Merge branch 'mpi-master' into wip-k-fmlpwip-k-fmlp

Conflicts:
	litmus/sched_cedf.c

1 files changed, 906 insertions, 0 deletions

diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
new file mode 100644
index 000000000000..f9d03abcd04c
--- /dev/null
+++ b/fs/nfs/nfs4filelayout.c
@@ -0,0 +1,906 @@
+/*
+ *  Module for the pnfs nfs4 file layout driver.
+ *  Defines all I/O and Policy interface operations, plus code
+ *  to register itself with the pNFS client.
+ *
+ *  Copyright (c) 2002
+ *  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 "internal.h"
+#include "nfs4filelayout.h"
+
+#define NFSDBG_FACILITY         NFSDBG_PNFS_LD
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Dean Hildebrand <dhildebz@umich.edu>");
+MODULE_DESCRIPTION("The NFSv4 file layout driver");
+
+#define FILELAYOUT_POLL_RETRY_MAX     (15*HZ)
+
+static loff_t
+filelayout_get_dense_offset(struct nfs4_filelayout_segment *flseg,
+                            loff_t offset)
+{
+        u32 stripe_width = flseg->stripe_unit * flseg->dsaddr->stripe_count;
+        u64 tmp;
+
+        offset -= flseg->pattern_offset;
+        tmp = offset;
+        do_div(tmp, stripe_width);
+
+        return tmp * flseg->stripe_unit + do_div(offset, flseg->stripe_unit);
+}
+
+/* This function is used by the layout driver to calculate the
+ * offset of the file on the dserver based on whether the
+ * layout type is STRIPE_DENSE or STRIPE_SPARSE
+ */
+static loff_t
+filelayout_get_dserver_offset(struct pnfs_layout_segment *lseg, loff_t offset)
+{
+        struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
+
+        switch (flseg->stripe_type) {
+        case STRIPE_SPARSE:
+                return offset;
+
+        case STRIPE_DENSE:
+                return filelayout_get_dense_offset(flseg, offset);
+        }
+
+        BUG();
+}
+
+/* For data server errors we don't recover from */
+static void
+filelayout_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);
+        }
+}
+
+static int filelayout_async_handle_error(struct rpc_task *task,
+                                         struct nfs4_state *state,
+                                         struct nfs_client *clp,
+                                         int *reset)
+{
+        if (task->tk_status >= 0)
+                return 0;
+
+        *reset = 0;
+
+        switch (task->tk_status) {
+        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);
+                break;
+        case -NFS4ERR_DELAY:
+        case -NFS4ERR_GRACE:
+        case -EKEYEXPIRED:
+                rpc_delay(task, FILELAYOUT_POLL_RETRY_MAX);
+                break;
+        case -NFS4ERR_RETRY_UNCACHED_REP:
+                break;
+        default:
+                dprintk("%s DS error. Retry through MDS %d\n", __func__,
+                        task->tk_status);
+                *reset = 1;
+                break;
+        }
+        task->tk_status = 0;
+        return -EAGAIN;
+}
+
+/* NFS_PROTO call done callback routines */
+
+static int filelayout_read_done_cb(struct rpc_task *task,
+                                struct nfs_read_data *data)
+{
+        struct nfs_client *clp = data->ds_clp;
+        int reset = 0;
+
+        dprintk("%s DS read\n", __func__);
+
+        if (filelayout_async_handle_error(task, data->args.context->state,
+                                          data->ds_clp, &reset) == -EAGAIN) {
+                dprintk("%s calling restart ds_clp %p ds_clp->cl_session %p\n",
+                        __func__, data->ds_clp, data->ds_clp->cl_session);
+                if (reset) {
+                        filelayout_set_lo_fail(data->lseg);
+                        nfs4_reset_read(task, data);
+                        clp = NFS_SERVER(data->inode)->nfs_client;
+                }
+                nfs_restart_rpc(task, clp);
+                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.
