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0209400cea
freebsd-skq/sys/vm/vnode_pager.c
Bryan Drewery a771bf748f Remove unused obj variable missed in r354870. 
Sponsored by:	Dell EMC
2021-03-17 15:29:15 -07:00

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/*-
* SPDX-License-Identifier: BSD-4-Clause
*
* 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("$FreeBSD$");
#include "opt_vm.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/sysctl.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/ktr.h>
#include <sys/limits.h>
#include <sys/conf.h>
#include <sys/refcount.h>
#include <sys/rwlock.h>
#include <sys/sf_buf.h>
#include <sys/domainset.h>
#include <machine/atomic.h>
#include <vm/vm.h>
#include <vm/vm_param.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>
#include <vm/uma.h>
static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address,
daddr_t *rtaddress, 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 *, int *);
static int vnode_pager_getpages_async(vm_object_t, vm_page_t *, int, int *,
int *, vop_getpages_iodone_t, void *);
static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, int, int *);
static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *);
static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
vm_ooffset_t, struct ucred *cred);
static int vnode_pager_generic_getpages_done(struct buf *);
static void vnode_pager_generic_getpages_done_async(struct buf *);
static void vnode_pager_update_writecount(vm_object_t, vm_offset_t,
vm_offset_t);
static void vnode_pager_release_writecount(vm_object_t, vm_offset_t,
vm_offset_t);
struct pagerops vnodepagerops = {
.pgo_alloc = vnode_pager_alloc,
.pgo_dealloc = vnode_pager_dealloc,
.pgo_getpages = vnode_pager_getpages,
.pgo_getpages_async = vnode_pager_getpages_async,
.pgo_putpages = vnode_pager_putpages,
.pgo_haspage = vnode_pager_haspage,
.pgo_update_writecount = vnode_pager_update_writecount,
.pgo_release_writecount = vnode_pager_release_writecount,
};
static struct domainset *vnode_domainset = NULL;
SYSCTL_PROC(_debug, OID_AUTO, vnode_domainset,
CTLTYPE_STRING | CTLFLAG_MPSAFE | CTLFLAG_RW, &vnode_domainset, 0,
sysctl_handle_domainset, "A", "Default vnode NUMA policy");
static int nvnpbufs;
SYSCTL_INT(_vm, OID_AUTO, vnode_pbufs, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
&nvnpbufs, 0, "number of physical buffers allocated for vnode pager");
static uma_zone_t vnode_pbuf_zone;
static void
vnode_pager_init(void *dummy)
{
#ifdef __LP64__
nvnpbufs = nswbuf * 2;
#else
nvnpbufs = nswbuf / 2;
#endif
TUNABLE_INT_FETCH("vm.vnode_pbufs", &nvnpbufs);
vnode_pbuf_zone = pbuf_zsecond_create("vnpbuf", nvnpbufs);
}
SYSINIT(vnode_pager, SI_SUB_CPU, SI_ORDER_ANY, vnode_pager_init, NULL);
/* Create the VM system backing object for this vnode */
int
vnode_create_vobject(struct vnode *vp, off_t isize, struct thread *td)
{
vm_object_t object;
vm_ooffset_t size = isize;
struct vattr va;
bool last;
if (!vn_isdisk(vp) && vn_canvmio(vp) == FALSE)
return (0);
object = vp->v_object;
if (object != NULL)
return (0);
if (size == 0) {
if (vn_isdisk(vp)) {
size = IDX_TO_OFF(INT_MAX);
} else {
if (VOP_GETATTR(vp, &va, td->td_ucred))
return (0);
size = va.va_size;
}
}
object = vnode_pager_alloc(vp, size, 0, 0, td->td_ucred);
/*
* Dereference the reference we just created. This assumes
* that the object is associated with the vp. We still have
* to serialize with vnode_pager_dealloc() for the last
* potential reference.
*/
VM_OBJECT_RLOCK(object);
last = refcount_release(&object->ref_count);
VM_OBJECT_RUNLOCK(object);
if (last)
vrele(vp);
KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object"));
return (0);
}
void
vnode_destroy_vobject(struct vnode *vp)
{
struct vm_object *obj;
obj = vp->v_object;
if (obj == NULL || obj->handle != vp)
return;
ASSERT_VOP_ELOCKED(vp, "vnode_destroy_vobject");
VM_OBJECT_WLOCK(obj);
MPASS(obj->type == OBJT_VNODE);
umtx_shm_object_terminated(obj);
if (obj->ref_count == 0) {
KASSERT((obj->flags & OBJ_DEAD) == 0,
("vnode_destroy_vobject: Terminating dead object"));
vm_object_set_flag(obj, OBJ_DEAD);
/*
* Clean pages and flush buffers.
*/
vm_object_page_clean(obj, 0, 0, OBJPC_SYNC);
VM_OBJECT_WUNLOCK(obj);
vinvalbuf(vp, V_SAVE, 0, 0);
BO_LOCK(&vp->v_bufobj);
vp->v_bufobj.bo_flag |= BO_DEAD;
BO_UNLOCK(&vp->v_bufobj);
VM_OBJECT_WLOCK(obj);
vm_object_terminate(obj);
} else {
/*
* Woe to the process that tries to page now :-).
*/
vm_pager_deallocate(obj);
VM_OBJECT_WUNLOCK(obj);
}
KASSERT(vp->v_object == NULL, ("vp %p obj %p", vp, vp->v_object));
}
/*
* Allocate (or lookup) pager for a vnode.
