1 /* $NetBSD: uvm_vnode.c,v 1.66 2005/06/27 02:29:32 thorpej 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 1.66 2005/06/27 02:29:32 thorpej Exp $"); 54 55 #include "fs_nfs.h" 56 #include "opt_uvmhist.h" 57 #include "opt_ddb.h" 58 59 #include <sys/param.h> 60 #include <sys/systm.h> 61 #include <sys/kernel.h> 62 #include <sys/proc.h> 63 #include <sys/malloc.h> 64 #include <sys/vnode.h> 65 #include <sys/disklabel.h> 66 #include <sys/ioctl.h> 67 #include <sys/fcntl.h> 68 #include <sys/conf.h> 69 #include <sys/pool.h> 70 #include <sys/mount.h> 71 72 #include <miscfs/specfs/specdev.h> 73 74 #include <uvm/uvm.h> 75 76 /* 77 * functions 78 */ 79 80 static void uvn_detach(struct uvm_object *); 81 static int uvn_get(struct uvm_object *, voff_t, struct vm_page **, int *, 82 int, vm_prot_t, int, int); 83 static int uvn_put(struct uvm_object *, voff_t, voff_t, int); 84 static void uvn_reference(struct uvm_object *); 85 86 static int uvn_findpage(struct uvm_object *, voff_t, struct vm_page **, 87 int); 88 89 /* 90 * master pager structure 91 */ 92 93 struct uvm_pagerops uvm_vnodeops = { 94 NULL, 95 uvn_reference, 96 uvn_detach, 97 NULL, 98 uvn_get, 99 uvn_put, 100 }; 101 102 /* 103 * the ops! 104 */ 105 106 /* 107 * uvn_attach 108 * 109 * attach a vnode structure to a VM object. if the vnode is already 110 * attached, then just bump the reference count by one and return the 111 * VM object. if not already attached, attach and return the new VM obj. 112 * the "accessprot" tells the max access the attaching thread wants to 113 * our pages. 114 * 115 * => caller must _not_ already be holding the lock on the uvm_object. 116 * => in fact, nothing should be locked so that we can sleep here. 117 * => note that uvm_object is first thing in vnode structure, so their 118 * pointers are equiv. 119 */ 120 121 struct uvm_object * 122 uvn_attach(void *arg, vm_prot_t accessprot) 123 { 124 struct vnode *vp = arg; 125 struct uvm_object *uobj = &vp->v_uobj; 126 struct vattr vattr; 127 const struct bdevsw *bdev; 128 int result; 129 struct partinfo pi; 130 voff_t used_vnode_size; 131 UVMHIST_FUNC("uvn_attach"); UVMHIST_CALLED(maphist); 132 133 UVMHIST_LOG(maphist, "(vn=0x%x)", arg,0,0,0); 134 used_vnode_size = (voff_t)0; 135 136 /* 137 * first get a lock on the uobj. 138 */ 139 140 simple_lock(&uobj->vmobjlock); 141 while (vp->v_flag & VXLOCK) { 142 vp->v_flag |= VXWANT; 143 UVMHIST_LOG(maphist, " SLEEPING on blocked vn",0,0,0,0); 144 UVM_UNLOCK_AND_WAIT(uobj, &uobj->vmobjlock, FALSE, 145 "uvn_attach", 0); 146 simple_lock(&uobj->vmobjlock); 147 UVMHIST_LOG(maphist," WOKE UP",0,0,0,0); 148 } 149 150 /* 151 * if we're mapping a BLK device, make sure it is a disk. 152 */ 153 if (vp->v_type == VBLK) { 154 bdev = bdevsw_lookup(vp->v_rdev); 155 if (bdev == NULL || bdev->d_type != D_DISK) { 156 simple_unlock(&uobj->vmobjlock); 157 UVMHIST_LOG(maphist,"<- done (VBLK not D_DISK!)", 158 0,0,0,0); 159 return(NULL); 160 } 161 } 162 KASSERT(vp->v_type == VREG || vp->v_type == VBLK); 163 164 /* 165 * set up our idea of the size 166 * if this hasn't been done already. 167 */ 168 if (vp->v_size == VSIZENOTSET) { 169 170 171 vp->v_flag |= VXLOCK; 172 simple_unlock(&uobj->vmobjlock); /* drop lock in case we sleep */ 173 /* XXX: curproc? */ 174 if (vp->v_type == VBLK) { 175 /* 176 * We could implement this as a specfs getattr call, but: 177 * 178 * (1) VOP_GETATTR() would get the file system 179 * vnode operation, not the specfs operation. 180 * 181 * (2) All we want is the size, anyhow. 