The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/vm/vnode_pager.c

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    1 /*-
    2  * Copyright (c) 1990 University of Utah.
    3  * Copyright (c) 1991 The Regents of the University of California.
    4  * All rights reserved.
    5  * Copyright (c) 1993, 1994 John S. Dyson
    6  * Copyright (c) 1995, David Greenman
    7  *
    8  * This code is derived from software contributed to Berkeley by
    9  * the Systems Programming Group of the University of Utah Computer
   10  * Science Department.
   11  *
   12  * Redistribution and use in source and binary forms, with or without
   13  * modification, are permitted provided that the following conditions
   14  * are met:
   15  * 1. Redistributions of source code must retain the above copyright
   16  *    notice, this list of conditions and the following disclaimer.
   17  * 2. Redistributions in binary form must reproduce the above copyright
   18  *    notice, this list of conditions and the following disclaimer in the
   19  *    documentation and/or other materials provided with the distribution.
   20  * 3. All advertising materials mentioning features or use of this software
   21  *    must display the following acknowledgement:
   22  *      This product includes software developed by the University of
   23  *      California, Berkeley and its contributors.
   24  * 4. Neither the name of the University nor the names of its contributors
   25  *    may be used to endorse or promote products derived from this software
   26  *    without specific prior written permission.
   27  *
   28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   38  * SUCH DAMAGE.
   39  *
   40  *      from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91
   41  */
   42 
   43 /*
   44  * Page to/from files (vnodes).
   45  */
   46 
   47 /*
   48  * TODO:
   49  *      Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will
   50  *      greatly re-simplify the vnode_pager.
   51  */
   52 
   53 #include <sys/cdefs.h>
   54 __FBSDID("$FreeBSD: releng/8.2/sys/vm/vnode_pager.c 204304 2010-02-25 10:40:52Z kib $");
   55 
   56 #include <sys/param.h>
   57 #include <sys/systm.h>
   58 #include <sys/proc.h>
   59 #include <sys/vnode.h>
   60 #include <sys/mount.h>
   61 #include <sys/bio.h>
   62 #include <sys/buf.h>
   63 #include <sys/vmmeter.h>
   64 #include <sys/limits.h>
   65 #include <sys/conf.h>
   66 #include <sys/sf_buf.h>
   67 
   68 #include <machine/atomic.h>
   69 
   70 #include <vm/vm.h>
   71 #include <vm/vm_object.h>
   72 #include <vm/vm_page.h>
   73 #include <vm/vm_pager.h>
   74 #include <vm/vm_map.h>
   75 #include <vm/vnode_pager.h>
   76 #include <vm/vm_extern.h>
   77 
   78 static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address,
   79     daddr_t *rtaddress, int *run);
   80 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m);
   81 static int vnode_pager_input_old(vm_object_t object, vm_page_t m);
   82 static void vnode_pager_dealloc(vm_object_t);
   83 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int);
   84 static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *);
   85 static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *);
   86 static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
   87     vm_ooffset_t, struct ucred *cred);
   88 
   89 struct pagerops vnodepagerops = {
   90         .pgo_alloc =    vnode_pager_alloc,
   91         .pgo_dealloc =  vnode_pager_dealloc,
   92         .pgo_getpages = vnode_pager_getpages,
   93         .pgo_putpages = vnode_pager_putpages,
   94         .pgo_haspage =  vnode_pager_haspage,
   95 };
   96 
   97 int vnode_pbuf_freecnt;
   98 
   99 /* Create the VM system backing object for this vnode */
  100 int
  101 vnode_create_vobject(struct vnode *vp, off_t isize, struct thread *td)
  102 {
  103         vm_object_t object;
  104         vm_ooffset_t size = isize;
  105         struct vattr va;
  106 
  107         if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE)
  108                 return (0);
  109 
  110         while ((object = vp->v_object) != NULL) {
  111                 VM_OBJECT_LOCK(object);
  112                 if (!(object->flags & OBJ_DEAD)) {
  113                         VM_OBJECT_UNLOCK(object);
  114                         return (0);
  115                 }
  116                 VOP_UNLOCK(vp, 0);
  117                 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
  118                 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vodead", 0);
  119                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
  120         }
  121 
  122         if (size == 0) {
  123                 if (vn_isdisk(vp, NULL)) {
  124                         size = IDX_TO_OFF(INT_MAX);
  125                 } else {
  126                         if (VOP_GETATTR(vp, &va, td->td_ucred))
  127                                 return (0);
  128                         size = va.va_size;
  129                 }
  130         }
  131 
  132         object = vnode_pager_alloc(vp, size, 0, 0, td->td_ucred);
  133         /*
  134          * Dereference the reference we just created.  This assumes
  135          * that the object is associated with the vp.
  136          */
  137         VM_OBJECT_LOCK(object);
  138         object->ref_count--;
  139         VM_OBJECT_UNLOCK(object);
  140         vrele(vp);
  141 
  142         KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object"));
  143 
  144         return (0);
  145 }
  146 
  147 void
  148 vnode_destroy_vobject(struct vnode *vp)
  149 {
  150         struct vm_object *obj;
  151 
  152         obj = vp->v_object;
  153         if (obj == NULL)
  154                 return;
  155         ASSERT_VOP_ELOCKED(vp, "vnode_destroy_vobject");
  156         VM_OBJECT_LOCK(obj);
  157         if (obj->ref_count == 0) {
  158                 /*
  159                  * vclean() may be called twice. The first time
  160                  * removes the primary reference to the object,
  161                  * the second time goes one further and is a
  162                  * special-case to terminate the object.
