FreeBSD-5.3/sys/vm/vnode_pager.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
* Copyright (c) 1995, David Greenman
*
* 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
*/
/*
* Page to/from files (vnodes).
*/
/*
* TODO:
* Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will
* greatly re-simplify the vnode_pager.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/vm/vnode_pager.c,v 1.196 2004/05/06 05:03:23 alc Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/vmmeter.h>
#include <sys/conf.h>
#include <sys/sf_buf.h>
#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <vm/vm_map.h>
#include <vm/vnode_pager.h>
#include <vm/vm_extern.h>
static void vnode_pager_init(void);
static vm_offset_t vnode_pager_addr(struct vnode *vp, vm_ooffset_t address,
int *run);
static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m);
static int vnode_pager_input_old(vm_object_t object, vm_page_t m);
static void vnode_pager_dealloc(vm_object_t);
static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int);
static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *);
static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *);
struct pagerops vnodepagerops = {
.pgo_init = vnode_pager_init,
.pgo_alloc = vnode_pager_alloc,
.pgo_dealloc = vnode_pager_dealloc,
.pgo_getpages = vnode_pager_getpages,
.pgo_putpages = vnode_pager_putpages,
.pgo_haspage = vnode_pager_haspage,
};
int vnode_pbuf_freecnt;
static void
vnode_pager_init(void)
{
vnode_pbuf_freecnt = nswbuf / 2 + 1;
}
/*
* Allocate (or lookup) pager for a vnode.
* Handle is a vnode pointer.
*
* MPSAFE
*/
vm_object_t
vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
vm_ooffset_t offset)
{
vm_object_t object;
struct vnode *vp;
/*
* Pageout to vnode, no can do yet.
*/
if (handle == NULL)
return (NULL);
vp = (struct vnode *) handle;
ASSERT_VOP_LOCKED(vp, "vnode_pager_alloc");
/*
* Prevent race condition when allocating the object. This
* can happen with NFS vnodes since the nfsnode isn't locked.
*/
VI_LOCK(vp);
while (vp->v_iflag & VI_OLOCK) {
vp->v_iflag |= VI_OWANT;
msleep(vp, VI_MTX(vp), PVM, "vnpobj", 0);
}
vp->v_iflag |= VI_OLOCK;
VI_UNLOCK(vp);
/*
* If the object is being terminated, wait for it to
* go away.
*/
while ((object = vp->v_object) != NULL) {
VM_OBJECT_LOCK(object);
if ((object->flags & OBJ_DEAD) == 0)
break;
msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vadead", 0);
}
if (vp->v_usecount == 0)
panic("vnode_pager_alloc: no vnode reference");
if (object == NULL) {
/*
* And an object of the appropriate size
*/
object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size)));
object->un_pager.vnp.vnp_size = size;
object->handle = handle;
vp->v_object = object;
} else {
object->ref_count++;
VM_OBJECT_UNLOCK(object);
}
VI_LOCK(vp);
vp->v_usecount++;
vp->v_iflag &= ~VI_OLOCK;
if (vp->v_iflag & VI_OWANT) {
vp->v_iflag &= ~VI_OWANT;
wakeup(vp);
}
VI_UNLOCK(vp);
return (object);
}
/*
* The object must be locked.
*/
static void
vnode_pager_dealloc(object)
vm_object_t object;
{
struct vnode *vp = object->handle;
if (vp == NULL)
panic("vnode_pager_dealloc: pager already dealloced");
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
vm_object_pip_wait(object, "vnpdea");
object->handle = NULL;
object->type = OBJT_DEAD;
ASSERT_VOP_LOCKED(vp, "vnode_pager_dealloc");
vp->v_object = NULL;
vp->v_vflag &= ~(VV_TEXT | VV_OBJBUF);
}
static boolean_t
vnode_pager_haspage(object, pindex, before, after)
vm_object_t object;
vm_pindex_t pindex;
int *before;
int *after;
{
struct vnode *vp = object->handle;
daddr_t bn;
int err;
daddr_t reqblock;
int poff;
int bsize;
int pagesperblock, blocksperpage;
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
/*
* If no vp or vp is doomed or marked transparent to VM, we do not
* have the page.
