rc)
 +			goto out_err_free;
 +
 +		idnode = nfs4_find_get_deviceid(NFS_SERVER(lh->plh_inode),
 +						&devid, lh->plh_lc_cred,
 +						gfp_flags);
 +		/*
 +		 * upon success, mirror_ds is allocated by previous
 +		 * getdeviceinfo, or newly by .alloc_deviceid_node
 +		 * nfs4_find_get_deviceid failure is indeed getdeviceinfo falure
 +		 */
 +		if (idnode)
 +			fls->mirror_array[i]->mirror_ds =
 +				FF_LAYOUT_MIRROR_DS(idnode);
 +		else
 +			goto out_err_free;
 +
 +		/* efficiency */
 +		rc = -EIO;
 +		p = xdr_inline_decode(&stream, 4);
 +		if (!p)
 +			goto out_err_free;
 +		fls->mirror_array[i]->efficiency = be32_to_cpup(p);
 +
 +		/* stateid */
 +		rc = decode_stateid(&stream, &fls->mirror_array[i]->stateid);
 +		if (rc)
 +			goto out_err_free;
 +
 +		/* fh */
 +		p = xdr_inline_decode(&stream, 4);
 +		if (!p)
 +			goto out_err_free;
 +		fh_count = be32_to_cpup(p);
 +
 +		fls->mirror_array[i]->fh_versions =
 +			kzalloc(fh_count * sizeof(struct nfs_fh),
 +				gfp_flags);
 +		if (fls->mirror_array[i]->fh_versions == NULL) {
 +			rc = -ENOMEM;
 +			goto out_err_free;
 +		}
 +
 +		for (j = 0; j < fh_count; j++) {
 +			rc = decode_nfs_fh(&stream,
 +					   &fls->mirror_array[i]->fh_versions[j]);
 +			if (rc)
 +				goto out_err_free;
 +		}
 +
 +		fls->mirror_array[i]->fh_versions_cnt = fh_count;
 +
 +		/* user */
 +		rc = decode_name(&stream, &fls->mirror_array[i]->uid);
 +		if (rc)
 +			goto out_err_free;
 +
 +		/* group */
 +		rc = decode_name(&stream, &fls->mirror_array[i]->gid);
 +		if (rc)
 +			goto out_err_free;
 +
 +		dprintk("%s: uid %d gid %d\n", __func__,
 +			fls->mirror_array[i]->uid,
 +			fls->mirror_array[i]->gid);
 +	}
 +
 +	ff_layout_sort_mirrors(fls);
 +	rc = ff_layout_check_layout(lgr);
 +	if (rc)
 +		goto out_err_free;
 +
 +	ret = &fls->generic_hdr;
 +	dprintk("<-- %s (success)\n", __func__);
 +out_free_page:
 +	__free_page(scratch);
 +	return ret;
 +out_err_free:
 +	_ff_layout_free_lseg(fls);
 +	ret = ERR_PTR(rc);
 +	dprintk("<-- %s (%d)\n", __func__, rc);
 +	goto out_free_page;
 +}
 +
 +static bool ff_layout_has_rw_segments(struct pnfs_layout_hdr *layout)
 +{
 +	struct pnfs_layout_segment *lseg;
 +
 +	list_for_each_entry(lseg, &layout->plh_segs, pls_list)
 +		if (lseg->pls_range.iomode == IOMODE_RW)
 +			return true;
 +
 +	return false;
 +}
 +
 +static void
 +ff_layout_free_lseg(struct pnfs_layout_segment *lseg)
 +{
 +	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
 +	int i;
 +
 +	dprintk("--> %s\n", __func__);
 +
 +	for (i = 0; i < fls->mirror_array_cnt; i++) {
 +		if (fls->mirror_array[i]) {
 +			nfs4_ff_layout_put_deviceid(fls->mirror_array[i]->mirror_ds);
 +			fls->mirror_array[i]->mirror_ds = NULL;
 +			if (fls->mirror_array[i]->cred) {
 +				put_rpccred(fls->mirror_array[i]->cred);
 +				fls->mirror_array[i]->cred = NULL;
 +			}
 +		}
 +	}
 +
 +	if (lseg->pls_range.iomode == IOMODE_RW) {
 +		struct nfs4_flexfile_layout *ffl;
 +		struct inode *inode;
 +
 +		ffl = FF_LAYOUT_FROM_HDR(lseg->pls_layout);
 +		inode = ffl->generic_hdr.plh_inode;
 +		spin_lock(&inode->i_lock);
 +		if (!ff_layout_has_rw_segments(lseg->pls_layout)) {
 +			ffl->commit_info.nbuckets = 0;
 +			kfree(ffl->commit_info.buckets);
 +			ffl->commit_info.buckets = NULL;
 +		}
 +		spin_unlock(&inode->i_lock);
 +	}
 +	_ff_layout_free_lseg(fls);
 +}
 +
 +/* Return 1 until we have multiple lsegs support */
 +static int
 +ff_layout_get_lseg_count(struct nfs4_ff_layout_segment *fls)
 +{
 +	return 1;
 +}
 +
 +static int
 +ff_layout_alloc_commit_info(struct pnfs_layout_segment *lseg,
 +			    struct nfs_commit_info *cinfo,
 +			    gfp_t gfp_flags)
 +{
 +	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
 +	struct pnfs_commit_bucket *buckets;
 +	int size;
 +
 +	if (cinfo->ds->nbuckets != 0) {
 +		/* This assumes there is only one RW lseg per file.
 +		 * To support multiple lseg per file, we need to
 +		 * change struct pnfs_commit_bucket to allow dynamic
 +		 * increasing nbuckets.