* Handle is a vnode pointer.
*/
vm_object_t
vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
vm_ooffset_t offset, struct ucred *cred)
{
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");
VNPASS(vp->v_usecount > 0, vp);
retry:
object = vp->v_object;
if (object == NULL) {
/*
* Add 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->un_pager.vnp.writemappings = 0;
object->domain.dr_policy = vnode_domainset;
object->handle = handle;
if ((vp->v_vflag & VV_VMSIZEVNLOCK) != 0) {
VM_OBJECT_WLOCK(object);
vm_object_set_flag(object, OBJ_SIZEVNLOCK);
VM_OBJECT_WUNLOCK(object);
}
VI_LOCK(vp);
if (vp->v_object != NULL) {
/*
* Object has been created while we were allocating.
*/
VI_UNLOCK(vp);
VM_OBJECT_WLOCK(object);
KASSERT(object->ref_count == 1,
("leaked ref %p %d", object, object->ref_count));
object->type = OBJT_DEAD;
refcount_init(&object->ref_count, 0);
VM_OBJECT_WUNLOCK(object);
vm_object_destroy(object);
goto retry;
}
vp->v_object = object;
VI_UNLOCK(vp);
vrefact(vp);
} else {
vm_object_reference(object);
#if VM_NRESERVLEVEL > 0
if ((object->flags & OBJ_COLORED) == 0) {
VM_OBJECT_WLOCK(object);
vm_object_color(object, 0);
VM_OBJECT_WUNLOCK(object);
}
#endif
}
return (object);
}
/*
* The object must be locked.
*/
static void
vnode_pager_dealloc(vm_object_t object)
{
struct vnode *vp;
int refs;
vp = object->handle;
if (vp == NULL)
panic("vnode_pager_dealloc: pager already dealloced");
VM_OBJECT_ASSERT_WLOCKED(object);
vm_object_pip_wait(object, "vnpdea");
refs = object->ref_count;
object->handle = NULL;
object->type = OBJT_DEAD;
ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc");
if (object->un_pager.vnp.writemappings > 0) {
object->un_pager.vnp.writemappings = 0;
VOP_ADD_WRITECOUNT_CHECKED(vp, -1);
CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
__func__, vp, vp->v_writecount);
}
vp->v_object = NULL;
VI_LOCK(vp);
/*
* vm_map_entry_set_vnode_text() cannot reach this vnode by
* following object->handle. Clear all text references now.
* This also clears the transient references from
* kern_execve(), which is fine because dead_vnodeops uses nop
* for VOP_UNSET_TEXT().
*/
if (vp->v_writecount < 0)
vp->v_writecount = 0;
VI_UNLOCK(vp);
VM_OBJECT_WUNLOCK(object);
if (refs > 0)
vunref(vp);
VM_OBJECT_WLOCK(object);
}
static boolean_t
vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
int *after)
{
struct vnode *vp = object->handle;
daddr_t bn;
uintptr_t lockstate;
int err;
daddr_t reqblock;
int poff;
int bsize;
int pagesperblock, blocksperpage;
VM_OBJECT_ASSERT_LOCKED(object);
/*
* If no vp or vp is doomed or marked transparent to VM, we do not
* have the page.
*/
if (vp == NULL || VN_IS_DOOMED(vp))
return FALSE;
/*
* If the offset is beyond end of file we do
* not have the page.
*/
if (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;
}
lockstate = VM_OBJECT_DROP(object);
err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before);
VM_OBJECT_PICKUP(object, lockstate);
if (err)
return TRUE;
if (bn == -1)
return FALSE;
if (pagesperblock > 0) {
poff = pindex - (reqblock * pagesperblock);
if (before) {
*before *= pagesperblock;
*before += poff;
}
if (after) {
/*
* The BMAP vop can report a partial block in the
* 'after', but must not report blocks after EOF.
* Assert the latter, and truncate 'after' in case
* of the former.
*/
KASSERT((reqblock + *after) * pagesperblock <
roundup2(object->size, pagesperblock),
("%s: reqblock %jd after %d size %ju", __func__,
(intmax_t )reqblock, *after,
(uintmax_t )object->size));
*after *= pagesperblock;
*after += pagesperblock - (poff + 1);
if (pindex + *after >= object->size)
*after = object->size - 1 - pindex;
}
} 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(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;
#ifdef DEBUG_VFS_LOCKS
{
struct mount *mp;
mp = vp->v_mount;
if (mp != NULL && (mp->mnt_kern_flag & MNTK_VMSETSIZE_BUG) == 0)
assert_vop_elocked(vp,
"vnode_pager_setsize and not locked vnode");
}
#endif
VM_OBJECT_WLOCK(object);
if (object->type == OBJT_DEAD) {
VM_OBJECT_WUNLOCK(object);
return;
}
KASSERT(object->type == OBJT_VNODE,
("not vnode-backed object %p", object));
if (nsize == object->un_pager.vnp.vnp_size) {
/*
* Hasn't changed size
*/
VM_OBJECT_WUNLOCK(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,
0);
/*
* 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))
goto out;
m = vm_page_grab(object, OFF_TO_IDX(nsize), VM_ALLOC_NOCREAT);
if (m == NULL)
goto out;
if (!vm_page_none_valid(m)) {
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);
/*
* Update the valid bits to reflect the blocks that
* have been zeroed. Some of these valid bits may
* have already been set.