+ */
+static void
+filelayout_set_layoutcommit(struct nfs_write_data *wdata)
+{
+        if (FILELAYOUT_LSEG(wdata->lseg)->commit_through_mds ||
+            wdata->res.verf->committed == NFS_FILE_SYNC)
+                return;
+
+        pnfs_set_layoutcommit(wdata);
+        dprintk("%s ionde %lu pls_end_pos %lu\n", __func__, wdata->inode->i_ino,
+                (unsigned long) wdata->lseg->pls_end_pos);
+}
+
+/*
+ * 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 filelayout_read_prepare(struct rpc_task *task, void *data)
+{
+        struct nfs_read_data *rdata = (struct nfs_read_data *)data;
+
+        rdata->read_done_cb = filelayout_read_done_cb;
+
+        if (nfs41_setup_sequence(rdata->ds_clp->cl_session,
+                                &rdata->args.seq_args, &rdata->res.seq_res,
+                                0, task))
+                return;
+
+        rpc_call_start(task);
+}
+
+static void filelayout_read_call_done(struct rpc_task *task, void *data)
+{
+        struct nfs_read_data *rdata = (struct nfs_read_data *)data;
+
+        dprintk("--> %s task->tk_status %d\n", __func__, task->tk_status);
+
+        /* Note this may cause RPC to be resent */
+        rdata->mds_ops->rpc_call_done(task, data);
+}
+
+static void filelayout_read_release(void *data)
+{
+        struct nfs_read_data *rdata = (struct nfs_read_data *)data;
+
+        rdata->mds_ops->rpc_release(data);
+}
+
+static int filelayout_write_done_cb(struct rpc_task *task,
+                                struct nfs_write_data *data)
+{
+        int reset = 0;
+
+        if (filelayout_async_handle_error(task, data->args.context->state,
+                                          data->ds_clp, &reset) == -EAGAIN) {
+                struct nfs_client *clp;
+
+                dprintk("%s calling restart ds_clp %p ds_clp->cl_session %p\n",
+                        __func__, data->ds_clp, data->ds_clp->cl_session);
+                if (reset) {
+                        filelayout_set_lo_fail(data->lseg);
+                        nfs4_reset_write(task, data);
+                        clp = NFS_SERVER(data->inode)->nfs_client;
+                } else
+                        clp = data->ds_clp;
+                nfs_restart_rpc(task, clp);
+                return -EAGAIN;
+        }
+
+        filelayout_set_layoutcommit(data);
+        return 0;
+}
+
+/* Fake up some data that will cause nfs_commit_release to retry the writes. */
+static void prepare_to_resend_writes(struct nfs_write_data *data)
+{
+        struct nfs_page *first = nfs_list_entry(data->pages.next);
+
+        data->task.tk_status = 0;
+        memcpy(data->verf.verifier, first->wb_verf.verifier,
+               sizeof(first->wb_verf.verifier));
+        data->verf.verifier[0]++; /* ensure verifier mismatch */
+}
+
+static int filelayout_commit_done_cb(struct rpc_task *task,
+                                     struct nfs_write_data *data)
+{
+        int reset = 0;
+
+        if (filelayout_async_handle_error(task, data->args.context->state,
+                                          data->ds_clp, &reset) == -EAGAIN) {
+                dprintk("%s calling restart ds_clp %p ds_clp->cl_session %p\n",
+                        __func__, data->ds_clp, data->ds_clp->cl_session);
+                if (reset) {
+                        prepare_to_resend_writes(data);
+                        filelayout_set_lo_fail(data->lseg);
+                } else
+                        nfs_restart_rpc(task, data->ds_clp);
+                return -EAGAIN;
+        }
+
+        return 0;
+}
+
+static void filelayout_write_prepare(struct rpc_task *task, void *data)
+{
+        struct nfs_write_data *wdata = (struct nfs_write_data *)data;
+
+        if (nfs41_setup_sequence(wdata->ds_clp->cl_session,
+                                &wdata->args.seq_args, &wdata->res.seq_res,
+                                0, task))
+                return;
+
+        rpc_call_start(task);
+}
+
+static void filelayout_write_call_done(struct rpc_task *task, void *data)
+{
+        struct nfs_write_data *wdata = (struct nfs_write_data *)data;
+
+        /* Note this may cause RPC to be resent */
+        wdata->mds_ops->rpc_call_done(task, data);
+}