 +		 */
 +		return 0;
 +	}
 +
 +	size = ff_layout_get_lseg_count(fls) * FF_LAYOUT_MIRROR_COUNT(lseg);
 +
 +	buckets = kcalloc(size, sizeof(struct pnfs_commit_bucket),
 +			  gfp_flags);
 +	if (!buckets)
 +		return -ENOMEM;
 +	else {
 +		int i;
 +
 +		spin_lock(cinfo->lock);
 +		if (cinfo->ds->nbuckets != 0)
 +			kfree(buckets);
 +		else {
 +			cinfo->ds->buckets = buckets;
 +			cinfo->ds->nbuckets = size;
 +			for (i = 0; i < size; i++) {
 +				INIT_LIST_HEAD(&buckets[i].written);
 +				INIT_LIST_HEAD(&buckets[i].committing);
 +				/* mark direct verifier as unset */
 +				buckets[i].direct_verf.committed =
 +					NFS_INVALID_STABLE_HOW;
 +			}
 +		}
 +		spin_unlock(cinfo->lock);
 +		return 0;
 +	}
 +}
 +
 +static struct nfs4_pnfs_ds *
 +ff_layout_choose_best_ds_for_read(struct nfs_pageio_descriptor *pgio,
 +				  int *best_idx)
 +{
 +	struct nfs4_ff_layout_segment *fls;
 +	struct nfs4_pnfs_ds *ds;
 +	int idx;
 +
 +	fls = FF_LAYOUT_LSEG(pgio->pg_lseg);
 +	/* mirrors are sorted by efficiency */
 +	for (idx = 0; idx < fls->mirror_array_cnt; idx++) {
 +		ds = nfs4_ff_layout_prepare_ds(pgio->pg_lseg, idx, false);
 +		if (ds) {
 +			*best_idx = idx;
 +			return ds;
 +		}
 +	}
 +
 +	return NULL;
 +}
 +
 +static void
 +ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
 +			struct nfs_page *req)
 +{
 +	struct nfs_pgio_mirror *pgm;
 +	struct nfs4_ff_layout_mirror *mirror;
 +	struct nfs4_pnfs_ds *ds;
 +	int ds_idx;
 +
 +	/* Use full layout for now */
 +	if (!pgio->pg_lseg)
 +		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
 +						   req->wb_context,
 +						   0,
 +						   NFS4_MAX_UINT64,
 +						   IOMODE_READ,
 +						   GFP_KERNEL);
 +	/* If no lseg, fall back to read through mds */
 +	if (pgio->pg_lseg == NULL)
 +		goto out_mds;
 +
 +	ds = ff_layout_choose_best_ds_for_read(pgio, &ds_idx);
 +	if (!ds)
 +		goto out_mds;
 +	mirror = FF_LAYOUT_COMP(pgio->pg_lseg, ds_idx);
 +
 +	pgio->pg_mirror_idx = ds_idx;
 +
 +	/* read always uses only one mirror - idx 0 for pgio layer */
 +	pgm = &pgio->pg_mirrors[0];
 +	pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].rsize;
 +
 +	return;
 +out_mds:
 +	pnfs_put_lseg(pgio->pg_lseg);
 +	pgio->pg_lseg = NULL;
 +	nfs_pageio_reset_read_mds(pgio);
 +}
 +
 +static void
 +ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio,
 +			struct nfs_page *req)
 +{
 +	struct nfs4_ff_layout_mirror *mirror;
 +	struct nfs_pgio_mirror *pgm;
 +	struct nfs_commit_info cinfo;
 +	struct nfs4_pnfs_ds *ds;
 +	int i;
 +	int status;
 +
 +	if (!pgio->pg_lseg)
 +		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
 +						   req->wb_context,
 +						   0,
 +						   NFS4_MAX_UINT64,
 +						   IOMODE_RW,
 +						   GFP_NOFS);
 +	/* If no lseg, fall back to write through mds */
 +	if (pgio->pg_lseg == NULL)
 +		goto out_mds;
 +
 +	nfs_init_cinfo(&cinfo, pgio->pg_inode, pgio->pg_dreq);
 +	status = ff_layout_alloc_commit_info(pgio->pg_lseg, &cinfo, GFP_NOFS);
 +	if (status < 0)
 +		goto out_mds;
 +
 +	/* Use a direct mapping of ds_idx to pgio mirror_idx */
 +	if (WARN_ON_ONCE(pgio->pg_mirror_count !=
 +	    FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg)))
 +		goto out_mds;
 +
 +	for (i = 0; i < pgio->pg_mirror_count; i++) {
 +		ds = nfs4_ff_layout_prepare_ds(pgio->pg_lseg, i, true);
 +		if (!ds)
 +			goto out_mds;
 +		pgm = &pgio->pg_mirrors[i];
 +		mirror = FF_LAYOUT_COMP(pgio->pg_lseg, i);
 +		pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].wsize;
 +	}
 +
 +	return;
 +
 +out_mds:
 +	pnfs_put_lseg(pgio->pg_lseg);
 +	pgio->pg_lseg = NULL;
 +	nfs_pageio_reset_write_mds(pgio);
 +}
 +
 +static unsigned int
 +ff_layout_pg_get_mirror_count_write(struct nfs_pageio_descriptor *pgio,
 +				    struct nfs_page *req)
 +{
 +	if (!pgio->pg_lseg)
 +		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
 +						   req->wb_context,
 +						   0,
 +						   NFS4_MAX_UINT64,
 +						   IOMODE_RW,
 +						   GFP_NOFS);
 +	if (pgio->pg_lseg)
 +		return FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg);
 +
 +	/* no lseg means that pnfs is not in use, so no mirroring here */
 +	pnfs_put_lseg(pgio->pg_lseg);
 +	pgio->pg_lseg = NULL;
 +	nfs_pageio_reset_write_mds(pgio);
 +	return 1;
 +}
 +
 +static const struct nfs_pageio_ops ff_layout_pg_read_ops = {
 +	.pg_init = ff_layout_pg_init_read,
 +	.pg_test = pnfs_generic_pg_test,
 +	.pg_doio = pnfs_generic_pg_readpages,
 +	.pg_cleanup = pnfs_generic_pg_cleanup,
 +};
 +
 +static const struct nfs_pageio_ops ff_layout_pg_write_ops = {
 +	.pg_init = ff_layout_pg_init_write,
 +	.pg_test = pnfs_generic_pg_test,
 +	.pg_doio = pnfs_generic_pg_writepages,
 +	.pg_get_mirror_count = ff_layout_pg_get_mirror_count_write,
 +	.pg_cleanup = pnfs_generic_pg_cleanup,
 +};
 +
 +static void ff_layout_reset_write(struct nfs_pgio_header *hdr, bool retry_pnfs)
 +{
 +	struct rpc_task *task = &hdr->task;
 +
 +	pnfs_layoutcommit_inode(hdr->inode, false);
 +
 +	if (retry_pnfs) {