*/
vm_page_set_valid_range(m, base, size);
/*
* Round "base" to the next block boundary so that the
* dirty bit for a partially zeroed block is not
* cleared.
*/
base = roundup2(base, DEV_BSIZE);
/*
* Clear out partial-page dirty bits.
*
* note that we do not clear out the valid
* bits. This would prevent bogus_page
* replacement from working properly.
*/
vm_page_clear_dirty(m, base, PAGE_SIZE - base);
}
vm_page_xunbusy(m);
}
out:
#if defined(__powerpc__) && !defined(__powerpc64__)
object->un_pager.vnp.vnp_size = nsize;
#else
atomic_store_64(&object->un_pager.vnp.vnp_size, nsize);
#endif
object->size = nobjsize;
VM_OBJECT_WUNLOCK(object);
}
/*
* calculate the linear (byte) disk address of specified virtual
* file address
*/
static int
vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress,
int *run)
{
int bsize;
int err;
daddr_t vblock;
daddr_t voffset;
if (VN_IS_DOOMED(vp))
return -1;
bsize = vp->v_mount->mnt_stat.f_iosize;
vblock = address / bsize;
voffset = address % bsize;
err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL);
if (err == 0) {
if (*rtaddress != -1)
*rtaddress += voffset / DEV_BSIZE;
if (run) {
*run += 1;
*run *= bsize / PAGE_SIZE;
*run -= voffset / PAGE_SIZE;
}
}
return (err);
}
/*
* small block filesystem vnode pager input
*/
static int
vnode_pager_input_smlfs(vm_object_t object, vm_page_t m)
{
struct vnode *vp;
struct bufobj *bo;
struct buf *bp;
struct sf_buf *sf;
daddr_t fileaddr;
vm_offset_t bsize;
vm_page_bits_t bits;
int error, i;
error = 0;
vp = object->handle;
if (VN_IS_DOOMED(vp))
return VM_PAGER_BAD;
bsize = vp->v_mount->mnt_stat.f_iosize;
VOP_BMAP(vp, 0, &bo, 0, NULL, NULL);
sf = sf_buf_alloc(m, 0);
for (i = 0; i < PAGE_SIZE / bsize; i++) {
vm_ooffset_t address;
bits = vm_page_bits(i * bsize, bsize);
if (m->valid & bits)
continue;
address = IDX_TO_OFF(m->pindex) + i * bsize;
if (address >= object->un_pager.vnp.vnp_size) {
fileaddr = -1;
} else {
error = vnode_pager_addr(vp, address, &fileaddr, NULL);
if (error)
break;
}
if (fileaddr != -1) {
bp = uma_zalloc(vnode_pbuf_zone, M_WAITOK);
/* 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;
pbgetbo(bo, bp);
bp->b_vp = vp;
bp->b_bcount = bsize;
bp->b_bufsize = bsize;
bp->b_runningbufspace = bp->b_bufsize;
atomic_add_long(&runningbufspace, bp->b_runningbufspace);
/* do the input */
bp->b_iooffset = dbtob(bp->b_blkno);
bstrategy(bp);
bwait(bp, PVM, "vnsrd");
if ((bp->b_ioflags & BIO_ERROR) != 0) {
KASSERT(bp->b_error != 0,
("%s: buf error but b_error == 0\n", __func__));
error = bp->b_error;
}
/*
* free the buffer header back to the swap buffer pool
*/
bp->b_vp = NULL;
pbrelbo(bp);
uma_zfree(vnode_pbuf_zone, bp);
if (error)
break;
} else
bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize);
KASSERT((m->dirty & bits) == 0,
("vnode_pager_input_smlfs: page %p is dirty", m));
vm_page_bits_set(m, &m->valid, bits);
}
sf_buf_free(sf);
if (error) {
return VM_PAGER_ERROR;
}
return VM_PAGER_OK;
}
/*
* old style vnode pager input routine
*/
static int
vnode_pager_input_old(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_ASSERT_WLOCKED(object);
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_WUNLOCK(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_WLOCK(object);
}
KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m));
if (!error)
vm_page_valid(m);
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(vm_object_t object, vm_page_t *m, int count, int *rbehind,
int *rahead)
{
struct vnode *vp;
int rtval;
/* Handle is stable with paging in progress. */
vp = object->handle;
rtval = VOP_GETPAGES(vp, m, count, rbehind, rahead);
KASSERT(rtval != EOPNOTSUPP,
("vnode_pager: FS getpages not implemented\n"));
return rtval;
}
static int
vnode_pager_getpages_async(vm_object_t object, vm_page_t *m, int count,
int *rbehind, int *rahead, vop_getpages_iodone_t iodone, void *arg)
{
struct vnode *vp;
int rtval;
vp = object->handle;
rtval = VOP_GETPAGES_ASYNC(vp, m, count, rbehind, rahead, iodone, arg);
KASSERT(rtval != EOPNOTSUPP,
("vnode_pager: FS getpages_async not implemented\n"));
return (rtval);
}
/*
* The implementation of VOP_GETPAGES() and VOP_GETPAGES_ASYNC() for
* local filesystems, where partially valid pages can only occur at
* the end of file.
