freebsd-dev/sys/vm/vnode_pager.c
David Greenman f6b04d2bfb Changes from John Dyson and myself:
Fixed remaining known bugs in the buffer IO and VM system.

vfs_bio.c:
Fixed some race conditions and locking bugs. Improved performance
by removing some (now) unnecessary code and fixing some broken
logic.
Fixed process accounting of # of FS outputs.
Properly handle NFS interrupts (B_EINTR).

(various)
Replaced calls to clrbuf() with calls to an optimized routine
called vfs_bio_clrbuf().

(various FS sync)
Sync out modified vnode_pager backed pages.

ffs_vnops.c:
Do two passes: Sync out file data first, then indirect blocks.

vm_fault.c:
Fixed deadly embrace caused by acquiring locks in the wrong order.

vnode_pager.c:
Changed to use buffer I/O system for writing out modified pages. This
should fix the problem with the modification date previous not getting
updated. Also dramatically simplifies the code. Note that this is
going to change in the future and be implemented via VOP_PUTPAGES().

vm_object.c:
Fixed a pile of bugs related to cleaning (vnode) objects. The performance
of vm_object_page_clean() is terrible when dealing with huge objects,
but this will change when we implement a binary tree to keep the object
pages sorted.

vm_pageout.c:
Fixed broken clustering of pageouts. Fixed race conditions and other
lockup style bugs in the scanning of pages. Improved performance.
1995-04-09 06:03:56 +00:00

1010 lines
22 KiB
C

/*
* Copyright (c) 1990 University of Utah.
* Copyright (c) 1991 The Regents of the University of California.
* All rights reserved.
* Copyright (c) 1993,1994 John S. Dyson
*
* 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 1.36 1995/03/21 23:09:53 davidg Exp $
*/
/*
* Page to/from files (vnodes).
*
* TODO:
* pageouts
* fix credential use (uses current process credentials now)
*/
/*
* 1) Supports multiple - block reads/writes
* 2) Bypasses buffer cache for reads
*
* TODO:
* Implement getpage/putpage interface for filesystems. Should
* greatly re-simplify the vnode_pager.
*
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/vnode.h>
#include <sys/uio.h>
#include <sys/mount.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vnode_pager.h>
#include <sys/buf.h>
#include <miscfs/specfs/specdev.h>
int vnode_pager_putmulti();
void vnode_pager_init();
void vnode_pager_dealloc();
int vnode_pager_getpage();
int vnode_pager_getmulti();
int vnode_pager_putpage();
boolean_t vnode_pager_haspage();
struct pagerops vnodepagerops = {
vnode_pager_init,
vnode_pager_alloc,
vnode_pager_dealloc,
vnode_pager_getpage,
vnode_pager_getmulti,
vnode_pager_putpage,
vnode_pager_putmulti,
vnode_pager_haspage
};
static int vnode_pager_input(vn_pager_t vnp, vm_page_t * m, int count, int reqpage);
static int vnode_pager_output(vn_pager_t vnp, vm_page_t * m, int count, int *rtvals);
extern vm_map_t pager_map;
struct pagerlst vnode_pager_list; /* list of managed vnodes */
#define MAXBP (PAGE_SIZE/DEV_BSIZE);
void
vnode_pager_init()
{
TAILQ_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, offset)
caddr_t handle;
vm_size_t size;
vm_prot_t prot;
vm_offset_t offset;
{
register vm_pager_t pager;
register vn_pager_t vnp;
vm_object_t object, tobject;
struct vattr vattr;
struct vnode *vp;
struct proc *p = curproc; /* XXX */
int rtval;
/*
* 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;
while ((object = (vm_object_t) vp->v_vmdata) &&
(object->flags & OBJ_DEAD))
tsleep((caddr_t) object, PVM, "vadead", 0);
pager = NULL;
if (object != NULL)
pager = object->pager;
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 ((rtval = VOP_GETATTR(vp, &vattr, p->p_ucred, p)) == 0) {
object = vm_object_allocate(round_page(vattr.va_size));
object->flags = OBJ_CANPERSIST;
vm_object_enter(object, pager);
object->pager = pager;
} 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;
TAILQ_INSERT_TAIL(&vnode_pager_list, pager, 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) object;
} else {
/*
* vm_object_lookup() will remove the object from the cache if
* found and also gain a reference to the object.