+
+static void filelayout_write_release(void *data)
+{
+        struct nfs_write_data *wdata = (struct nfs_write_data *)data;
+
+        wdata->mds_ops->rpc_release(data);
+}
+
+static void filelayout_commit_release(void *data)
+{
+        struct nfs_write_data *wdata = (struct nfs_write_data *)data;
+
+        nfs_commit_release_pages(wdata);
+        if (atomic_dec_and_test(&NFS_I(wdata->inode)->commits_outstanding))
+                nfs_commit_clear_lock(NFS_I(wdata->inode));
+        nfs_commitdata_release(wdata);
+}
+
+struct rpc_call_ops filelayout_read_call_ops = {
+        .rpc_call_prepare = filelayout_read_prepare,
+        .rpc_call_done = filelayout_read_call_done,
+        .rpc_release = filelayout_read_release,
+};
+
+struct rpc_call_ops filelayout_write_call_ops = {
+        .rpc_call_prepare = filelayout_write_prepare,
+        .rpc_call_done = filelayout_write_call_done,
+        .rpc_release = filelayout_write_release,
+};
+
+struct rpc_call_ops filelayout_commit_call_ops = {
+        .rpc_call_prepare = filelayout_write_prepare,
+        .rpc_call_done = filelayout_write_call_done,
+        .rpc_release = filelayout_commit_release,
+};
+
+static enum pnfs_try_status
+filelayout_read_pagelist(struct nfs_read_data *data)
+{
+        struct pnfs_layout_segment *lseg = data->lseg;
+        struct nfs4_pnfs_ds *ds;
+        loff_t offset = data->args.offset;
+        u32 j, idx;
+        struct nfs_fh *fh;
+        int status;
+
+        dprintk("--> %s ino %lu pgbase %u req %Zu@%llu\n",
+                __func__, data->inode->i_ino,
+                data->args.pgbase, (size_t)data->args.count, offset);
+
+        /* Retrieve the correct rpc_client for the byte range */
+        j = nfs4_fl_calc_j_index(lseg, offset);
+        idx = nfs4_fl_calc_ds_index(lseg, j);
+        ds = nfs4_fl_prepare_ds(lseg, idx);
+        if (!ds) {
+                /* Either layout fh index faulty, or ds connect failed */
+                set_bit(lo_fail_bit(IOMODE_RW), &lseg->pls_layout->plh_flags);
+                set_bit(lo_fail_bit(IOMODE_READ), &lseg->pls_layout->plh_flags);
+                return PNFS_NOT_ATTEMPTED;
+        }
+        dprintk("%s USE DS:ip %x %hu\n", __func__,
+                ntohl(ds->ds_ip_addr), ntohs(ds->ds_port));
+
+        /* No multipath support. Use first DS */
+        data->ds_clp = ds->ds_clp;
+        fh = nfs4_fl_select_ds_fh(lseg, j);
+        if (fh)
+                data->args.fh = fh;
+
+        data->args.offset = filelayout_get_dserver_offset(lseg, offset);
+        data->mds_offset = offset;
+
+        /* Perform an asynchronous read to ds */
+        status = nfs_initiate_read(data, ds->ds_clp->cl_rpcclient,
+                                   &filelayout_read_call_ops);
+        BUG_ON(status != 0);
+        return PNFS_ATTEMPTED;
+}
+
+/* Perform async writes. */
+static enum pnfs_try_status
+filelayout_write_pagelist(struct nfs_write_data *data, int sync)
+{
+        struct pnfs_layout_segment *lseg = data->lseg;
+        struct nfs4_pnfs_ds *ds;
+        loff_t offset = data->args.offset;
+        u32 j, idx;
+        struct nfs_fh *fh;
+        int status;
+
+        /* Retrieve the correct rpc_client for the byte range */
+        j = nfs4_fl_calc_j_index(lseg, offset);
+        idx = nfs4_fl_calc_ds_index(lseg, j);
+        ds = nfs4_fl_prepare_ds(lseg, idx);
+        if (!ds) {
+                printk(KERN_ERR "%s: prepare_ds failed, use MDS\n", __func__);
+                set_bit(lo_fail_bit(IOMODE_RW), &lseg->pls_layout->plh_flags);
+                set_bit(lo_fail_bit(IOMODE_READ), &lseg->pls_layout->plh_flags);
+                return PNFS_NOT_ATTEMPTED;
+        }
+        dprintk("%s ino %lu sync %d req %Zu@%llu DS:%x:%hu\n", __func__,
+                data->inode->i_ino, sync, (size_t) data->args.count, offset,
+                ntohl(ds->ds_ip_addr), ntohs(ds->ds_port));
+
+        data->write_done_cb = filelayout_write_done_cb;
+        data->ds_clp = ds->ds_clp;
+        fh = nfs4_fl_select_ds_fh(lseg, j);
+        if (fh)
+                data->args.fh = fh;
+        /*
+         * Get the file offset on the dserver. Set the write offset to
+         * this offset and save the original offset.