 +		dprintk("%s Reset task %5u for i/o through pNFS "
 +			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
 +			hdr->task.tk_pid,
 +			hdr->inode->i_sb->s_id,
 +			(unsigned long long)NFS_FILEID(hdr->inode),
 +			hdr->args.count,
 +			(unsigned long long)hdr->args.offset);
 +
 +		if (!hdr->dreq) {
 +			struct nfs_open_context *ctx;
 +
 +			ctx = nfs_list_entry(hdr->pages.next)->wb_context;
 +			set_bit(NFS_CONTEXT_RESEND_WRITES, &ctx->flags);
 +			hdr->completion_ops->error_cleanup(&hdr->pages);
 +		} else {
 +			nfs_direct_set_resched_writes(hdr->dreq);
 +			/* fake unstable write to let common nfs resend pages */
 +			hdr->verf.committed = NFS_UNSTABLE;
 +			hdr->good_bytes = 0;
 +		}
 +		return;
 +	}
 +
 +	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
 +		dprintk("%s Reset task %5u for i/o through MDS "
 +			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
 +			hdr->task.tk_pid,
 +			hdr->inode->i_sb->s_id,
 +			(unsigned long long)NFS_FILEID(hdr->inode),
 +			hdr->args.count,
 +			(unsigned long long)hdr->args.offset);
 +
 +		task->tk_status = pnfs_write_done_resend_to_mds(hdr);
 +	}
 +}
 +
 +static void ff_layout_reset_read(struct nfs_pgio_header *hdr)
 +{
 +	struct rpc_task *task = &hdr->task;
 +
 +	pnfs_layoutcommit_inode(hdr->inode, false);
 +
 +	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
 +		dprintk("%s Reset task %5u for i/o through MDS "
 +			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
 +			hdr->task.tk_pid,
 +			hdr->inode->i_sb->s_id,
 +			(unsigned long long)NFS_FILEID(hdr->inode),
 +			hdr->args.count,
 +			(unsigned long long)hdr->args.offset);
 +
 +		task->tk_status = pnfs_read_done_resend_to_mds(hdr);
 +	}
 +}
 +
 +static int ff_layout_async_handle_error_v4(struct rpc_task *task,
 +					   struct nfs4_state *state,
 +					   struct nfs_client *clp,
 +					   struct pnfs_layout_segment *lseg,
 +					   int idx)
 +{
 +	struct pnfs_layout_hdr *lo = lseg->pls_layout;
 +	struct inode *inode = lo->plh_inode;
 +	struct nfs_server *mds_server = NFS_SERVER(inode);
 +
 +	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);
 +	struct nfs_client *mds_client = mds_server->nfs_client;
 +	struct nfs4_slot_table *tbl = &clp->cl_session->fc_slot_table;
 +
 +	if (task->tk_status >= 0)
 +		return 0;
 +
 +	switch (task->tk_status) {
 +	/* MDS state errors */
 +	case -NFS4ERR_DELEG_REVOKED:
 +	case -NFS4ERR_ADMIN_REVOKED:
 +	case -NFS4ERR_BAD_STATEID:
 +		if (state == NULL)
 +			break;
 +		nfs_remove_bad_delegation(state->inode);
 +	case -NFS4ERR_OPENMODE:
 +		if (state == NULL)
 +			break;
 +		if (nfs4_schedule_stateid_recovery(mds_server, state) < 0)
 +			goto out_bad_stateid;
 +		goto wait_on_recovery;
 +	case -NFS4ERR_EXPIRED:
 +		if (state != NULL) {
 +			if (nfs4_schedule_stateid_recovery(mds_server, state) < 0)
 +				goto out_bad_stateid;
 +		}
 +		nfs4_schedule_lease_recovery(mds_client);
 +		goto wait_on_recovery;
 +	/* DS session errors */
 +	case -NFS4ERR_BADSESSION:
 +	case -NFS4ERR_BADSLOT:
 +	case -NFS4ERR_BAD_HIGH_SLOT:
 +	case -NFS4ERR_DEADSESSION:
 +	case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
 +	case -NFS4ERR_SEQ_FALSE_RETRY:
 +	case -NFS4ERR_SEQ_MISORDERED:
 +		dprintk("%s ERROR %d, Reset session. Exchangeid "
 +			"flags 0x%x\n", __func__, task->tk_status,
 +			clp->cl_exchange_flags);
 +		nfs4_schedule_session_recovery(clp->cl_session, task->tk_status);
 +		break;
 +	case -NFS4ERR_DELAY:
 +	case -NFS4ERR_GRACE:
 +		rpc_delay(task, FF_LAYOUT_POLL_RETRY_MAX);
 +		break;
 +	case -NFS4ERR_RETRY_UNCACHED_REP:
 +		break;
 +	/* Invalidate Layout errors */
 +	case -NFS4ERR_PNFS_NO_LAYOUT:
 +	case -ESTALE:           /* mapped NFS4ERR_STALE */
 +	case -EBADHANDLE:       /* mapped NFS4ERR_BADHANDLE */
 +	case -EISDIR:           /* mapped NFS4ERR_ISDIR */
 +	case -NFS4ERR_FHEXPIRED:
 +	case -NFS4ERR_WRONG_TYPE:
 +		dprintk("%s Invalid layout error %d\n", __func__,
 +			task->tk_status);
 +		/*
 +		 * Destroy layout so new i/o will get a new layout.
 +		 * Layout will not be destroyed until all current lseg
 +		 * references are put. Mark layout as invalid to resend failed
 +		 * i/o and all i/o waiting on the slot table to the MDS until
 +		 * layout is destroyed and a new valid layout is obtained.
 +		 */
 +		pnfs_destroy_layout(NFS_I(inode));
 +		rpc_wake_up(&tbl->slot_tbl_waitq);
 +		goto reset;
 +	/* RPC connection errors */
 +	case -ECONNREFUSED:
 +	case -EHOSTDOWN:
 +	case -EHOSTUNREACH:
 +	case -ENETUNREACH:
 +	case -EIO:
 +	case -ETIMEDOUT:
 +	case -EPIPE:
 +		dprintk("%s DS connection error %d\n", __func__,
 +			task->tk_status);
 +		nfs4_mark_deviceid_unavailable(devid);
 +		rpc_wake_up(&tbl->slot_tbl_waitq);
 +		/* fall through */
 +	default:
 +		if (ff_layout_has_available_ds(lseg))
 +			return -NFS4ERR_RESET_TO_PNFS;
 +reset:
 +		dprintk("%s Retry through MDS. Error %d\n", __func__,
 +			task->tk_status);
 +		return -NFS4ERR_RESET_TO_MDS;
 +	}
 +out:
 +	task->tk_status = 0;