*/
(void) vm_object_lookup(pager);
}
if( vp->v_type == VREG)
vp->v_flag |= VVMIO;
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;
vm_object_t object;
vp = vnp->vnp_vp;
if (vp) {
int s = splbio();
object = (vm_object_t) vp->v_vmdata;
if (object) {
while (object->paging_in_progress) {
object->flags |= OBJ_PIPWNT;
tsleep(object, PVM, "vnpdea", 0);
}
}
splx(s);
vp->v_vmdata = NULL;
vp->v_flag &= ~(VTEXT | VVMIO);
vp->v_flag |= VAGE;
vrele(vp);
}
TAILQ_REMOVE(&vnode_pager_list, pager, pg_list);
free((caddr_t) vnp, M_VMPGDATA);
free((caddr_t) pager, M_VMPAGER);
}
int
vnode_pager_getmulti(pager, m, count, reqpage, sync)
vm_pager_t pager;
vm_page_t *m;
int count;
int reqpage;
boolean_t sync;
{
return vnode_pager_input((vn_pager_t) pager->pg_data, m, count, reqpage);
}
int
vnode_pager_getpage(pager, m, sync)
vm_pager_t pager;
vm_page_t m;
boolean_t sync;
{
vm_page_t marray[1];
if (pager == NULL)
return FALSE;
marray[0] = m;
return vnode_pager_input((vn_pager_t) pager->pg_data, marray, 1, 0);
}
boolean_t
vnode_pager_putpage(pager, m, sync)
vm_pager_t pager;
vm_page_t m;
boolean_t sync;
{
vm_page_t marray[1];
int rtvals[1];
if (pager == NULL)
return FALSE;
marray[0] = m;
vnode_pager_output((vn_pager_t) pager->pg_data, marray, 1, rtvals);
return rtvals[0];
}
int
vnode_pager_putmulti(pager, m, c, sync, rtvals)
vm_pager_t pager;
vm_page_t *m;
int c;
boolean_t sync;
int *rtvals;
{
return vnode_pager_output((vn_pager_t) pager->pg_data, m, c, rtvals);
}
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;
register struct vnode *vp = vnp->vnp_vp;
daddr_t bn;
int err;
daddr_t block;
/*
* If filesystem no longer mounted or offset beyond end of file we do
* not have the page.
*/
if ((vp->v_mount == NULL) || (offset >= vnp->vnp_size))
return FALSE;
block = offset / vp->v_mount->mnt_stat.f_iosize;
if (incore(vp, block))
return TRUE;
/*
* 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(vp, block, (struct vnode **) 0, &bn, 0);
if (err)
return (TRUE);
return ((long) bn < 0 ? FALSE : TRUE);
}
/*
* 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
*/
object = (vm_object_t) vp->v_vmdata;
if (object == NULL)
return;
if ((pager = object->pager) == NULL)
return;
vnp = (vn_pager_t) pager->pg_data;
if (nsize == vnp->vnp_size)
return;
/*
* File has shrunk. Toss any cached pages beyond the new EOF.
*/
if (nsize < vnp->vnp_size) {
if (round_page((vm_offset_t) nsize) < vnp->vnp_size) {
vm_object_lock(object);
vm_object_page_remove(object,
round_page((vm_offset_t) nsize), vnp->vnp_size, FALSE);
vm_object_unlock(object);
}
/*
* this gets rid of garbage at the end of a page that is now
* only partially backed by the vnode...
