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uvm_vnode.c
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uvm_vnode.c
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/* $NetBSD: uvm_vnode.c,v 1.80 2007/02/22 06:05:02 thorpej Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
* Copyright (c) 1991, 1993
* The Regents of the University of California.
* Copyright (c) 1990 University of Utah.
*
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the Systems Programming Group of the University of Utah Computer
* Science Department.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Charles D. Cranor,
* Washington University, 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.
*
* @(#)vnode_pager.c 8.8 (Berkeley) 2/13/94
* from: Id: uvm_vnode.c,v 1.1.2.26 1998/02/02 20:38:07 chuck Exp
*/
/*
* uvm_vnode.c: the vnode pager.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: uvm_vnode.c,v 1.80 2007/02/22 06:05:02 thorpej Exp $");
#include "fs_nfs.h"
#include "opt_uvmhist.h"
#include "opt_ddb.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/vnode.h>
#include <sys/disklabel.h>
#include <sys/ioctl.h>
#include <sys/fcntl.h>
#include <sys/conf.h>
#include <sys/pool.h>
#include <sys/mount.h>
#include <miscfs/specfs/specdev.h>
#include <uvm/uvm.h>
#include <uvm/uvm_readahead.h>
/*
* functions
*/
static void uvn_detach(struct uvm_object *);
static int uvn_get(struct uvm_object *, voff_t, struct vm_page **, int *,
int, vm_prot_t, int, int);
static int uvn_put(struct uvm_object *, voff_t, voff_t, int);
static void uvn_reference(struct uvm_object *);
static int uvn_findpage(struct uvm_object *, voff_t, struct vm_page **,
int);
/*
* master pager structure
*/
struct uvm_pagerops uvm_vnodeops = {
NULL,
uvn_reference,
uvn_detach,
NULL,
uvn_get,
uvn_put,
};
/*
* the ops!
*/
/*
* uvn_attach
*
* attach a vnode structure to a VM object. if the vnode is already
* attached, then just bump the reference count by one and return the
* VM object. if not already attached, attach and return the new VM obj.
* the "accessprot" tells the max access the attaching thread wants to
* our pages.
*
* => caller must _not_ already be holding the lock on the uvm_object.
* => in fact, nothing should be locked so that we can sleep here.
* => note that uvm_object is first thing in vnode structure, so their
* pointers are equiv.
*/
struct uvm_object *
uvn_attach(void *arg, vm_prot_t accessprot)
{
struct vnode *vp = arg;
struct uvm_object *uobj = &vp->v_uobj;
struct vattr vattr;
const struct bdevsw *bdev;
int result;
struct partinfo pi;
voff_t used_vnode_size;
UVMHIST_FUNC("uvn_attach"); UVMHIST_CALLED(maphist);
UVMHIST_LOG(maphist, "(vn=0x%x)", arg,0,0,0);
used_vnode_size = (voff_t)0;
/*
* first get a lock on the uobj.
*/
simple_lock(&uobj->vmobjlock);
while (vp->v_flag & VXLOCK) {
vp->v_flag |= VXWANT;
UVMHIST_LOG(maphist, " SLEEPING on blocked vn",0,0,0,0);
UVM_UNLOCK_AND_WAIT(uobj, &uobj->vmobjlock, false,
"uvn_attach", 0);
simple_lock(&uobj->vmobjlock);
UVMHIST_LOG(maphist," WOKE UP",0,0,0,0);
}
/*
* if we're mapping a BLK device, make sure it is a disk.
*/
if (vp->v_type == VBLK) {
bdev = bdevsw_lookup(vp->v_rdev);
if (bdev == NULL || bdev->d_type != D_DISK) {
simple_unlock(&uobj->vmobjlock);
UVMHIST_LOG(maphist,"<- done (VBLK not D_DISK!)",
0,0,0,0);
return(NULL);
}
}
KASSERT(vp->v_type == VREG || vp->v_type == VBLK);
/*
* set up our idea of the size
* if this hasn't been done already.
*/
if (vp->v_size == VSIZENOTSET) {
vp->v_flag |= VXLOCK;
simple_unlock(&uobj->vmobjlock); /* drop lock in case we sleep */
/* XXX: curproc? */
if (vp->v_type == VBLK) {
/*
* We could implement this as a specfs getattr call, but:
*
* (1) VOP_GETATTR() would get the file system
* vnode operation, not the specfs operation.
*
* (2) All we want is the size, anyhow.
