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freebsd-nq/sys/vm/vnode_pager.c
David Greenman a481f20029 Provide support for upcoming merged VM/buffer cache, and fixed a few bugs 
that haven't appeared to manifest themselves (yet).

Submitted by:	John Dyson
1994-08-07 13:10:43 +00:00

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/*
* 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 1.5 1994/08/06 10:25:50 davidg Exp $
*/
/*
* Page to/from files (vnodes).
*
* TODO:
* pageouts
* fix credential use (uses current process credentials now)
*/
/*
* MODIFICATIONS:
* John S. Dyson 08 Dec 93
*
* This file in conjunction with some vm_fault mods, eliminate the performance
* advantage for using the buffer cache and minimize memory copies.
*
* 1) Supports multiple - block reads
* 2) Bypasses buffer cache for reads
*
* TODO:
*
* 1) Totally bypass buffer cache for reads
* (Currently will still sometimes use buffer cache for reads)
* 2) Bypass buffer cache for writes
* (Code does not support it, but mods are simple)
*/
#include <sys/param.h>
#include <sys/systm.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();
vm_pager_t vnode_pager_alloc(caddr_t, vm_offset_t, vm_prot_t, vm_offset_t);
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);
struct buf * getpbuf();
void relpbuf(struct buf * bp);
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;
struct vattr vattr;
struct vnode *vp;
struct proc *p = curproc; /* XXX */
/*
* 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;
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) 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);
}
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 */
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);
}
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;
{
int err;
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;
{
int err;
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;
daddr_t bn;
int err;
/*
* Offset beyond end of file, do not have the page
*/
if (offset >= vnp->vnp_size) {
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_iosize,
(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
*/
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;
/*
* 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,
round_page((vm_offset_t) nsize), vnp->vnp_size);
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);
}
}
} else {
/*
* this allows the filesystem and VM cache to stay in sync if
* the VM page hasn't been modified... After the page is
* removed -- it will be faulted back in from the filesystem
* cache.
*/
if (vnp->vnp_size & PAGE_MASK) {
vm_page_t m;
m = vm_page_lookup(object, trunc_page(vnp->vnp_size));
if (m && (m->flags & PG_CLEAN)) {
vm_object_lock(object);
vm_object_page_remove(object,
vnp->vnp_size, vnp->vnp_size);
vm_object_unlock(object);
}
}
}
vnp->vnp_size = (vm_offset_t) nsize;
object->size = round_page(nsize);
vm_object_deallocate(object);
}
void
vnode_pager_umount(mp)
register struct mount *mp;
{
register vm_pager_t pager, npager;
struct vnode *vp;
pager = vnode_pager_list.tqh_first;
while (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 = pager->pg_list.tqe_next;
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);
}
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)
struct vnode *vp;
vm_offset_t address;
{
int rtaddress;
int bsize;
vm_offset_t block;
struct vnode *rtvp;
int err;
int vblock, voffset;
bsize = vp->v_mount->mnt_stat.f_iosize;
vblock = address / bsize;
voffset = address % bsize;
err = VOP_BMAP(vp, vblock, &rtvp, &block, 0);
if (err)
rtaddress = -1;
else
rtaddress = block * DEV_BSIZE + voffset;
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);
if( bp->b_flags & B_ASYNC) {
vm_offset_t paddr;
vm_page_t m;
vm_object_t obj = 0;
int i;
int npages;
paddr = (vm_offset_t) bp->b_data;
if( bp->b_bufsize != bp->b_bcount)
bzero( bp->b_data + bp->b_bcount,
bp->b_bufsize - bp->b_bcount);
npages = (bp->b_bufsize + PAGE_SIZE - 1) / PAGE_SIZE;
/*
printf("bcount: %d, bufsize: %d, npages: %d\n",