*/
if (nsize & PAGE_MASK) {
vm_offset_t kva;
vm_page_t m;
m = vm_page_lookup(object, trunc_page((vm_offset_t) nsize));
if (m) {
kva = vm_pager_map_page(m);
bzero((caddr_t) kva + (nsize & PAGE_MASK),
round_page(nsize) - nsize);
vm_pager_unmap_page(kva);
}
}
}
vnp->vnp_size = (vm_offset_t) nsize;
object->size = round_page(nsize);
}
void
vnode_pager_umount(mp)
register struct mount *mp;
{
register vm_pager_t pager, npager;
struct vnode *vp;
for (pager = vnode_pager_list.tqh_first; pager != NULL; pager = npager) {
/*
* Save the next pointer now since uncaching may terminate the
* object and render pager invalid
*/
npager = pager->pg_list.tqe_next;
vp = ((vn_pager_t) pager->pg_data)->vnp_vp;
if (mp == (struct mount *) 0 || vp->v_mount == mp) {
VOP_LOCK(vp);
(void) vnode_pager_uncache(vp);
VOP_UNLOCK(vp);
}
}
}
/*
* Remove vnode associated object from the object cache.
* This routine must be called with the vnode locked.
*
* XXX unlock the vnode.
* We must do this since uncaching the object may result in its
* destruction which may initiate paging activity which may necessitate
* re-locking the vnode.
*/
boolean_t
vnode_pager_uncache(vp)
register struct vnode *vp;
{
register vm_object_t object;
boolean_t uncached;
vm_pager_t pager;
/*
* Not a mapped vnode
*/
object = (vm_object_t) vp->v_vmdata;
if (object == NULL)
return (TRUE);
pager = object->pager;
if (pager == NULL)
return (TRUE);
#ifdef DEBUG
if (!VOP_ISLOCKED(vp)) {
extern int (**nfsv2_vnodeop_p)();
if (vp->v_op != nfsv2_vnodeop_p)
panic("vnode_pager_uncache: vnode not locked!");
}
#endif
/*
* 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);
VOP_UNLOCK(vp);
pager_cache(object, FALSE);
VOP_LOCK(vp);
} else
uncached = TRUE;
return (uncached);
}
void
vnode_pager_freepage(m)
vm_page_t m;
{
PAGE_WAKEUP(m);
vm_page_free(m);
}
/*
* calculate the linear (byte) disk address of specified virtual
* file address
*/
vm_offset_t
vnode_pager_addr(vp, address, run)
struct vnode *vp;
vm_offset_t address;
int *run;
{
int rtaddress;
int bsize;
vm_offset_t block;
struct vnode *rtvp;
int err;
int vblock, voffset;
if ((int) address < 0)
return -1;
bsize = vp->v_mount->mnt_stat.f_iosize;
vblock = address / bsize;
voffset = address % bsize;
err = VOP_BMAP(vp, vblock, &rtvp, &block, run);
if (err || (block == -1))
rtaddress = -1;
else {
rtaddress = block + voffset / DEV_BSIZE;
if( run) {
*run += 1;
*run *= bsize/PAGE_SIZE;
*run -= voffset/PAGE_SIZE;
}
}
return rtaddress;
}
/*
* interrupt routine for I/O completion
*/
void
vnode_pager_iodone(bp)
struct buf *bp;
{
bp->b_flags |= B_DONE;
wakeup((caddr_t) bp);
}
/*
* small block file system vnode pager input
*/
int
vnode_pager_input_smlfs(vnp, m)
vn_pager_t vnp;
vm_page_t m;
{
int i;
int s;
struct vnode *dp, *vp;
struct buf *bp;
vm_offset_t kva;
int fileaddr;
int block;
vm_offset_t bsize;
int error = 0;
vp = vnp->vnp_vp;
bsize = vp->v_mount->mnt_stat.f_iosize;
VOP_BMAP(vp, 0, &dp, 0, 0);
kva = vm_pager_map_page(m);