+         */
+        data->args.offset = filelayout_get_dserver_offset(lseg, offset);
+
+        /* Perform an asynchronous write */
+        status = nfs_initiate_write(data, ds->ds_clp->cl_rpcclient,
+                                    &filelayout_write_call_ops, sync);
+        BUG_ON(status != 0);
+        return PNFS_ATTEMPTED;
+}
+
+/*
+ * filelayout_check_layout()
+ *
+ * Make sure layout segment parameters are sane WRT the device.
+ * At this point no generic layer initialization of the lseg has occurred,
+ * and nothing has been added to the layout_hdr cache.
+ *
+ */
+static int
+filelayout_check_layout(struct pnfs_layout_hdr *lo,
+                        struct nfs4_filelayout_segment *fl,
+                        struct nfs4_layoutget_res *lgr,
+                        struct nfs4_deviceid *id,
+                        gfp_t gfp_flags)
+{
+        struct nfs4_deviceid_node *d;
+        struct nfs4_file_layout_dsaddr *dsaddr;
+        int status = -EINVAL;
+        struct nfs_server *nfss = NFS_SERVER(lo->plh_inode);
+
+        dprintk("--> %s\n", __func__);
+
+        if (fl->pattern_offset > lgr->range.offset) {
+                dprintk("%s pattern_offset %lld too large\n",
+                                __func__, fl->pattern_offset);
+                goto out;
+        }
+
+        if (!fl->stripe_unit || fl->stripe_unit % PAGE_SIZE) {
+                dprintk("%s Invalid stripe unit (%u)\n",
+                        __func__, fl->stripe_unit);
+                goto out;
+        }
+
+        /* find and reference the deviceid */
+        d = nfs4_find_get_deviceid(NFS_SERVER(lo->plh_inode)->pnfs_curr_ld,
+                                   NFS_SERVER(lo->plh_inode)->nfs_client, id);
+        if (d == NULL) {
+                dsaddr = get_device_info(lo->plh_inode, id, gfp_flags);
+                if (dsaddr == NULL)
+                        goto out;
+        } else
+                dsaddr = container_of(d, struct nfs4_file_layout_dsaddr, id_node);
+        fl->dsaddr = dsaddr;
+
+        if (fl->first_stripe_index < 0 ||
+            fl->first_stripe_index >= dsaddr->stripe_count) {
+                dprintk("%s Bad first_stripe_index %d\n",
+                                __func__, fl->first_stripe_index);
+                goto out_put;
+        }
+
+        if ((fl->stripe_type == STRIPE_SPARSE &&
+            fl->num_fh > 1 && fl->num_fh != dsaddr->ds_num) ||
+            (fl->stripe_type == STRIPE_DENSE &&
+            fl->num_fh != dsaddr->stripe_count)) {
+                dprintk("%s num_fh %u not valid for given packing\n",
+                        __func__, fl->num_fh);
+                goto out_put;
+        }
+
+        if (fl->stripe_unit % nfss->rsize || fl->stripe_unit % nfss->wsize) {
+                dprintk("%s Stripe unit (%u) not aligned with rsize %u "
+                        "wsize %u\n", __func__, fl->stripe_unit, nfss->rsize,
+                        nfss->wsize);
+        }
+
+        status = 0;
+out:
+        dprintk("--> %s returns %d\n", __func__, status);
+        return status;
+out_put:
+        nfs4_fl_put_deviceid(dsaddr);
+        goto out;
+}
+
+static void filelayout_free_fh_array(struct nfs4_filelayout_segment *fl)
+{
+        int i;
+
+        for (i = 0; i < fl->num_fh; i++) {
+                if (!fl->fh_array[i])
+                        break;
+                kfree(fl->fh_array[i]);
+        }
+        kfree(fl->fh_array);
+        fl->fh_array = NULL;
+}
+
+static void
+_filelayout_free_lseg(struct nfs4_filelayout_segment *fl)
+{
+        filelayout_free_fh_array(fl);
+        kfree(fl);
+}
+
+static int
+filelayout_decode_layout(struct pnfs_layout_hdr *flo,