bp->b_bcount, bp->b_bufsize, npages);
*/
for( i = 0; i < npages; i++) {
m = PHYS_TO_VM_PAGE(pmap_kextract(paddr + i * PAGE_SIZE));
obj = m->object;
if( m) {
m->flags |= PG_CLEAN;
m->flags &= ~(PG_LAUNDRY|PG_FAKE);
PAGE_WAKEUP(m);
} else {
panic("vnode_pager_iodone: page is gone!!!");
}
}
pmap_qremove( paddr, npages);
if( obj) {
--obj->paging_in_progress;
if( obj->paging_in_progress == 0)
wakeup((caddr_t) obj);
} else {
panic("vnode_pager_iodone: object is gone???");
}
HOLDRELE(bp->b_vp);
relpbuf(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;
vm_offset_t paging_offset;
struct vnode *dp, *vp;
struct buf *bp;
vm_offset_t foff;
vm_offset_t kva;
int fileaddr;
int block;
vm_offset_t bsize;
int error = 0;
paging_offset = m->object->paging_offset;
vp = vnp->vnp_vp;
bsize = vp->v_mount->mnt_stat.f_iosize;
foff = m->offset + paging_offset;
VOP_BMAP(vp, foff, &dp, 0, 0);
kva = vm_pager_map_page(m);
for (i = 0; i < PAGE_SIZE / bsize; i++) {
/*
* calculate logical block and offset
*/
block = foff / bsize + i;
s = splbio();
while (bp = incore(vp, block)) {
int amount;
/*
* wait until the buffer is avail or gone
*/
if (bp->b_flags & B_BUSY) {
bp->b_flags |= B_WANTED;
tsleep((caddr_t) bp, PVM, "vnwblk", 0);
continue;
}
amount = bsize;
if ((foff + bsize) > vnp->vnp_size)
amount = vnp->vnp_size - foff;
/*
* make sure that this page is in the buffer
*/
if ((amount > 0) && amount <= bp->b_bcount) {
bp->b_flags |= B_BUSY;
splx(s);
/*
* copy the data from the buffer
*/
bcopy(bp->b_un.b_addr, (caddr_t) kva + i * bsize, amount);
if (amount < bsize) {
bzero((caddr_t) kva + amount, bsize - amount);
}
bp->b_flags &= ~B_BUSY;
wakeup((caddr_t) bp);
goto nextblock;
}
break;
}
splx(s);
fileaddr = vnode_pager_addr(vp, foff + i * bsize);
if (fileaddr != -1) {
bp = getpbuf();
VHOLD(vp);
/* 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 / DEV_BSIZE;
bgetvp(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);
HOLDRELE(vp);
if (error)
break;
} else {
bzero((caddr_t) kva + i * bsize, bsize);
}
nextblock:
}
vm_pager_unmap_page(kva);
if (error) {
return VM_PAGER_FAIL;
}
pmap_clear_modify(VM_PAGE_TO_PHYS(m));
m->flags |= PG_CLEAN;
m->flags &= ~PG_LAUNDRY;
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;
{
int i;
struct uio auio;
struct iovec aiov;
int error;
int size;
vm_offset_t foff;
vm_offset_t kva;
error = 0;
foff = m->offset + m->object->paging_offset;
/*
* Return failure if beyond current EOF
*/
if (foff >= vnp->vnp_size) {
return VM_PAGER_BAD;
} else {
size = PAGE_SIZE;
if (foff + size > vnp->vnp_size)
size = vnp->vnp_size - foff;
/*
* 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 = 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->flags |= PG_CLEAN;
m->flags &= ~PG_LAUNDRY;
return error ? VM_PAGER_FAIL : 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, j;
vm_offset_t kva, foff;
int size, sizea;
struct proc *p = curproc; /* XXX */
vm_object_t object;
vm_offset_t paging_offset;
struct vnode *dp, *vp;
int bsize;
int first, last;
int reqaddr, firstaddr;
int block, offset;
int nbp;
struct buf *bp, *bpa;
int counta;
int s;
int failflag;
int errtype = 0; /* 0 is file type otherwise vm type */
int error = 0;
object = m[reqpage]->object; /* all vm_page_t items are in same
* object */
paging_offset = object->paging_offset;
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 + paging_offset;
/*
* if we can't bmap, use old VOP code
*/
if (VOP_BMAP(vp, foff, &dp, 0, 0)) {
for (i = 0; i < count; i++) {
if (i != reqpage) {
vnode_pager_freepage(m[i]);
}
}
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]);
}
}
return vnode_pager_input_smlfs(vnp, m[reqpage]);
}
/*
* here on direct device I/O
*/
/*
* This pathetic hack gets data from the buffer cache, if it's there.
* I believe that this is not really necessary, and the ends can be
* gotten by defaulting to the normal vfs read behavior, but this
* might be more efficient, because the will NOT invoke read-aheads
* and one of the purposes of this code is to bypass the buffer cache
* and keep from flushing it by reading in a program.
