1 /* $NetBSD: uvm_vnode.c,v 1.52 2001/09/15 20:36:47 chs Exp $ */ 2 3 /* 4 * Copyright (c) 1997 Charles D. Cranor and Washington University. 5 * Copyright (c) 1991, 1993 6 * The Regents of the University of California. 7 * Copyright (c) 1990 University of Utah. 8 * 9 * All rights reserved. 10 * 11 * This code is derived from software contributed to Berkeley by 12 * the Systems Programming Group of the University of Utah Computer 13 * Science Department. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 3. All advertising materials mentioning features or use of this software 24 * must display the following acknowledgement: 25 * This product includes software developed by Charles D. Cranor, 26 * Washington University, the University of California, Berkeley and 27 * its contributors. 28 * 4. Neither the name of the University nor the names of its contributors 29 * may be used to endorse or promote products derived from this software 30 * without specific prior written permission. 31 * 32 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 33 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 34 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 35 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 36 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 40 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 41 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 42 * SUCH DAMAGE. 43 * 44 * @(#)vnode_pager.c 8.8 (Berkeley) 2/13/94 45 * from: Id: uvm_vnode.c,v 1.1.2.26 1998/02/02 20:38:07 chuck Exp 46 */ 47 48 #include "fs_nfs.h" 49 #include "opt_uvmhist.h" 50 #include "opt_ddb.h" 51 52 /* 53 * uvm_vnode.c: the vnode pager. 54 */ 55 56 #include <sys/param.h> 57 #include <sys/systm.h> 58 #include <sys/kernel.h> 59 #include <sys/proc.h> 60 #include <sys/malloc.h> 61 #include <sys/vnode.h> 62 #include <sys/disklabel.h> 63 #include <sys/ioctl.h> 64 #include <sys/fcntl.h> 65 #include <sys/conf.h> 66 #include <sys/pool.h> 67 #include <sys/mount.h> 68 69 #include <miscfs/specfs/specdev.h> 70 71 #include <uvm/uvm.h> 72 73 /* 74 * functions 75 */ 76 77 void uvn_detach __P((struct uvm_object *)); 78 int uvn_get __P((struct uvm_object *, voff_t, struct vm_page **, int *, int, 79 vm_prot_t, int, int)); 80 int uvn_put __P((struct uvm_object *, voff_t, voff_t, int)); 81 void uvn_reference __P((struct uvm_object *)); 82 83 int uvn_findpage __P((struct uvm_object *, voff_t, struct vm_page **, int)); 84 85 /* 86 * master pager structure 87 */ 88 89 struct uvm_pagerops uvm_vnodeops = { 90 NULL, 91 uvn_reference, 92 uvn_detach, 93 NULL, 94 uvn_get, 95 uvn_put, 96 }; 97 98 /* 99 * the ops! 100 */ 101 102 /* 103 * uvn_attach 104 * 105 * attach a vnode structure to a VM object. if the vnode is already 106 * attached, then just bump the reference count by one and return the 107 * VM object. if not already attached, attach and return the new VM obj. 108 * the "accessprot" tells the max access the attaching thread wants to 109 * our pages. 110 * 111 * => caller must _not_ already be holding the lock on the uvm_object. 112 * => in fact, nothing should be locked so that we can sleep here. 113 * => note that uvm_object is first thing in vnode structure, so their 114 * pointers are equiv. 