182 */ 183 bdev = bdevsw_lookup(vp->v_rdev); 184 if (bdev != NULL) { 185 result = (*bdev->d_ioctl)(vp->v_rdev, DIOCGPART, 186 (caddr_t)&pi, FREAD, curproc); 187 } else { 188 result = ENXIO; 189 } 190 if (result == 0) { 191 /* XXX should remember blocksize */ 192 used_vnode_size = (voff_t)pi.disklab->d_secsize * 193 (voff_t)pi.part->p_size; 194 } 195 } else { 196 result = VOP_GETATTR(vp, &vattr, curproc->p_ucred, curproc); 197 if (result == 0) 198 used_vnode_size = vattr.va_size; 199 } 200 201 /* relock object */ 202 simple_lock(&uobj->vmobjlock); 203 204 if (vp->v_flag & VXWANT) { 205 wakeup(vp); 206 } 207 vp->v_flag &= ~(VXLOCK|VXWANT); 208 209 if (result != 0) { 210 simple_unlock(&uobj->vmobjlock); 211 UVMHIST_LOG(maphist,"<- done (VOP_GETATTR FAILED!)", 0,0,0,0); 212 return(NULL); 213 } 214 vp->v_size = used_vnode_size; 215 216 } 217 218 simple_unlock(&uobj->vmobjlock); 219 UVMHIST_LOG(maphist,"<- done, refcnt=%d", vp->v_usecount, 220 0, 0, 0); 221 return uobj; 222 } 223 224 225 /* 226 * uvn_reference 227 * 228 * duplicate a reference to a VM object. Note that the reference 229 * count must already be at least one (the passed in reference) so 230 * there is no chance of the uvn being killed or locked out here. 231 * 232 * => caller must call with object unlocked. 233 * => caller must be using the same accessprot as was used at attach time 234 */ 235 236 static void 237 uvn_reference(struct uvm_object *uobj) 238 { 239 VREF((struct vnode *)uobj); 240 } 241 242 243 /* 244 * uvn_detach 245 * 246 * remove a reference to a VM object. 247 * 248 * => caller must call with object unlocked and map locked. 249 */ 250 251 static void 252 uvn_detach(struct uvm_object *uobj) 253 { 254 vrele((struct vnode *)uobj); 255 } 256 257 /* 258 * uvn_put: flush page data to backing store. 259 * 260 * => object must be locked on entry! VOP_PUTPAGES must unlock it. 261 * => flags: PGO_SYNCIO -- use sync. I/O 262 * => note: caller must set PG_CLEAN and pmap_clear_modify (if needed) 263 */ 264 265 static int 266 uvn_put(struct uvm_object *uobj, voff_t offlo, voff_t offhi, int flags) 267 { 268 struct vnode *vp = (struct vnode *)uobj; 269 int error; 270 271 LOCK_ASSERT(simple_lock_held(&vp->v_interlock)); 272 error = VOP_PUTPAGES(vp, offlo, offhi, flags); 273 LOCK_ASSERT(!simple_lock_held(&vp->v_interlock)); 274 return error; 275 } 276 277 278 /* 279 * uvn_get: get pages (synchronously) from backing store 280 * 281 * => prefer map unlocked (not required) 282 * => object must be locked! we will _unlock_ it before starting any I/O. 283 * => flags: PGO_ALLPAGES: get all of the pages 284 * PGO_LOCKED: fault data structures are locked 285 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 286 * => NOTE: caller must check for released pages!! 287 */ 288 289 static int 290 uvn_get(struct uvm_object *uobj, voff_t offset, 291 struct vm_page **pps /* IN/OUT */, 292 int *npagesp /* IN (OUT if PGO_LOCKED)*/, 293 int centeridx, vm_prot_t access_type, int advice, int flags) 294 { 295 struct vnode *vp = (struct vnode *)uobj; 296 int error; 297 UVMHIST_FUNC("uvn_get"); UVMHIST_CALLED(ubchist); 298 299 UVMHIST_LOG(ubchist, "vp %p off 0x%x", vp, (int)offset, 0,0); 300 error = VOP_GETPAGES(vp, offset, pps, npagesp, centeridx, 301 access_type, advice, flags); 302 return error; 303 } 304 305 306 /* 307 * uvn_findpages: 308 * return the page for the uobj and offset requested, allocating if needed. 309 * => uobj must be locked. 