  163                  *
  164                  * don't double-terminate the object
  165                  */
  166                 if ((obj->flags & OBJ_DEAD) == 0)
  167                         vm_object_terminate(obj);
  168                 else
  169                         VM_OBJECT_UNLOCK(obj);
  170         } else {
  171                 /*
  172                  * Woe to the process that tries to page now :-).
  173                  */
  174                 vm_pager_deallocate(obj);
  175                 VM_OBJECT_UNLOCK(obj);
  176         }
  177         vp->v_object = NULL;
  178 }
  179 
  180 
  181 /*
  182  * Allocate (or lookup) pager for a vnode.
  183  * Handle is a vnode pointer.
  184  *
  185  * MPSAFE
  186  */
  187 vm_object_t
  188 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
  189     vm_ooffset_t offset, struct ucred *cred)
  190 {
  191         vm_object_t object;
  192         struct vnode *vp;
  193 
  194         /*
  195          * Pageout to vnode, no can do yet.
  196          */
  197         if (handle == NULL)
  198                 return (NULL);
  199 
  200         vp = (struct vnode *) handle;
  201 
  202         /*
  203          * If the object is being terminated, wait for it to
  204          * go away.
  205          */
  206 retry:
  207         while ((object = vp->v_object) != NULL) {
  208                 VM_OBJECT_LOCK(object);
  209                 if ((object->flags & OBJ_DEAD) == 0)
  210                         break;
  211                 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
  212                 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vadead", 0);
  213         }
  214 
  215         if (vp->v_usecount == 0)
  216                 panic("vnode_pager_alloc: no vnode reference");
  217 
  218         if (object == NULL) {
  219                 /*
  220                  * Add an object of the appropriate size
  221                  */
  222                 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size)));
  223 
  224                 object->un_pager.vnp.vnp_size = size;
  225 
  226                 object->handle = handle;
  227                 VI_LOCK(vp);
  228                 if (vp->v_object != NULL) {
  229                         /*
  230                          * Object has been created while we were sleeping
  231                          */
  232                         VI_UNLOCK(vp);
  233                         vm_object_destroy(object);
  234                         goto retry;
  235                 }
  236                 vp->v_object = object;
  237                 VI_UNLOCK(vp);
  238         } else {
  239                 object->ref_count++;
  240                 VM_OBJECT_UNLOCK(object);
  241         }
  242         vref(vp);
  243         return (object);
  244 }
  245 
  246 /*
  247  *      The object must be locked.
  248  */
  249 static void
  250 vnode_pager_dealloc(object)
  251         vm_object_t object;
  252 {
  253         struct vnode *vp;
  254         int refs;
  255 
  256         vp = object->handle;
  257         if (vp == NULL)
  258                 panic("vnode_pager_dealloc: pager already dealloced");
  259 
  260         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
  261         vm_object_pip_wait(object, "vnpdea");
  262         refs = object->ref_count;
  263 
  264         object->handle = NULL;
  265         object->type = OBJT_DEAD;
  266         if (object->flags & OBJ_DISCONNECTWNT) {
  267                 vm_object_clear_flag(object, OBJ_DISCONNECTWNT);
  268                 wakeup(object);
  269         }
  270         ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc");
  271         vp->v_object = NULL;
  272         vp->v_vflag &= ~VV_TEXT;
  273         while (refs-- > 0)
  274                 vunref(vp);
  275 }
  276 
  277 static boolean_t
  278 vnode_pager_haspage(object, pindex, before, after)
  279         vm_object_t object;
  280         vm_pindex_t pindex;
  281         int *before;
  282         int *after;
  283 {
  284         struct vnode *vp = object->handle;
  285         daddr_t bn;
  286         int err;
  287         daddr_t reqblock;
  288         int poff;
  289         int bsize;
  290         int pagesperblock, blocksperpage;
  291         int vfslocked;
  292 
  293         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
  294         /*
  295          * If no vp or vp is doomed or marked transparent to VM, we do not
  296          * have the page.
  297          */
  298         if (vp == NULL || vp->v_iflag & VI_DOOMED)
  299                 return FALSE;
  300         /*
  301          * If the offset is beyond end of file we do
  302          * not have the page.
  303          */
  304         if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size)
  305                 return FALSE;
  306 
  307         bsize = vp->v_mount->mnt_stat.f_iosize;
  308         pagesperblock = bsize / PAGE_SIZE;
  309         blocksperpage = 0;
  310         if (pagesperblock > 0) {
  311                 reqblock = pindex / pagesperblock;
  312         } else {
  313                 blocksperpage = (PAGE_SIZE / bsize);
  314                 reqblock = pindex * blocksperpage;
  315         }
  316         VM_OBJECT_UNLOCK(object);
  317         vfslocked = VFS_LOCK_GIANT(vp->v_mount);
  318         err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before);
  319         VFS_UNLOCK_GIANT(vfslocked);
  320         VM_OBJECT_LOCK(object);
  321         if (err)
  322                 return TRUE;
  323         if (bn == -1)
  324                 return FALSE;
  325         if (pagesperblock > 0) {
  326                 poff = pindex - (reqblock * pagesperblock);
  327                 if (before) {
  328                         *before *= pagesperblock;
  329                         *before += poff;
  330                 }
  331                 if (after) {
  332                         int numafter;
  333                         *after *= pagesperblock;
  334                         numafter = pagesperblock - (poff + 1);
  335                         if (IDX_TO_OFF(pindex + numafter) >
  336                             object->un_pager.vnp.vnp_size) {
  337                                 numafter =
  338                                     OFF_TO_IDX(object->un_pager.vnp.vnp_size) -
  339                                     pindex;
  340                         }
  341                         *after += numafter;
  342                 }
  343         } else {
  344                 if (before) {
  345                         *before /= blocksperpage;
  346                 }
  347 
  348                 if (after) {
  349                         *after /= blocksperpage;
  350                 }
  351         }
  352         return TRUE;
  353 }
  354 
  355 /*
  356  * Lets the VM system know about a change in size for a file.