 +	return -EAGAIN;
 +out_bad_stateid:
 +	task->tk_status = -EIO;
 +	return 0;
 +wait_on_recovery:
 +	rpc_sleep_on(&mds_client->cl_rpcwaitq, task, NULL);
 +	if (test_bit(NFS4CLNT_MANAGER_RUNNING, &mds_client->cl_state) == 0)
 +		rpc_wake_up_queued_task(&mds_client->cl_rpcwaitq, task);
 +	goto out;
 +}
 +
 +/* Retry all errors through either pNFS or MDS except for -EJUKEBOX */
 +static int ff_layout_async_handle_error_v3(struct rpc_task *task,
 +					   struct pnfs_layout_segment *lseg,
 +					   int idx)
 +{
 +	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);
 +
 +	if (task->tk_status >= 0)
 +		return 0;
 +
 +	if (task->tk_status != -EJUKEBOX) {
 +		dprintk("%s DS connection error %d\n", __func__,
 +			task->tk_status);
 +		nfs4_mark_deviceid_unavailable(devid);
 +		if (ff_layout_has_available_ds(lseg))
 +			return -NFS4ERR_RESET_TO_PNFS;
 +		else
 +			return -NFS4ERR_RESET_TO_MDS;
 +	}
 +
 +	if (task->tk_status == -EJUKEBOX)
 +		nfs_inc_stats(lseg->pls_layout->plh_inode, NFSIOS_DELAY);
 +	task->tk_status = 0;
 +	rpc_restart_call(task);
 +	rpc_delay(task, NFS_JUKEBOX_RETRY_TIME);
 +	return -EAGAIN;
 +}
 +
 +static int ff_layout_async_handle_error(struct rpc_task *task,
 +					struct nfs4_state *state,
 +					struct nfs_client *clp,
 +					struct pnfs_layout_segment *lseg,
 +					int idx)
 +{
 +	int vers = clp->cl_nfs_mod->rpc_vers->number;
 +
 +	switch (vers) {
 +	case 3:
 +		return ff_layout_async_handle_error_v3(task, lseg, idx);
 +	case 4:
 +		return ff_layout_async_handle_error_v4(task, state, clp,
 +						       lseg, idx);
 +	default:
 +		/* should never happen */
 +		WARN_ON_ONCE(1);
 +		return 0;
 +	}
 +}
 +
 +static void ff_layout_io_track_ds_error(struct pnfs_layout_segment *lseg,
 +					int idx, u64 offset, u64 length,
 +					u32 status, int opnum)
 +{
 +	struct nfs4_ff_layout_mirror *mirror;
 +	int err;
 +
 +	mirror = FF_LAYOUT_COMP(lseg, idx);
 +	err = ff_layout_track_ds_error(FF_LAYOUT_FROM_HDR(lseg->pls_layout),
 +				       mirror, offset, length, status, opnum,
 +				       GFP_NOIO);
 +	dprintk("%s: err %d op %d status %u\n", __func__, err, opnum, status);
 +}
 +
 +/* NFS_PROTO call done callback routines */
 +
 +static int ff_layout_read_done_cb(struct rpc_task *task,
 +				struct nfs_pgio_header *hdr)
 +{
 +	struct inode *inode;
 +	int err;
 +
 +	trace_nfs4_pnfs_read(hdr, task->tk_status);
 +	if (task->tk_status == -ETIMEDOUT && !hdr->res.op_status)
 +		hdr->res.op_status = NFS4ERR_NXIO;
 +	if (task->tk_status < 0 && hdr->res.op_status)
 +		ff_layout_io_track_ds_error(hdr->lseg, hdr->pgio_mirror_idx,
 +					    hdr->args.offset, hdr->args.count,
 +					    hdr->res.op_status, OP_READ);
 +	err = ff_layout_async_handle_error(task, hdr->args.context->state,
 +					   hdr->ds_clp, hdr->lseg,
 +					   hdr->pgio_mirror_idx);
 +
 +	switch (err) {
 +	case -NFS4ERR_RESET_TO_PNFS:
 +		set_bit(NFS_LAYOUT_RETURN_BEFORE_CLOSE,
 +			&hdr->lseg->pls_layout->plh_flags);
 +		pnfs_read_resend_pnfs(hdr);
 +		return task->tk_status;
 +	case -NFS4ERR_RESET_TO_MDS:
 +		inode = hdr->lseg->pls_layout->plh_inode;
 +		pnfs_error_mark_layout_for_return(inode, hdr->lseg);
 +		ff_layout_reset_read(hdr);
 +		return task->tk_status;
 +	case -EAGAIN:
 +		rpc_restart_call_prepare(task);
 +		return -EAGAIN;
 +	}
 +
 +	return 0;
 +}
 +
 +/*
 + * We reference the rpc_cred of the first WRITE that triggers the need for
 + * a LAYOUTCOMMIT, and use it to send the layoutcommit compound.
 + * rfc5661 is not clear about which credential should be used.
 + *
 + * Flexlayout client should treat DS replied FILE_SYNC as DATA_SYNC, so
 + * to follow http://www.rfc-editor.org/errata_search.php?rfc=5661&eid=2751
 + * we always send layoutcommit after DS writes.
 + */
 +static void
 +ff_layout_set_layoutcommit(struct nfs_pgio_header *hdr)
 +{
 +	pnfs_set_layoutcommit(hdr);
 +	dprintk("%s inode %lu pls_end_pos %lu\n", __func__, hdr->inode->i_ino,
 +		(unsigned long) NFS_I(hdr->inode)->layout->plh_lwb);
 +}
 +
 +static bool
 +ff_layout_reset_to_mds(struct pnfs_layout_segment *lseg, int idx)
 +{
 +	/* No mirroring for now */
 +	struct nfs4_deviceid_node *node = FF_LAYOUT_DEVID_NODE(lseg, idx);
 +
 +	return ff_layout_test_devid_unavailable(node);
 +}
 +
 +static int ff_layout_read_prepare_common(struct rpc_task *task,
 +					 struct nfs_pgio_header *hdr)
 +{
 +	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
 +		rpc_exit(task, -EIO);
 +		return -EIO;
 +	}
 +	if (ff_layout_reset_to_mds(hdr->lseg, hdr->pgio_mirror_idx)) {
 +		dprintk("%s task %u reset io to MDS\n", __func__, task->tk_pid);
 +		if (ff_layout_has_available_ds(hdr->lseg))
 +			pnfs_read_resend_pnfs(hdr);
 +		else
 +			ff_layout_reset_read(hdr);
 +		rpc_exit(task, 0);
 +		return -EAGAIN;
 +	}
 +	hdr->pgio_done_cb = ff_layout_read_done_cb;
 +
 +	return 0;
 +}
 +
 +/*
 + * Call ops for the async read/write cases
 + * In the case of dense layouts, the offset needs to be reset to its
 + * original value.