*/
if (vp == NULL)
return FALSE;
VI_LOCK(vp);
if (vp->v_iflag & VI_DOOMED) {
VI_UNLOCK(vp);
return FALSE;
}
VI_UNLOCK(vp);
/*
* If filesystem no longer mounted or offset beyond end of file we do
* not have the page.
*/
if ((vp->v_mount == NULL) ||
(IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size))
return FALSE;
bsize = vp->v_mount->mnt_stat.f_iosize;
pagesperblock = bsize / PAGE_SIZE;
blocksperpage = 0;
if (pagesperblock > 0) {
reqblock = pindex / pagesperblock;
} else {
blocksperpage = (PAGE_SIZE / bsize);
reqblock = pindex * blocksperpage;
}
VM_OBJECT_UNLOCK(object);
err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before);
VM_OBJECT_LOCK(object);
if (err)
return TRUE;
if (bn == -1)
return FALSE;
if (pagesperblock > 0) {
poff = pindex - (reqblock * pagesperblock);
if (before) {
*before *= pagesperblock;
*before += poff;
}
if (after) {
int numafter;
*after *= pagesperblock;
numafter = pagesperblock - (poff + 1);
if (IDX_TO_OFF(pindex + numafter) >
object->un_pager.vnp.vnp_size) {
numafter =
OFF_TO_IDX(object->un_pager.vnp.vnp_size) -
pindex;
}
*after += numafter;
}
} else {
if (before) {
*before /= blocksperpage;
}
if (after) {
*after /= blocksperpage;
}
}
return TRUE;
}
/*
* Lets the VM system know about a change in size for a file.
* 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;
vm_ooffset_t nsize;
{
vm_object_t object;
vm_page_t m;
vm_pindex_t nobjsize;
if ((object = vp->v_object) == NULL)
return;
VM_OBJECT_LOCK(object);
if (nsize == object->un_pager.vnp.vnp_size) {
/*
* Hasn't changed size
*/
VM_OBJECT_UNLOCK(object);
return;
}
nobjsize = OFF_TO_IDX(nsize + PAGE_MASK);
if (nsize < object->un_pager.vnp.vnp_size) {
/*
* File has shrunk. Toss any cached pages beyond the new EOF.
*/
if (nobjsize < object->size)
vm_object_page_remove(object, nobjsize, object->size,
FALSE);
/*
* this gets rid of garbage at the end of a page that is now
* only partially backed by the vnode.
*
* XXX for some reason (I don't know yet), if we take a
* completely invalid page and mark it partially valid
* it can screw up NFS reads, so we don't allow the case.
*/
if ((nsize & PAGE_MASK) &&
(m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL &&
m->valid != 0) {
int base = (int)nsize & PAGE_MASK;
int size = PAGE_SIZE - base;
/*
* Clear out partial-page garbage in case
* the page has been mapped.
*/
pmap_zero_page_area(m, base, size);
/*
* XXX work around SMP data integrity race
* by unmapping the page from user processes.
* The garbage we just cleared may be mapped
* to a user process running on another cpu
* and this code is not running through normal
* I/O channels which handle SMP issues for
* us, so unmap page to synchronize all cpus.
*
* XXX should vm_pager_unmap_page() have
* dealt with this?
*/
vm_page_lock_queues();
pmap_remove_all(m);
/*
* Clear out partial-page dirty bits. This
* has the side effect of setting the valid
* bits, but that is ok. There are a bunch
* of places in the VM system where we expected
* m->dirty == VM_PAGE_BITS_ALL. The file EOF
* case is one of them. If the page is still
* partially dirty, make it fully dirty.
*
* note that we do not clear out the valid
* bits. This would prevent bogus_page
* replacement from working properly.