*/
int
vnode_pager_local_getpages(struct vop_getpages_args *ap)
{
return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count,
ap->a_rbehind, ap->a_rahead, NULL, NULL));
}
int
vnode_pager_local_getpages_async(struct vop_getpages_async_args *ap)
{
int error;
error = vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count,
ap->a_rbehind, ap->a_rahead, ap->a_iodone, ap->a_arg);
if (error != 0 && ap->a_iodone != NULL)
ap->a_iodone(ap->a_arg, ap->a_m, ap->a_count, error);
return (error);
}
/*
* 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(struct vnode *vp, vm_page_t *m, int count,
int *a_rbehind, int *a_rahead, vop_getpages_iodone_t iodone, void *arg)
{
vm_object_t object;
struct bufobj *bo;
struct buf *bp;
off_t foff;
#ifdef INVARIANTS
off_t blkno0;
#endif
int bsize, pagesperblock;
int error, before, after, rbehind, rahead, poff, i;
int bytecount, secmask;
KASSERT(vp->v_type != VCHR && vp->v_type != VBLK,
("%s does not support devices", __func__));
if (VN_IS_DOOMED(vp))
return (VM_PAGER_BAD);
object = vp->v_object;
foff = IDX_TO_OFF(m[0]->pindex);
bsize = vp->v_mount->mnt_stat.f_iosize;
pagesperblock = bsize / PAGE_SIZE;
KASSERT(foff < object->un_pager.vnp.vnp_size,
("%s: page %p offset beyond vp %p size", __func__, m[0], vp));
KASSERT(count <= atop(maxphys),
("%s: requested %d pages", __func__, count));
/*
* The last page has valid blocks. Invalid part can only
* exist at the end of file, and the page is made fully valid
* by zeroing in vm_pager_get_pages().
*/
if (!vm_page_none_valid(m[count - 1]) && --count == 0) {
if (iodone != NULL)
iodone(arg, m, 1, 0);
return (VM_PAGER_OK);
}
bp = uma_zalloc(vnode_pbuf_zone, M_WAITOK);
MPASS((bp->b_flags & B_MAXPHYS) != 0);
/*
* Get the underlying device blocks for the file with VOP_BMAP().
* If the file system doesn't support VOP_BMAP, use old way of
* getting pages via VOP_READ.
*/
error = VOP_BMAP(vp, foff / bsize, &bo, &bp->b_blkno, &after, &before);
if (error == EOPNOTSUPP) {
uma_zfree(vnode_pbuf_zone, bp);
VM_OBJECT_WLOCK(object);
for (i = 0; i < count; i++) {
VM_CNT_INC(v_vnodein);
VM_CNT_INC(v_vnodepgsin);
error = vnode_pager_input_old(object, m[i]);
if (error)
break;
}
VM_OBJECT_WUNLOCK(object);
return (error);
} else if (error != 0) {
uma_zfree(vnode_pbuf_zone, bp);
return (VM_PAGER_ERROR);
}
/*
* If the file system supports BMAP, but blocksize is smaller
* than a page size, then use special small filesystem code.
*/
if (pagesperblock == 0) {
uma_zfree(vnode_pbuf_zone, bp);
for (i = 0; i < count; i++) {
VM_CNT_INC(v_vnodein);
VM_CNT_INC(v_vnodepgsin);
error = vnode_pager_input_smlfs(object, m[i]);
if (error)
break;
}
return (error);
}
/*
* A sparse file can be encountered only for a single page request,
* which may not be preceded by call to vm_pager_haspage().
*/
if (bp->b_blkno == -1) {
KASSERT(count == 1,
("%s: array[%d] request to a sparse file %p", __func__,
count, vp));
uma_zfree(vnode_pbuf_zone, bp);
pmap_zero_page(m[0]);
KASSERT(m[0]->dirty == 0, ("%s: page %p is dirty",
__func__, m[0]));
vm_page_valid(m[0]);
return (VM_PAGER_OK);
}
#ifdef INVARIANTS
blkno0 = bp->b_blkno;
#endif
bp->b_blkno += (foff % bsize) / DEV_BSIZE;
/* Recalculate blocks available after/before to pages. */
poff = (foff % bsize) / PAGE_SIZE;
before *= pagesperblock;
before += poff;
after *= pagesperblock;
after += pagesperblock - (poff + 1);
if (m[0]->pindex + after >= object->size)
after = object->size - 1 - m[0]->pindex;
KASSERT(count <= after + 1, ("%s: %d pages asked, can do only %d",
__func__, count, after + 1));
after -= count - 1;
/* Trim requested rbehind/rahead to possible values. */
rbehind = a_rbehind ? *a_rbehind : 0;
rahead = a_rahead ? *a_rahead : 0;
rbehind = min(rbehind, before);
rbehind = min(rbehind, m[0]->pindex);
rahead = min(rahead, after);
rahead = min(rahead, object->size - m[count - 1]->pindex);
/*
* Check that total amount of pages fit into buf. Trim rbehind and
* rahead evenly if not.
*/
if (rbehind + rahead + count > atop(maxphys)) {
int trim, sum;
trim = rbehind + rahead + count - atop(maxphys) + 1;
sum = rbehind + rahead;
if (rbehind == before) {
/* Roundup rbehind trim to block size. */
rbehind -= roundup(trim * rbehind / sum, pagesperblock);
if (rbehind < 0)
rbehind = 0;
} else
rbehind -= trim * rbehind / sum;
rahead -= trim * rahead / sum;
}
KASSERT(rbehind + rahead + count <= atop(maxphys),
("%s: behind %d ahead %d count %d maxphys %lu", __func__,
rbehind, rahead, count, maxphys));
/*
* Fill in the bp->b_pages[] array with requested and optional
* read behind or read ahead pages. Read behind pages are looked
* up in a backward direction, down to a first cached page. Same
* for read ahead pages, but there is no need to shift the array
* in case of encountering a cached page.