for (i = 0; i < PAGE_SIZE / bsize; i++) {
if ((vm_page_bits(m->offset + i * bsize, bsize) & m->valid))
continue;
fileaddr = vnode_pager_addr(vp, m->offset + i * bsize, (int *)0);
if (fileaddr != -1) {
bp = getpbuf();
/* build a minimal buffer header */
bp->b_flags = B_BUSY | B_READ | B_CALL;
bp->b_iodone = vnode_pager_iodone;
bp->b_proc = curproc;
bp->b_rcred = bp->b_wcred = bp->b_proc->p_ucred;
if (bp->b_rcred != NOCRED)
crhold(bp->b_rcred);
if (bp->b_wcred != NOCRED)
crhold(bp->b_wcred);
bp->b_un.b_addr = (caddr_t) kva + i * bsize;
bp->b_blkno = fileaddr;
pbgetvp(dp, bp);
bp->b_bcount = bsize;
bp->b_bufsize = bsize;
/* do the input */
VOP_STRATEGY(bp);
/* we definitely need to be at splbio here */
s = splbio();
while ((bp->b_flags & B_DONE) == 0) {
tsleep((caddr_t) bp, PVM, "vnsrd", 0);
}
splx(s);
if ((bp->b_flags & B_ERROR) != 0)
error = EIO;
/*
* free the buffer header back to the swap buffer pool
*/
relpbuf(bp);
if (error)
break;
vm_page_set_clean(m, (i * bsize) & (PAGE_SIZE-1), bsize);
vm_page_set_valid(m, (i * bsize) & (PAGE_SIZE-1), bsize);
} else {
vm_page_set_clean(m, (i * bsize) & (PAGE_SIZE-1), bsize);
bzero((caddr_t) kva + i * bsize, bsize);
}
nextblock:
}
vm_pager_unmap_page(kva);
pmap_clear_modify(VM_PAGE_TO_PHYS(m));
if (error) {
return VM_PAGER_ERROR;
}
return VM_PAGER_OK;
}
/*
* old style vnode pager output routine
*/
int
vnode_pager_input_old(vnp, m)
vn_pager_t vnp;
vm_page_t m;
{
struct uio auio;
struct iovec aiov;
int error;
int size;
vm_offset_t kva;
error = 0;
/*
* Return failure if beyond current EOF
*/
if (m->offset >= vnp->vnp_size) {
return VM_PAGER_BAD;
} else {
size = PAGE_SIZE;
if (m->offset + size > vnp->vnp_size)
size = vnp->vnp_size - m->offset;
/*
* 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 = m->offset;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_rw = UIO_READ;
auio.uio_resid = size;
auio.uio_procp = (struct proc *) 0;
error = VOP_READ(vnp->vnp_vp, &auio, 0, curproc->p_ucred);
if (!error) {
register int count = size - auio.uio_resid;
if (count == 0)
error = EINVAL;
else if (count != PAGE_SIZE)
bzero((caddr_t) kva + count, PAGE_SIZE - count);
}
vm_pager_unmap_page(kva);
}
pmap_clear_modify(VM_PAGE_TO_PHYS(m));
m->dirty = 0;
return error ? VM_PAGER_ERROR : VM_PAGER_OK;
}
/*
* generic vnode pager input routine
*/
int
vnode_pager_input(vnp, m, count, reqpage)
register vn_pager_t vnp;
vm_page_t *m;
int count, reqpage;
{
int i;
vm_offset_t kva, foff;
int size;
vm_object_t object;
struct vnode *dp, *vp;
int bsize;
int first, last;
int firstaddr;
int block, offset;
int runpg;
int runend;
struct buf *bp;
int s;
int failflag;
int error = 0;
object = m[reqpage]->object; /* all vm_page_t items are in same
* object */
vp = vnp->vnp_vp;
bsize = vp->v_mount->mnt_stat.f_iosize;
/* get the UNDERLYING device for the file with VOP_BMAP() */
/*
* originally, we did not check for an error return value -- assuming
* an fs always has a bmap entry point -- that assumption is wrong!!!