*/
vm_page_set_validclean(m, base, size);
if (m->dirty != 0)
m->dirty = VM_PAGE_BITS_ALL;
vm_page_unlock_queues();
}
}
object->un_pager.vnp.vnp_size = nsize;
object->size = nobjsize;
VM_OBJECT_UNLOCK(object);
}
/*
* calculate the linear (byte) disk address of specified virtual
* file address
*/
static vm_offset_t
vnode_pager_addr(vp, address, run)
struct vnode *vp;
vm_ooffset_t address;
int *run;
{
int rtaddress;
int bsize;
daddr_t block;
int err;
daddr_t vblock;
int voffset;
GIANT_REQUIRED;
if ((int) address < 0)
return -1;
if (vp->v_mount == NULL)
return -1;
bsize = vp->v_mount->mnt_stat.f_iosize;
vblock = address / bsize;
voffset = address % bsize;
err = VOP_BMAP(vp, vblock, NULL, &block, run, NULL);
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;
}
/*
* small block filesystem vnode pager input
*/
static int
vnode_pager_input_smlfs(object, m)
vm_object_t object;
vm_page_t m;
{
int i;
struct vnode *dp, *vp;
struct buf *bp;
struct sf_buf *sf;
int fileaddr;
vm_offset_t bsize;
int error = 0;
GIANT_REQUIRED;
vp = object->handle;
if (vp->v_mount == NULL)
return VM_PAGER_BAD;
bsize = vp->v_mount->mnt_stat.f_iosize;
VOP_BMAP(vp, 0, &dp, 0, NULL, NULL);
sf = sf_buf_alloc(m, 0);
for (i = 0; i < PAGE_SIZE / bsize; i++) {
vm_ooffset_t address;
if (vm_page_bits(i * bsize, bsize) & m->valid)
continue;
address = IDX_TO_OFF(m->pindex) + i * bsize;
if (address >= object->un_pager.vnp.vnp_size) {
fileaddr = -1;
} else {
fileaddr = vnode_pager_addr(vp, address, NULL);
}
if (fileaddr != -1) {
bp = getpbuf(&vnode_pbuf_freecnt);
/* build a minimal buffer header */
bp->b_iocmd = BIO_READ;
bp->b_iodone = bdone;
KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
bp->b_rcred = crhold(curthread->td_ucred);
bp->b_wcred = crhold(curthread->td_ucred);
bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize;
bp->b_blkno = fileaddr;
pbgetvp(dp, bp);
bp->b_bcount = bsize;
bp->b_bufsize = bsize;
bp->b_runningbufspace = bp->b_bufsize;
runningbufspace += bp->b_runningbufspace;
/* do the input */
bp->b_iooffset = dbtob(bp->b_blkno);
if (dp->v_type == VCHR)
VOP_SPECSTRATEGY(bp->b_vp, bp);
else
VOP_STRATEGY(bp->b_vp, bp);
/* we definitely need to be at splvm here */
bwait(bp, PVM, "vnsrd");
if ((bp->b_ioflags & BIO_ERROR) != 0)
error = EIO;
/*
* free the buffer header back to the swap buffer pool
*/
relpbuf(bp, &vnode_pbuf_freecnt);
if (error)
break;
VM_OBJECT_LOCK(object);
vm_page_lock_queues();
vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize);
vm_page_unlock_queues();
VM_OBJECT_UNLOCK(object);
} else {
VM_OBJECT_LOCK(object);
vm_page_lock_queues();
vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize);
vm_page_unlock_queues();
VM_OBJECT_UNLOCK(object);
bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize);
}
}
sf_buf_free(sf);
vm_page_lock_queues();
pmap_clear_modify(m);
vm_page_unlock_queues();
if (error) {
return VM_PAGER_ERROR;
}
return VM_PAGER_OK;
}
/*
* old style vnode pager output routine
*/
static int
vnode_pager_input_old(object, m)
vm_object_t object;
vm_page_t m;
{
struct uio auio;
struct iovec aiov;
int error;
int size;
struct sf_buf *sf;
struct vnode *vp;
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
error = 0;
/*
* Return failure if beyond current EOF
*/
if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) {
return VM_PAGER_BAD;
} else {
size = PAGE_SIZE;
if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size)
size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex);
vp = object->handle;
VM_OBJECT_UNLOCK(object);
/*
* Allocate a kernel virtual address and initialize so that
* we can use VOP_READ/WRITE routines.