+                         struct nfs4_filelayout_segment *fl,
+                         struct nfs4_layoutget_res *lgr,
+                         struct nfs4_deviceid *id,
+                         gfp_t gfp_flags)
+{
+        struct xdr_stream stream;
+        struct xdr_buf buf;
+        struct page *scratch;
+        __be32 *p;
+        uint32_t nfl_util;
+        int i;
+
+        dprintk("%s: set_layout_map Begin\n", __func__);
+
+        scratch = alloc_page(gfp_flags);
+        if (!scratch)
+                return -ENOMEM;
+
+        xdr_init_decode_pages(&stream, &buf, lgr->layoutp->pages, lgr->layoutp->len);
+        xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
+
+        /* 20 = ufl_util (4), first_stripe_index (4), pattern_offset (8),
+         * num_fh (4) */
+        p = xdr_inline_decode(&stream, NFS4_DEVICEID4_SIZE + 20);
+        if (unlikely(!p))
+                goto out_err;
+
+        memcpy(id, p, sizeof(*id));
+        p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);
+        nfs4_print_deviceid(id);
+
+        nfl_util = be32_to_cpup(p++);
+        if (nfl_util & NFL4_UFLG_COMMIT_THRU_MDS)
+                fl->commit_through_mds = 1;
+        if (nfl_util & NFL4_UFLG_DENSE)
+                fl->stripe_type = STRIPE_DENSE;
+        else
+                fl->stripe_type = STRIPE_SPARSE;
+        fl->stripe_unit = nfl_util & ~NFL4_UFLG_MASK;
+
+        fl->first_stripe_index = be32_to_cpup(p++);
+        p = xdr_decode_hyper(p, &fl->pattern_offset);
+        fl->num_fh = be32_to_cpup(p++);
+
+        dprintk("%s: nfl_util 0x%X num_fh %u fsi %u po %llu\n",
+                __func__, nfl_util, fl->num_fh, fl->first_stripe_index,
+                fl->pattern_offset);
+
+        /* Note that a zero value for num_fh is legal for STRIPE_SPARSE.
+         * Futher checking is done in filelayout_check_layout */
+        if (fl->num_fh < 0 || fl->num_fh >
+            max(NFS4_PNFS_MAX_STRIPE_CNT, NFS4_PNFS_MAX_MULTI_CNT))
+                goto out_err;
+
+        if (fl->num_fh > 0) {
+                fl->fh_array = kzalloc(fl->num_fh * sizeof(struct nfs_fh *),
+                                       gfp_flags);
+                if (!fl->fh_array)
+                        goto out_err;
+        }
+
+        for (i = 0; i < fl->num_fh; i++) {
+                /* Do we want to use a mempool here? */
+                fl->fh_array[i] = kmalloc(sizeof(struct nfs_fh), gfp_flags);
+                if (!fl->fh_array[i])
+                        goto out_err_free;
+
+                p = xdr_inline_decode(&stream, 4);
+                if (unlikely(!p))
+                        goto out_err_free;
+                fl->fh_array[i]->size = be32_to_cpup(p++);
+                if (sizeof(struct nfs_fh) < fl->fh_array[i]->size) {
+                        printk(KERN_ERR "Too big fh %d received %d\n",
+                               i, fl->fh_array[i]->size);
+                        goto out_err_free;
+                }
+
+                p = xdr_inline_decode(&stream, fl->fh_array[i]->size);
+                if (unlikely(!p))
+                        goto out_err_free;
+                memcpy(fl->fh_array[i]->data, p, fl->fh_array[i]->size);
+                dprintk("DEBUG: %s: fh len %d\n", __func__,
+                        fl->fh_array[i]->size);
+        }
+
+        __free_page(scratch);
+        return 0;
+
+out_err_free:
+        filelayout_free_fh_array(fl);
+out_err:
+        __free_page(scratch);
+        return -EIO;
+}
+
+static void
+filelayout_free_lseg(struct pnfs_layout_segment *lseg)
+{
+        struct nfs4_filelayout_segment *fl = FILELAYOUT_LSEG(lseg);