*/
/*
* calculate logical block and offset
*/
block = foff / bsize;
offset = foff % bsize;
s = splbio();
/*
* if we have a buffer in core, then try to use it
*/
while (bp = incore(vp, block)) {
int amount;
/*
* wait until the buffer is avail or gone
*/
if (bp->b_flags & B_BUSY) {
bp->b_flags |= B_WANTED;
tsleep((caddr_t) bp, PVM, "vnwblk", 0);
continue;
}
amount = PAGE_SIZE;
if ((foff + amount) > vnp->vnp_size)
amount = vnp->vnp_size - foff;
/*
* make sure that this page is in the buffer
*/
if ((amount > 0) && (offset + amount) <= bp->b_bcount) {
bp->b_flags |= B_BUSY;
splx(s);
kva = kmem_alloc_pageable( pager_map, PAGE_SIZE);
/*
* map the requested page
*/
pmap_qenter(kva, &m[reqpage], 1);
/*
* copy the data from the buffer
*/
bcopy(bp->b_un.b_addr + offset, (caddr_t) kva, amount);
if (amount < PAGE_SIZE) {
bzero((caddr_t) kva + amount, PAGE_SIZE - amount);
}
/*
* unmap the page and free the kva
*/
pmap_qremove( kva, 1);
kmem_free_wakeup(pager_map, kva, PAGE_SIZE);
/*
* release the buffer back to the block subsystem
*/
bp->b_flags &= ~B_BUSY;
wakeup((caddr_t) bp);
/*
* we did not have to do any work to get the requested
* page, the read behind/ahead does not justify a read
*/
for (i = 0; i < count; i++) {
if (i != reqpage) {
vnode_pager_freepage(m[i]);
}
}
count = 1;
reqpage = 0;
m[0] = m[reqpage];
/*
* sorry for the goto
*/
goto finishup;
}
/*
* buffer is nowhere to be found, read from the disk
*/
break;
}
splx(s);
reqaddr = vnode_pager_addr(vp, foff);
s = splbio();
/*
* Make sure that our I/O request is contiguous. Scan backward and
* stop for the first discontiguous entry or stop for a page being in
* buffer cache.
*/
failflag = 0;
first = reqpage;
for (i = reqpage - 1; i >= 0; --i) {
if (failflag ||
incore(vp, (foff + (i - reqpage) * PAGE_SIZE) / bsize) ||
(vnode_pager_addr(vp, m[i]->offset + paging_offset))
!= reqaddr + (i - reqpage) * PAGE_SIZE) {
vnode_pager_freepage(m[i]);
failflag = 1;
} else {
first = i;
}
}
/*
* Scan forward and stop for the first non-contiguous entry or stop
* for a page being in buffer cache.
*/
failflag = 0;
last = reqpage + 1;
for (i = reqpage + 1; i < count; i++) {
if (failflag ||
incore(vp, (foff + (i - reqpage) * PAGE_SIZE) / bsize) ||
(vnode_pager_addr(vp, m[i]->offset + paging_offset))
!= reqaddr + (i - reqpage) * PAGE_SIZE) {
vnode_pager_freepage(m[i]);
failflag = 1;
} else {
last = i + 1;
}
}
splx(s);
/*
* the first and last page have been calculated now, move input pages
* to be zero based...