*/
sf = sf_buf_alloc(m, 0);
aiov.iov_base = (caddr_t)sf_buf_kva(sf);
aiov.iov_len = size;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_offset = IDX_TO_OFF(m->pindex);
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_rw = UIO_READ;
auio.uio_resid = size;
auio.uio_td = curthread;
error = VOP_READ(vp, &auio, 0, curthread->td_ucred);
if (!error) {
int count = size - auio.uio_resid;
if (count == 0)
error = EINVAL;
else if (count != PAGE_SIZE)
bzero((caddr_t)sf_buf_kva(sf) + count,
PAGE_SIZE - count);
}
sf_buf_free(sf);
VM_OBJECT_LOCK(object);
}
vm_page_lock_queues();
pmap_clear_modify(m);
vm_page_undirty(m);
vm_page_unlock_queues();
if (!error)
m->valid = VM_PAGE_BITS_ALL;
return error ? VM_PAGER_ERROR : VM_PAGER_OK;
}
/*
* generic vnode pager input routine
*/
/*
* Local media VFS's that do not implement their own VOP_GETPAGES
* should have their VOP_GETPAGES call to vnode_pager_generic_getpages()
* to implement the previous behaviour.
*
* All other FS's should use the bypass to get to the local media
* backing vp's VOP_GETPAGES.
*/
static int
vnode_pager_getpages(object, m, count, reqpage)
vm_object_t object;
vm_page_t *m;
int count;
int reqpage;
{
int rtval;
struct vnode *vp;
int bytes = count * PAGE_SIZE;
vp = object->handle;
VM_OBJECT_UNLOCK(object);
mtx_lock(&Giant);
rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0);
KASSERT(rtval != EOPNOTSUPP,
("vnode_pager: FS getpages not implemented\n"));
mtx_unlock(&Giant);
VM_OBJECT_LOCK(object);
return rtval;
}
/*
* This is now called from local media FS's to operate against their
* own vnodes if they fail to implement VOP_GETPAGES.
*/
int
vnode_pager_generic_getpages(vp, m, bytecount, reqpage)
struct vnode *vp;
vm_page_t *m;
int bytecount;
int reqpage;
{
vm_object_t object;
vm_offset_t kva;
off_t foff, tfoff, nextoff;
int i, j, size, bsize, first, firstaddr;
struct vnode *dp;
int runpg;
int runend;
struct buf *bp;
int count;
int error = 0;
GIANT_REQUIRED;
object = vp->v_object;
count = bytecount / PAGE_SIZE;
if (vp->v_mount == NULL)
return VM_PAGER_BAD;
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 = IDX_TO_OFF(m[reqpage]->pindex);
/*
* if we can't bmap, use old VOP code
*/
if (VOP_BMAP(vp, 0, &dp, 0, NULL, NULL)) {
VM_OBJECT_LOCK(object);
vm_page_lock_queues();
for (i = 0; i < count; i++)
if (i != reqpage)
vm_page_free(m[i]);
vm_page_unlock_queues();
cnt.v_vnodein++;
cnt.v_vnodepgsin++;
error = vnode_pager_input_old(object, m[reqpage]);
VM_OBJECT_UNLOCK(object);
return (error);
/*
* 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 != nfs_mount_type)) {
VM_OBJECT_LOCK(object);
vm_page_lock_queues();
for (i = 0; i < count; i++)
if (i != reqpage)
vm_page_free(m[i]);
vm_page_unlock_queues();
VM_OBJECT_UNLOCK(object);
cnt.v_vnodein++;
cnt.v_vnodepgsin++;
return vnode_pager_input_smlfs(object, m[reqpage]);
}
/*
* If we have a completely valid page available to us, we can
* clean up and return. Otherwise we have to re-read the
* media.