+
+        dprintk("--> %s\n", __func__);
+        nfs4_fl_put_deviceid(fl->dsaddr);
+        kfree(fl->commit_buckets);
+        _filelayout_free_lseg(fl);
+}
+
+static struct pnfs_layout_segment *
+filelayout_alloc_lseg(struct pnfs_layout_hdr *layoutid,
+                      struct nfs4_layoutget_res *lgr,
+                      gfp_t gfp_flags)
+{
+        struct nfs4_filelayout_segment *fl;
+        int rc;
+        struct nfs4_deviceid id;
+
+        dprintk("--> %s\n", __func__);
+        fl = kzalloc(sizeof(*fl), gfp_flags);
+        if (!fl)
+                return NULL;
+
+        rc = filelayout_decode_layout(layoutid, fl, lgr, &id, gfp_flags);
+        if (rc != 0 || filelayout_check_layout(layoutid, fl, lgr, &id, gfp_flags)) {
+                _filelayout_free_lseg(fl);
+                return NULL;
+        }
+
+        /* This assumes there is only one IOMODE_RW lseg.  What
+         * we really want to do is have a layout_hdr level
+         * dictionary of <multipath_list4, fh> keys, each
+         * associated with a struct list_head, populated by calls
+         * to filelayout_write_pagelist().
+         * */
+        if ((!fl->commit_through_mds) && (lgr->range.iomode == IOMODE_RW)) {
+                int i;
+                int size = (fl->stripe_type == STRIPE_SPARSE) ?
+                        fl->dsaddr->ds_num : fl->dsaddr->stripe_count;
+
+                fl->commit_buckets = kcalloc(size, sizeof(struct list_head), gfp_flags);
+                if (!fl->commit_buckets) {
+                        filelayout_free_lseg(&fl->generic_hdr);
+                        return NULL;
+                }
+                fl->number_of_buckets = size;
+                for (i = 0; i < size; i++)
+                        INIT_LIST_HEAD(&fl->commit_buckets[i]);
+        }
+        return &fl->generic_hdr;
+}
+
+/*
+ * filelayout_pg_test(). Called by nfs_can_coalesce_requests()
+ *
+ * return true  : coalesce page
+ * return false : don't coalesce page
+ */
+bool
+filelayout_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
+                   struct nfs_page *req)
+{
+        u64 p_stripe, r_stripe;
+        u32 stripe_unit;
+
+        if (!pnfs_generic_pg_test(pgio, prev, req) ||
+            !nfs_generic_pg_test(pgio, prev, req))
+                return false;
+
+        if (!pgio->pg_lseg)
+                return 1;
+        p_stripe = (u64)prev->wb_index << PAGE_CACHE_SHIFT;
+        r_stripe = (u64)req->wb_index << PAGE_CACHE_SHIFT;
+        stripe_unit = FILELAYOUT_LSEG(pgio->pg_lseg)->stripe_unit;
+
+        do_div(p_stripe, stripe_unit);
+        do_div(r_stripe, stripe_unit);
+
+        return (p_stripe == r_stripe);
+}
+
+static bool filelayout_mark_pnfs_commit(struct pnfs_layout_segment *lseg)
+{
+        return !FILELAYOUT_LSEG(lseg)->commit_through_mds;
+}
+
+static u32 select_bucket_index(struct nfs4_filelayout_segment *fl, u32 j)
+{
+        if (fl->stripe_type == STRIPE_SPARSE)
+                return nfs4_fl_calc_ds_index(&fl->generic_hdr, j);
+        else
+                return j;
+}
+
+struct list_head *filelayout_choose_commit_list(struct nfs_page *req)
+{
+        struct pnfs_layout_segment *lseg = req->wb_commit_lseg;
+        struct nfs4_filelayout_segment *fl = FILELAYOUT_LSEG(lseg);
+        u32 i, j;
+        struct list_head *list;
+
+        /* Note that we are calling nfs4_fl_calc_j_index on each page
+         * that ends up being committed to a data server.  An attractive
+         * alternative is to add a field to nfs_write_data and nfs_page
+         * to store the value calculated in filelayout_write_pagelist
+         * and just use that here.
