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Annotation of Net2/vm/vnode_pager.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1990 University of Utah.
        !             3:  * Copyright (c) 1991 The Regents of the University of California.
        !             4:  * All rights reserved.
        !             5:  *
        !             6:  * This code is derived from software contributed to Berkeley by
        !             7:  * the Systems Programming Group of the University of Utah Computer
        !             8:  * Science Department.
        !             9:  *
        !            10:  * Redistribution and use in source and binary forms, with or without
        !            11:  * modification, are permitted provided that the following conditions
        !            12:  * are met:
        !            13:  * 1. Redistributions of source code must retain the above copyright
        !            14:  *    notice, this list of conditions and the following disclaimer.
        !            15:  * 2. Redistributions in binary form must reproduce the above copyright
        !            16:  *    notice, this list of conditions and the following disclaimer in the
        !            17:  *    documentation and/or other materials provided with the distribution.
        !            18:  * 3. All advertising materials mentioning features or use of this software
        !            19:  *    must display the following acknowledgement:
        !            20:  *     This product includes software developed by the University of
        !            21:  *     California, Berkeley and its contributors.
        !            22:  * 4. Neither the name of the University nor the names of its contributors
        !            23:  *    may be used to endorse or promote products derived from this software
        !            24:  *    without specific prior written permission.
        !            25:  *
        !            26:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
        !            27:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            28:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            29:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            30:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            31:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            32:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            33:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            34:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            35:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            36:  * SUCH DAMAGE.
        !            37:  *
        !            38:  *     @(#)vnode_pager.c       7.5 (Berkeley) 4/20/91
        !            39:  */
        !            40: 
        !            41: /*
        !            42:  * Page to/from files (vnodes).
        !            43:  *
        !            44:  * TODO:
        !            45:  *     pageouts
        !            46:  *     fix credential use (uses current process credentials now)
        !            47:  */
        !            48: #include "vnodepager.h"
        !            49: #if NVNODEPAGER > 0
        !            50: 
        !            51: #include "param.h"
        !            52: #include "proc.h"
        !            53: #include "malloc.h"
        !            54: #include "vnode.h"
        !            55: #include "uio.h"
        !            56: #include "mount.h"
        !            57: 
        !            58: #include "vm_param.h"
        !            59: #include "lock.h"
        !            60: #include "queue.h"
        !            61: #include "vm_prot.h"
        !            62: #include "vm_object.h"
        !            63: #include "vm_page.h"
        !            64: #include "vnode_pager.h"
        !            65: 
        !            66: queue_head_t   vnode_pager_list;       /* list of managed vnodes */
        !            67: 
        !            68: #ifdef DEBUG
        !            69: int    vpagerdebug = 0x00;
        !            70: #define        VDB_FOLLOW      0x01
        !            71: #define VDB_INIT       0x02
        !            72: #define VDB_IO         0x04
        !            73: #define VDB_FAIL       0x08
        !            74: #define VDB_ALLOC      0x10
        !            75: #define VDB_SIZE       0x20
        !            76: #endif
        !            77: 
        !            78: void
        !            79: vnode_pager_init()
        !            80: {
        !            81: #ifdef DEBUG
        !            82:        if (vpagerdebug & VDB_FOLLOW)
        !            83:                printf("vnode_pager_init()\n");
        !            84: #endif
        !            85:        queue_init(&vnode_pager_list);
        !            86: }
        !            87: 
        !            88: /*
        !            89:  * Allocate (or lookup) pager for a vnode.
        !            90:  * Handle is a vnode pointer.
        !            91:  */
        !            92: vm_pager_t
        !            93: vnode_pager_alloc(handle, size, prot)
        !            94:        caddr_t handle;
        !            95:        vm_size_t size;
        !            96:        vm_prot_t prot;
        !            97: {
        !            98:        register vm_pager_t pager;
        !            99:        register vn_pager_t vnp;
        !           100:        vm_object_t object;
        !           101:        struct vattr vattr;
        !           102:        struct vnode *vp;
        !           103:        struct proc *p = curproc;       /* XXX */
        !           104: 
        !           105: #ifdef DEBUG
        !           106:        if (vpagerdebug & (VDB_FOLLOW|VDB_ALLOC))
        !           107:                printf("vnode_pager_alloc(%x, %x, %x)\n", handle, size, prot);
        !           108: #endif
        !           109:        /*
        !           110:         * Pageout to vnode, no can do yet.
