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[unix-history] / sys / vm / vnode_pager.c
/*
* Copyright (c) 1990 University of Utah.
* Copyright (c) 1991 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the Systems Programming Group of the University of Utah Computer
* Science Department.
*
* 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 the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91
* $Id: vnode_pager.c,v 1.6 1993/12/19 23:24:18 wollman Exp $
*/
/*
* Page to/from files (vnodes).
*
* TODO:
* pageouts
* fix credential use (uses current process credentials now)
*/
#include "param.h"
#include "systm.h"
#include "proc.h"
#include "malloc.h"
#include "vnode.h"
#include "uio.h"
#include "mount.h"
#include "vm_param.h"
#include "lock.h"
#include "queue.h"
#include "vm_prot.h"
#include "vm_object.h"
#include "vm_page.h"
#include "vnode_pager.h"
struct pagerops vnodepagerops = {
vnode_pager_init,
vnode_pager_alloc,
vnode_pager_dealloc,
vnode_pager_getpage,
vnode_pager_putpage,
vnode_pager_haspage
};
static int vnode_pager_io(vn_pager_t, vm_page_t, enum uio_rw);
queue_head_t vnode_pager_list; /* list of managed vnodes */
#ifdef DEBUG
int vpagerdebug = 0x00;
#define VDB_FOLLOW 0x01
#define VDB_INIT 0x02
#define VDB_IO 0x04
#define VDB_FAIL 0x08
#define VDB_ALLOC 0x10
#define VDB_SIZE 0x20
#endif
void
vnode_pager_init()
{
#ifdef DEBUG
if (vpagerdebug & VDB_FOLLOW)
printf("vnode_pager_init()\n");
#endif
queue_init(&vnode_pager_list);
}
/*
* Allocate (or lookup) pager for a vnode.
* Handle is a vnode pointer.
*/
vm_pager_t
vnode_pager_alloc(handle, size, prot)
caddr_t handle;
vm_size_t size;
vm_prot_t prot;
{
register vm_pager_t pager;
register vn_pager_t vnp;
vm_object_t object;
struct vattr vattr;
struct vnode *vp;
struct proc *p = curproc; /* XXX */
#ifdef DEBUG
if (vpagerdebug & (VDB_FOLLOW|VDB_ALLOC))
printf("vnode_pager_alloc(%x, %x, %x)\n", handle, size, prot);
#endif
/*
* Pageout to vnode, no can do yet.
*/
if (handle == NULL)
return(NULL);
/*
* Vnodes keep a pointer to any associated pager so no need to
* lookup with vm_pager_lookup.
*/
vp = (struct vnode *)handle;
pager = (vm_pager_t)vp->v_vmdata;
if (pager == NULL) {
/*
* Allocate pager structures
*/
pager = (vm_pager_t)malloc(sizeof *pager, M_VMPAGER, M_WAITOK);
if (pager == NULL)
return(NULL);
vnp = (vn_pager_t)malloc(sizeof *vnp, M_VMPGDATA, M_WAITOK);
if (vnp == NULL) {
free((caddr_t)pager, M_VMPAGER);
return(NULL);
}
/*
* And an object of the appropriate size
*/
if (VOP_GETATTR(vp, &vattr, p->p_ucred, p) == 0) {
object = vm_object_allocate(round_page(vattr.va_size));
vm_object_enter(object, pager);
vm_object_setpager(object, pager, 0, TRUE);
} else {
free((caddr_t)vnp, M_VMPGDATA);
free((caddr_t)pager, M_VMPAGER);
return(NULL);
}
/*
* Hold a reference to the vnode and initialize pager data.
*/
VREF(vp);
vnp->vnp_flags = 0;
vnp->vnp_vp = vp;
vnp->vnp_size = vattr.va_size;
queue_enter(&vnode_pager_list, pager, vm_pager_t, pg_list);
pager->pg_handle = handle;
pager->pg_type = PG_VNODE;
pager->pg_ops = &vnodepagerops;
pager->pg_data = (caddr_t)vnp;
vp->v_vmdata = (caddr_t)pager;
} else {
/*
* vm_object_lookup() will remove the object from the
* cache if found and also gain a reference to the object.