+         */
+        j = nfs4_fl_calc_j_index(lseg,
+                                 (loff_t)req->wb_index << PAGE_CACHE_SHIFT);
+        i = select_bucket_index(fl, j);
+        list = &fl->commit_buckets[i];
+        if (list_empty(list)) {
+                /* Non-empty buckets hold a reference on the lseg */
+                get_lseg(lseg);
+        }
+        return list;
+}
+
+static u32 calc_ds_index_from_commit(struct pnfs_layout_segment *lseg, u32 i)
+{
+        struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
+
+        if (flseg->stripe_type == STRIPE_SPARSE)
+                return i;
+        else
+                return nfs4_fl_calc_ds_index(lseg, i);
+}
+
+static struct nfs_fh *
+select_ds_fh_from_commit(struct pnfs_layout_segment *lseg, u32 i)
+{
+        struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
+
+        if (flseg->stripe_type == STRIPE_SPARSE) {
+                if (flseg->num_fh == 1)
+                        i = 0;
+                else if (flseg->num_fh == 0)
+                        /* Use the MDS OPEN fh set in nfs_read_rpcsetup */
+                        return NULL;
+        }
+        return flseg->fh_array[i];
+}
+
+static int filelayout_initiate_commit(struct nfs_write_data *data, int how)
+{
+        struct pnfs_layout_segment *lseg = data->lseg;
+        struct nfs4_pnfs_ds *ds;
+        u32 idx;
+        struct nfs_fh *fh;
+
+        idx = calc_ds_index_from_commit(lseg, data->ds_commit_index);
+        ds = nfs4_fl_prepare_ds(lseg, idx);
+        if (!ds) {
+                printk(KERN_ERR "%s: prepare_ds failed, use MDS\n", __func__);
+                set_bit(lo_fail_bit(IOMODE_RW), &lseg->pls_layout->plh_flags);
+                set_bit(lo_fail_bit(IOMODE_READ), &lseg->pls_layout->plh_flags);
+                prepare_to_resend_writes(data);
+                data->mds_ops->rpc_release(data);
+                return -EAGAIN;
+        }
+        dprintk("%s ino %lu, how %d\n", __func__, data->inode->i_ino, how);
+        data->write_done_cb = filelayout_commit_done_cb;
+        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(data, ds->ds_clp->cl_rpcclient,
+                                   &filelayout_commit_call_ops, how);
+}
+
+/*
+ * This is only useful while we are using whole file layouts.
