/*
* 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 <linux/module.h>
#include <linux/sunrpc/metrics.h>
#include "internal.h"
#include "delegation.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 stripe_no;
u32 rem;
offset -= flseg->pattern_offset;
stripe_no = div_u64(offset, stripe_width);
div_u64_rem(offset, flseg->stripe_unit, &rem);
return stripe_no * flseg->stripe_unit + rem;
}
/* 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();
}
static void filelayout_reset_write(struct nfs_write_data *data)
{
struct nfs_pgio_header *hdr = data->header;
struct rpc_task *task = &data->task;
if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
dprintk("%s Reset task %5u for i/o through MDS "
&qu