path: root/fs/nfs/blocklayout/blocklayout.c

/*
 *  linux/fs/nfs/blocklayout/blocklayout.c
 *
 *  Module for the NFSv4.1 pNFS block layout driver.
 *
 *  Copyright (c) 2006 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  Andy Adamson <andros@citi.umich.edu>
 *  Fred Isaman <iisaman@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 from the
 * university of michigan as to its fitness for any purpose, and without
 * warranty by the university of michigan of any kind, either express
 * or implied, including without limitation the implied warranties of
 * merchantability and fitness for a particular purpose.  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 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/module.h>
#include <linux/init.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/bio.h>		/* struct bio */
#include <linux/buffer_head.h>	/* various write calls */
#include <linux/prefetch.h>

#include "../pnfs.h"
#include "../internal.h"
#include "blocklayout.h"

#define NFSDBG_FACILITY	NFSDBG_PNFS_LD

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Andy Adamson <andros@citi.umich.edu>");
MODULE_DESCRIPTION("The NFSv4.1 pNFS Block layout driver");

static void print_page(struct page *page)
{
	dprintk("PRINTPAGE page %p\n", page);
	dprintk("	PagePrivate %d\n", PagePrivate(page));
	dprintk("	PageUptodate %d\n", PageUptodate(page));
	dprintk("	PageError %d\n", PageError(page));
	dprintk("	PageDirty %d\n", PageDirty(page));
	dprintk("	PageReferenced %d\n", PageReferenced(page));
	dprintk("	PageLocked %d\n", PageLocked(page));
	dprintk("	PageWriteback %d\n", PageWriteback(page));
	dprintk("	PageMappedToDisk %d\n", PageMappedToDisk(page));
	dprintk("\n");
}

/* Given the be associated with isect, determine if page data needs to be
 * initialized.
 */
static int is_hole(struct pnfs_block_extent *be, sector_t isect)
{
	if (be->be_state == PNFS_BLOCK_NONE_DATA)
		return 1;
	else if (be->be_state != PNFS_BLOCK_INVALID_DATA)
		return 0;
	else
		return !bl_is_sector_init(be->be_inval, isect);
}

/* Given the be associated with isect, determine if page data can be
 * written to disk.
 */
static int is_writable(struct pnfs_block_extent *be, sector_t isect)
{
	return (be->be_state == PNFS_BLOCK_READWRITE_DATA ||
		be->be_state == PNFS_BLOCK_INVALID_DATA);
}

/* The data we are handed might be spread across several bios.  We need
 * to track when the last one is finished.
 */
struct parallel_io {
	struct kref refcnt;
	void (*pnfs_callback) (void *data, int num_se);
	void *data;
	int bse_count;
};

static inline struct parallel_io *alloc_parallel(void *data)
{
	struct parallel_io *rv;

	rv  = kmalloc(sizeof(*rv), GFP_NOFS);
	if (rv) {
		rv->data = data;
		kref_init(&rv->refcnt);
		rv->bse_count = 0;
	}
	return rv;
}

static inline void get_parallel(struct parallel_io *p)