+ */
+static struct pnfs_layout_segment *find_only_write_lseg(struct inode *inode)
+{
+        struct pnfs_layout_segment *lseg, *rv = NULL;
+
+        spin_lock(&inode->i_lock);
+        list_for_each_entry(lseg, &NFS_I(inode)->layout->plh_segs, pls_list)
+                if (lseg->pls_range.iomode == IOMODE_RW)
+                        rv = get_lseg(lseg);
+        spin_unlock(&inode->i_lock);
+        return rv;
+}
+
+static int alloc_ds_commits(struct inode *inode, struct list_head *list)
+{
+        struct pnfs_layout_segment *lseg;
+        struct nfs4_filelayout_segment *fl;
+        struct nfs_write_data *data;
+        int i, j;
+
+        /* Won't need this when non-whole file layout segments are supported
+         * instead we will use a pnfs_layout_hdr structure */
+        lseg = find_only_write_lseg(inode);
+        if (!lseg)
+                return 0;
+        fl = FILELAYOUT_LSEG(lseg);
+        for (i = 0; i < fl->number_of_buckets; i++) {
+                if (list_empty(&fl->commit_buckets[i]))
+                        continue;
+                data = nfs_commitdata_alloc();
+                if (!data)
+                        goto out_bad;
+                data->ds_commit_index = i;
+                data->lseg = lseg;
+                list_add(&data->pages, list);
+        }
+        put_lseg(lseg);
+        return 0;
+
+out_bad:
+        for (j = i; j < fl->number_of_buckets; j++) {
+                if (list_empty(&fl->commit_buckets[i]))
+                        continue;
+                nfs_retry_commit(&fl->commit_buckets[i], lseg);
+                put_lseg(lseg);  /* associated with emptying bucket */
+        }
+        put_lseg(lseg);
+        /* Caller will clean up entries put on list */
+        return -ENOMEM;
+}
+
+/* This follows nfs_commit_list pretty closely */
+static int
+filelayout_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
+                           int how)
+{
+        struct nfs_write_data   *data, *tmp;
+        LIST_HEAD(list);
+
+        if (!list_empty(mds_pages)) {
+                data = nfs_commitdata_alloc();
+                if (!data)
+                        goto out_bad;
+                data->lseg = NULL;
+                list_add(&data->pages, &list);
+        }
+
+        if (alloc_ds_commits(inode, &list))
+                goto out_bad;
+
+        list_for_each_entry_safe(data, tmp, &list, pages) {
+                list_del_init(&data->pages);
+                atomic_inc(&NFS_I(inode)->commits_outstanding);
+                if (!data->lseg) {
+                        nfs_init_commit(data, mds_pages, NULL);
+                        nfs_initiate_commit(data, NFS_CLIENT(inode),
+                                            data->mds_ops, how);
+                } else {
+                        nfs_init_commit(data, &FILELAYOUT_LSEG(data->lseg)->commit_buckets[data->ds_commit_index], data->lseg);
+                        filelayout_initiate_commit(data, how);
+                }
+        }
+        return 0;
+ out_bad:
+        list_for_each_entry_safe(data, tmp, &list, pages) {
+                nfs_retry_commit(&data->pages, data->lseg);
+                list_del_init(&data->pages);
+                nfs_commit_free(data);
+        }
+        nfs_retry_commit(mds_pages, NULL);
+        nfs_commit_clear_lock(NFS_I(inode));
+        return -ENOMEM;
+}
+
+static void
+filelayout_free_deveiceid_node(struct nfs4_deviceid_node *d)
+{
+        nfs4_fl_free_deviceid(container_of(d, struct nfs4_file_layout_dsaddr, id_node));
+}
+
+static struct pnfs_layoutdriver_type filelayout_type = {
+        .id                     = LAYOUT_NFSV4_1_FILES,
+        .name                   = "LAYOUT_NFSV4_1_FILES",
+        .owner                  = THIS_MODULE,
+        .alloc_lseg             = filelayout_alloc_lseg,
+        .free_lseg              = filelayout_free_lseg,
+        .pg_test                = filelayout_pg_test,
+        .mark_pnfs_commit       = filelayout_mark_pnfs_commit,
+        .choose_commit_list     = filelayout_choose_commit_list,
+        .commit_pagelist        = filelayout_commit_pagelist,
+        .read_pagelist          = filelayout_read_pagelist,
+        .write_pagelist         = filelayout_write_pagelist,
+        .free_deviceid_node     = filelayout_free_deveiceid_node,
+};
+
+static int __init nfs4filelayout_init(void)
+{
+        printk(KERN_INFO "%s: NFSv4 File Layout Driver Registering...\n",
+               __func__);
+        return pnfs_register_layoutdriver(&filelayout_type);
+}
+
+static void __exit nfs4filelayout_exit(void)
+{
+        printk(KERN_INFO "%s: NFSv4 File Layout Driver Unregistering...\n",
+               __func__);
+        pnfs_unregister_layoutdriver(&filelayout_type);
+}
+
+module_init(nfs4filelayout_init);
+module_exit(nfs4filelayout_exit);