 + */
 +static void ff_layout_read_prepare_v3(struct rpc_task *task, void *data)
 +{
 +	struct nfs_pgio_header *hdr = data;
 +
 +	if (ff_layout_read_prepare_common(task, hdr))
 +		return;
 +
 +	rpc_call_start(task);
 +}
 +
 +static int ff_layout_setup_sequence(struct nfs_client *ds_clp,
 +				    struct nfs4_sequence_args *args,
 +				    struct nfs4_sequence_res *res,
 +				    struct rpc_task *task)
 +{
 +	if (ds_clp->cl_session)
 +		return nfs41_setup_sequence(ds_clp->cl_session,
 +					   args,
 +					   res,
 +					   task);
 +	return nfs40_setup_sequence(ds_clp->cl_slot_tbl,
 +				   args,
 +				   res,
 +				   task);
 +}
 +
 +static void ff_layout_read_prepare_v4(struct rpc_task *task, void *data)
 +{
 +	struct nfs_pgio_header *hdr = data;
 +
 +	if (ff_layout_read_prepare_common(task, hdr))
 +		return;
 +
 +	if (ff_layout_setup_sequence(hdr->ds_clp,
 +				     &hdr->args.seq_args,
 +				     &hdr->res.seq_res,
 +				     task))
 +		return;
 +
 +	if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
 +			hdr->args.lock_context, FMODE_READ) == -EIO)
 +		rpc_exit(task, -EIO); /* lost lock, terminate I/O */
 +}
 +
 +static void ff_layout_read_call_done(struct rpc_task *task, void *data)
 +{
 +	struct nfs_pgio_header *hdr = data;
 +
 +	dprintk("--> %s task->tk_status %d\n", __func__, task->tk_status);
 +
 +	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
 +	    task->tk_status == 0) {
 +		nfs4_sequence_done(task, &hdr->res.seq_res);
 +		return;
 +	}
 +
 +	/* Note this may cause RPC to be resent */
 +	hdr->mds_ops->rpc_call_done(task, hdr);
 +}
 +
 +static void ff_layout_read_count_stats(struct rpc_task *task, void *data)
 +{
 +	struct nfs_pgio_header *hdr = data;
 +
 +	rpc_count_iostats_metrics(task,
 +	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_READ]);
 +}
 +
 +static int ff_layout_write_done_cb(struct rpc_task *task,
 +				struct nfs_pgio_header *hdr)
 +{
 +	struct inode *inode;
 +	int err;
 +
 +	trace_nfs4_pnfs_write(hdr, task->tk_status);
 +	if (task->tk_status == -ETIMEDOUT && !hdr->res.op_status)
 +		hdr->res.op_status = NFS4ERR_NXIO;
 +	if (task->tk_status < 0 && hdr->res.op_status)
 +		ff_layout_io_track_ds_error(hdr->lseg, hdr->pgio_mirror_idx,
 +					    hdr->args.offset, hdr->args.count,
 +					    hdr->res.op_status, OP_WRITE);
 +	err = ff_layout_async_handle_error(task, hdr->args.context->state,
 +					   hdr->ds_clp, hdr->lseg,
 +					   hdr->pgio_mirror_idx);
 +
 +	switch (err) {
 +	case -NFS4ERR_RESET_TO_PNFS:
 +	case -NFS4ERR_RESET_TO_MDS:
 +		inode = hdr->lseg->pls_layout->plh_inode;
 +		pnfs_error_mark_layout_for_return(inode, hdr->lseg);
 +		if (err == -NFS4ERR_RESET_TO_PNFS) {
 +			pnfs_set_retry_layoutget(hdr->lseg->pls_layout);
 +			ff_layout_reset_write(hdr, true);
 +		} else {
 +			pnfs_clear_retry_layoutget(hdr->lseg->pls_layout);
 +			ff_layout_reset_write(hdr, false);
 +		}
 +		return task->tk_status;
 +	case -EAGAIN:
 +		rpc_restart_call_prepare(task);
 +		return -EAGAIN;
 +	}
 +
 +	if (hdr->res.verf->committed == NFS_FILE_SYNC ||
 +	    hdr->res.verf->committed == NFS_DATA_SYNC)
 +		ff_layout_set_layoutcommit(hdr);
 +
 +	return 0;
 +}
 +
 +static int ff_layout_commit_done_cb(struct rpc_task *task,
 +				     struct nfs_commit_data *data)
 +{
 +	struct inode *inode;
 +	int err;
 +
 +	trace_nfs4_pnfs_commit_ds(data, task->tk_status);
 +	if (task->tk_status == -ETIMEDOUT && !data->res.op_status)
 +		data->res.op_status = NFS4ERR_NXIO;
 +	if (task->tk_status < 0 && data->res.op_status)
 +		ff_layout_io_track_ds_error(data->lseg, data->ds_commit_index,
 +					    data->args.offset, data->args.count,
 +					    data->res.op_status, OP_COMMIT);
 +	err = ff_layout_async_handle_error(task, NULL, data->ds_clp,
 +					   data->lseg, data->ds_commit_index);
 +
 +	switch (err) {
 +	case -NFS4ERR_RESET_TO_PNFS:
 +	case -NFS4ERR_RESET_TO_MDS:
 +		inode = data->lseg->pls_layout->plh_inode;
 +		pnfs_error_mark_layout_for_return(inode, data->lseg);
 +		if (err == -NFS4ERR_RESET_TO_PNFS)
 +			pnfs_set_retry_layoutget(data->lseg->pls_layout);
 +		else
 +			pnfs_clear_retry_layoutget(data->lseg->pls_layout);
 +		pnfs_generic_prepare_to_resend_writes(data);
 +		return -EAGAIN;
 +	case -EAGAIN:
 +		rpc_restart_call_prepare(task);
 +		return -EAGAIN;
 +	}
 +
 +	if (data->verf.committed == NFS_UNSTABLE)
 +		pnfs_commit_set_layoutcommit(data);
 +
 +	return 0;
 +}
 +
 +static int ff_layout_write_prepare_common(struct rpc_task *task,
 +					  struct nfs_pgio_header *hdr)
 +{
 +	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
 +		rpc_exit(task, -EIO);
 +		return -EIO;
 +	}
 +
 +	if (ff_layout_reset_to_mds(hdr->lseg, hdr->pgio_mirror_idx)) {
 +		bool retry_pnfs;
 +
 +		retry_pnfs = ff_layout_has_available_ds(hdr->lseg);
 +		dprintk("%s task %u reset io to %s\n", __func__,
 +			task->tk_pid, retry_pnfs ? "pNFS" : "MDS");
 +		ff_layout_reset_write(hdr, retry_pnfs);
 +		rpc_exit(task, 0);
 +		return -EAGAIN;
 +	}
 +
 +	return 0;
 +}
 +
 +static void ff_layout_write_prepare_v3(struct rpc_task *task, void *data)
 +{
 +	struct nfs_pgio_header *hdr = data;
 +
 +	if (ff_layout_write_prepare_common(task, hdr))
 +		return;
 +
 +	rpc_call_start(task);
 +}
 +
 +static void ff_layout_write_prepare_v4(struct rpc_task *task, void *data)
 +{
 +	struct nfs_pgio_header *hdr = data;
 +
 +	if (ff_layout_write_prepare_common(task, hdr))
 +		return;
 +
 +	if (ff_layout_setup_sequence(hdr->ds_clp,
 +				     &hdr->args.seq_args,
 +				     &hdr->res.seq_res,
 +				     task))
 +		return;
 +
 +	if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
 +			hdr->args.lock_context, FMODE_WRITE) == -EIO)
 +		rpc_exit(task, -EIO); /* lost lock, terminate I/O */
 +}
 +
 +static void ff_layout_write_call_done(struct rpc_task *task, void *data)
 +{