*/
foff = m[reqpage]->offset;
/*
* if we can't bmap, use old VOP code
*/
if (VOP_BMAP(vp, 0, &dp, 0, 0)) {
for (i = 0; i < count; i++) {
if (i != reqpage) {
vnode_pager_freepage(m[i]);
}
}
cnt.v_vnodein++;
cnt.v_vnodepgsin++;
return vnode_pager_input_old(vnp, m[reqpage]);
/*
* if the blocksize is smaller than a page size, then use
* special small filesystem code. NFS sometimes has a small
* blocksize, but it can handle large reads itself.
*/
} else if ((PAGE_SIZE / bsize) > 1 &&
(vp->v_mount->mnt_stat.f_type != MOUNT_NFS)) {
for (i = 0; i < count; i++) {
if (i != reqpage) {
vnode_pager_freepage(m[i]);
}
}
cnt.v_vnodein++;
cnt.v_vnodepgsin++;
return vnode_pager_input_smlfs(vnp, m[reqpage]);
}
/*
* if ANY DEV_BSIZE blocks are valid on a large filesystem block
* then, the entire page is valid --
*/
if (m[reqpage]->valid) {
m[reqpage]->valid = VM_PAGE_BITS_ALL;
for (i = 0; i < count; i++) {
if (i != reqpage)
vnode_pager_freepage(m[i]);
}
return VM_PAGER_OK;
}
/*
* here on direct device I/O
*/
firstaddr = -1;
/*
* calculate the run that includes the required page
*/
for(first = 0, i = 0; i < count; i = runend) {
firstaddr = vnode_pager_addr(vp, m[i]->offset, &runpg);
if (firstaddr == -1) {
if( i == reqpage && foff < vnp->vnp_size) {
printf("vnode_pager_input: unexpected missing page: firstaddr: %d, foff: %d, vnp_size: %d\n",
firstaddr, foff, vnp->vnp_size);
panic("vnode_pager_input:...");
}
vnode_pager_freepage(m[i]);
runend = i + 1;
first = runend;
continue;
}
runend = i + runpg;
if( runend <= reqpage) {
int j;
for(j = i; j < runend; j++) {
vnode_pager_freepage(m[j]);
}
} else {
if( runpg < (count - first)) {
for(i=first + runpg; i < count; i++)
vnode_pager_freepage(m[i]);
count = first + runpg;
}
break;
}
first = runend;
}
/*
* the first and last page have been calculated now, move input pages
* to be zero based...
*/
if (first != 0) {
for (i = first; i < count; i++) {
m[i - first] = m[i];
}
count -= first;
reqpage -= first;
}
/*
* calculate the file virtual address for the transfer
*/
foff = m[0]->offset;
/*
* calculate the size of the transfer
*/
size = count * PAGE_SIZE;
if ((foff + size) > vnp->vnp_size)
size = vnp->vnp_size - foff;
/*
* round up physical size for real devices
*/
if (dp->v_type == VBLK || dp->v_type == VCHR)
size = (size + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1);
bp = getpbuf();
kva = (vm_offset_t) bp->b_data;
/*
* and map the pages to be read into the kva
*/
pmap_qenter(kva, m, count);
/* build a minimal buffer header */
bp->b_flags = B_BUSY | B_READ | B_CALL;
bp->b_iodone = vnode_pager_iodone;
/* B_PHYS is not set, but it is nice to fill this in */
bp->b_proc = curproc;
bp->b_rcred = bp->b_wcred = bp->b_proc->p_ucred;
if (bp->b_rcred != NOCRED)
crhold(bp->b_rcred);
if (bp->b_wcred != NOCRED)
crhold(bp->b_wcred);
bp->b_blkno = firstaddr;
pbgetvp(dp, bp);
bp->b_bcount = size;
bp->b_bufsize = size;
cnt.v_vnodein++;
cnt.v_vnodepgsin += count;
/* do the input */
VOP_STRATEGY(bp);
s = splbio();
/* we definitely need to be at splbio here */
while ((bp->b_flags & B_DONE) == 0) {
tsleep((caddr_t) bp, PVM, "vnread", 0);
}
splx(s);
if ((bp->b_flags & B_ERROR) != 0)
error = EIO;
if (!error) {
if (size != count * PAGE_SIZE)
bzero((caddr_t) kva + size, PAGE_SIZE * count - size);
}
pmap_qremove(kva, count);
/*
* free the buffer header back to the swap buffer pool
*/
relpbuf(bp);
finishup:
for (i = 0; i < count; i++) {
pmap_clear_modify(VM_PAGE_TO_PHYS(m[i]));
m[i]->dirty = 0;
m[i]->valid = VM_PAGE_BITS_ALL;
if (i != reqpage) {
/*
* whether or not to leave the page activated is up in
* the air, but we should put the page on a page queue
* somewhere. (it already is in the object). Result:
* It appears that emperical results show that
* deactivating pages is best.