*/
bdev = bdevsw_lookup(vp->v_rdev);
if (bdev != NULL) {
result = (*bdev->d_ioctl)(vp->v_rdev, DIOCGPART,
(caddr_t)&pi, FREAD, curlwp);
} else {
result = ENXIO;
}
if (result == 0) {
/* XXX should remember blocksize */
used_vnode_size = (voff_t)pi.disklab->d_secsize *
(voff_t)pi.part->p_size;
}
} else {
result = VOP_GETATTR(vp, &vattr, curlwp->l_cred, curlwp);
if (result == 0)
used_vnode_size = vattr.va_size;
}
/* relock object */
simple_lock(&uobj->vmobjlock);
if (vp->v_flag & VXWANT) {
wakeup(vp);
}
vp->v_flag &= ~(VXLOCK|VXWANT);
if (result != 0) {
simple_unlock(&uobj->vmobjlock);
UVMHIST_LOG(maphist,"<- done (VOP_GETATTR FAILED!)", 0,0,0,0);
return(NULL);
}
vp->v_size = used_vnode_size;
}
simple_unlock(&uobj->vmobjlock);
UVMHIST_LOG(maphist,"<- done, refcnt=%d", vp->v_usecount,
0, 0, 0);
return uobj;
}
/*
* uvn_reference
*
* duplicate a reference to a VM object. Note that the reference
* count must already be at least one (the passed in reference) so
* there is no chance of the uvn being killed or locked out here.
*
* => caller must call with object unlocked.
* => caller must be using the same accessprot as was used at attach time
*/
static void
uvn_reference(struct uvm_object *uobj)
{
VREF((struct vnode *)uobj);
}
/*
* uvn_detach
*
* remove a reference to a VM object.
*
* => caller must call with object unlocked and map locked.
*/
static void
uvn_detach(struct uvm_object *uobj)
{
vrele((struct vnode *)uobj);
}
/*
* uvn_put: flush page data to backing store.
*
* => object must be locked on entry! VOP_PUTPAGES must unlock it.
* => flags: PGO_SYNCIO -- use sync. I/O
* => note: caller must set PG_CLEAN and pmap_clear_modify (if needed)
*/
static int
uvn_put(struct uvm_object *uobj, voff_t offlo, voff_t offhi, int flags)
{
struct vnode *vp = (struct vnode *)uobj;
int error;
LOCK_ASSERT(simple_lock_held(&vp->v_interlock));
error = VOP_PUTPAGES(vp, offlo, offhi, flags);
LOCK_ASSERT(!simple_lock_held(&vp->v_interlock));
return error;
}
/*
* uvn_get: get pages (synchronously) from backing store
*
* => prefer map unlocked (not required)
* => object must be locked! we will _unlock_ it before starting any I/O.
* => flags: PGO_ALLPAGES: get all of the pages
* PGO_LOCKED: fault data structures are locked
* => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx]
* => NOTE: caller must check for released pages!!
*/
static int
uvn_get(struct uvm_object *uobj, voff_t offset,
struct vm_page **pps /* IN/OUT */,
int *npagesp /* IN (OUT if PGO_LOCKED)*/,
int centeridx, vm_prot_t access_type, int advice, int flags)
{
struct vnode *vp = (struct vnode *)uobj;
int error;
UVMHIST_FUNC("uvn_get"); UVMHIST_CALLED(ubchist);
UVMHIST_LOG(ubchist, "vp %p off 0x%x", vp, (int)offset, 0,0);
if ((access_type & VM_PROT_WRITE) == 0 && (flags & PGO_LOCKED) == 0) {
simple_unlock(&vp->v_interlock);
vn_ra_allocctx(vp);
uvm_ra_request(vp->v_ractx, advice, uobj, offset,
*npagesp << PAGE_SHIFT);
simple_lock(&vp->v_interlock);
}
error = VOP_GETPAGES(vp, offset, pps, npagesp, centeridx,
access_type, advice, flags);
LOCK_ASSERT(((flags & PGO_LOCKED) != 0 &&
simple_lock_held(&vp->v_interlock)) ||
((flags & PGO_LOCKED) == 0 &&
!simple_lock_held(&vp->v_interlock)));
return error;
}
/*
* uvn_findpages:
* return the page for the uobj and offset requested, allocating if needed.
* => uobj must be locked.
* => returned pages will be BUSY.