  357  * We adjust our own internal size and flush any cached pages in
  358  * the associated object that are affected by the size change.
  359  *
  360  * Note: this routine may be invoked as a result of a pager put
  361  * operation (possibly at object termination time), so we must be careful.
  362  */
  363 void
  364 vnode_pager_setsize(vp, nsize)
  365         struct vnode *vp;
  366         vm_ooffset_t nsize;
  367 {
  368         vm_object_t object;
  369         vm_page_t m;
  370         vm_pindex_t nobjsize;
  371 
  372         if ((object = vp->v_object) == NULL)
  373                 return;
  374 /*      ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */
  375         VM_OBJECT_LOCK(object);
  376         if (nsize == object->un_pager.vnp.vnp_size) {
  377                 /*
  378                  * Hasn't changed size
  379                  */
  380                 VM_OBJECT_UNLOCK(object);
  381                 return;
  382         }
  383         nobjsize = OFF_TO_IDX(nsize + PAGE_MASK);
  384         if (nsize < object->un_pager.vnp.vnp_size) {
  385                 /*
  386                  * File has shrunk. Toss any cached pages beyond the new EOF.
  387                  */
  388                 if (nobjsize < object->size)
  389                         vm_object_page_remove(object, nobjsize, object->size,
  390                             FALSE);
  391                 /*
  392                  * this gets rid of garbage at the end of a page that is now
  393                  * only partially backed by the vnode.
  394                  *
  395                  * XXX for some reason (I don't know yet), if we take a
  396                  * completely invalid page and mark it partially valid
  397                  * it can screw up NFS reads, so we don't allow the case.
  398                  */
  399                 if ((nsize & PAGE_MASK) &&
  400                     (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL &&
  401                     m->valid != 0) {
  402                         int base = (int)nsize & PAGE_MASK;
  403                         int size = PAGE_SIZE - base;
  404 
  405                         /*
  406                          * Clear out partial-page garbage in case
  407                          * the page has been mapped.
  408                          */
  409                         pmap_zero_page_area(m, base, size);
  410 
  411                         /*
  412                          * Update the valid bits to reflect the blocks that
  413                          * have been zeroed.  Some of these valid bits may
  414                          * have already been set.
  415                          */
  416                         vm_page_set_valid(m, base, size);
  417 
  418                         /*
  419                          * Round "base" to the next block boundary so that the
  420                          * dirty bit for a partially zeroed block is not
  421                          * cleared.
  422                          */
  423                         base = roundup2(base, DEV_BSIZE);
  424 
  425                         /*
  426                          * Clear out partial-page dirty bits.
  427                          *
  428                          * note that we do not clear out the valid
  429                          * bits.  This would prevent bogus_page
  430                          * replacement from working properly.
  431                          */
  432                         vm_page_lock_queues();
  433                         vm_page_clear_dirty(m, base, PAGE_SIZE - base);
  434                         vm_page_unlock_queues();
  435                 } else if ((nsize & PAGE_MASK) &&
  436                     __predict_false(object->cache != NULL)) {
  437                         vm_page_cache_free(object, OFF_TO_IDX(nsize),
  438                             nobjsize);
  439                 }
  440         }
  441         object->un_pager.vnp.vnp_size = nsize;
  442         object->size = nobjsize;
  443         VM_OBJECT_UNLOCK(object);
  444 }
  445 
  446 /*
  447  * calculate the linear (byte) disk address of specified virtual
  448  * file address
  449  */
  450 static int
  451 vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress,
  452     int *run)
  453 {
  454         int bsize;
  455         int err;
  456         daddr_t vblock;
  457         daddr_t voffset;
  458 
  459         if (address < 0)
  460                 return -1;
  461 
  462         if (vp->v_iflag & VI_DOOMED)
  463                 return -1;
  464 
  465         bsize = vp->v_mount->mnt_stat.f_iosize;
  466         vblock = address / bsize;
  467         voffset = address % bsize;
  468 
  469         err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL);
  470         if (err == 0) {
  471                 if (*rtaddress != -1)
  472                         *rtaddress += voffset / DEV_BSIZE;
  473                 if (run) {
  474                         *run += 1;
  475                         *run *= bsize/PAGE_SIZE;
  476                         *run -= voffset/PAGE_SIZE;
  477                 }
  478         }
  479 
  480         return (err);
  481 }
  482 
  483 /*
  484  * small block filesystem vnode pager input
  485  */
  486 static int
  487 vnode_pager_input_smlfs(object, m)
  488         vm_object_t object;
  489         vm_page_t m;
  490 {
  491         int bits, i;
  492         struct vnode *vp;
  493         struct bufobj *bo;
  494         struct buf *bp;
  495         struct sf_buf *sf;
  496         daddr_t fileaddr;
  497         vm_offset_t bsize;
  498         int error = 0;
  499 
  500         vp = object->handle;
  501         if (vp->v_iflag & VI_DOOMED)
  502                 return VM_PAGER_BAD;
  503 
  504         bsize = vp->v_mount->mnt_stat.f_iosize;
  505 
