1 /* $NetBSD: uvm_vnode.c,v 1.69 2005/12/11 12:25:29 christos 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 /* 49 * uvm_vnode.c: the vnode pager. 50 */ 51 52 #include <sys/cdefs.h> 53 __KERNEL_RCSID(0, "$NetBSD: uvm_vnode.c,v 1.69 2005/12/11 12:25:29 christos Exp $"); 54 55 #include "fs_nfs.h" 56 #include "opt_uvmhist.h" 57 #include "opt_readahead.h" 58 #include "opt_ddb.h" 59 60 #include <sys/param.h> 61 #include <sys/systm.h> 62 #include <sys/kernel.h> 63 #include <sys/proc.h> 64 #include <sys/malloc.h> 65 #include <sys/vnode.h> 66 #include <sys/disklabel.h> 67 #include <sys/ioctl.h> 68 #include <sys/fcntl.h> 69 #include <sys/conf.h> 70 #include <sys/pool.h> 71 #include <sys/mount.h> 72 73 #include <miscfs/specfs/specdev.h> 74 75 #include <uvm/uvm.h> 76 #include <uvm/uvm_readahead.h> 77 78 /* 79 * functions 80 */ 81 82 static void uvn_detach(struct uvm_object *); 83 static int uvn_get(struct uvm_object *, voff_t, struct vm_page **, int *, 84 int, vm_prot_t, int, int); 85 static int uvn_put(struct uvm_object *, voff_t, voff_t, int); 86 static void uvn_reference(struct uvm_object *); 87 88 static int uvn_findpage(struct uvm_object *, voff_t, struct vm_page **, 89 int); 90 91 /* 92 * master pager structure 93 */ 94 95 struct uvm_pagerops uvm_vnodeops = { 96 NULL, 97 uvn_reference, 98 uvn_detach, 99 NULL, 100 uvn_get, 101 uvn_put, 102 }; 103 104 /* 105 * the ops! 106 */ 107 108 /* 109 * uvn_attach 110 * 111 * attach a vnode structure to a VM object. if the vnode is already 112 * attached, then just bump the reference count by one and return the 113 * VM object. if not already attached, attach and return the new VM obj. 114 * the "accessprot" tells the max access the attaching thread wants to 115 * our pages. 116 * 117 * => caller must _not_ already be holding the lock on the uvm_object. 118 * => in fact, nothing should be locked so that we can sleep here. 119 * => note that uvm_object is first thing in vnode structure, so their 120 * pointers are equiv. 121 */ 122 123 struct uvm_object * 124 uvn_attach(void *arg, vm_prot_t accessprot) 125 { 126 struct vnode *vp = arg; 127 struct uvm_object *uobj = &vp->v_uobj; 128 struct vattr vattr; 129 const struct bdevsw *bdev; 130 int result; 131 struct partinfo pi; 132 voff_t used_vnode_size; 133 UVMHIST_FUNC("uvn_attach"); UVMHIST_CALLED(maphist); 134 135 UVMHIST_LOG(maphist, "(vn=0x%x)", arg,0,0,0); 136 used_vnode_size = (voff_t)0; 137 138 /* 139 * first get a lock on the uobj. 140 */ 141 142 simple_lock(&uobj->vmobjlock); 143 while (vp->v_flag & VXLOCK) { 144 vp->v_flag |= VXWANT; 145 UVMHIST_LOG(maphist, " SLEEPING on blocked vn",0,0,0,0); 146 UVM_UNLOCK_AND_WAIT(uobj, &uobj->vmobjlock, FALSE, 147 "uvn_attach", 0); 148 simple_lock(&uobj->vmobjlock); 149 UVMHIST_LOG(maphist," WOKE UP",0,0,0,0); 150 } 151 152 /* 153 * if we're mapping a BLK device, make sure it is a disk. 154 */ 155 if (vp->v_type == VBLK) { 156 bdev = bdevsw_lookup(vp->v_rdev); 157 if (bdev == NULL || bdev->d_type != D_DISK) { 158 simple_unlock(&uobj->vmobjlock); 159 UVMHIST_LOG(maphist,"<- done (VBLK not D_DISK!)", 160 0,0,0,0); 161 return(NULL); 162 } 163 } 164 KASSERT(vp->v_type == VREG || vp->v_type == VBLK); 165 166 /* 167 * set up our idea of the size 168 * if this hasn't been done already. 