NFSv4.1: implement generic pnfs layer write switch

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / nfs / nfs4filelayout.c

/*
 *  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 "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;
        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;
}

/*
 * 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);
}

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,
};

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;
}

static enum pnfs_try_status
filelayout_write_pagelist(struct nfs_write_data *data, int sync)
{
        return PNFS_NOT_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)
{
        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 to large\n",
                                __func__, fl->pattern_offset);
                goto out;
        }

        if (fl->stripe_unit % PAGE_SIZE) {
                dprintk("%s Stripe unit (%u) not page aligned\n",
                        __func__, fl->stripe_unit);
                goto out;
        }

        /* find and reference the deviceid */
        dsaddr = nfs4_fl_find_get_deviceid(id);
        if (dsaddr == NULL) {
                dsaddr = get_device_info(lo->plh_inode, id);
                if (dsaddr == NULL)
                        goto out;
        }
        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)
{
        uint32_t *p = (uint32_t *)lgr->layout.buf;
        uint32_t nfl_util;
        int i;

        dprintk("%s: set_layout_map Begin\n", __func__);

        memcpy(id, p, sizeof(*id));
        p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);
        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);

        fl->fh_array = kzalloc(fl->num_fh * sizeof(struct nfs_fh *),
                               GFP_KERNEL);
        if (!fl->fh_array)
                return -ENOMEM;

        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_KERNEL);
                if (!fl->fh_array[i]) {
                        filelayout_free_fh_array(fl);
                        return -ENOMEM;
                }
                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);
                        filelayout_free_fh_array(fl);
                        return -EIO;
                }
                memcpy(fl->fh_array[i]->data, p, fl->fh_array[i]->size);
                p += XDR_QUADLEN(fl->fh_array[i]->size);
                dprintk("DEBUG: %s: fh len %d\n", __func__,
                        fl->fh_array[i]->size);
        }

        return 0;
}

static struct pnfs_layout_segment *
filelayout_alloc_lseg(struct pnfs_layout_hdr *layoutid,
                      struct nfs4_layoutget_res *lgr)
{
        struct nfs4_filelayout_segment *fl;
        int rc;
        struct nfs4_deviceid id;

        dprintk("--> %s\n", __func__);
        fl = kzalloc(sizeof(*fl), GFP_KERNEL);
        if (!fl)
                return NULL;

        rc = filelayout_decode_layout(layoutid, fl, lgr, &id);
        if (rc != 0 || filelayout_check_layout(layoutid, fl, lgr, &id)) {
                _filelayout_free_lseg(fl);
                return NULL;
        }
        return &fl->generic_hdr;
}

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);
        _filelayout_free_lseg(fl);
}

/*
 * filelayout_pg_test(). Called by nfs_can_coalesce_requests()
 *
 * return 1 :  coalesce page
 * return 0 :  don't coalesce page
 */
int
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 (!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 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,
        .read_pagelist          = filelayout_read_pagelist,
        .write_pagelist         = filelayout_write_pagelist,
};

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);