*/
i = bp->b_npages = 0;
if (rbehind) {
vm_pindex_t startpindex, tpindex;
vm_page_t p;
VM_OBJECT_WLOCK(object);
startpindex = m[0]->pindex - rbehind;
if ((p = TAILQ_PREV(m[0], pglist, listq)) != NULL &&
p->pindex >= startpindex)
startpindex = p->pindex + 1;
/* tpindex is unsigned; beware of numeric underflow. */
for (tpindex = m[0]->pindex - 1;
tpindex >= startpindex && tpindex < m[0]->pindex;
tpindex--, i++) {
p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL);
if (p == NULL) {
/* Shift the array. */
for (int j = 0; j < i; j++)
bp->b_pages[j] = bp->b_pages[j +
tpindex + 1 - startpindex];
break;
}
bp->b_pages[tpindex - startpindex] = p;
}
bp->b_pgbefore = i;
bp->b_npages += i;
bp->b_blkno -= IDX_TO_OFF(i) / DEV_BSIZE;
} else
bp->b_pgbefore = 0;
/* Requested pages. */
for (int j = 0; j < count; j++, i++)
bp->b_pages[i] = m[j];
bp->b_npages += count;
if (rahead) {
vm_pindex_t endpindex, tpindex;
vm_page_t p;
if (!VM_OBJECT_WOWNED(object))
VM_OBJECT_WLOCK(object);
endpindex = m[count - 1]->pindex + rahead + 1;
if ((p = TAILQ_NEXT(m[count - 1], listq)) != NULL &&
p->pindex < endpindex)
endpindex = p->pindex;
if (endpindex > object->size)
endpindex = object->size;
for (tpindex = m[count - 1]->pindex + 1;
tpindex < endpindex; i++, tpindex++) {
p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL);
if (p == NULL)
break;
bp->b_pages[i] = p;
}
bp->b_pgafter = i - bp->b_npages;
bp->b_npages = i;
} else
bp->b_pgafter = 0;
if (VM_OBJECT_WOWNED(object))
VM_OBJECT_WUNLOCK(object);
/* Report back actual behind/ahead read. */
if (a_rbehind)
*a_rbehind = bp->b_pgbefore;
if (a_rahead)
*a_rahead = bp->b_pgafter;
#ifdef INVARIANTS
KASSERT(bp->b_npages <= atop(maxphys),
("%s: buf %p overflowed", __func__, bp));
for (int j = 1, prev = 0; j < bp->b_npages; j++) {
if (bp->b_pages[j] == bogus_page)
continue;
KASSERT(bp->b_pages[j]->pindex - bp->b_pages[prev]->pindex ==
j - prev, ("%s: pages array not consecutive, bp %p",
__func__, bp));
prev = j;
}
#endif
/*
* Recalculate first offset and bytecount with regards to read behind.
* Truncate bytecount to vnode real size and round up physical size
* for real devices.
*/
foff = IDX_TO_OFF(bp->b_pages[0]->pindex);
bytecount = bp->b_npages << PAGE_SHIFT;
if ((foff + bytecount) > object->un_pager.vnp.vnp_size)
bytecount = object->un_pager.vnp.vnp_size - foff;
secmask = bo->bo_bsize - 1;
KASSERT(secmask < PAGE_SIZE && secmask > 0,
("%s: sector size %d too large", __func__, secmask + 1));
bytecount = (bytecount + secmask) & ~secmask;
/*
* And map the pages to be read into the kva, if the filesystem
* requires mapped buffers.