*/
VM_OBJECT_LOCK(object);
if (m[reqpage]->valid == VM_PAGE_BITS_ALL) {
vm_page_lock_queues();
for (i = 0; i < count; i++)
if (i != reqpage)
vm_page_free(m[i]);
vm_page_unlock_queues();
VM_OBJECT_UNLOCK(object);
return VM_PAGER_OK;
}
m[reqpage]->valid = 0;
VM_OBJECT_UNLOCK(object);
/*
* 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,
IDX_TO_OFF(m[i]->pindex), &runpg);
if (firstaddr == -1) {
VM_OBJECT_LOCK(object);
if (i == reqpage && foff < object->un_pager.vnp.vnp_size) {
panic("vnode_pager_getpages: unexpected missing page: firstaddr: %d, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx",
firstaddr, (uintmax_t)(foff >> 32),
(uintmax_t)foff,
(uintmax_t)
(object->un_pager.vnp.vnp_size >> 32),
(uintmax_t)object->un_pager.vnp.vnp_size);
}
vm_page_lock_queues();
vm_page_free(m[i]);
vm_page_unlock_queues();
VM_OBJECT_UNLOCK(object);
runend = i + 1;
first = runend;
continue;
}
runend = i + runpg;
if (runend <= reqpage) {
VM_OBJECT_LOCK(object);
vm_page_lock_queues();
for (j = i; j < runend; j++)
vm_page_free(m[j]);
vm_page_unlock_queues();
VM_OBJECT_UNLOCK(object);
} else {
if (runpg < (count - first)) {
VM_OBJECT_LOCK(object);
vm_page_lock_queues();
for (i = first + runpg; i < count; i++)
vm_page_free(m[i]);
vm_page_unlock_queues();
VM_OBJECT_UNLOCK(object);
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 = IDX_TO_OFF(m[0]->pindex);
/*
* calculate the size of the transfer
*/
size = count * PAGE_SIZE;
if ((foff + size) > object->un_pager.vnp.vnp_size)
size = object->un_pager.vnp.vnp_size - foff;
/*
* round up physical size for real devices.
*/
if (dp->v_type == VBLK || dp->v_type == VCHR) {
int secmask = dp->v_rdev->si_bsize_phys - 1;
KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large\n", secmask + 1));
size = (size + secmask) & ~secmask;
}
bp = getpbuf(&vnode_pbuf_freecnt);
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_iocmd = BIO_READ;
bp->b_iodone = bdone;
KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
bp->b_rcred = crhold(curthread->td_ucred);
bp->b_wcred = crhold(curthread->td_ucred);
bp->b_blkno = firstaddr;
pbgetvp(dp, bp);
bp->b_bcount = size;
bp->b_bufsize = size;
bp->b_runningbufspace = bp->b_bufsize;
runningbufspace += bp->b_runningbufspace;
cnt.v_vnodein++;
cnt.v_vnodepgsin += count;
/* do the input */
bp->b_iooffset = dbtob(bp->b_blkno);
if (dp->v_type == VCHR)
VOP_SPECSTRATEGY(bp->b_vp, bp);
else
VOP_STRATEGY(bp->b_vp, bp);
bwait(bp, PVM, "vnread");
if ((bp->b_ioflags & BIO_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, &vnode_pbuf_freecnt);
VM_OBJECT_LOCK(object);
vm_page_lock_queues();
for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) {
vm_page_t mt;
nextoff = tfoff + PAGE_SIZE;
mt = m[i];
if (nextoff <= object->un_pager.vnp.vnp_size) {
/*
* Read filled up entire page.