*/
/*
* just in case someone was asking for this page we
* now tell them that it is ok to use
*/
if (!error) {
vm_page_deactivate(m[i]);
PAGE_WAKEUP(m[i]);
} else {
vnode_pager_freepage(m[i]);
}
}
}
if (error) {
printf("vnode_pager_input: I/O read error\n");
}
return (error ? VM_PAGER_ERROR : VM_PAGER_OK);
}
/*
* generic vnode pager output routine
*/
int
vnode_pager_output(vnp, m, count, rtvals)
vn_pager_t vnp;
vm_page_t *m;
int count;
int *rtvals;
{
int i;
struct vnode *vp;
int maxsize, ncount;
struct uio auio;
struct iovec aiov;
int error;
vp = vnp->vnp_vp;
for (i = 0; i < count; i++)
rtvals[i] = VM_PAGER_AGAIN;
if ((int) m[0]->offset < 0) {
printf("vnode_pager_output: attempt to write meta-data!!! -- 0x%x(%x)\n", m[0]->offset, m[0]->dirty);
rtvals[0] = VM_PAGER_BAD;
return VM_PAGER_BAD;
}
maxsize = count * PAGE_SIZE;
ncount = count;
if( maxsize + m[0]->offset > vnp->vnp_size) {
maxsize = vnp->vnp_size - m[0]->offset;
ncount = (maxsize + PAGE_SIZE - 1) / PAGE_SIZE;
if( ncount < count) {
for(i=ncount;i<count;i++) {
rtvals[i] = VM_PAGER_BAD;
}
if( ncount == 0) {
printf("vnode_pager_output: write past end of file: %d, %d\n",
m[0]->offset, vnp->vnp_size);
return rtvals[0];
}
}
}
for(i=0;i<count;i++) {
++m[i]->busy;
m[i]->flags &= ~PG_BUSY;
}
aiov.iov_base = (caddr_t) 0;
aiov.iov_len = maxsize;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_offset = m[0]->offset;
auio.uio_segflg = UIO_NOCOPY;
auio.uio_rw = UIO_WRITE;
auio.uio_resid = maxsize;
auio.uio_procp = (struct proc *) 0;
error = VOP_WRITE(vp, &auio, IO_VMIO, curproc->p_ucred);
cnt.v_vnodeout++;
cnt.v_vnodepgsout += ncount;
if( error) {
printf("vnode_pager_output: I/O error %d\n", error);
}
if( auio.uio_resid) {
printf("vnode_pager_output: residual I/O %d at %d\n", auio.uio_resid, m[0]->offset);
}
for(i=0;i < count;i++) {
--m[i]->busy;
if( i < ncount) {
rtvals[i] = VM_PAGER_OK;
}
if((m[i]->busy == 0) && (m[i]->flags & PG_WANTED))
wakeup((caddr_t) m[i]);
}
return rtvals[0];
}
struct vnode *
vnode_pager_lock(vm_object_t object) {
for(;object;object=object->shadow) {
vn_pager_t vnp;
if( !object->pager || (object->pager->pg_type != PG_VNODE))
continue;
vnp = (vn_pager_t) object->pager->pg_data;
VOP_LOCK(vnp->vnp_vp);
return vnp->vnp_vp;
}
return (struct vnode *)NULL;
}
void
vnode_pager_unlock(struct vnode *vp) {
VOP_UNLOCK(vp);
}