  506         VOP_BMAP(vp, 0, &bo, 0, NULL, NULL);
  507 
  508         sf = sf_buf_alloc(m, 0);
  509 
  510         for (i = 0; i < PAGE_SIZE / bsize; i++) {
  511                 vm_ooffset_t address;
  512 
  513                 bits = vm_page_bits(i * bsize, bsize);
  514                 if (m->valid & bits)
  515                         continue;
  516 
  517                 address = IDX_TO_OFF(m->pindex) + i * bsize;
  518                 if (address >= object->un_pager.vnp.vnp_size) {
  519                         fileaddr = -1;
  520                 } else {
  521                         error = vnode_pager_addr(vp, address, &fileaddr, NULL);
  522                         if (error)
  523                                 break;
  524                 }
  525                 if (fileaddr != -1) {
  526                         bp = getpbuf(&vnode_pbuf_freecnt);
  527 
  528                         /* build a minimal buffer header */
  529                         bp->b_iocmd = BIO_READ;
  530                         bp->b_iodone = bdone;
  531                         KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
  532                         KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
  533                         bp->b_rcred = crhold(curthread->td_ucred);
  534                         bp->b_wcred = crhold(curthread->td_ucred);
  535                         bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize;
  536                         bp->b_blkno = fileaddr;
  537                         pbgetbo(bo, bp);
  538                         bp->b_bcount = bsize;
  539                         bp->b_bufsize = bsize;
  540                         bp->b_runningbufspace = bp->b_bufsize;
  541                         atomic_add_long(&runningbufspace, bp->b_runningbufspace);
  542 
  543                         /* do the input */
  544                         bp->b_iooffset = dbtob(bp->b_blkno);
  545                         bstrategy(bp);
  546 
  547                         bwait(bp, PVM, "vnsrd");
  548 
  549                         if ((bp->b_ioflags & BIO_ERROR) != 0)
  550                                 error = EIO;
  551 
  552                         /*
  553                          * free the buffer header back to the swap buffer pool
  554                          */
  555                         pbrelbo(bp);
  556                         relpbuf(bp, &vnode_pbuf_freecnt);
  557                         if (error)
  558                                 break;
  559                 } else
  560                         bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize);
  561                 KASSERT((m->dirty & bits) == 0,
  562                     ("vnode_pager_input_smlfs: page %p is dirty", m));
  563                 VM_OBJECT_LOCK(object);
  564                 m->valid |= bits;
  565                 VM_OBJECT_UNLOCK(object);
  566         }
  567         sf_buf_free(sf);
  568         if (error) {
  569                 return VM_PAGER_ERROR;
  570         }
  571         return VM_PAGER_OK;
  572 }
  573 
  574 /*
  575  * old style vnode pager input routine
  576  */
  577 static int
  578 vnode_pager_input_old(object, m)
  579         vm_object_t object;
  580         vm_page_t m;
  581 {
  582         struct uio auio;
  583         struct iovec aiov;
  584         int error;
  585         int size;
  586         struct sf_buf *sf;
  587         struct vnode *vp;
  588 
  589         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
  590         error = 0;
  591 
  592         /*
  593          * Return failure if beyond current EOF
  594          */
  595         if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) {
  596                 return VM_PAGER_BAD;
  597         } else {
  598                 size = PAGE_SIZE;
  599                 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size)
  600                         size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex);
  601                 vp = object->handle;
  602                 VM_OBJECT_UNLOCK(object);
  603 
  604                 /*
  605                  * Allocate a kernel virtual address and initialize so that
  606                  * we can use VOP_READ/WRITE routines.
  607                  */
  608                 sf = sf_buf_alloc(m, 0);
  609 
  610                 aiov.iov_base = (caddr_t)sf_buf_kva(sf);
  611                 aiov.iov_len = size;
  612                 auio.uio_iov = &aiov;
  613                 auio.uio_iovcnt = 1;
  614                 auio.uio_offset = IDX_TO_OFF(m->pindex);
  615                 auio.uio_segflg = UIO_SYSSPACE;
  616                 auio.uio_rw = UIO_READ;
  617                 auio.uio_resid = size;
  618                 auio.uio_td = curthread;
  619 
  620                 error = VOP_READ(vp, &auio, 0, curthread->td_ucred);
  621                 if (!error) {
  622                         int count = size - auio.uio_resid;
  623 
  624                         if (count == 0)
  625                                 error = EINVAL;
  626                         else if (count != PAGE_SIZE)
  627                                 bzero((caddr_t)sf_buf_kva(sf) + count,
  628                                     PAGE_SIZE - count);
  629                 }
  630                 sf_buf_free(sf);
  631 
  632                 VM_OBJECT_LOCK(object);
  633         }
  634         KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m));
  635         if (!error)
  636                 m->valid = VM_PAGE_BITS_ALL;
  637         return error ? VM_PAGER_ERROR : VM_PAGER_OK;
  638 }
  639 
  640 /*
  641  * generic vnode pager input routine
  642  */
  643 
  644 /*
  645  * Local media VFS's that do not implement their own VOP_GETPAGES
  646  * should have their VOP_GETPAGES call to vnode_pager_generic_getpages()
  647  * to implement the previous behaviour.