115 */ 116 117 struct uvm_object * 118 uvn_attach(arg, accessprot) 119 void *arg; 120 vm_prot_t accessprot; 121 { 122 struct vnode *vp = arg; 123 struct uvm_object *uobj = &vp->v_uobj; 124 struct vattr vattr; 125 int result; 126 struct partinfo pi; 127 voff_t used_vnode_size; 128 UVMHIST_FUNC("uvn_attach"); UVMHIST_CALLED(maphist); 129 130 UVMHIST_LOG(maphist, "(vn=0x%x)", arg,0,0,0); 131 used_vnode_size = (voff_t)0; 132 133 /* 134 * first get a lock on the uobj. 135 */ 136 137 simple_lock(&uobj->vmobjlock); 138 while (vp->v_flag & VXLOCK) { 139 vp->v_flag |= VXWANT; 140 UVMHIST_LOG(maphist, " SLEEPING on blocked vn",0,0,0,0); 141 UVM_UNLOCK_AND_WAIT(uobj, &uobj->vmobjlock, FALSE, 142 "uvn_attach", 0); 143 simple_lock(&uobj->vmobjlock); 144 UVMHIST_LOG(maphist," WOKE UP",0,0,0,0); 145 } 146 147 /* 148 * if we're mapping a BLK device, make sure it is a disk. 149 */ 150 if (vp->v_type == VBLK && bdevsw[major(vp->v_rdev)].d_type != D_DISK) { 151 simple_unlock(&uobj->vmobjlock); 152 UVMHIST_LOG(maphist,"<- done (VBLK not D_DISK!)", 0,0,0,0); 153 return(NULL); 154 } 155 KASSERT(vp->v_type == VREG || vp->v_type == VBLK); 156 157 /* 158 * set up our idea of the size 159 * if this hasn't been done already. 160 */ 161 if (vp->v_size == VSIZENOTSET) { 162 163 164 vp->v_flag |= VXLOCK; 165 simple_unlock(&uobj->vmobjlock); /* drop lock in case we sleep */ 166 /* XXX: curproc? */ 167 if (vp->v_type == VBLK) { 168 /* 169 * We could implement this as a specfs getattr call, but: 170 * 171 * (1) VOP_GETATTR() would get the file system 172 * vnode operation, not the specfs operation. 173 * 174 * (2) All we want is the size, anyhow. 175 */ 176 result = (*bdevsw[major(vp->v_rdev)].d_ioctl)(vp->v_rdev, 177 DIOCGPART, (caddr_t)&pi, FREAD, curproc); 178 if (result == 0) { 179 /* XXX should remember blocksize */ 180 used_vnode_size = (voff_t)pi.disklab->d_secsize * 181 (voff_t)pi.part->p_size; 182 } 183 } else { 184 result = VOP_GETATTR(vp, &vattr, curproc->p_ucred, curproc); 185 if (result == 0) 186 used_vnode_size = vattr.va_size; 187 } 188 189 /* relock object */ 190 simple_lock(&uobj->vmobjlock); 191 192 if (vp->v_flag & VXWANT) { 193 wakeup(vp); 194 } 195 vp->v_flag &= ~(VXLOCK|VXWANT); 196 197 if (result != 0) { 198 simple_unlock(&uobj->vmobjlock); 199 UVMHIST_LOG(maphist,"<- done (VOP_GETATTR FAILED!)", 0,0,0,0); 200 return(NULL); 201 } 202 vp->v_size = used_vnode_size; 203 204 } 205 206 simple_unlock(&uobj->vmobjlock); 207 UVMHIST_LOG(maphist,"<- done, refcnt=%d", vp->v_usecount, 208 0, 0, 0); 209 return uobj; 210 } 211 212 213 /* 214 * uvn_reference 215 * 216 * duplicate a reference to a VM object. Note that the reference 217 * count must already be at least one (the passed in reference) so 218 * there is no chance of the uvn being killed or locked out here. 219 * 220 * => caller must call with object unlocked. 221 * => caller must be using the same accessprot as was used at attach time 222 */ 223 224 void 225 uvn_reference(uobj) 226 struct uvm_object *uobj; 227 { 228 VREF((struct vnode *)uobj); 229 } 230 231 232 /* 233 * uvn_detach 234 * 235 * remove a reference to a VM object. 