        !           111:         */
        !           112:        if (handle == NULL)
        !           113:                return(NULL);
        !           114: 
        !           115:        /*
        !           116:         * Vnodes keep a pointer to any associated pager so no need to
        !           117:         * lookup with vm_pager_lookup.
        !           118:         */
        !           119:        vp = (struct vnode *)handle;
        !           120:        pager = (vm_pager_t)vp->v_vmdata;
        !           121:        if (pager == NULL) {
        !           122:                /*
        !           123:                 * Allocate pager structures
        !           124:                 */
        !           125:                pager = (vm_pager_t)malloc(sizeof *pager, M_VMPAGER, M_WAITOK);
        !           126:                if (pager == NULL)
        !           127:                        return(NULL);
        !           128:                vnp = (vn_pager_t)malloc(sizeof *vnp, M_VMPGDATA, M_WAITOK);
        !           129:                if (vnp == NULL) {
        !           130:                        free((caddr_t)pager, M_VMPAGER);
        !           131:                        return(NULL);
        !           132:                }
        !           133:                /*
        !           134:                 * And an object of the appropriate size
        !           135:                 */
        !           136:                if (VOP_GETATTR(vp, &vattr, p->p_ucred, p) == 0) {
        !           137:                        object = vm_object_allocate(round_page(vattr.va_size));
        !           138:                        vm_object_enter(object, pager);
        !           139:                        vm_object_setpager(object, pager, 0, TRUE);
        !           140:                } else {
        !           141:                        free((caddr_t)vnp, M_VMPGDATA);
        !           142:                        free((caddr_t)pager, M_VMPAGER);
        !           143:                        return(NULL);
        !           144:                }
        !           145:                /*
        !           146:                 * Hold a reference to the vnode and initialize pager data.
        !           147:                 */
        !           148:                VREF(vp);
        !           149:                vnp->vnp_flags = 0;
        !           150:                vnp->vnp_vp = vp;
        !           151:                vnp->vnp_size = vattr.va_size;
        !           152:                queue_enter(&vnode_pager_list, pager, vm_pager_t, pg_list);
        !           153:                pager->pg_handle = handle;
        !           154:                pager->pg_type = PG_VNODE;
        !           155:                pager->pg_ops = &vnodepagerops;
        !           156:                pager->pg_data = (caddr_t)vnp;
        !           157:                vp->v_vmdata = (caddr_t)pager;
        !           158:        } else {
        !           159:                /*
        !           160:                 * vm_object_lookup() will remove the object from the
        !           161:                 * cache if found and also gain a reference to the object.
        !           162:                 */
        !           163:                object = vm_object_lookup(pager);
        !           164: #ifdef DEBUG
        !           165:                vnp = (vn_pager_t)pager->pg_data;
        !           166: #endif
        !           167:        }
        !           168: #ifdef DEBUG
        !           169:        if (vpagerdebug & VDB_ALLOC)
        !           170:                printf("vnode_pager_setup: vp %x sz %x pager %x object %x\n",
        !           171:                       vp, vnp->vnp_size, pager, object);
        !           172: #endif
        !           173:        return(pager);
        !           174: }
        !           175: 
        !           176: void
        !           177: vnode_pager_dealloc(pager)
        !           178:        vm_pager_t pager;
        !           179: {
        !           180:        register vn_pager_t vnp = (vn_pager_t)pager->pg_data;
        !           181:        register struct vnode *vp;
        !           182:        struct proc *p = curproc;               /* XXX */
        !           183: 
        !           184: #ifdef DEBUG
        !           185:        if (vpagerdebug & VDB_FOLLOW)
        !           186:                printf("vnode_pager_dealloc(%x)\n", pager);
        !           187: #endif
        !           188:        if (vp = vnp->vnp_vp) {
        !           189:                vp->v_vmdata = NULL;
        !           190:                vp->v_flag &= ~VTEXT;
        !           191: #if 0
        !           192:                /* can hang if done at reboot on NFS FS */
        !           193:                (void) VOP_FSYNC(vp, p->p_ucred, p);
        !           194: #endif
        !           195:                vrele(vp);
        !           196:        }
        !           197:        queue_remove(&vnode_pager_list, pager, vm_pager_t, pg_list);