*/
object = vm_object_lookup(pager);
#ifdef DEBUG
vnp = (vn_pager_t)pager->pg_data;
#endif
}
#ifdef DEBUG
if (vpagerdebug & VDB_ALLOC)
printf("vnode_pager_setup: vp %x sz %x pager %x object %x\n",
vp, vnp->vnp_size, pager, object);
#endif
return(pager);
}
void
vnode_pager_dealloc(pager)
vm_pager_t pager;
{
register vn_pager_t vnp = (vn_pager_t)pager->pg_data;
register struct vnode *vp;
struct proc *p = curproc; /* XXX */
#ifdef DEBUG
if (vpagerdebug & VDB_FOLLOW)
printf("vnode_pager_dealloc(%x)\n", pager);
#endif
if (vp = vnp->vnp_vp) {
vp->v_vmdata = NULL;
vp->v_flag &= ~VTEXT;
#if 0
/* can hang if done at reboot on NFS FS */
(void) VOP_FSYNC(vp, p->p_ucred, p);
#endif
vrele(vp);
}
queue_remove(&vnode_pager_list, pager, vm_pager_t, pg_list);
free((caddr_t)vnp, M_VMPGDATA);
free((caddr_t)pager, M_VMPAGER);
}
int
vnode_pager_getpage(pager, m, sync)
vm_pager_t pager;
vm_page_t m;
boolean_t sync;
{
#ifdef DEBUG
if (vpagerdebug & VDB_FOLLOW)
printf("vnode_pager_getpage(%x, %x)\n", pager, m);
#endif
return(vnode_pager_io((vn_pager_t)pager->pg_data, m, UIO_READ));
}
boolean_t
vnode_pager_putpage(pager, m, sync)
vm_pager_t pager;
vm_page_t m;
boolean_t sync;
{
int err;
#ifdef DEBUG
if (vpagerdebug & VDB_FOLLOW)
printf("vnode_pager_putpage(%x, %x)\n", pager, m);
#endif
if (pager == NULL)
return 0;
err = vnode_pager_io((vn_pager_t)pager->pg_data, m, UIO_WRITE);
if (err == VM_PAGER_OK) {
m->flags |= PG_CLEAN; /* XXX - wrong place */
pmap_clear_modify(VM_PAGE_TO_PHYS(m)); /* XXX - wrong place */
}
return(err);
}
boolean_t
vnode_pager_haspage(pager, offset)
vm_pager_t pager;
vm_offset_t offset;
{
register vn_pager_t vnp = (vn_pager_t)pager->pg_data;
daddr_t bn;
int err;
#ifdef DEBUG
if (vpagerdebug & VDB_FOLLOW)
printf("vnode_pager_haspage(%x, %x)\n", pager, offset);
#endif
/*
* Offset beyond end of file, do not have the page
*/
if (offset >= vnp->vnp_size) {
#ifdef DEBUG
if (vpagerdebug & (VDB_FAIL|VDB_SIZE))
printf("vnode_pager_haspage: pg %x, off %x, size %x\n",
pager, offset, vnp->vnp_size);
#endif
return(FALSE);
}
/*
* Read the index to find the disk block to read
* from. If there is no block, report that we don't
* have this data.
*
* Assumes that the vnode has whole page or nothing.
*/
err = VOP_BMAP(vnp->vnp_vp,
offset / vnp->vnp_vp->v_mount->mnt_stat.f_bsize,
(struct vnode **)0, &bn);
if (err) {
#ifdef DEBUG
if (vpagerdebug & VDB_FAIL)
printf("vnode_pager_haspage: BMAP err %d, pg %x, off %x\n",
err, pager, offset);
#endif
return(TRUE);
}
return((long)bn < 0 ? FALSE : TRUE);
}
/*
* (XXX)
* Lets the VM system know about a change in size for a file.
* If this vnode is mapped into some address space (i.e. we have a pager
* for it) we adjust our own internal size and flush any cached pages in
* the associated object that are affected by the size change.
*
* Note: this routine may be invoked as a result of a pager put
* operation (possibly at object termination time), so we must be careful.
*/
void
vnode_pager_setsize(vp, nsize)
struct vnode *vp;
u_long nsize;
{
register vn_pager_t vnp;
register vm_object_t object;
vm_pager_t pager;
/*
* Not a mapped vnode
*/
if (vp == NULL || vp->v_type != VREG || vp->v_vmdata == NULL)
return;
/*
* Hasn't changed size
*/
pager = (vm_pager_t)vp->v_vmdata;
vnp = (vn_pager_t)pager->pg_data;
if (nsize == vnp->vnp_size)
return;
/*
* No object.
* This can happen during object termination since
* vm_object_page_clean is called after the object
* has been removed from the hash table, and clean
* may cause vnode write operations which can wind
* up back here.
*/
object = vm_object_lookup(pager);
if (object == NULL)
return;
#ifdef DEBUG
if (vpagerdebug & (VDB_FOLLOW|VDB_SIZE))
printf("vnode_pager_setsize: vp %x obj %x osz %d nsz %d\n",
vp, object, vnp->vnp_size, nsize);
#endif
/*
* File has shrunk.