 +	struct nfs_pgio_header *hdr = data;
 +
 +	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
 +	    task->tk_status == 0) {
 +		nfs4_sequence_done(task, &hdr->res.seq_res);
 +		return;
 +	}
 +
 +	/* Note this may cause RPC to be resent */
 +	hdr->mds_ops->rpc_call_done(task, hdr);
 +}
 +
 +static void ff_layout_write_count_stats(struct rpc_task *task, void *data)
 +{
 +	struct nfs_pgio_header *hdr = data;
 +
 +	rpc_count_iostats_metrics(task,
 +	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_WRITE]);
 +}
 +
 +static void ff_layout_commit_prepare_v3(struct rpc_task *task, void *data)
 +{
 +	rpc_call_start(task);
 +}
 +
 +static void ff_layout_commit_prepare_v4(struct rpc_task *task, void *data)
 +{
 +	struct nfs_commit_data *wdata = data;
 +
 +	ff_layout_setup_sequence(wdata->ds_clp,
 +				 &wdata->args.seq_args,
 +				 &wdata->res.seq_res,
 +				 task);
 +}
 +
 +static void ff_layout_commit_count_stats(struct rpc_task *task, void *data)
 +{
 +	struct nfs_commit_data *cdata = data;
 +
 +	rpc_count_iostats_metrics(task,
 +	    &NFS_CLIENT(cdata->inode)->cl_metrics[NFSPROC4_CLNT_COMMIT]);
 +}
 +
 +static const struct rpc_call_ops ff_layout_read_call_ops_v3 = {
 +	.rpc_call_prepare = ff_layout_read_prepare_v3,
 +	.rpc_call_done = ff_layout_read_call_done,
 +	.rpc_count_stats = ff_layout_read_count_stats,
 +	.rpc_release = pnfs_generic_rw_release,
 +};
 +
 +static const struct rpc_call_ops ff_layout_read_call_ops_v4 = {
 +	.rpc_call_prepare = ff_layout_read_prepare_v4,
 +	.rpc_call_done = ff_layout_read_call_done,
 +	.rpc_count_stats = ff_layout_read_count_stats,
 +	.rpc_release = pnfs_generic_rw_release,
 +};
 +
 +static const struct rpc_call_ops ff_layout_write_call_ops_v3 = {
 +	.rpc_call_prepare = ff_layout_write_prepare_v3,
 +	.rpc_call_done = ff_layout_write_call_done,
 +	.rpc_count_stats = ff_layout_write_count_stats,
 +	.rpc_release = pnfs_generic_rw_release,
 +};
 +
 +static const struct rpc_call_ops ff_layout_write_call_ops_v4 = {
 +	.rpc_call_prepare = ff_layout_write_prepare_v4,
 +	.rpc_call_done = ff_layout_write_call_done,
 +	.rpc_count_stats = ff_layout_write_count_stats,
 +	.rpc_release = pnfs_generic_rw_release,
 +};
 +
 +static const struct rpc_call_ops ff_layout_commit_call_ops_v3 = {
 +	.rpc_call_prepare = ff_layout_commit_prepare_v3,
 +	.rpc_call_done = pnfs_generic_write_commit_done,
 +	.rpc_count_stats = ff_layout_commit_count_stats,
 +	.rpc_release = pnfs_generic_commit_release,
 +};
 +
 +static const struct rpc_call_ops ff_layout_commit_call_ops_v4 = {
 +	.rpc_call_prepare = ff_layout_commit_prepare_v4,
 +	.rpc_call_done = pnfs_generic_write_commit_done,
 +	.rpc_count_stats = ff_layout_commit_count_stats,
 +	.rpc_release = pnfs_generic_commit_release,
 +};
 +
 +static enum pnfs_try_status
 +ff_layout_read_pagelist(struct nfs_pgio_header *hdr)
 +{
 +	struct pnfs_layout_segment *lseg = hdr->lseg;
 +	struct nfs4_pnfs_ds *ds;
 +	struct rpc_clnt *ds_clnt;
 +	struct rpc_cred *ds_cred;
 +	loff_t offset = hdr->args.offset;
 +	u32 idx = hdr->pgio_mirror_idx;
 +	int vers;
 +	struct nfs_fh *fh;
 +
 +	dprintk("--> %s ino %lu pgbase %u req %Zu@%llu\n",
 +		__func__, hdr->inode->i_ino,
 +		hdr->args.pgbase, (size_t)hdr->args.count, offset);
 +
 +	ds = nfs4_ff_layout_prepare_ds(lseg, idx, false);
 +	if (!ds)
 +		goto out_failed;
 +
 +	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
 +						   hdr->inode);
 +	if (IS_ERR(ds_clnt))
 +		goto out_failed;
 +
 +	ds_cred = ff_layout_get_ds_cred(lseg, idx, hdr->cred);
 +	if (IS_ERR(ds_cred))
 +		goto out_failed;
 +
 +	vers = nfs4_ff_layout_ds_version(lseg, idx);
 +
 +	dprintk("%s USE DS: %s cl_count %d vers %d\n", __func__,
 +		ds->ds_remotestr, atomic_read(&ds->ds_clp->cl_count), vers);
 +
 +	atomic_inc(&ds->ds_clp->cl_count);
 +	hdr->ds_clp = ds->ds_clp;
 +	fh = nfs4_ff_layout_select_ds_fh(lseg, idx);
 +	if (fh)
 +		hdr->args.fh = fh;
 +
 +	/*
 +	 * Note that if we ever decide to split across DSes,
 +	 * then we may need to handle dense-like offsets.
 +	 */
 +	hdr->args.offset = offset;
 +	hdr->mds_offset = offset;
 +
 +	/* Perform an asynchronous read to ds */
 +	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
 +			  vers == 3 ? &ff_layout_read_call_ops_v3 :
 +				      &ff_layout_read_call_ops_v4,
 +			  0, RPC_TASK_SOFTCONN);
 +
 +	return PNFS_ATTEMPTED;
 +
 +out_failed:
 +	if (ff_layout_has_available_ds(lseg))
 +		return PNFS_TRY_AGAIN;
 +	return PNFS_NOT_ATTEMPTED;
 +}
 +
 +/* Perform async writes. */
 +static enum pnfs_try_status
 +ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
 +{
 +	struct pnfs_layout_segment *lseg = hdr->lseg;
 +	struct nfs4_pnfs_ds *ds;
 +	struct rpc_clnt *ds_clnt;
 +	struct rpc_cred *ds_cred;
 +	loff_t offset = hdr->args.offset;
 +	int vers;
 +	struct nfs_fh *fh;
 +	int idx = hdr->pgio_mirror_idx;
 +
 +	ds = nfs4_ff_layout_prepare_ds(lseg, idx, true);
 +	if (!ds)
 +		return PNFS_NOT_ATTEMPTED;
 +
 +	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
 +						   hdr->inode);
 +	if (IS_ERR(ds_clnt))
 +		return PNFS_NOT_ATTEMPTED;
 +
 +	ds_cred = ff_layout_get_ds_cred(lseg, idx, hdr->cred);
 +	if (IS_ERR(ds_cred))
 +		return PNFS_NOT_ATTEMPTED;
 +
 +	vers = nfs4_ff_layout_ds_version(lseg, idx);
 +
 +	dprintk("%s ino %lu sync %d req %Zu@%llu DS: %s cl_count %d vers %d\n",
 +		__func__, hdr->inode->i_ino, sync, (size_t) hdr->args.count,
 +		offset, ds->ds_remotestr, atomic_read(&ds->ds_clp->cl_count),
 +		vers);
 +
 +	hdr->pgio_done_cb = ff_layout_write_done_cb;
 +	atomic_inc(&ds->ds_clp->cl_count);
 +	hdr->ds_clp = ds->ds_clp;
 +	hdr->ds_commit_idx = idx;
 +	fh = nfs4_ff_layout_select_ds_fh(lseg, idx);
 +	if (fh)
 +		hdr->args.fh = fh;
 +
 +	/*
 +	 * Note that if we ever decide to split across DSes,
 +	 * then we may need to handle dense-like offsets.