  648  *
  649  * All other FS's should use the bypass to get to the local media
  650  * backing vp's VOP_GETPAGES.
  651  */
  652 static int
  653 vnode_pager_getpages(object, m, count, reqpage)
  654         vm_object_t object;
  655         vm_page_t *m;
  656         int count;
  657         int reqpage;
  658 {
  659         int rtval;
  660         struct vnode *vp;
  661         int bytes = count * PAGE_SIZE;
  662         int vfslocked;
  663 
  664         vp = object->handle;
  665         VM_OBJECT_UNLOCK(object);
  666         vfslocked = VFS_LOCK_GIANT(vp->v_mount);
  667         rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0);
  668         KASSERT(rtval != EOPNOTSUPP,
  669             ("vnode_pager: FS getpages not implemented\n"));
  670         VFS_UNLOCK_GIANT(vfslocked);
  671         VM_OBJECT_LOCK(object);
  672         return rtval;
  673 }
  674 
  675 /*
  676  * This is now called from local media FS's to operate against their
  677  * own vnodes if they fail to implement VOP_GETPAGES.
  678  */
  679 int
  680 vnode_pager_generic_getpages(vp, m, bytecount, reqpage)
  681         struct vnode *vp;
  682         vm_page_t *m;
  683         int bytecount;
  684         int reqpage;
  685 {
  686         vm_object_t object;
  687         vm_offset_t kva;
  688         off_t foff, tfoff, nextoff;
  689         int i, j, size, bsize, first;
  690         daddr_t firstaddr, reqblock;
  691         struct bufobj *bo;
  692         int runpg;
  693         int runend;
  694         struct buf *bp;
  695         int count;
  696         int error;
  697 
  698         object = vp->v_object;
  699         count = bytecount / PAGE_SIZE;
  700 
  701         KASSERT(vp->v_type != VCHR && vp->v_type != VBLK,
  702             ("vnode_pager_generic_getpages does not support devices"));
  703         if (vp->v_iflag & VI_DOOMED)
  704                 return VM_PAGER_BAD;
  705 
  706         bsize = vp->v_mount->mnt_stat.f_iosize;
  707 
  708         /* get the UNDERLYING device for the file with VOP_BMAP() */
  709 
  710         /*
  711          * originally, we did not check for an error return value -- assuming
  712          * an fs always has a bmap entry point -- that assumption is wrong!!!
  713          */
  714         foff = IDX_TO_OFF(m[reqpage]->pindex);
  715 
  716         /*
  717          * if we can't bmap, use old VOP code
  718          */
  719         error = VOP_BMAP(vp, foff / bsize, &bo, &reqblock, NULL, NULL);
  720         if (error == EOPNOTSUPP) {
  721                 VM_OBJECT_LOCK(object);
  722                 vm_page_lock_queues();
  723                 for (i = 0; i < count; i++)
  724                         if (i != reqpage)
  725                                 vm_page_free(m[i]);
  726                 vm_page_unlock_queues();
  727                 PCPU_INC(cnt.v_vnodein);
  728                 PCPU_INC(cnt.v_vnodepgsin);
  729                 error = vnode_pager_input_old(object, m[reqpage]);
  730                 VM_OBJECT_UNLOCK(object);
  731                 return (error);
  732         } else if (error != 0) {
  733                 VM_OBJECT_LOCK(object);
  734                 vm_page_lock_queues();
  735                 for (i = 0; i < count; i++)
  736                         if (i != reqpage)
  737                                 vm_page_free(m[i]);
  738                 vm_page_unlock_queues();
  739                 VM_OBJECT_UNLOCK(object);
  740                 return (VM_PAGER_ERROR);
  741 
  742                 /*
  743                  * if the blocksize is smaller than a page size, then use
  744                  * special small filesystem code.  NFS sometimes has a small
  745                  * blocksize, but it can handle large reads itself.
  746                  */
  747         } else if ((PAGE_SIZE / bsize) > 1 &&
  748             (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) {
  749                 VM_OBJECT_LOCK(object);
  750                 vm_page_lock_queues();
  751                 for (i = 0; i < count; i++)
  752                         if (i != reqpage)
  753                                 vm_page_free(m[i]);
  754                 vm_page_unlock_queues();
  755                 VM_OBJECT_UNLOCK(object);
  756                 PCPU_INC(cnt.v_vnodein);
  757                 PCPU_INC(cnt.v_vnodepgsin);
  758                 return vnode_pager_input_smlfs(object, m[reqpage]);
  759         }
  760 
  761         /*
  762          * If we have a completely valid page available to us, we can
  763          * clean up and return.  Otherwise we have to re-read the
  764          * media.