236 * 237 * => caller must call with object unlocked and map locked. 238 */ 239 240 void 241 uvn_detach(uobj) 242 struct uvm_object *uobj; 243 { 244 vrele((struct vnode *)uobj); 245 } 246 247 /* 248 * uvn_put: flush page data to backing store. 249 * 250 * => object must be locked! we will _unlock_ it before starting I/O. 251 * => flags: PGO_SYNCIO -- use sync. I/O 252 * => note: caller must set PG_CLEAN and pmap_clear_modify (if needed) 253 */ 254 255 int 256 uvn_put(uobj, off, len, flags) 257 struct uvm_object *uobj; 258 voff_t off; 259 voff_t len; 260 int flags; 261 { 262 struct vnode *vp = (struct vnode *)uobj; 263 int error; 264 265 error = VOP_PUTPAGES(vp, off, len, flags); 266 return error; 267 } 268 269 270 /* 271 * uvn_get: get pages (synchronously) from backing store 272 * 273 * => prefer map unlocked (not required) 274 * => object must be locked! we will _unlock_ it before starting any I/O. 275 * => flags: PGO_ALLPAGES: get all of the pages 276 * PGO_LOCKED: fault data structures are locked 277 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 278 * => NOTE: caller must check for released pages!! 279 */ 280 281 int 282 uvn_get(uobj, offset, pps, npagesp, centeridx, access_type, advice, flags) 283 struct uvm_object *uobj; 284 voff_t offset; 285 struct vm_page **pps; /* IN/OUT */ 286 int *npagesp; /* IN (OUT if PGO_LOCKED) */ 287 int centeridx; 288 vm_prot_t access_type; 289 int advice, flags; 290 { 291 struct vnode *vp = (struct vnode *)uobj; 292 int error; 293 UVMHIST_FUNC("uvn_get"); UVMHIST_CALLED(ubchist); 294 295 UVMHIST_LOG(ubchist, "vp %p off 0x%x", vp, (int)offset, 0,0); 296 error = VOP_GETPAGES(vp, offset, pps, npagesp, centeridx, 297 access_type, advice, flags); 298 return error; 299 } 300 301 302 /* 303 * uvn_findpages: 304 * return the page for the uobj and offset requested, allocating if needed. 305 * => uobj must be locked. 306 * => returned pages will be BUSY. 307 */ 308 309 void 310 uvn_findpages(uobj, offset, npagesp, pgs, flags) 311 struct uvm_object *uobj; 312 voff_t offset; 313 int *npagesp; 314 struct vm_page **pgs; 315 int flags; 316 { 317 int i, count, npages, rv; 318 319 count = 0; 320 npages = *npagesp; 321 if (flags & UFP_BACKWARD) { 322 for (i = npages - 1; i >= 0; i--, offset -= PAGE_SIZE) { 323 rv = uvn_findpage(uobj, offset, &pgs[i], flags); 324 if (flags & UFP_DIRTYONLY && rv == 0) { 325 break; 326 } 327 count++; 328 } 329 } else { 330 for (i = 0; i < npages; i++, offset += PAGE_SIZE) { 331 rv = uvn_findpage(uobj, offset, &pgs[i], flags); 332 if (flags & UFP_DIRTYONLY && rv == 0) { 333 break; 334 } 335 count++; 336 } 337 } 338 *npagesp = count; 339 } 340 341 int 342 uvn_findpage(uobj, offset, pgp, flags) 343 struct uvm_object *uobj; 344 voff_t offset; 345 struct vm_page **pgp; 346 int flags; 347 { 348 struct vm_page *pg; 349 boolean_t dirty; 350 UVMHIST_FUNC("uvn_findpage"); UVMHIST_CALLED(ubchist); 351 UVMHIST_LOG(ubchist, "vp %p off 0x%lx", uobj, offset,0,0); 352 353 if (*pgp != NULL) { 354 UVMHIST_LOG(ubchist, "dontcare", 0,0,0,0); 355 return 0; 356 } 357 for (;;) { 358 /* look for an existing page */ 359 pg = uvm_pagelookup(uobj, offset); 