*/
mt->valid = VM_PAGE_BITS_ALL;
vm_page_undirty(mt); /* should be an assert? XXX */
pmap_clear_modify(mt);
} else {
/*
* Read did not fill up entire page. Since this
* is getpages, the page may be mapped, so we have
* to zero the invalid portions of the page even
* though we aren't setting them valid.
*
* Currently we do not set the entire page valid,
* we just try to clear the piece that we couldn't
* read.
*/
vm_page_set_validclean(mt, 0,
object->un_pager.vnp.vnp_size - tfoff);
/* handled by vm_fault now */
/* vm_page_zero_invalid(mt, FALSE); */
}
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 empirical 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) {
if (mt->flags & PG_WANTED)
vm_page_activate(mt);
else
vm_page_deactivate(mt);
vm_page_wakeup(mt);
} else {
vm_page_free(mt);
}
}
}
vm_page_unlock_queues();
VM_OBJECT_UNLOCK(object);
if (error) {
printf("vnode_pager_getpages: I/O read error\n");
}
return (error ? VM_PAGER_ERROR : VM_PAGER_OK);
}
/*
* EOPNOTSUPP is no longer legal. For local media VFS's that do not
* implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to
* vnode_pager_generic_putpages() to implement the previous behaviour.
*
* All other FS's should use the bypass to get to the local media
* backing vp's VOP_PUTPAGES.
*/
static void
vnode_pager_putpages(object, m, count, sync, rtvals)
vm_object_t object;
vm_page_t *m;
int count;
boolean_t sync;
int *rtvals;
{
int rtval;
struct vnode *vp;
struct mount *mp;
int bytes = count * PAGE_SIZE;
GIANT_REQUIRED;
/*
* Force synchronous operation if we are extremely low on memory
* to prevent a low-memory deadlock. VOP operations often need to
* allocate more memory to initiate the I/O ( i.e. do a BMAP
* operation ). The swapper handles the case by limiting the amount
* of asynchronous I/O, but that sort of solution doesn't scale well
* for the vnode pager without a lot of work.
*
* Also, the backing vnode's iodone routine may not wake the pageout
* daemon up. This should be probably be addressed XXX.
*/
if ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min)
sync |= OBJPC_SYNC;
/*
* Call device-specific putpages function
*/
vp = object->handle;
VM_OBJECT_UNLOCK(object);
if (vp->v_type != VREG)
mp = NULL;
(void)vn_start_write(vp, &mp, V_WAIT);
rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0);
KASSERT(rtval != EOPNOTSUPP,
("vnode_pager: stale FS putpages\n"));
vn_finished_write(mp);
VM_OBJECT_LOCK(object);
}
/*
* This is now called from local media FS's to operate against their
* own vnodes if they fail to implement VOP_PUTPAGES.
*
* This is typically called indirectly via the pageout daemon and
* clustering has already typically occured, so in general we ask the
* underlying filesystem to write the data out asynchronously rather
* then delayed.
*/
int
vnode_pager_generic_putpages(vp, m, bytecount, flags, rtvals)
struct vnode *vp;
vm_page_t *m;
int bytecount;
int flags;
int *rtvals;
{
int i;
vm_object_t object;
int count;
int maxsize, ncount;
vm_ooffset_t poffset;
struct uio auio;
struct iovec aiov;
int error;
int ioflags;
GIANT_REQUIRED;
object = vp->v_object;
count = bytecount / PAGE_SIZE;
for (i = 0; i < count; i++)
rtvals[i] = VM_PAGER_AGAIN;
if ((int) m[0]->pindex < 0) {
printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n",
(long)m[0]->pindex, (u_long)m[0]->dirty);
rtvals[0] = VM_PAGER_BAD;
return VM_PAGER_BAD;
}
maxsize = count * PAGE_SIZE;
ncount = count;
poffset = IDX_TO_OFF(m[0]->pindex);
/*
* If the page-aligned write is larger then the actual file we
* have to invalidate pages occuring beyond the file EOF. However,
* there is an edge case where a file may not be page-aligned where
* the last page is partially invalid. In this case the filesystem
* may not properly clear the dirty bits for the entire page (which
* could be VM_PAGE_BITS_ALL due to the page having been mmap()d).