*/
if ((vp->v_mount->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 &&
unmapped_buf_allowed) {
bp->b_data = unmapped_buf;
bp->b_offset = 0;
} else {
bp->b_data = bp->b_kvabase;
pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages);
}
/* Build a minimal buffer header. */
bp->b_iocmd = BIO_READ;
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);
pbgetbo(bo, bp);
bp->b_vp = vp;
bp->b_bcount = bp->b_bufsize = bp->b_runningbufspace = bytecount;
bp->b_iooffset = dbtob(bp->b_blkno);
KASSERT(IDX_TO_OFF(m[0]->pindex - bp->b_pages[0]->pindex) ==
(blkno0 - bp->b_blkno) * DEV_BSIZE +
IDX_TO_OFF(m[0]->pindex) % bsize,
("wrong offsets bsize %d m[0] %ju b_pages[0] %ju "
"blkno0 %ju b_blkno %ju", bsize,
(uintmax_t)m[0]->pindex, (uintmax_t)bp->b_pages[0]->pindex,
(uintmax_t)blkno0, (uintmax_t)bp->b_blkno));
atomic_add_long(&runningbufspace, bp->b_runningbufspace);
VM_CNT_INC(v_vnodein);
VM_CNT_ADD(v_vnodepgsin, bp->b_npages);
if (iodone != NULL) { /* async */
bp->b_pgiodone = iodone;
bp->b_caller1 = arg;
bp->b_iodone = vnode_pager_generic_getpages_done_async;
bp->b_flags |= B_ASYNC;
BUF_KERNPROC(bp);
bstrategy(bp);
return (VM_PAGER_OK);
} else {
bp->b_iodone = bdone;
bstrategy(bp);
bwait(bp, PVM, "vnread");
error = vnode_pager_generic_getpages_done(bp);
for (i = 0; i < bp->b_npages; i++)
bp->b_pages[i] = NULL;
bp->b_vp = NULL;
pbrelbo(bp);
uma_zfree(vnode_pbuf_zone, bp);
return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK);
}
}
static void
vnode_pager_generic_getpages_done_async(struct buf *bp)
{
int error;
error = vnode_pager_generic_getpages_done(bp);
/* Run the iodone upon the requested range. */
bp->b_pgiodone(bp->b_caller1, bp->b_pages + bp->b_pgbefore,
bp->b_npages - bp->b_pgbefore - bp->b_pgafter, error);
for (int i = 0; i < bp->b_npages; i++)
bp->b_pages[i] = NULL;
bp->b_vp = NULL;
pbrelbo(bp);
uma_zfree(vnode_pbuf_zone, bp);
}
static int
vnode_pager_generic_getpages_done(struct buf *bp)
{
vm_object_t object;
off_t tfoff, nextoff;
int i, error;
KASSERT((bp->b_ioflags & BIO_ERROR) == 0 || bp->b_error != 0,
("%s: buf error but b_error == 0\n", __func__));
error = (bp->b_ioflags & BIO_ERROR) != 0 ? bp->b_error : 0;
object = bp->b_vp->v_object;
if (error == 0 && bp->b_bcount != bp->b_npages * PAGE_SIZE) {
if (!buf_mapped(bp)) {
bp->b_data = bp->b_kvabase;
pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages,
bp->b_npages);
}
bzero(bp->b_data + bp->b_bcount,
PAGE_SIZE * bp->b_npages - bp->b_bcount);
}
if (buf_mapped(bp)) {
pmap_qremove((vm_offset_t)bp->b_data, bp->b_npages);
bp->b_data = unmapped_buf;
}
/*
* If the read failed, we must free any read ahead/behind pages here.
* The requested pages are freed by the caller (for sync requests)
* or by the bp->b_pgiodone callback (for async requests).
*/
if (error != 0) {
VM_OBJECT_WLOCK(object);
for (i = 0; i < bp->b_pgbefore; i++)
vm_page_free_invalid(bp->b_pages[i]);
for (i = bp->b_npages - bp->b_pgafter; i < bp->b_npages; i++)
vm_page_free_invalid(bp->b_pages[i]);
VM_OBJECT_WUNLOCK(object);
return (error);
}
/* Read lock to protect size. */
VM_OBJECT_RLOCK(object);
for (i = 0, tfoff = IDX_TO_OFF(bp->b_pages[0]->pindex);
i < bp->b_npages; i++, tfoff = nextoff) {
vm_page_t mt;
nextoff = tfoff + PAGE_SIZE;
mt = bp->b_pages[i];
if (mt == bogus_page)
continue;
if (nextoff <= object->un_pager.vnp.vnp_size) {
/*
* Read filled up entire page.
*/
vm_page_valid(mt);
KASSERT(mt->dirty == 0,
("%s: page %p is dirty", __func__, mt));
KASSERT(!pmap_page_is_mapped(mt),
("%s: page %p is mapped", __func__, mt));
} else {
/*
* Read did not fill up entire page.
*
* Currently we do not set the entire page valid,
* we just try to clear the piece that we couldn't
* read.
*/
vm_page_set_valid_range(mt, 0,
object->un_pager.vnp.vnp_size - tfoff);
KASSERT((mt->dirty & vm_page_bits(0,
object->un_pager.vnp.vnp_size - tfoff)) == 0,
("%s: page %p is dirty", __func__, mt));
}
if (i < bp->b_pgbefore || i >= bp->b_npages - bp->b_pgafter)
vm_page_readahead_finish(mt);
}
VM_OBJECT_RUNLOCK(object);
return (error);
}
/*
* 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(vm_object_t object, vm_page_t *m, int count,
int flags, int *rtvals)
{
int rtval;
struct vnode *vp;
int bytes = count * PAGE_SIZE;
/*
* 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 (vm_page_count_min())
flags |= VM_PAGER_PUT_SYNC;
/*
* Call device-specific putpages function
*/
vp = object->handle;
VM_OBJECT_WUNLOCK(object);
rtval = VOP_PUTPAGES(vp, m, bytes, flags, rtvals);
KASSERT(rtval != EOPNOTSUPP,
("vnode_pager: stale FS putpages\n"));
VM_OBJECT_WLOCK(object);
}
static int
vn_off2bidx(vm_ooffset_t offset)
{
return ((offset & PAGE_MASK) / DEV_BSIZE);
}
static bool
vn_dirty_blk(vm_page_t m, vm_ooffset_t offset)
{
KASSERT(IDX_TO_OFF(m->pindex) <= offset &&
offset < IDX_TO_OFF(m->pindex + 1),
("page %p pidx %ju offset %ju", m, (uintmax_t)m->pindex,
(uintmax_t)offset));
return ((m->dirty & ((vm_page_bits_t)1 << vn_off2bidx(offset))) != 0);
}
/*
* 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 occurred, so in general we ask the
* underlying filesystem to write the data out asynchronously rather
* then delayed.