169 */ 170 if (vp->v_size == VSIZENOTSET) { 171 172 173 vp->v_flag |= VXLOCK; 174 simple_unlock(&uobj->vmobjlock); /* drop lock in case we sleep */ 175 /* XXX: curproc? */ 176 if (vp->v_type == VBLK) { 177 /* 178 * We could implement this as a specfs getattr call, but: 179 * 180 * (1) VOP_GETATTR() would get the file system 181 * vnode operation, not the specfs operation. 182 * 183 * (2) All we want is the size, anyhow. 184 */ 185 bdev = bdevsw_lookup(vp->v_rdev); 186 if (bdev != NULL) { 187 result = (*bdev->d_ioctl)(vp->v_rdev, DIOCGPART, 188 (caddr_t)&pi, FREAD, curlwp); 189 } else { 190 result = ENXIO; 191 } 192 if (result == 0) { 193 /* XXX should remember blocksize */ 194 used_vnode_size = (voff_t)pi.disklab->d_secsize * 195 (voff_t)pi.part->p_size; 196 } 197 } else { 198 result = VOP_GETATTR(vp, &vattr, curproc->p_ucred, curlwp); 199 if (result == 0) 200 used_vnode_size = vattr.va_size; 201 } 202 203 /* relock object */ 204 simple_lock(&uobj->vmobjlock); 205 206 if (vp->v_flag & VXWANT) { 207 wakeup(vp); 208 } 209 vp->v_flag &= ~(VXLOCK|VXWANT); 210 211 if (result != 0) { 212 simple_unlock(&uobj->vmobjlock); 213 UVMHIST_LOG(maphist,"<- done (VOP_GETATTR FAILED!)", 0,0,0,0); 214 return(NULL); 215 } 216 vp->v_size = used_vnode_size; 217 218 } 219 220 simple_unlock(&uobj->vmobjlock); 221 UVMHIST_LOG(maphist,"<- done, refcnt=%d", vp->v_usecount, 222 0, 0, 0); 223 return uobj; 224 } 225 226 227 /* 228 * uvn_reference 229 * 230 * duplicate a reference to a VM object. Note that the reference 231 * count must already be at least one (the passed in reference) so 232 * there is no chance of the uvn being killed or locked out here. 233 * 234 * => caller must call with object unlocked. 235 * => caller must be using the same accessprot as was used at attach time 236 */ 237 238 static void 239 uvn_reference(struct uvm_object *uobj) 240 { 241 VREF((struct vnode *)uobj); 242 } 243 244 245 /* 246 * uvn_detach 247 * 248 * remove a reference to a VM object. 249 * 250 * => caller must call with object unlocked and map locked. 251 */ 252 253 static void 254 uvn_detach(struct uvm_object *uobj) 255 { 256 vrele((struct vnode *)uobj); 257 } 258 259 /* 260 * uvn_put: flush page data to backing store. 261 * 262 * => object must be locked on entry! VOP_PUTPAGES must unlock it. 263 * => flags: PGO_SYNCIO -- use sync. I/O 264 * => note: caller must set PG_CLEAN and pmap_clear_modify (if needed) 265 */ 266 267 static int 268 uvn_put(struct uvm_object *uobj, voff_t offlo, voff_t offhi, int flags) 269 { 270 struct vnode *vp = (struct vnode *)uobj; 271 int error; 272 273 LOCK_ASSERT(simple_lock_held(&vp->v_interlock)); 274 error = VOP_PUTPAGES(vp, offlo, offhi, flags); 275 LOCK_ASSERT(!simple_lock_held(&vp->v_interlock)); 276 return error; 277 } 278 279 280 /* 281 * uvn_get: get pages (synchronously) from backing store 282 * 283 * => prefer map unlocked (not required) 284 * => object must be locked! we will _unlock_ it before starting any I/O. 285 * => flags: PGO_ALLPAGES: get all of the pages 286 * PGO_LOCKED: fault data structures are locked 287 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 288 * => NOTE: caller must check for released pages!! 