*/
count = last;
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 + paging_offset;
/*
* and get the disk physical address (in bytes)
*/
firstaddr = vnode_pager_addr(vp, foff);
/*
* 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);
counta = 0;
if( count*PAGE_SIZE > bsize)
counta = (count - reqpage) - 1;
bpa = 0;
sizea = 0;
if( counta) {
bpa = getpbuf();
count -= counta;
sizea = size - count*PAGE_SIZE;
size = count * PAGE_SIZE;
}
bp = getpbuf();
kva = (vm_offset_t)bp->b_data;
/*
* and map the pages to be read into the kva
*/
pmap_qenter(kva, m, count);
VHOLD(vp);
/* 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 / DEV_BSIZE;
bgetvp(dp, bp);
bp->b_bcount = size;
bp->b_bufsize = size;
/* do the input */
VOP_STRATEGY(bp);
if( counta) {
for(i=0;i<counta;i++) {
vm_page_deactivate(m[count+i]);
}
pmap_qenter((vm_offset_t)bpa->b_data, &m[count], counta);
++m[count]->object->paging_in_progress;
VHOLD(vp);
bpa->b_flags = B_BUSY | B_READ | B_CALL | B_ASYNC;
bpa->b_iodone = vnode_pager_iodone;
/* B_PHYS is not set, but it is nice to fill this in */
bpa->b_proc = curproc;
bpa->b_rcred = bpa->b_wcred = bpa->b_proc->p_ucred;
if (bpa->b_rcred != NOCRED)
crhold(bpa->b_rcred);
if (bpa->b_wcred != NOCRED)
crhold(bpa->b_wcred);
bpa->b_blkno = (firstaddr + count * PAGE_SIZE) / DEV_BSIZE;
bgetvp(dp, bpa);
bpa->b_bcount = sizea;
bpa->b_bufsize = counta*PAGE_SIZE;
VOP_STRATEGY(bpa);
}
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);
HOLDRELE(vp);
finishup:
for (i = 0; i < count; i++) {
m[i]->flags |= PG_CLEAN;
m[i]->flags &= ~PG_LAUNDRY;
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]);
m[i]->flags &= ~PG_FAKE;
} else {
vnode_pager_freepage(m[i]);
}
}
}
if (error) {
printf("vnode pager read error: %d\n", error);
}
if (errtype)
return error;
return (error ? VM_PAGER_FAIL : VM_PAGER_OK);
}
/*
* old-style vnode pager output routine
*/
int
vnode_pager_output_old(vnp, m)
register vn_pager_t vnp;
vm_page_t m;
{
vm_offset_t foff;
vm_offset_t kva;
vm_offset_t size;
struct iovec aiov;
struct uio auio;
struct vnode *vp;
int error;
vp = vnp->vnp_vp;
foff = m->offset + m->object->paging_offset;
/*
* Return failure if beyond current EOF
*/
if (foff >= vnp->vnp_size) {
return VM_PAGER_BAD;
} else {
size = PAGE_SIZE;
if (foff + size > vnp->vnp_size)
size = vnp->vnp_size - foff;
/*
* Allocate a kernel virtual address and initialize so that
* we can use VOP_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 = UIO_WRITE;
auio.uio_resid = size;
auio.uio_procp = (struct proc *) 0;
error = VOP_WRITE(vp, &auio, 0, curproc->p_ucred);
if (!error) {
if ((size - auio.uio_resid) == 0) {
error = EINVAL;
}
}
vm_pager_unmap_page(kva);
return error ? VM_PAGER_FAIL : VM_PAGER_OK;
}
}
/*
* vnode pager output on a small-block file system
*/
int
vnode_pager_output_smlfs(vnp, m)
vn_pager_t vnp;
vm_page_t m;
{
int i;
int s;
vm_offset_t paging_offset;
struct vnode *dp, *vp;
struct buf *bp;
vm_offset_t foff;
vm_offset_t kva;
int fileaddr;
int block;
vm_offset_t bsize;
int error = 0;
paging_offset = m->object->paging_offset;
vp = vnp->vnp_vp;
bsize = vp->v_mount->mnt_stat.f_iosize;
foff = m->offset + paging_offset;
VOP_BMAP(vp, foff, &dp, 0, 0);
kva = vm_pager_map_page(m);
for (i = 0; !error && i < (PAGE_SIZE / bsize); i++) {
/*
* calculate logical block and offset
*/
fileaddr = vnode_pager_addr(vp, foff + i * bsize);
if (fileaddr != -1) {
s = splbio();
if (bp = incore(vp, (foff / bsize) + i)) {
bp = getblk(vp, (foff / bsize) + i, bp->b_bufsize, 0, 0);
bp->b_flags |= B_INVAL;
brelse(bp);
}
splx(s);
bp = getpbuf();
VHOLD(vp);
/* build a minimal buffer header */
bp->b_flags = B_BUSY | B_CALL | B_WRITE;
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 / DEV_BSIZE;