  765          */
  766         VM_OBJECT_LOCK(object);
  767         if (m[reqpage]->valid == VM_PAGE_BITS_ALL) {
  768                 vm_page_lock_queues();
  769                 for (i = 0; i < count; i++)
  770                         if (i != reqpage)
  771                                 vm_page_free(m[i]);
  772                 vm_page_unlock_queues();
  773                 VM_OBJECT_UNLOCK(object);
  774                 return VM_PAGER_OK;
  775         } else if (reqblock == -1) {
  776                 pmap_zero_page(m[reqpage]);
  777                 KASSERT(m[reqpage]->dirty == 0,
  778                     ("vnode_pager_generic_getpages: page %p is dirty", m));
  779                 m[reqpage]->valid = VM_PAGE_BITS_ALL;
  780                 vm_page_lock_queues();
  781                 for (i = 0; i < count; i++)
  782                         if (i != reqpage)
  783                                 vm_page_free(m[i]);
  784                 vm_page_unlock_queues();
  785                 VM_OBJECT_UNLOCK(object);
  786                 return (VM_PAGER_OK);
  787         }
  788         m[reqpage]->valid = 0;
  789         VM_OBJECT_UNLOCK(object);
  790 
  791         /*
  792          * here on direct device I/O
  793          */
  794         firstaddr = -1;
  795 
  796         /*
  797          * calculate the run that includes the required page
  798          */
  799         for (first = 0, i = 0; i < count; i = runend) {
  800                 if (vnode_pager_addr(vp, IDX_TO_OFF(m[i]->pindex), &firstaddr,
  801                     &runpg) != 0) {
  802                         VM_OBJECT_LOCK(object);
  803                         vm_page_lock_queues();
  804                         for (; i < count; i++)
  805                                 if (i != reqpage)
  806                                         vm_page_free(m[i]);
  807                         vm_page_unlock_queues();
  808                         VM_OBJECT_UNLOCK(object);
  809                         return (VM_PAGER_ERROR);
  810                 }
  811                 if (firstaddr == -1) {
  812                         VM_OBJECT_LOCK(object);
  813                         if (i == reqpage && foff < object->un_pager.vnp.vnp_size) {
  814                                 panic("vnode_pager_getpages: unexpected missing page: firstaddr: %jd, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx",
  815                                     (intmax_t)firstaddr, (uintmax_t)(foff >> 32),
  816                                     (uintmax_t)foff,
  817                                     (uintmax_t)
  818                                     (object->un_pager.vnp.vnp_size >> 32),
  819                                     (uintmax_t)object->un_pager.vnp.vnp_size);
  820                         }
  821                         vm_page_lock_queues();
  822                         vm_page_free(m[i]);
  823                         vm_page_unlock_queues();
  824                         VM_OBJECT_UNLOCK(object);
  825                         runend = i + 1;
  826                         first = runend;
  827                         continue;
  828                 }
  829                 runend = i + runpg;
  830                 if (runend <= reqpage) {
  831                         VM_OBJECT_LOCK(object);
  832                         vm_page_lock_queues();
  833                         for (j = i; j < runend; j++)
  834                                 vm_page_free(m[j]);
  835                         vm_page_unlock_queues();
  836                         VM_OBJECT_UNLOCK(object);
  837                 } else {
  838                         if (runpg < (count - first)) {
  839                                 VM_OBJECT_LOCK(object);
  840                                 vm_page_lock_queues();
  841                                 for (i = first + runpg; i < count; i++)
  842                                         vm_page_free(m[i]);
  843                                 vm_page_unlock_queues();
  844                                 VM_OBJECT_UNLOCK(object);
  845                                 count = first + runpg;
  846                         }
  847                         break;
  848                 }
  849                 first = runend;
  850         }
  851 
  852         /*
  853          * the first and last page have been calculated now, move input pages
  854          * to be zero based...
  855          */
  856         if (first != 0) {
  857                 m += first;
  858                 count -= first;
  859                 reqpage -= first;
  860         }
  861 
  862         /*
  863          * calculate the file virtual address for the transfer
  864          */
  865         foff = IDX_TO_OFF(m[0]->pindex);
  866 
  867         /*
  868          * calculate the size of the transfer
  869          */
  870         size = count * PAGE_SIZE;
  871         KASSERT(count > 0, ("zero count"));
  872         if ((foff + size) > object->un_pager.vnp.vnp_size)
  873                 size = object->un_pager.vnp.vnp_size - foff;
  874         KASSERT(size > 0, ("zero size"));
  875 
  876         /*
  877          * round up physical size for real devices.
  878          */
  879         if (1) {
  880                 int secmask = bo->bo_bsize - 1;
  881                 KASSERT(secmask < PAGE_SIZE && secmask > 0,
  882                     ("vnode_pager_generic_getpages: sector size %d too large",
  883                     secmask + 1));
  884                 size = (size + secmask) & ~secmask;
  885         }
  886 
  887         bp = getpbuf(&vnode_pbuf_freecnt);
  888         kva = (vm_offset_t) bp->b_data;
  889 
  890         /*
  891          * and map the pages to be read into the kva
  892          */
  893         pmap_qenter(kva, m, count);
  894 
  895         /* build a minimal buffer header */
  896         bp->b_iocmd = BIO_READ;
  897         bp->b_iodone = bdone;
  898         KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
  899         KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
  900         bp->b_rcred = crhold(curthread->td_ucred);
  901         bp->b_wcred = crhold(curthread->td_ucred);
  902         bp->b_blkno = firstaddr;
  903         pbgetbo(bo, bp);
  904         bp->b_bcount = size;
  905         bp->b_bufsize = size;
  906         bp->b_runningbufspace = bp->b_bufsize;
  907         atomic_add_long(&runningbufspace, bp->b_runningbufspace);
  908 
  909         PCPU_INC(cnt.v_vnodein);
  910         PCPU_ADD(cnt.v_vnodepgsin, count);
  911 
  912         /* do the input */
  913         bp->b_iooffset = dbtob(bp->b_blkno);
  914         bstrategy(bp);
  915 
  916         bwait(bp, PVM, "vnread");
  917 
  918         if ((bp->b_ioflags & BIO_ERROR) != 0)
  919                 error = EIO;
  920 
  921         if (!error) {
  922                 if (size != count * PAGE_SIZE)
  923                         bzero((caddr_t) kva + size, PAGE_SIZE * count - size);
  924         }
  925         pmap_qremove(kva, count);
  926 
  927         /*
  928          * free the buffer header back to the swap buffer pool
  929          */
  930         pbrelbo(bp);
  931         relpbuf(bp, &vnode_pbuf_freecnt);
  932 
  933         VM_OBJECT_LOCK(object);
  934         vm_page_lock_queues();
  935         for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) {
  936                 vm_page_t mt;
  937 
  938                 nextoff = tfoff + PAGE_SIZE;
  939                 mt = m[i];
  940 
  941                 if (nextoff <= object->un_pager.vnp.vnp_size) {
  942                         /*
  943                          * Read filled up entire page.