360 361 /* nope? allocate one now */ 362 if (pg == NULL) { 363 if (flags & UFP_NOALLOC) { 364 UVMHIST_LOG(ubchist, "noalloc", 0,0,0,0); 365 return 0; 366 } 367 pg = uvm_pagealloc(uobj, offset, NULL, 0); 368 if (pg == NULL) { 369 if (flags & UFP_NOWAIT) { 370 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 371 return 0; 372 } 373 simple_unlock(&uobj->vmobjlock); 374 uvm_wait("uvn_fp1"); 375 simple_lock(&uobj->vmobjlock); 376 continue; 377 } 378 if (UVM_OBJ_IS_VTEXT(uobj)) { 379 uvmexp.vtextpages++; 380 } else { 381 uvmexp.vnodepages++; 382 } 383 UVMHIST_LOG(ubchist, "alloced %p", pg,0,0,0); 384 break; 385 } else if (flags & UFP_NOCACHE) { 386 UVMHIST_LOG(ubchist, "nocache",0,0,0,0); 387 return 0; 388 } 389 390 /* page is there, see if we need to wait on it */ 391 if ((pg->flags & PG_BUSY) != 0) { 392 if (flags & UFP_NOWAIT) { 393 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 394 return 0; 395 } 396 pg->flags |= PG_WANTED; 397 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, 0, 398 "uvn_fp2", 0); 399 simple_lock(&uobj->vmobjlock); 400 continue; 401 } 402 403 /* skip PG_RDONLY pages if requested */ 404 if ((flags & UFP_NORDONLY) && (pg->flags & PG_RDONLY)) { 405 UVMHIST_LOG(ubchist, "nordonly",0,0,0,0); 406 return 0; 407 } 408 409 /* stop on clean pages if requested */ 410 if (flags & UFP_DIRTYONLY) { 411 dirty = pmap_clear_modify(pg) || 412 (pg->flags & PG_CLEAN) == 0; 413 pg->flags |= PG_CLEAN; 414 if (!dirty) { 415 return 0; 416 } 417 } 418 419 /* mark the page BUSY and we're done. */ 420 pg->flags |= PG_BUSY; 421 UVM_PAGE_OWN(pg, "uvn_findpage"); 422 UVMHIST_LOG(ubchist, "found %p", pg,0,0,0); 423 break; 424 } 425 *pgp = pg; 426 return 1; 427 } 428 429 /* 430 * uvm_vnp_setsize: grow or shrink a vnode uobj 431 * 432 * grow => just update size value 433 * shrink => toss un-needed pages 434 * 435 * => we assume that the caller has a reference of some sort to the 436 * vnode in question so that it will not be yanked out from under 437 * us. 438 */ 439 440 void 441 uvm_vnp_setsize(vp, newsize) 442 struct vnode *vp; 443 voff_t newsize; 444 { 445 struct uvm_object *uobj = &vp->v_uobj; 446 voff_t pgend = round_page(newsize); 447 UVMHIST_FUNC("uvm_vnp_setsize"); UVMHIST_CALLED(ubchist); 448 449 simple_lock(&uobj->vmobjlock); 450 UVMHIST_LOG(ubchist, "vp %p old 0x%x new 0x%x", 451 vp, vp->v_size, newsize, 0); 452 453 /* 454 * now check if the size has changed: if we shrink we had better 455 * toss some pages... 456 */ 457 458 if (vp->v_size > pgend && vp->v_size != VSIZENOTSET) { 459 (void) uvn_put(uobj, pgend, 0, PGO_FREE); 460 } else { 461 simple_unlock(&uobj->vmobjlock); 462 } 463 vp->v_size = newsize; 464 } 465 466 /* 467 * uvm_vnp_zerorange: set a range of bytes in a file to zero. 468 */ 469 470 void 471 uvm_vnp_zerorange(vp, off, len) 472 struct vnode *vp; 473 off_t off; 474 size_t len; 475 { 476 void *win; 477 478 /* 479 * XXXUBC invent kzero() and use it 480 */ 481 482 while (len) { 483 vsize_t bytelen = len; 484 485 win = ubc_alloc(&vp->v_uobj, off, &bytelen, UBC_WRITE); 486 memset(win, 0, bytelen); 487 ubc_release(win, 0); 488 489 off += bytelen; 490 len -= bytelen; 491 } 492 } 493