289 */ 290 291 static int 292 uvn_get(struct uvm_object *uobj, voff_t offset, 293 struct vm_page **pps /* IN/OUT */, 294 int *npagesp /* IN (OUT if PGO_LOCKED)*/, 295 int centeridx, vm_prot_t access_type, int advice, int flags) 296 { 297 struct vnode *vp = (struct vnode *)uobj; 298 int error; 299 #if defined(READAHEAD_STATS) 300 int orignpages = *npagesp; 301 #endif /* defined(READAHEAD_STATS) */ 302 303 UVMHIST_FUNC("uvn_get"); UVMHIST_CALLED(ubchist); 304 305 UVMHIST_LOG(ubchist, "vp %p off 0x%x", vp, (int)offset, 0,0); 306 307 if ((access_type & VM_PROT_WRITE) == 0 && (flags & PGO_LOCKED) == 0) { 308 simple_unlock(&vp->v_interlock); 309 vn_ra_allocctx(vp); 310 uvm_ra_request(vp->v_ractx, advice, uobj, offset, 311 *npagesp << PAGE_SHIFT); 312 simple_lock(&vp->v_interlock); 313 } 314 315 error = VOP_GETPAGES(vp, offset, pps, npagesp, centeridx, 316 access_type, advice, flags); 317 318 #if defined(READAHEAD_STATS) 319 if (((flags & PGO_LOCKED) != 0 && *npagesp > 0) || 320 ((flags & (PGO_LOCKED|PGO_SYNCIO)) == PGO_SYNCIO && error == 0)) { 321 int i; 322 323 if ((flags & PGO_LOCKED) == 0) { 324 simple_lock(&uobj->vmobjlock); 325 } 326 for (i = 0; i < orignpages; i++) { 327 struct vm_page *pg = pps[i]; 328 329 if (pg == NULL || pg == PGO_DONTCARE) { 330 continue; 331 } 332 if ((pg->flags & PG_SPECULATIVE) != 0) { 333 pg->flags &= ~PG_SPECULATIVE; 334 uvm_ra_hit.ev_count++; 335 } 336 } 337 if ((flags & PGO_LOCKED) == 0) { 338 simple_unlock(&uobj->vmobjlock); 339 } 340 } 341 #endif /* defined(READAHEAD_STATS) */ 342 343 return error; 344 } 345 346 347 /* 348 * uvn_findpages: 349 * return the page for the uobj and offset requested, allocating if needed. 350 * => uobj must be locked. 351 * => returned pages will be BUSY. 352 */ 353 354 int 355 uvn_findpages(struct uvm_object *uobj, voff_t offset, int *npagesp, 356 struct vm_page **pgs, int flags) 357 { 358 int i, count, found, npages, rv; 359 360 count = found = 0; 361 npages = *npagesp; 362 if (flags & UFP_BACKWARD) { 363 for (i = npages - 1; i >= 0; i--, offset -= PAGE_SIZE) { 364 rv = uvn_findpage(uobj, offset, &pgs[i], flags); 365 if (rv == 0) { 366 if (flags & UFP_DIRTYONLY) 367 break; 368 } else 369 found++; 370 count++; 371 } 372 } else { 373 for (i = 0; i < npages; i++, offset += PAGE_SIZE) { 374 rv = uvn_findpage(uobj, offset, &pgs[i], flags); 375 if (rv == 0) { 376 if (flags & UFP_DIRTYONLY) 377 break; 378 } else 379 found++; 380 count++; 381 } 382 } 383 *npagesp = count; 384 return (found); 385 } 386 387 static int 388 uvn_findpage(struct uvm_object *uobj, voff_t offset, struct vm_page **pgp, 389 int flags) 390 { 391 struct vm_page *pg; 392 boolean_t dirty; 393 UVMHIST_FUNC("uvn_findpage"); UVMHIST_CALLED(ubchist); 394 UVMHIST_LOG(ubchist, "vp %p off 0x%lx", uobj, offset,0,0); 395 396 if (*pgp != NULL) { 397 UVMHIST_LOG(ubchist, "dontcare", 0,0,0,0); 398 return 0; 399 } 400 for (;;) { 401 /* look for an existing page */ 402 pg = uvm_pagelookup(uobj, offset); 403 404 /* nope? allocate one now */ 405 if (pg == NULL) { 406 if (flags & UFP_NOALLOC) { 407 UVMHIST_LOG(ubchist, "noalloc", 0,0,0,0); 408 return 0; 409 } 410 pg = uvm_pagealloc(uobj, offset, NULL, 0); 411 if (pg == NULL) { 412 if (flags & UFP_NOWAIT) { 413 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 414 return 0; 415 } 416 simple_unlock(&uobj->vmobjlock); 417 uvm_wait("uvn_fp1"); 418 simple_lock(&uobj->vmobjlock); 419 continue; 420 } 421 UVMHIST_LOG(ubchist, "alloced %p", pg,0,0,0); 422 break; 423 } else if (flags & UFP_NOCACHE) { 424 UVMHIST_LOG(ubchist, "nocache",0,0,0,0); 425 return 0; 426 } 427 428 /* page is there, see if we need to wait on it */ 429 if ((pg->flags & PG_BUSY) != 0) { 430 if (flags & UFP_NOWAIT) { 431 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 432 return 0; 433 } 434 pg->flags |= PG_WANTED; 435 UVMHIST_LOG(ubchist, "wait %p", pg,0,0,0); 436 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, 0, 437 "uvn_fp2", 0); 438 simple_lock(&uobj->vmobjlock); 439 continue; 440 } 441 442 /* skip PG_RDONLY pages if requested */ 443 if ((flags & UFP_NORDONLY) && (pg->flags & PG_RDONLY)) { 444 UVMHIST_LOG(ubchist, "nordonly",0,0,0,0); 445 return 0; 446 } 447 448 /* stop on clean pages if requested */ 449 if (flags & UFP_DIRTYONLY) { 450 dirty = pmap_clear_modify(pg) || 451 (pg->flags & PG_CLEAN) == 0; 452 pg->flags |= PG_CLEAN; 453 if (!dirty) { 454 UVMHIST_LOG(ubchist, "dirtonly", 0,0,0,0); 455 return 0; 456 } 457 } 458 459 /* mark the page BUSY and we're done. */ 460 pg->flags |= PG_BUSY; 461 UVM_PAGE_OWN(pg, "uvn_findpage"); 462 UVMHIST_LOG(ubchist, "found %p", pg,0,0,0); 463 break; 464 } 465 *pgp = pg; 466 return 1; 467 } 468 469 /* 470 * uvm_vnp_setsize: grow or shrink a vnode uobj 471 * 472 * grow => just update size value 473 * shrink => toss un-needed pages 474 * 475 * => we assume that the caller has a reference of some sort to the 476 * vnode in question so that it will not be yanked out from under 477 * us. 478 */ 479 480 void 481 uvm_vnp_setsize(struct vnode *vp, voff_t newsize) 482 { 483 struct uvm_object *uobj = &vp->v_uobj; 484 voff_t pgend = round_page(newsize); 485 UVMHIST_FUNC("uvm_vnp_setsize"); UVMHIST_CALLED(ubchist); 486 487 simple_lock(&uobj->vmobjlock); 488 UVMHIST_LOG(ubchist, "vp %p old 0x%x new 0x%x", 489 vp, vp->v_size, newsize, 0); 490 491 /* 492 * now check if the size has changed: if we shrink we had better 493 * toss some pages... 494 */ 495 496 if (vp->v_size > pgend && vp->v_size != VSIZENOTSET) { 497 (void) uvn_put(uobj, pgend, 0, PGO_FREE | PGO_SYNCIO); 498 } else { 499 simple_unlock(&uobj->vmobjlock); 500 } 501 vp->v_size = newsize; 502 } 503 504 /* 505 * uvm_vnp_zerorange: set a range of bytes in a file to zero. 506 */ 507 508 void 509 uvm_vnp_zerorange(struct vnode *vp, off_t off, size_t len) 510 { 511 void *win; 512 int flags; 513 514 /* 515 * XXXUBC invent kzero() and use it 516 */ 517 518 while (len) { 519 vsize_t bytelen = len; 520 521 win = ubc_alloc(&vp->v_uobj, off, &bytelen, UVM_ADV_NORMAL, 522 UBC_WRITE); 523 memset(win, 0, bytelen); 524 flags = UBC_WANT_UNMAP(vp) ? UBC_UNMAP : 0; 525 ubc_release(win, flags); 526 527 off += bytelen; 528 len -= bytelen; 529 } 530 } 531