*/
int
uvn_findpages(struct uvm_object *uobj, voff_t offset, int *npagesp,
struct vm_page **pgs, int flags)
{
int i, count, found, npages, rv;
count = found = 0;
npages = *npagesp;
if (flags & UFP_BACKWARD) {
for (i = npages - 1; i >= 0; i--, offset -= PAGE_SIZE) {
rv = uvn_findpage(uobj, offset, &pgs[i], flags);
if (rv == 0) {
if (flags & UFP_DIRTYONLY)
break;
} else
found++;
count++;
}
} else {
for (i = 0; i < npages; i++, offset += PAGE_SIZE) {
rv = uvn_findpage(uobj, offset, &pgs[i], flags);
if (rv == 0) {
if (flags & UFP_DIRTYONLY)
break;
} else
found++;
count++;
}
}
*npagesp = count;
return (found);
}
static int
uvn_findpage(struct uvm_object *uobj, voff_t offset, struct vm_page **pgp,
int flags)
{
struct vm_page *pg;
bool dirty;
UVMHIST_FUNC("uvn_findpage"); UVMHIST_CALLED(ubchist);
UVMHIST_LOG(ubchist, "vp %p off 0x%lx", uobj, offset,0,0);
if (*pgp != NULL) {
UVMHIST_LOG(ubchist, "dontcare", 0,0,0,0);
return 0;
}
for (;;) {
/* look for an existing page */
pg = uvm_pagelookup(uobj, offset);
/* nope? allocate one now */
if (pg == NULL) {
if (flags & UFP_NOALLOC) {
UVMHIST_LOG(ubchist, "noalloc", 0,0,0,0);
return 0;
}
pg = uvm_pagealloc(uobj, offset, NULL, 0);
if (pg == NULL) {
if (flags & UFP_NOWAIT) {
UVMHIST_LOG(ubchist, "nowait",0,0,0,0);
return 0;
}
simple_unlock(&uobj->vmobjlock);
uvm_wait("uvn_fp1");
simple_lock(&uobj->vmobjlock);
continue;
}
UVMHIST_LOG(ubchist, "alloced %p", pg,0,0,0);
break;
} else if (flags & UFP_NOCACHE) {
UVMHIST_LOG(ubchist, "nocache",0,0,0,0);
return 0;
}
/* page is there, see if we need to wait on it */
if ((pg->flags & PG_BUSY) != 0) {
if (flags & UFP_NOWAIT) {
UVMHIST_LOG(ubchist, "nowait",0,0,0,0);
return 0;
}
pg->flags |= PG_WANTED;
UVMHIST_LOG(ubchist, "wait %p", pg,0,0,0);
UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, 0,
"uvn_fp2", 0);
simple_lock(&uobj->vmobjlock);
continue;
}
/* skip PG_RDONLY pages if requested */
if ((flags & UFP_NORDONLY) && (pg->flags & PG_RDONLY)) {
UVMHIST_LOG(ubchist, "nordonly",0,0,0,0);
return 0;
}
/* stop on clean pages if requested */
if (flags & UFP_DIRTYONLY) {
dirty = pmap_clear_modify(pg) ||
(pg->flags & PG_CLEAN) == 0;
pg->flags |= PG_CLEAN;
if (!dirty) {
UVMHIST_LOG(ubchist, "dirtonly", 0,0,0,0);
return 0;
}
}
/* mark the page BUSY and we're done. */
pg->flags |= PG_BUSY;
UVM_PAGE_OWN(pg, "uvn_findpage");
UVMHIST_LOG(ubchist, "found %p", pg,0,0,0);
break;
}
*pgp = pg;
return 1;
}
/*
* uvm_vnp_setsize: grow or shrink a vnode uobj
*
* grow => just update size value
* shrink => toss un-needed pages
*
* => we assume that the caller has a reference of some sort to the
* vnode in question so that it will not be yanked out from under
* us.
*/
void
uvm_vnp_setsize(struct vnode *vp, voff_t newsize)
{
struct uvm_object *uobj = &vp->v_uobj;
voff_t pgend = round_page(newsize);
voff_t oldsize;
UVMHIST_FUNC("uvm_vnp_setsize"); UVMHIST_CALLED(ubchist);
simple_lock(&uobj->vmobjlock);
UVMHIST_LOG(ubchist, "vp %p old 0x%x new 0x%x",
vp, vp->v_size, newsize, 0);
/*
* now check if the size has changed: if we shrink we had better
* toss some pages...
*/
oldsize = vp->v_size;
if (oldsize > pgend && oldsize != VSIZENOTSET) {
(void) uvn_put(uobj, pgend, 0, PGO_FREE | PGO_SYNCIO);
simple_lock(&uobj->vmobjlock);
}
vp->v_size = newsize;
simple_unlock(&uobj->vmobjlock);
}
/*
* uvm_vnp_zerorange: set a range of bytes in a file to zero.
*/
void
uvm_vnp_zerorange(struct vnode *vp, off_t off, size_t len)
{
void *win;
int flags;
/*
* XXXUBC invent kzero() and use it
*/
while (len) {
vsize_t bytelen = len;
win = ubc_alloc(&vp->v_uobj, off, &bytelen, UVM_ADV_NORMAL,
UBC_WRITE);
memset(win, 0, bytelen);
flags = UBC_WANT_UNMAP(vp) ? UBC_UNMAP : 0;
ubc_release(win, flags);
off += bytelen;
len -= bytelen;
}
}
bool
uvn_text_p(struct uvm_object *uobj)
{
struct vnode *vp = (struct vnode *)uobj;
return (vp->v_flag & VEXECMAP) != 0;
}
bool
uvn_clean_p(struct uvm_object *uobj)
{
struct vnode *vp = (struct vnode *)uobj;
return (vp->v_flag & VONWORKLST) == 0;
}
bool
uvn_needs_writefault_p(struct uvm_object *uobj)
{
struct vnode *vp = (struct vnode *)uobj;
return uvn_clean_p(uobj) ||
(vp->v_flag & (VWRITEMAP|VWRITEMAPDIRTY)) == VWRITEMAP;
}