* Toss any cached pages beyond the new EOF.
*/
if (nsize < vnp->vnp_size) {
vm_object_lock(object);
vm_object_page_remove(object,
(vm_offset_t)nsize, vnp->vnp_size);
vm_object_unlock(object);
}
vnp->vnp_size = (vm_offset_t)nsize;
vm_object_deallocate(object);
}
void
vnode_pager_umount(mp)
register struct mount *mp;
{
register vm_pager_t pager, npager;
struct vnode *vp;
pager = (vm_pager_t) queue_first(&vnode_pager_list);
while (!queue_end(&vnode_pager_list, (queue_entry_t)pager)) {
/*
* Save the next pointer now since uncaching may
* terminate the object and render pager invalid
*/
vp = ((vn_pager_t)pager->pg_data)->vnp_vp;
npager = (vm_pager_t) queue_next(&pager->pg_list);
if (mp == (struct mount *)0 || vp->v_mount == mp)
(void) vnode_pager_uncache(vp);
pager = npager;
}
}
/*
* Remove vnode associated object from the object cache.
*
* Note: this routine may be invoked as a result of a pager put
* operation (possibly at object termination time), so we must be careful.
*/
boolean_t
vnode_pager_uncache(vp)
register struct vnode *vp;
{
register vm_object_t object;
boolean_t uncached, locked;
vm_pager_t pager;
/*
* Not a mapped vnode
*/
pager = (vm_pager_t)vp->v_vmdata;
if (pager == NULL)
return (TRUE);
/*
* Unlock the vnode if it is currently locked.
* We do this since uncaching the object may result
* in its destruction which may initiate paging
* activity which may necessitate locking the vnode.
*/
locked = VOP_ISLOCKED(vp);
if (locked)
VOP_UNLOCK(vp);
/*
* Must use vm_object_lookup() as it actually removes
* the object from the cache list.
*/
object = vm_object_lookup(pager);
if (object) {
uncached = (object->ref_count <= 1);
pager_cache(object, FALSE);
} else
uncached = TRUE;
if (locked)
VOP_LOCK(vp);
return(uncached);
}
static int
vnode_pager_io(vnp, m, rw)
register vn_pager_t vnp;
vm_page_t m;
enum uio_rw rw;
{
struct uio auio;
struct iovec aiov;
vm_offset_t kva, foff;
int error, size;
struct proc *p = curproc; /* XXX */
#ifdef DEBUG
if (vpagerdebug & VDB_FOLLOW)
printf("vnode_pager_io(%x, %x, %c): vnode %x\n",
vnp, m, rw == UIO_READ ? 'R' : 'W', vnp->vnp_vp);
#endif
foff = m->offset + m->object->paging_offset;
/*
* Return failure if beyond current EOF
*/
if (foff >= vnp->vnp_size) {
#ifdef DEBUG
if (vpagerdebug & VDB_SIZE)
printf("vnode_pager_io: vp %x, off %d size %d\n",
vnp->vnp_vp, foff, vnp->vnp_size);
#endif
return(VM_PAGER_BAD);
}
if (foff + PAGE_SIZE > vnp->vnp_size)
size = vnp->vnp_size - foff;
else
size = PAGE_SIZE;
/*
* Allocate a kernel virtual address and initialize so that
* we can use VOP_READ/WRITE routines.
*/
kva = vm_pager_map_page(m);
aiov.iov_base = (caddr_t)kva;
aiov.iov_len = size;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_offset = foff;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_rw = rw;
auio.uio_resid = size;
auio.uio_procp = (struct proc *)0;
#ifdef DEBUG
if (vpagerdebug & VDB_IO)
printf("vnode_pager_io: vp %x kva %x foff %x size %x",
vnp->vnp_vp, kva, foff, size);
#endif
if (rw == UIO_READ)
error = VOP_READ(vnp->vnp_vp, &auio, 0, p->p_ucred);
else
error = VOP_WRITE(vnp->vnp_vp, &auio, 0, p->p_ucred);
#ifdef DEBUG
if (vpagerdebug & VDB_IO) {
if (error || auio.uio_resid)
printf(" returns error %x, resid %x",
error, auio.uio_resid);
printf("\n");
}
#endif
if (!error) {
register int count = size - auio.uio_resid;
if (count == 0)
error = EINVAL;
else if (count != PAGE_SIZE && rw == UIO_READ)
bzero((caddr_t)(kva + count), PAGE_SIZE - count);
}
vm_pager_unmap_page(kva);
return (error ? VM_PAGER_FAIL : VM_PAGER_OK);
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.