        !           198:        free((caddr_t)vnp, M_VMPGDATA);
        !           199:        free((caddr_t)pager, M_VMPAGER);
        !           200: }
        !           201: 
        !           202: vnode_pager_getpage(pager, m, sync)
        !           203:        vm_pager_t pager;
        !           204:        vm_page_t m;
        !           205:        boolean_t sync;
        !           206: {
        !           207: 
        !           208: #ifdef DEBUG
        !           209:        if (vpagerdebug & VDB_FOLLOW)
        !           210:                printf("vnode_pager_getpage(%x, %x)\n", pager, m);
        !           211: #endif
        !           212:        return(vnode_pager_io((vn_pager_t)pager->pg_data, m, UIO_READ));
        !           213: }
        !           214: 
        !           215: boolean_t
        !           216: vnode_pager_putpage(pager, m, sync)
        !           217:        vm_pager_t pager;
        !           218:        vm_page_t m;
        !           219:        boolean_t sync;
        !           220: {
        !           221:        int err;
        !           222: 
        !           223: #ifdef DEBUG
        !           224:        if (vpagerdebug & VDB_FOLLOW)
        !           225:                printf("vnode_pager_putpage(%x, %x)\n", pager, m);
        !           226: #endif
        !           227:        if (pager == NULL)
        !           228:                return;
        !           229:        err = vnode_pager_io((vn_pager_t)pager->pg_data, m, UIO_WRITE);
        !           230:        if (err == VM_PAGER_OK) {
        !           231:                m->clean = TRUE;                        /* XXX - wrong place */
        !           232:                pmap_clear_modify(VM_PAGE_TO_PHYS(m));  /* XXX - wrong place */
        !           233:        }
        !           234:        return(err);
        !           235: }
        !           236: 
        !           237: boolean_t
        !           238: vnode_pager_haspage(pager, offset)
        !           239:        vm_pager_t pager;
        !           240:        vm_offset_t offset;
        !           241: {
        !           242:        register vn_pager_t vnp = (vn_pager_t)pager->pg_data;
        !           243:        daddr_t bn;
        !           244:        int err;
        !           245: 
        !           246: #ifdef DEBUG
        !           247:        if (vpagerdebug & VDB_FOLLOW)
        !           248:                printf("vnode_pager_haspage(%x, %x)\n", pager, offset);
        !           249: #endif
        !           250: 
        !           251:        /*
        !           252:         * Offset beyond end of file, do not have the page
        !           253:         */
        !           254:        if (offset >= vnp->vnp_size) {
        !           255: #ifdef DEBUG
        !           256:                if (vpagerdebug & (VDB_FAIL|VDB_SIZE))
        !           257:                        printf("vnode_pager_haspage: pg %x, off %x, size %x\n",
        !           258:                               pager, offset, vnp->vnp_size);
        !           259: #endif
        !           260:                return(FALSE);
        !           261:        }
        !           262: 
        !           263:        /*
        !           264:         * Read the index to find the disk block to read
        !           265:         * from.  If there is no block, report that we don't
        !           266:         * have this data.
        !           267:         *
        !           268:         * Assumes that the vnode has whole page or nothing.
        !           269:         */
        !           270:        err = VOP_BMAP(vnp->vnp_vp,
        !           271:                       offset / vnp->vnp_vp->v_mount->mnt_stat.f_bsize,
        !           272:                       (struct vnode **)0, &bn);
        !           273:        if (err) {
        !           274: #ifdef DEBUG
        !           275:                if (vpagerdebug & VDB_FAIL)
        !           276:                        printf("vnode_pager_haspage: BMAP err %d, pg %x, off %x\n",
        !           277:                               err, pager, offset);
        !           278: #endif
        !           279:                return(TRUE);
        !           280:        }
        !           281:        return((long)bn < 0 ? FALSE : TRUE);
        !           282: }
        !           283: 
        !           284: /*
        !           285:  * (XXX)
        !           286:  * Lets the VM system know about a change in size for a file.
        !           287:  * If this vnode is mapped into some address space (i.e. we have a pager
        !           288:  * for it) we adjust our own internal size and flush any cached pages in
        !           289:  * the associated object that are affected by the size change.
        !           290:  *
        !           291:  * Note: this routine may be invoked as a result of a pager put
        !           292:  * operation (possibly at object termination time), so we must be careful.