 +	 */
 +	hdr->args.offset = offset;
 +
 +	/* Perform an asynchronous write */
 +	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
 +			  vers == 3 ? &ff_layout_write_call_ops_v3 :
 +				      &ff_layout_write_call_ops_v4,
 +			  sync, RPC_TASK_SOFTCONN);
 +	return PNFS_ATTEMPTED;
 +}
 +
 +static void
 +ff_layout_mark_request_commit(struct nfs_page *req,
 +			      struct pnfs_layout_segment *lseg,
 +			      struct nfs_commit_info *cinfo,
 +			      u32 ds_commit_idx)
 +{
 +	struct list_head *list;
 +	struct pnfs_commit_bucket *buckets;
 +
 +	spin_lock(cinfo->lock);
 +	buckets = cinfo->ds->buckets;
 +	list = &buckets[ds_commit_idx].written;
 +	if (list_empty(list)) {
 +		/* Non-empty buckets hold a reference on the lseg.  That ref
 +		 * is normally transferred to the COMMIT call and released
 +		 * there.  It could also be released if the last req is pulled
 +		 * off due to a rewrite, in which case it will be done in
 +		 * pnfs_common_clear_request_commit
 +		 */
 +		WARN_ON_ONCE(buckets[ds_commit_idx].wlseg != NULL);
 +		buckets[ds_commit_idx].wlseg = pnfs_get_lseg(lseg);
 +	}
 +	set_bit(PG_COMMIT_TO_DS, &req->wb_flags);
 +	cinfo->ds->nwritten++;
 +
 +	/* nfs_request_add_commit_list(). We need to add req to list without
 +	 * dropping cinfo lock.
 +	 */
 +	set_bit(PG_CLEAN, &(req)->wb_flags);
 +	nfs_list_add_request(req, list);
 +	cinfo->mds->ncommit++;
 +	spin_unlock(cinfo->lock);
 +	if (!cinfo->dreq) {
 +		inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
- 		inc_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info,
++		inc_bdi_stat(inode_to_bdi(page_file_mapping(req->wb_page)->host),
 +			     BDI_RECLAIMABLE);
 +		__mark_inode_dirty(req->wb_context->dentry->d_inode,
 +				   I_DIRTY_DATASYNC);
 +	}
 +}
 +
 +static u32 calc_ds_index_from_commit(struct pnfs_layout_segment *lseg, u32 i)
 +{
 +	return i;
 +}
 +
 +static struct nfs_fh *
 +select_ds_fh_from_commit(struct pnfs_layout_segment *lseg, u32 i)
 +{
 +	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
 +
 +	/* FIXME: Assume that there is only one NFS version available
 +	 * for the DS.
 +	 */
 +	return &flseg->mirror_array[i]->fh_versions[0];
 +}
 +
 +static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
 +{
 +	struct pnfs_layout_segment *lseg = data->lseg;
 +	struct nfs4_pnfs_ds *ds;
 +	struct rpc_clnt *ds_clnt;
 +	struct rpc_cred *ds_cred;
 +	u32 idx;
 +	int vers;
 +	struct nfs_fh *fh;
 +
 +	idx = calc_ds_index_from_commit(lseg, data->ds_commit_index);
 +	ds = nfs4_ff_layout_prepare_ds(lseg, idx, true);
 +	if (!ds)
 +		goto out_err;
 +
 +	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
 +						   data->inode);
 +	if (IS_ERR(ds_clnt))
 +		goto out_err;
 +
 +	ds_cred = ff_layout_get_ds_cred(lseg, idx, data->cred);
 +	if (IS_ERR(ds_cred))
 +		goto out_err;
 +
 +	vers = nfs4_ff_layout_ds_version(lseg, idx);
 +
 +	dprintk("%s ino %lu, how %d cl_count %d vers %d\n", __func__,
 +		data->inode->i_ino, how, atomic_read(&ds->ds_clp->cl_count),
 +		vers);
 +	data->commit_done_cb = ff_layout_commit_done_cb;
 +	data->cred = ds_cred;
 +	atomic_inc(&ds->ds_clp->cl_count);
 +	data->ds_clp = ds->ds_clp;
 +	fh = select_ds_fh_from_commit(lseg, data->ds_commit_index);
 +	if (fh)
 +		data->args.fh = fh;
 +	return nfs_initiate_commit(ds_clnt, data, ds->ds_clp->rpc_ops,
 +				   vers == 3 ? &ff_layout_commit_call_ops_v3 :
 +					       &ff_layout_commit_call_ops_v4,
 +				   how, RPC_TASK_SOFTCONN);
 +out_err:
 +	pnfs_generic_prepare_to_resend_writes(data);
 +	pnfs_generic_commit_release(data);
 +	return -EAGAIN;
 +}
 +
 +static int
 +ff_layout_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
 +			   int how, struct nfs_commit_info *cinfo)
 +{
 +	return pnfs_generic_commit_pagelist(inode, mds_pages, how, cinfo,
 +					    ff_layout_initiate_commit);
 +}
 +
 +static struct pnfs_ds_commit_info *
 +ff_layout_get_ds_info(struct inode *inode)
 +{
 +	struct pnfs_layout_hdr *layout = NFS_I(inode)->layout;
 +
 +	if (layout == NULL)
 +		return NULL;
 +
 +	return &FF_LAYOUT_FROM_HDR(layout)->commit_info;
 +}
 +
 +static void
 +ff_layout_free_deveiceid_node(struct nfs4_deviceid_node *d)
 +{
 +	nfs4_ff_layout_free_deviceid(container_of(d, struct nfs4_ff_layout_ds,
 +						  id_node));
 +}
 +
 +static int ff_layout_encode_ioerr(struct nfs4_flexfile_layout *flo,
 +				  struct xdr_stream *xdr,
 +				  const struct nfs4_layoutreturn_args *args)
 +{
 +	struct pnfs_layout_hdr *hdr = &flo->generic_hdr;
 +	__be32 *start;
 +	int count = 0, ret = 0;
 +
 +	start = xdr_reserve_space(xdr, 4);
 +	if (unlikely(!start))
 +		return -E2BIG;
 +
 +	/* This assume we always return _ALL_ layouts */
 +	spin_lock(&hdr->plh_inode->i_lock);
 +	ret = ff_layout_encode_ds_ioerr(flo, xdr, &count, &args->range);
 +	spin_unlock(&hdr->plh_inode->i_lock);
 +
 +	*start = cpu_to_be32(count);
 +
 +	return ret;
 +}
 +
 +/* report nothing for now */
 +static void ff_layout_encode_iostats(struct nfs4_flexfile_layout *flo,
 +				     struct xdr_stream *xdr,