  944                          */
  945                         mt->valid = VM_PAGE_BITS_ALL;
  946                         KASSERT(mt->dirty == 0,
  947                             ("vnode_pager_generic_getpages: page %p is dirty",
  948                             mt));
  949                         KASSERT(!pmap_page_is_mapped(mt),
  950                             ("vnode_pager_generic_getpages: page %p is mapped",
  951                             mt));
  952                 } else {
  953                         /*
  954                          * Read did not fill up entire page.
  955                          *
  956                          * Currently we do not set the entire page valid,
  957                          * we just try to clear the piece that we couldn't
  958                          * read.
  959                          */
  960                         vm_page_set_valid(mt, 0,
  961                             object->un_pager.vnp.vnp_size - tfoff);
  962                         KASSERT((mt->dirty & vm_page_bits(0,
  963                             object->un_pager.vnp.vnp_size - tfoff)) == 0,
  964                             ("vnode_pager_generic_getpages: page %p is dirty",
  965                             mt));
  966                 }
  967                 
  968                 if (i != reqpage) {
  969 
  970                         /*
  971                          * whether or not to leave the page activated is up in
  972                          * the air, but we should put the page on a page queue
  973                          * somewhere. (it already is in the object). Result:
  974                          * It appears that empirical results show that
  975                          * deactivating pages is best.
  976                          */
  977 
  978                         /*
  979                          * just in case someone was asking for this page we
  980                          * now tell them that it is ok to use
  981                          */
  982                         if (!error) {
  983                                 if (mt->oflags & VPO_WANTED)
  984                                         vm_page_activate(mt);
  985                                 else
  986                                         vm_page_deactivate(mt);
  987                                 vm_page_wakeup(mt);
  988                         } else {
  989                                 vm_page_free(mt);
  990                         }
  991                 }
  992         }
  993         vm_page_unlock_queues();
  994         VM_OBJECT_UNLOCK(object);
  995         if (error) {
  996                 printf("vnode_pager_getpages: I/O read error\n");
  997         }
  998         return (error ? VM_PAGER_ERROR : VM_PAGER_OK);
  999 }
 1000 
 1001 /*
 1002  * EOPNOTSUPP is no longer legal.  For local media VFS's that do not
 1003  * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to
 1004  * vnode_pager_generic_putpages() to implement the previous behaviour.
 1005  *
 1006  * All other FS's should use the bypass to get to the local media
 1007  * backing vp's VOP_PUTPAGES.
 1008  */
 1009 static void
 1010 vnode_pager_putpages(object, m, count, sync, rtvals)
 1011         vm_object_t object;
 1012         vm_page_t *m;
 1013         int count;
 1014         boolean_t sync;
 1015         int *rtvals;
 1016 {
 1017         int rtval;
 1018         struct vnode *vp;
 1019         int bytes = count * PAGE_SIZE;
 1020 
 1021         /*
 1022          * Force synchronous operation if we are extremely low on memory
 1023          * to prevent a low-memory deadlock.  VOP operations often need to
 1024          * allocate more memory to initiate the I/O ( i.e. do a BMAP 
 1025          * operation ).  The swapper handles the case by limiting the amount
 1026          * of asynchronous I/O, but that sort of solution doesn't scale well
 1027          * for the vnode pager without a lot of work.
 1028          *
 1029          * Also, the backing vnode's iodone routine may not wake the pageout
 1030          * daemon up.  This should be probably be addressed XXX.
 1031          */
 1032 
 1033         if ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min)
 1034                 sync |= OBJPC_SYNC;
 1035 
 1036         /*
 1037          * Call device-specific putpages function
 1038          */
 1039         vp = object->handle;
 1040         VM_OBJECT_UNLOCK(object);
 1041         rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0);
 1042         KASSERT(rtval != EOPNOTSUPP, 
 1043             ("vnode_pager: stale FS putpages\n"));
 1044         VM_OBJECT_LOCK(object);
 1045 }
 1046 
 1047 
 1048 /*
 1049  * This is now called from local media FS's to operate against their
 1050  * own vnodes if they fail to implement VOP_PUTPAGES.