*/
int
vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount,
int flags, int *rtvals)
{
vm_object_t object;
vm_page_t m;
vm_ooffset_t maxblksz, next_offset, poffset, prev_offset;
struct uio auio;
struct iovec aiov;
off_t prev_resid, wrsz;
int count, error, i, maxsize, ncount, pgoff, ppscheck;
bool in_hole;
static struct timeval lastfail;
static int curfail;
object = vp->v_object;
count = bytecount / PAGE_SIZE;
for (i = 0; i < count; i++)
rtvals[i] = VM_PAGER_ERROR;
if ((int64_t)ma[0]->pindex < 0) {
printf("vnode_pager_generic_putpages: "
"attempt to write meta-data 0x%jx(%lx)\n",
(uintmax_t)ma[0]->pindex, (u_long)ma[0]->dirty);
rtvals[0] = VM_PAGER_BAD;
return (VM_PAGER_BAD);
}
maxsize = count * PAGE_SIZE;
ncount = count;
poffset = IDX_TO_OFF(ma[0]->pindex);
/*
* If the page-aligned write is larger then the actual file we
* have to invalidate pages occurring 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 busied 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.
*/
VM_OBJECT_RLOCK(object);
if (maxsize + poffset > object->un_pager.vnp.vnp_size) {
if (object->un_pager.vnp.vnp_size > poffset) {
maxsize = object->un_pager.vnp.vnp_size - poffset;
ncount = btoc(maxsize);
if ((pgoff = (int)maxsize & PAGE_MASK) != 0) {
pgoff = roundup2(pgoff, DEV_BSIZE);
/*
* If the page is busy and the following
* conditions hold, then the page's dirty
* field cannot be concurrently changed by a
* pmap operation.
*/
m = ma[ncount - 1];
vm_page_assert_sbusied(m);
KASSERT(!pmap_page_is_write_mapped(m),
("vnode_pager_generic_putpages: page %p is not read-only", m));
MPASS(m->dirty != 0);
vm_page_clear_dirty(m, pgoff, PAGE_SIZE -
pgoff);
}
} else {
maxsize = 0;
ncount = 0;
}
for (i = ncount; i < count; i++)
rtvals[i] = VM_PAGER_BAD;
}
VM_OBJECT_RUNLOCK(object);
auio.uio_iov = &aiov;
auio.uio_segflg = UIO_NOCOPY;
auio.uio_rw = UIO_WRITE;
auio.uio_td = NULL;
maxblksz = roundup2(poffset + maxsize, DEV_BSIZE);
for (prev_offset = poffset; prev_offset < maxblksz;) {
/* Skip clean blocks. */
for (in_hole = true; in_hole && prev_offset < maxblksz;) {
m = ma[OFF_TO_IDX(prev_offset - poffset)];
for (i = vn_off2bidx(prev_offset);
i < sizeof(vm_page_bits_t) * NBBY &&
prev_offset < maxblksz; i++) {
if (vn_dirty_blk(m, prev_offset)) {
in_hole = false;
break;
}
prev_offset += DEV_BSIZE;
}
}
if (in_hole)
goto write_done;
/* Find longest run of dirty blocks. */
for (next_offset = prev_offset; next_offset < maxblksz;) {
m = ma[OFF_TO_IDX(next_offset - poffset)];
for (i = vn_off2bidx(next_offset);
i < sizeof(vm_page_bits_t) * NBBY &&
next_offset < maxblksz; i++) {
if (!vn_dirty_blk(m, next_offset))
goto start_write;
next_offset += DEV_BSIZE;
}
}
start_write:
if (next_offset > poffset + maxsize)
next_offset = poffset + maxsize;
/*
* Getting here requires finding a dirty block in the
* 'skip clean blocks' loop.
*/
MPASS(prev_offset < next_offset);
aiov.iov_base = NULL;
auio.uio_iovcnt = 1;
auio.uio_offset = prev_offset;
prev_resid = auio.uio_resid = aiov.iov_len = next_offset -
prev_offset;
error = VOP_WRITE(vp, &auio,
vnode_pager_putpages_ioflags(flags), curthread->td_ucred);
wrsz = prev_resid - auio.uio_resid;
if (wrsz == 0) {
if (ppsratecheck(&lastfail, &curfail, 1) != 0) {
vn_printf(vp, "vnode_pager_putpages: "
"zero-length write at %ju resid %zd\n",
auio.uio_offset, auio.uio_resid);
}
break;
}
/* Adjust the starting offset for next iteration. */
prev_offset += wrsz;
MPASS(auio.uio_offset == prev_offset);
ppscheck = 0;
if (error != 0 && (ppscheck = ppsratecheck(&lastfail,
&curfail, 1)) != 0)
vn_printf(vp, "vnode_pager_putpages: I/O error %d\n",
error);
if (auio.uio_resid != 0 && (ppscheck != 0 ||
ppsratecheck(&lastfail, &curfail, 1) != 0))
vn_printf(vp, "vnode_pager_putpages: residual I/O %zd "
"at %ju\n", auio.uio_resid,
(uintmax_t)ma[0]->pindex);
if (error != 0 || auio.uio_resid != 0)
break;
}
write_done:
/* Mark completely processed pages. */
for (i = 0; i < OFF_TO_IDX(prev_offset - poffset); i++)
rtvals[i] = VM_PAGER_OK;
/* Mark partial EOF page. */
if (prev_offset == poffset + maxsize && (prev_offset & PAGE_MASK) != 0)
rtvals[i++] = VM_PAGER_OK;
/* Unwritten pages in range, free bonus if the page is clean. */
for (; i < ncount; i++)
rtvals[i] = ma[i]->dirty == 0 ? VM_PAGER_OK : VM_PAGER_ERROR;
VM_CNT_ADD(v_vnodepgsout, i);
VM_CNT_INC(v_vnodeout);
return (rtvals[0]);
}
int
vnode_pager_putpages_ioflags(int pager_flags)
{
int ioflags;
/*
* Pageouts are already clustered, use IO_ASYNC to 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 ((pager_flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) != 0)
ioflags |= IO_SYNC;
else if ((pager_flags & VM_PAGER_CLUSTER_OK) == 0)
ioflags |= IO_ASYNC;
ioflags |= (pager_flags & VM_PAGER_PUT_INVAL) != 0 ? IO_INVAL: 0;
ioflags |= (pager_flags & VM_PAGER_PUT_NOREUSE) != 0 ? IO_NOREUSE : 0;
ioflags |= IO_SEQMAX << IO_SEQSHIFT;
return (ioflags);
}
/*
* vnode_pager_undirty_pages().