 +				     const struct nfs4_layoutreturn_args *args)
 +{
 +	__be32 *p;
 +
 +	p = xdr_reserve_space(xdr, 4);
 +	if (likely(p))
 +		*p = cpu_to_be32(0);
 +}
 +
 +static struct nfs4_deviceid_node *
 +ff_layout_alloc_deviceid_node(struct nfs_server *server,
 +			      struct pnfs_device *pdev, gfp_t gfp_flags)
 +{
 +	struct nfs4_ff_layout_ds *dsaddr;
 +
 +	dsaddr = nfs4_ff_alloc_deviceid_node(server, pdev, gfp_flags);
 +	if (!dsaddr)
 +		return NULL;
 +	return &dsaddr->id_node;
 +}
 +
 +static void
 +ff_layout_encode_layoutreturn(struct pnfs_layout_hdr *lo,
 +			      struct xdr_stream *xdr,
 +			      const struct nfs4_layoutreturn_args *args)
 +{
 +	struct nfs4_flexfile_layout *flo = FF_LAYOUT_FROM_HDR(lo);
 +	__be32 *start;
 +
 +	dprintk("%s: Begin\n", __func__);
 +	start = xdr_reserve_space(xdr, 4);
 +	BUG_ON(!start);
 +
 +	if (ff_layout_encode_ioerr(flo, xdr, args))
 +		goto out;
 +
 +	ff_layout_encode_iostats(flo, xdr, args);
 +out:
 +	*start = cpu_to_be32((xdr->p - start - 1) * 4);
 +	dprintk("%s: Return\n", __func__);
 +}
 +
 +static struct pnfs_layoutdriver_type flexfilelayout_type = {
 +	.id			= LAYOUT_FLEX_FILES,
 +	.name			= "LAYOUT_FLEX_FILES",
 +	.owner			= THIS_MODULE,
 +	.alloc_layout_hdr	= ff_layout_alloc_layout_hdr,
 +	.free_layout_hdr	= ff_layout_free_layout_hdr,
 +	.alloc_lseg		= ff_layout_alloc_lseg,
 +	.free_lseg		= ff_layout_free_lseg,
 +	.pg_read_ops		= &ff_layout_pg_read_ops,
 +	.pg_write_ops		= &ff_layout_pg_write_ops,
 +	.get_ds_info		= ff_layout_get_ds_info,
 +	.free_deviceid_node	= ff_layout_free_deveiceid_node,
 +	.mark_request_commit	= ff_layout_mark_request_commit,
 +	.clear_request_commit	= pnfs_generic_clear_request_commit,
 +	.scan_commit_lists	= pnfs_generic_scan_commit_lists,
 +	.recover_commit_reqs	= pnfs_generic_recover_commit_reqs,
 +	.commit_pagelist	= ff_layout_commit_pagelist,
 +	.read_pagelist		= ff_layout_read_pagelist,
 +	.write_pagelist		= ff_layout_write_pagelist,
 +	.alloc_deviceid_node    = ff_layout_alloc_deviceid_node,
 +	.encode_layoutreturn    = ff_layout_encode_layoutreturn,
 +};
 +
 +static int __init nfs4flexfilelayout_init(void)
 +{
 +	printk(KERN_INFO "%s: NFSv4 Flexfile Layout Driver Registering...\n",
 +	       __func__);
 +	return pnfs_register_layoutdriver(&flexfilelayout_type);
 +}
 +
 +static void __exit nfs4flexfilelayout_exit(void)
 +{
 +	printk(KERN_INFO "%s: NFSv4 Flexfile Layout Driver Unregistering...\n",
 +	       __func__);
 +	pnfs_unregister_layoutdriver(&flexfilelayout_type);
 +}
 +
 +MODULE_ALIAS("nfs-layouttype4-4");
 +
 +MODULE_LICENSE("GPL");
 +MODULE_DESCRIPTION("The NFSv4 flexfile layout driver");
 +
 +module_init(nfs4flexfilelayout_init);
 +module_exit(nfs4flexfilelayout_exit);
diff --cc fs/nfs/write.c
index bcf83e535f29,298abcc5281b..88a6d2196ece
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@@ -1604,10 -1561,10 +1604,10 @@@ void nfs_retry_commit(struct list_head 
  	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,
+ 			dec_bdi_stat(inode_to_bdi(page_file_mapping(req->wb_page)->host),
  				     BDI_RECLAIMABLE);
  		}
  		nfs_unlock_and_release_request(req);
diff --cc mm/page-writeback.c
index 6a73e47e81c6,d4cbb4bd7d1c..45e187b2d971
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@@ -2311,12 -2310,14 +2313,12 @@@ EXPORT_SYMBOL(clear_page_dirty_for_io)
  int test_clear_page_writeback(struct page *page)
  {
  	struct address_space *mapping = page_mapping(page);
 -	unsigned long memcg_flags;
  	struct mem_cgroup *memcg;
 -	bool locked;
  	int ret;
  
 -	memcg = mem_cgroup_begin_page_stat(page, &locked, &memcg_flags);
 +	memcg = mem_cgroup_begin_page_stat(page);
  	if (mapping) {
- 		struct backing_dev_info *bdi = mapping->backing_dev_info;
+ 		struct backing_dev_info *bdi = inode_to_bdi(mapping->host);
  		unsigned long flags;
  
  		spin_lock_irqsave(&mapping->tree_lock, flags);
@@@ -2346,12 -2347,14 +2348,12 @@@
  int __test_set_page_writeback(struct page *page, bool keep_write)
  {
  	struct address_space *mapping = page_mapping(page);
 -	unsigned long memcg_flags;
  	struct mem_cgroup *memcg;
 -	bool locked;
  	int ret;
  
 -	memcg = mem_cgroup_begin_page_stat(page, &locked, &memcg_flags);
 +	memcg = mem_cgroup_begin_page_stat(page);
  	if (mapping) {
- 		struct backing_dev_info *bdi = mapping->backing_dev_info;
+ 		struct backing_dev_info *bdi = inode_to_bdi(mapping->host);
  		unsigned long flags;
  
  		spin_lock_irqsave(&mapping->tree_lock, flags);
diff --cc mm/swap.c
index 5b3087228b99,4e0109a2f37b..cd3a5e64cea9
--- a/mm/swap.c
+++ b/mm/swap.c
@@@ -1138,10 -1138,10 +1138,8 @@@ void __init swap_setup(void
  #ifdef CONFIG_SWAP
  	int i;
  
- 	if (bdi_init(swapper_spaces[0].backing_dev_info))
- 		panic("Failed to init swap bdi");
 -	for (i = 0; i < MAX_SWAPFILES; i++) {
 +	for (i = 0; i < MAX_SWAPFILES; i++)
  		spin_lock_init(&swapper_spaces[i].tree_lock);
 -		INIT_LIST_HEAD(&swapper_spaces[i].i_mmap_nonlinear);
 -	}
  #endif
  
  	/* Use a smaller cluster for small-memory machines */