        !           293:  */
        !           294: vnode_pager_setsize(vp, nsize)
        !           295:        struct vnode *vp;
        !           296:        u_long nsize;
        !           297: {
        !           298:        register vn_pager_t vnp;
        !           299:        register vm_object_t object;
        !           300:        vm_pager_t pager;
        !           301: 
        !           302:        /*
        !           303:         * Not a mapped vnode
        !           304:         */
        !           305:        if (vp == NULL || vp->v_type != VREG || vp->v_vmdata == NULL)
        !           306:                return;
        !           307:        /*
        !           308:         * Hasn't changed size
        !           309:         */
        !           310:        pager = (vm_pager_t)vp->v_vmdata;
        !           311:        vnp = (vn_pager_t)pager->pg_data;
        !           312:        if (nsize == vnp->vnp_size)
        !           313:                return;
        !           314:        /*
        !           315:         * No object.
        !           316:         * This can happen during object termination since
        !           317:         * vm_object_page_clean is called after the object
        !           318:         * has been removed from the hash table, and clean
        !           319:         * may cause vnode write operations which can wind
        !           320:         * up back here.
        !           321:         */
        !           322:        object = vm_object_lookup(pager);
        !           323:        if (object == NULL)
        !           324:                return;
        !           325: 
        !           326: #ifdef DEBUG
        !           327:        if (vpagerdebug & (VDB_FOLLOW|VDB_SIZE))
        !           328:                printf("vnode_pager_setsize: vp %x obj %x osz %d nsz %d\n",
        !           329:                       vp, object, vnp->vnp_size, nsize);
        !           330: #endif
        !           331:        /*
        !           332:         * File has shrunk.
        !           333:         * Toss any cached pages beyond the new EOF.
        !           334:         */
        !           335:        if (nsize < vnp->vnp_size) {
        !           336:                vm_object_lock(object);
        !           337:                vm_object_page_remove(object,
        !           338:                                      (vm_offset_t)nsize, vnp->vnp_size);
        !           339:                vm_object_unlock(object);
        !           340:        }
        !           341:        vnp->vnp_size = (vm_offset_t)nsize;
        !           342:        vm_object_deallocate(object);
        !           343: }
        !           344: 
        !           345: vnode_pager_umount(mp)
        !           346:        register struct mount *mp;
        !           347: {
        !           348:        register vm_pager_t pager, npager;
        !           349:        struct vnode *vp;
        !           350: 
        !           351:        pager = (vm_pager_t) queue_first(&vnode_pager_list);
        !           352:        while (!queue_end(&vnode_pager_list, (queue_entry_t)pager)) {
        !           353:                /*
        !           354:                 * Save the next pointer now since uncaching may
        !           355:                 * terminate the object and render pager invalid
        !           356:                 */
        !           357:                vp = ((vn_pager_t)pager->pg_data)->vnp_vp;
        !           358:                npager = (vm_pager_t) queue_next(&pager->pg_list);
        !           359:                if (mp == (struct mount *)0 || vp->v_mount == mp)
        !           360:                        (void) vnode_pager_uncache(vp);
        !           361:                pager = npager;
        !           362:        }
        !           363: }
        !           364: 
        !           365: /*
        !           366:  * Remove vnode associated object from the object cache.
        !           367:  *
        !           368:  * Note: this routine may be invoked as a result of a pager put
        !           369:  * operation (possibly at object termination time), so we must be careful.
        !           370:  */
        !           371: boolean_t
        !           372: vnode_pager_uncache(vp)
        !           373:        register struct vnode *vp;
        !           374: {
        !           375:        register vm_object_t object;
        !           376:        boolean_t uncached, locked;
        !           377:        vm_pager_t pager;
        !           378: 
        !           379:        /*
        !           380:         * Not a mapped vnode
        !           381:         */
        !           382:        pager = (vm_pager_t)vp->v_vmdata;
        !           383:        if (pager == NULL)
        !           384:                return (TRUE);
        !           385:        /*
        !           386:         * Unlock the vnode if it is currently locked.
        !           387:         * We do this since uncaching the object may result
        !           388:         * in its destruction which may initiate paging
        !           389:         * activity which may necessitate locking the vnode.
