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freebsd/sys/vm/default_pager.c
David Greenman 6cde7a165f Fixed two potentially serious classes of bugs:
1) The vnode pager wasn't properly tracking the file size due to
   "size" being page rounded in some cases and not in others.
   This sometimes resulted in corrupted files. First noticed by
   Terry Lambert.
   Fixed by changing the "size" pager_alloc parameter to be a 64bit
   byte value (as opposed to a 32bit page index) and changing the
   pagers and their callers to deal with this properly.
2) Fixed a bogus type cast in round_page() and trunc_page() that
   caused some 64bit offsets and sizes to be scrambled. Removing
   the cast required adding casts at a few dozen callers.
   There may be problems with other bogus casts in close-by
   macros. A quick check seemed to indicate that those were okay,
   however.
1998-10-13 08:24:45 +00:00

163 lines
4.5 KiB
C

/*
* Copyright (c) 1995, David Greenman
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by David Greenman.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: default_pager.c,v 1.15 1998/02/06 12:14:20 eivind Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/vmmeter.h>
#include <vm/vm.h>
#include <vm/vm_prot.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <vm/default_pager.h>
#include <vm/swap_pager.h>
static vm_object_t default_pager_alloc __P((void *, vm_ooffset_t, vm_prot_t,
vm_ooffset_t));
static void default_pager_dealloc __P((vm_object_t));
static int default_pager_getpages __P((vm_object_t, vm_page_t *, int, int));
static int default_pager_putpages __P((vm_object_t, vm_page_t *, int,
boolean_t, int *));
static boolean_t default_pager_haspage __P((vm_object_t, vm_pindex_t, int *,
int *));
/*
* pagerops for OBJT_DEFAULT - "default pager".
*/
struct pagerops defaultpagerops = {
NULL,
default_pager_alloc,
default_pager_dealloc,
default_pager_getpages,
default_pager_putpages,
default_pager_haspage,
NULL
};
/*
* no_pager_alloc just returns an initialized object.
*/
static vm_object_t
default_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
vm_ooffset_t offset)
{
if (handle != NULL)
panic("default_pager_alloc: handle specified");
return vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(round_page(offset + size)));
}
static void
default_pager_dealloc(object)
vm_object_t object;
{
/*
* OBJT_DEFAULT objects have no special resources allocated to them.
*/
}
/*
* The default pager has no backing store, so we always return
* failure.
*/
static int
default_pager_getpages(object, m, count, reqpage)
vm_object_t object;
vm_page_t *m;
int count;
int reqpage;
{
return VM_PAGER_FAIL;
}
static int
default_pager_putpages(object, m, c, sync, rtvals)
vm_object_t object;
vm_page_t *m;
int c;
boolean_t sync;
int *rtvals;
{
int i;
/*
* Try to convert the object type into a OBJT_SWAP.
* If the swp structure allocation fails, convert it
* back to OBJT_DEFAULT and return failure. Otherwise
* pass this putpages to the swap pager.
*/
object->type = OBJT_SWAP;
if (swap_pager_swp_alloc(object, M_KERNEL) != 0) {
object->type = OBJT_DEFAULT;
for (i = 0; i < c; i++)
rtvals[i] = VM_PAGER_FAIL;
return VM_PAGER_FAIL;
}
return swap_pager_putpages(object, m, c, sync, rtvals);
}
static boolean_t
default_pager_haspage(object, pindex, before, after)
vm_object_t object;
vm_pindex_t pindex;
int *before;
int *after;
{
return FALSE;
}
void
default_pager_convert_to_swap(object)
vm_object_t object;
{
object->type = OBJT_SWAP;
if (swap_pager_swp_alloc(object, M_KERNEL) != 0) {
object->type = OBJT_DEFAULT;
}
}
void
default_pager_convert_to_swapq(object)
vm_object_t object;
{
if (object &&
(object->type == OBJT_DEFAULT) &&
(object != kernel_object && object != kmem_object) &&
(object->size > ((cnt.v_page_count - cnt.v_wire_count) / 4)))
default_pager_convert_to_swap(object);
}