 1051  *
 1052  * This is typically called indirectly via the pageout daemon and
 1053  * clustering has already typically occured, so in general we ask the
 1054  * underlying filesystem to write the data out asynchronously rather
 1055  * then delayed.
 1056  */
 1057 int
 1058 vnode_pager_generic_putpages(vp, m, bytecount, flags, rtvals)
 1059         struct vnode *vp;
 1060         vm_page_t *m;
 1061         int bytecount;
 1062         int flags;
 1063         int *rtvals;
 1064 {
 1065         int i;
 1066         vm_object_t object;
 1067         int count;
 1068 
 1069         int maxsize, ncount;
 1070         vm_ooffset_t poffset;
 1071         struct uio auio;
 1072         struct iovec aiov;
 1073         int error;
 1074         int ioflags;
 1075         int ppscheck = 0;
 1076         static struct timeval lastfail;
 1077         static int curfail;
 1078 
 1079         object = vp->v_object;
 1080         count = bytecount / PAGE_SIZE;
 1081 
 1082         for (i = 0; i < count; i++)
 1083                 rtvals[i] = VM_PAGER_AGAIN;
 1084 
 1085         if ((int64_t)m[0]->pindex < 0) {
 1086                 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n",
 1087                         (long)m[0]->pindex, (u_long)m[0]->dirty);
 1088                 rtvals[0] = VM_PAGER_BAD;
 1089                 return VM_PAGER_BAD;
 1090         }
 1091 
 1092         maxsize = count * PAGE_SIZE;
 1093         ncount = count;
 1094 
 1095         poffset = IDX_TO_OFF(m[0]->pindex);
 1096 
 1097         /*
 1098          * If the page-aligned write is larger then the actual file we
 1099          * have to invalidate pages occuring beyond the file EOF.  However,
 1100          * there is an edge case where a file may not be page-aligned where
 1101          * the last page is partially invalid.  In this case the filesystem
 1102          * may not properly clear the dirty bits for the entire page (which
 1103          * could be VM_PAGE_BITS_ALL due to the page having been mmap()d).
 1104          * With the page locked we are free to fix-up the dirty bits here.
 1105          *
 1106          * We do not under any circumstances truncate the valid bits, as
 1107          * this will screw up bogus page replacement.
 1108          */
 1109         if (maxsize + poffset > object->un_pager.vnp.vnp_size) {
 1110                 if (object->un_pager.vnp.vnp_size > poffset) {
 1111                         int pgoff;
 1112 
 1113                         maxsize = object->un_pager.vnp.vnp_size - poffset;
 1114                         ncount = btoc(maxsize);
 1115                         if ((pgoff = (int)maxsize & PAGE_MASK) != 0) {
 1116                                 vm_page_lock_queues();
 1117                                 vm_page_clear_dirty(m[ncount - 1], pgoff,
 1118                                         PAGE_SIZE - pgoff);
 1119                                 vm_page_unlock_queues();
 1120                         }
 1121                 } else {
 1122                         maxsize = 0;
 1123                         ncount = 0;
 1124                 }
 1125                 if (ncount < count) {
 1126                         for (i = ncount; i < count; i++) {
 1127                                 rtvals[i] = VM_PAGER_BAD;
 1128                         }
 1129                 }
 1130         }
 1131 
 1132         /*
 1133          * pageouts are already clustered, use IO_ASYNC t o force a bawrite()
 1134          * rather then a bdwrite() to prevent paging I/O from saturating 
 1135          * the buffer cache.  Dummy-up the sequential heuristic to cause
 1136          * large ranges to cluster.  If neither IO_SYNC or IO_ASYNC is set,
 1137          * the system decides how to cluster.
 1138          */
 1139         ioflags = IO_VMIO;
 1140         if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL))
 1141                 ioflags |= IO_SYNC;
 1142         else if ((flags & VM_PAGER_CLUSTER_OK) == 0)
 1143                 ioflags |= IO_ASYNC;
 1144         ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0;
 1145         ioflags |= IO_SEQMAX << IO_SEQSHIFT;
 1146 
 1147         aiov.iov_base = (caddr_t) 0;
 1148         aiov.iov_len = maxsize;
 1149         auio.uio_iov = &aiov;
 1150         auio.uio_iovcnt = 1;
 1151         auio.uio_offset = poffset;
 1152         auio.uio_segflg = UIO_NOCOPY;
 1153         auio.uio_rw = UIO_WRITE;
 1154         auio.uio_resid = maxsize;
 1155         auio.uio_td = (struct thread *) 0;
 1156         error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred);
 1157         PCPU_INC(cnt.v_vnodeout);
 1158         PCPU_ADD(cnt.v_vnodepgsout, ncount);
 1159 
 1160         if (error) {
 1161                 if ((ppscheck = ppsratecheck(&lastfail, &curfail, 1)))
 1162                         printf("vnode_pager_putpages: I/O error %d\n", error);
 1163         }
 1164         if (auio.uio_resid) {
 1165                 if (ppscheck || ppsratecheck(&lastfail, &curfail, 1))
 1166                         printf("vnode_pager_putpages: residual I/O %zd at %lu\n",
 1167                             auio.uio_resid, (u_long)m[0]->pindex);
 1168         }
 1169         for (i = 0; i < ncount; i++) {
 1170                 rtvals[i] = VM_PAGER_OK;
 1171         }
 1172         return rtvals[0];
 1173 }

Cache object: 18993fd5398f49e9b6b1227cabf8a6a9


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