* With the page locked we are free to fix-up the dirty bits here.
*
* We do not under any circumstances truncate the valid bits, as
* this will screw up bogus page replacement.
*/
if (maxsize + poffset > object->un_pager.vnp.vnp_size) {
if (object->un_pager.vnp.vnp_size > poffset) {
int pgoff;
maxsize = object->un_pager.vnp.vnp_size - poffset;
ncount = btoc(maxsize);
if ((pgoff = (int)maxsize & PAGE_MASK) != 0) {
vm_page_lock_queues();
vm_page_clear_dirty(m[ncount - 1], pgoff,
PAGE_SIZE - pgoff);
vm_page_unlock_queues();
}
} else {
maxsize = 0;
ncount = 0;
}
if (ncount < count) {
for (i = ncount; i < count; i++) {
rtvals[i] = VM_PAGER_BAD;
}
}
}
/*
* pageouts are already clustered, use IO_ASYNC t o force a bawrite()
* rather then a bdwrite() to prevent paging I/O from saturating
* the buffer cache. Dummy-up the sequential heuristic to cause
* large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set,
* the system decides how to cluster.
*/
ioflags = IO_VMIO;
if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL))
ioflags |= IO_SYNC;
else if ((flags & VM_PAGER_CLUSTER_OK) == 0)
ioflags |= IO_ASYNC;
ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0;
ioflags |= IO_SEQMAX << IO_SEQSHIFT;
aiov.iov_base = (caddr_t) 0;
aiov.iov_len = maxsize;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_offset = poffset;
auio.uio_segflg = UIO_NOCOPY;
auio.uio_rw = UIO_WRITE;
auio.uio_resid = maxsize;
auio.uio_td = (struct thread *) 0;
error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred);
cnt.v_vnodeout++;
cnt.v_vnodepgsout += ncount;
if (error) {
printf("vnode_pager_putpages: I/O error %d\n", error);
}
if (auio.uio_resid) {
printf("vnode_pager_putpages: residual I/O %d at %lu\n",
auio.uio_resid, (u_long)m[0]->pindex);
}
for (i = 0; i < ncount; i++) {
rtvals[i] = VM_PAGER_OK;
}
return rtvals[0];
}
struct vnode *
vnode_pager_lock(vm_object_t first_object)
{
struct vnode *vp;
vm_object_t backing_object, object;
VM_OBJECT_LOCK_ASSERT(first_object, MA_OWNED);
for (object = first_object; object != NULL; object = backing_object) {
if (object->type != OBJT_VNODE) {
if ((backing_object = object->backing_object) != NULL)
VM_OBJECT_LOCK(backing_object);
if (object != first_object)
VM_OBJECT_UNLOCK(object);
continue;
}
retry:
if (object->flags & OBJ_DEAD) {
if (object != first_object)
VM_OBJECT_UNLOCK(object);
return NULL;
}
vp = object->handle;
VI_LOCK(vp);
VM_OBJECT_UNLOCK(object);
if (first_object != object)
VM_OBJECT_UNLOCK(first_object);
if (vget(vp, LK_CANRECURSE | LK_INTERLOCK | LK_NOPAUSE |
LK_RETRY | LK_SHARED, curthread)) {
VM_OBJECT_LOCK(first_object);
if (object != first_object)
VM_OBJECT_LOCK(object);
if (object->type != OBJT_VNODE) {
if (object != first_object)
VM_OBJECT_UNLOCK(object);
return NULL;
}
printf("vnode_pager_lock: retrying\n");
goto retry;
}
VM_OBJECT_LOCK(first_object);
return (vp);
}
return NULL;
}