*
* A helper to mark pages as clean after pageout that was possibly
* done with a short write. The lpos argument specifies the page run
* length in bytes, and the written argument specifies how many bytes
* were actually written. eof is the offset past the last valid byte
* in the vnode using the absolute file position of the first byte in
* the run as the base from which it is computed.
*/
void
vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written, off_t eof,
int lpos)
{
int i, pos, pos_devb;
if (written == 0 && eof >= lpos)
return;
for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) {
if (pos < trunc_page(written)) {
rtvals[i] = VM_PAGER_OK;
vm_page_undirty(ma[i]);
} else {
/* Partially written page. */
rtvals[i] = VM_PAGER_AGAIN;
vm_page_clear_dirty(ma[i], 0, written & PAGE_MASK);
}
}
if (eof >= lpos) /* avoid truncation */
return;
for (pos = eof, i = OFF_TO_IDX(trunc_page(pos)); pos < lpos; i++) {
if (pos != trunc_page(pos)) {
/*
* The page contains the last valid byte in
* the vnode, mark the rest of the page as
* clean, potentially making the whole page
* clean.
*/
pos_devb = roundup2(pos & PAGE_MASK, DEV_BSIZE);
vm_page_clear_dirty(ma[i], pos_devb, PAGE_SIZE -
pos_devb);
/*
* If the page was cleaned, report the pageout
* on it as successful. msync() no longer
* needs to write out the page, endlessly
* creating write requests and dirty buffers.
*/
if (ma[i]->dirty == 0)
rtvals[i] = VM_PAGER_OK;
pos = round_page(pos);
} else {
/* vm_pageout_flush() clears dirty */
rtvals[i] = VM_PAGER_BAD;
pos += PAGE_SIZE;
}
}
}
static void
vnode_pager_update_writecount(vm_object_t object, vm_offset_t start,
vm_offset_t end)
{
struct vnode *vp;
vm_ooffset_t old_wm;
VM_OBJECT_WLOCK(object);
if (object->type != OBJT_VNODE) {
VM_OBJECT_WUNLOCK(object);
return;
}
old_wm = object->un_pager.vnp.writemappings;
object->un_pager.vnp.writemappings += (vm_ooffset_t)end - start;
vp = object->handle;
if (old_wm == 0 && object->un_pager.vnp.writemappings != 0) {
ASSERT_VOP_LOCKED(vp, "v_writecount inc");
VOP_ADD_WRITECOUNT_CHECKED(vp, 1);
CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d",
__func__, vp, vp->v_writecount);
} else if (old_wm != 0 && object->un_pager.vnp.writemappings == 0) {
ASSERT_VOP_LOCKED(vp, "v_writecount dec");
VOP_ADD_WRITECOUNT_CHECKED(vp, -1);
CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
__func__, vp, vp->v_writecount);
}
VM_OBJECT_WUNLOCK(object);
}
static void
vnode_pager_release_writecount(vm_object_t object, vm_offset_t start,
vm_offset_t end)
{
struct vnode *vp;
struct mount *mp;
vm_offset_t inc;
VM_OBJECT_WLOCK(object);
/*
* First, recheck the object type to account for the race when
* the vnode is reclaimed.
*/
if (object->type != OBJT_VNODE) {
VM_OBJECT_WUNLOCK(object);
return;
}
/*
* Optimize for the case when writemappings is not going to
* zero.
*/
inc = end - start;
if (object->un_pager.vnp.writemappings != inc) {
object->un_pager.vnp.writemappings -= inc;
VM_OBJECT_WUNLOCK(object);
return;
}
vp = object->handle;
vhold(vp);
VM_OBJECT_WUNLOCK(object);
mp = NULL;
vn_start_write(vp, &mp, V_WAIT);
vn_lock(vp, LK_SHARED | LK_RETRY);
/*
* Decrement the object's writemappings, by swapping the start
* and end arguments for vnode_pager_update_writecount(). If
* there was not a race with vnode reclaimation, then the
* vnode's v_writecount is decremented.
*/
vnode_pager_update_writecount(object, end, start);
VOP_UNLOCK(vp);
vdrop(vp);
if (mp != NULL)
vn_finished_write(mp);
}
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