bgetvp(dp, bp);
++dp->v_numoutput;
/* for NFS */
bp->b_dirtyoff = 0;
bp->b_dirtyend = bsize;
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, "vnswrt", 0);
}
splx(s);
if ((bp->b_flags & B_ERROR) != 0)
error = EIO;
/*
* free the buffer header back to the swap buffer pool
*/
relpbuf(bp);
HOLDRELE(vp);
}
}
vm_pager_unmap_page(kva);
if (error)
return VM_PAGER_FAIL;
else
return 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, j;
vm_offset_t kva, foff;
int size;
struct proc *p = curproc; /* XXX */
vm_object_t object;
vm_offset_t paging_offset;
struct vnode *dp, *vp;
struct buf *bp;
vm_offset_t reqaddr;
int bsize;
int s;
int error = 0;
retryoutput:
object = m[0]->object; /* all vm_page_t items are in same object */
paging_offset = object->paging_offset;
vp = vnp->vnp_vp;
bsize = vp->v_mount->mnt_stat.f_iosize;
for (i = 0; i < count; i++)
rtvals[i] = VM_PAGER_AGAIN;
/*
* if the filesystem does not have a bmap, then use the old code
*/
if (VOP_BMAP(vp, m[0]->offset + paging_offset, &dp, 0, 0)) {
rtvals[0] = vnode_pager_output_old(vnp, m[0]);
pmap_clear_modify(VM_PAGE_TO_PHYS(m[0]));
m[0]->flags |= PG_CLEAN;
m[0]->flags &= ~PG_LAUNDRY;
return rtvals[0];
}
/*
* if the filesystem has a small blocksize, then use the small block
* filesystem output code
*/
if ((bsize < PAGE_SIZE) &&
(vp->v_mount->mnt_stat.f_type != MOUNT_NFS)) {
for (i = 0; i < count; i++) {
rtvals[i] = vnode_pager_output_smlfs(vnp, m[i]);
if (rtvals[i] == VM_PAGER_OK) {
pmap_clear_modify(VM_PAGE_TO_PHYS(m[i]));
m[i]->flags |= PG_CLEAN;
m[i]->flags &= ~PG_LAUNDRY;
}
}
return rtvals[0];
}
for (i = 0; i < count; i++) {
foff = m[i]->offset + paging_offset;
if (foff >= vnp->vnp_size) {
for (j = i; j < count; j++)
rtvals[j] = VM_PAGER_BAD;
count = i;
break;
}
}
if (count == 0) {
return rtvals[0];
}
foff = m[0]->offset + paging_offset;
reqaddr = vnode_pager_addr(vp, foff);
/*
* Scan forward and stop for the first non-contiguous entry or stop
* for a page being in buffer cache.
*/
for (i = 1; i < count; i++) {
if (vnode_pager_addr(vp, m[i]->offset + paging_offset)
!= reqaddr + i * PAGE_SIZE) {
count = i;
break;
}
}
/*
* 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);
printf("vnode: writing foff: %d, devoff: %d, size: %d\n",
foff, reqaddr, size);
/*
* next invalidate the incore vfs_bio data
*/
for (i = 0; i < count; i++) {
int filblock = (foff + i * PAGE_SIZE) / bsize;
struct buf *fbp;
s = splbio();
if (fbp = incore(vp, filblock)) {
fbp = getblk(vp, filblock, fbp->b_bufsize, 0, 0);
if (fbp->b_flags & B_DELWRI) {
if (fbp->b_bufsize <= PAGE_SIZE)
fbp->b_flags &= ~B_DELWRI;
else {
bwrite(fbp);
fbp = getblk(vp, filblock,
fbp->b_bufsize, 0, 0);
}
}
fbp->b_flags |= B_INVAL;
brelse(fbp);
}
splx(s);
}
VHOLD(vp);
/* build a minimal buffer header */
bp->b_flags = B_BUSY | B_WRITE | 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 = reqaddr / DEV_BSIZE;
bgetvp(dp, bp);
++dp->v_numoutput;
/* for NFS */
bp->b_dirtyoff = 0;
bp->b_dirtyend = size;
bp->b_bcount = size;
bp->b_bufsize = size;
/* do the output */
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, "vnwrite", 0);
}
splx(s);
if ((bp->b_flags & B_ERROR) != 0)
error = EIO;
pmap_qremove( kva, count);
/*
* free the buffer header back to the swap buffer pool
*/
relpbuf(bp);
HOLDRELE(vp);
if (!error) {
for (i = 0; i < count; i++) {
pmap_clear_modify(VM_PAGE_TO_PHYS(m[i]));
m[i]->flags |= PG_CLEAN;
m[i]->flags &= ~PG_LAUNDRY;
rtvals[i] = VM_PAGER_OK;
}
} else if (count != 1) {
error = 0;
count = 1;
goto retryoutput;
}
if (error) {
printf("vnode pager write error: %d\n", error);
}
return (error ? VM_PAGER_FAIL : VM_PAGER_OK);
}
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