        !           390:         */
        !           391:        locked = VOP_ISLOCKED(vp);
        !           392:        if (locked)
        !           393:                VOP_UNLOCK(vp);
        !           394:        /*
        !           395:         * Must use vm_object_lookup() as it actually removes
        !           396:         * the object from the cache list.
        !           397:         */
        !           398:        object = vm_object_lookup(pager);
        !           399:        if (object) {
        !           400:                uncached = (object->ref_count <= 1);
        !           401:                pager_cache(object, FALSE);
        !           402:        } else
        !           403:                uncached = TRUE;
        !           404:        if (locked)
        !           405:                VOP_LOCK(vp);
        !           406:        return(uncached);
        !           407: }
        !           408: 
        !           409: vnode_pager_io(vnp, m, rw)
        !           410:        register vn_pager_t vnp;
        !           411:        vm_page_t m;
        !           412:        enum uio_rw rw;
        !           413: {
        !           414:        struct uio auio;
        !           415:        struct iovec aiov;
        !           416:        vm_offset_t kva, foff;
        !           417:        int error, size;
        !           418:        struct proc *p = curproc;               /* XXX */
        !           419: 
        !           420: #ifdef DEBUG
        !           421:        if (vpagerdebug & VDB_FOLLOW)
        !           422:                printf("vnode_pager_io(%x, %x, %c): vnode %x\n",
        !           423:                       vnp, m, rw == UIO_READ ? 'R' : 'W', vnp->vnp_vp);
        !           424: #endif
        !           425:        foff = m->offset + m->object->paging_offset;
        !           426:        /*
        !           427:         * Return failure if beyond current EOF
        !           428:         */
        !           429:        if (foff >= vnp->vnp_size) {
        !           430: #ifdef DEBUG
        !           431:                if (vpagerdebug & VDB_SIZE)
        !           432:                        printf("vnode_pager_io: vp %x, off %d size %d\n",
        !           433:                               vnp->vnp_vp, foff, vnp->vnp_size);
        !           434: #endif
        !           435:                return(VM_PAGER_BAD);
        !           436:        }
        !           437:        if (foff + PAGE_SIZE > vnp->vnp_size)
        !           438:                size = vnp->vnp_size - foff;
        !           439:        else
        !           440:                size = PAGE_SIZE;
        !           441:        /*
        !           442:         * Allocate a kernel virtual address and initialize so that
        !           443:         * we can use VOP_READ/WRITE routines.
        !           444:         */
        !           445:        kva = vm_pager_map_page(m);
        !           446:        aiov.iov_base = (caddr_t)kva;
        !           447:        aiov.iov_len = size;
        !           448:        auio.uio_iov = &aiov;
        !           449:        auio.uio_iovcnt = 1;
        !           450:        auio.uio_offset = foff;
        !           451:        auio.uio_segflg = UIO_SYSSPACE;
        !           452:        auio.uio_rw = rw;
        !           453:        auio.uio_resid = size;
        !           454:        auio.uio_procp = (struct proc *)0;
        !           455: #ifdef DEBUG
        !           456:        if (vpagerdebug & VDB_IO)
        !           457:                printf("vnode_pager_io: vp %x kva %x foff %x size %x",
        !           458:                       vnp->vnp_vp, kva, foff, size);
        !           459: #endif
        !           460:        if (rw == UIO_READ)
        !           461:                error = VOP_READ(vnp->vnp_vp, &auio, 0, p->p_ucred);
        !           462:        else
        !           463:                error = VOP_WRITE(vnp->vnp_vp, &auio, 0, p->p_ucred);
        !           464: #ifdef DEBUG
        !           465:        if (vpagerdebug & VDB_IO) {
        !           466:                if (error || auio.uio_resid)
        !           467:                        printf(" returns error %x, resid %x",
        !           468:                               error, auio.uio_resid);
        !           469:                printf("\n");
        !           470:        }
        !           471: #endif
        !           472:        if (!error) {
        !           473:                register int count = size - auio.uio_resid;
        !           474: 
        !           475:                if (count == 0)
        !           476:                        error = EINVAL;
        !           477:                else if (count != PAGE_SIZE && rw == UIO_READ)
        !           478:                        bzero(kva + count, PAGE_SIZE - count);
        !           479:        }
        !           480:        vm_pager_unmap_page(kva);
        !           481:        return (error ? VM_PAGER_FAIL : VM_PAGER_OK);
        !           482: }
        !           483: #endif

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