310 * => returned pages will be BUSY. 311 */ 312 313 int 314 uvn_findpages(struct uvm_object *uobj, voff_t offset, int *npagesp, 315 struct vm_page **pgs, int flags) 316 { 317 int i, count, found, npages, rv; 318 319 count = found = 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 (rv == 0) { 325 if (flags & UFP_DIRTYONLY) 326 break; 327 } else 328 found++; 329 count++; 330 } 331 } else { 332 for (i = 0; i < npages; i++, offset += PAGE_SIZE) { 333 rv = uvn_findpage(uobj, offset, &pgs[i], flags); 334 if (rv == 0) { 335 if (flags & UFP_DIRTYONLY) 336 break; 337 } else 338 found++; 339 count++; 340 } 341 } 342 *npagesp = count; 343 return (found); 344 } 345 346 static int 347 uvn_findpage(struct uvm_object *uobj, voff_t offset, struct vm_page **pgp, 348 int flags) 349 { 350 struct vm_page *pg; 351 boolean_t dirty; 352 UVMHIST_FUNC("uvn_findpage"); UVMHIST_CALLED(ubchist); 353 UVMHIST_LOG(ubchist, "vp %p off 0x%lx", uobj, offset,0,0); 354 355 if (*pgp != NULL) { 356 UVMHIST_LOG(ubchist, "dontcare", 0,0,0,0); 357 return 0; 358 } 359 for (;;) { 360 /* look for an existing page */ 361 pg = uvm_pagelookup(uobj, offset); 362 363 /* nope? allocate one now */ 364 if (pg == NULL) { 365 if (flags & UFP_NOALLOC) { 366 UVMHIST_LOG(ubchist, "noalloc", 0,0,0,0); 367 return 0; 368 } 369 pg = uvm_pagealloc(uobj, offset, NULL, 0); 370 if (pg == NULL) { 371 if (flags & UFP_NOWAIT) { 372 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 373 return 0; 374 } 375 simple_unlock(&uobj->vmobjlock); 376 uvm_wait("uvn_fp1"); 377 simple_lock(&uobj->vmobjlock); 378 continue; 379 } 380 UVMHIST_LOG(ubchist, "alloced %p", pg,0,0,0); 381 break; 382 } else if (flags & UFP_NOCACHE) { 383 UVMHIST_LOG(ubchist, "nocache",0,0,0,0); 384 return 0; 385 } 386 387 /* page is there, see if we need to wait on it */ 388 if ((pg->flags & PG_BUSY) != 0) { 389 if (flags & UFP_NOWAIT) { 390 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 391 return 0; 392 } 393 pg->flags |= PG_WANTED; 394 UVMHIST_LOG(ubchist, "wait %p", pg,0,0,0); 395 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, 0, 396 "uvn_fp2", 0); 397 simple_lock(&uobj->vmobjlock); 398 continue; 399 } 400 401 /* skip PG_RDONLY pages if requested */ 402 if ((flags & UFP_NORDONLY) && (pg->flags & PG_RDONLY)) { 403 UVMHIST_LOG(ubchist, "nordonly",0,0,0,0); 404 return 0; 405 } 406 407 /* stop on clean pages if requested */ 408 if (flags & UFP_DIRTYONLY) { 409 dirty = pmap_clear_modify(pg) || 410 (pg->flags & PG_CLEAN) == 0; 411 pg->flags |= PG_CLEAN; 412 if (!dirty) { 413 UVMHIST_LOG(ubchist, "dirtonly", 0,0,0,0); 414 return 0; 415 } 416 } 417 418 /* mark the page BUSY and we're done. */ 419 pg->flags |= PG_BUSY; 420 UVM_PAGE_OWN(pg, "uvn_findpage"); 421 UVMHIST_LOG(ubchist, "found %p", pg,0,0,0); 422 break; 423 } 424 *pgp = pg; 425 return 1; 426 } 427 428 /* 429 * uvm_vnp_setsize: grow or shrink a vnode uobj 430 * 431 * grow => just update size value 432 * shrink => toss un-needed pages 433 * 434 * => we assume that the caller has a reference of some sort to the 435 * vnode in question so that it will not be yanked out from under 436 * us. 437 */ 438 439 void 440 uvm_vnp_setsize(struct vnode *vp, voff_t newsize) 441 { 442 struct uvm_object *uobj = &vp->v_uobj; 443 voff_t pgend = round_page(newsize); 444 UVMHIST_FUNC("uvm_vnp_setsize"); UVMHIST_CALLED(ubchist); 445 446 simple_lock(&uobj->vmobjlock); 447 UVMHIST_LOG(ubchist, "vp %p old 0x%x new 0x%x", 448 vp, vp->v_size, newsize, 0); 449 450 /* 451 * now check if the size has changed: if we shrink we had better 452 * toss some pages... 453 */ 454 455 if (vp->v_size > pgend && vp->v_size != VSIZENOTSET) { 456 (void) uvn_put(uobj, pgend, 0, PGO_FREE | PGO_SYNCIO); 457 } else { 458 simple_unlock(&uobj->vmobjlock); 459 } 460 vp->v_size = newsize; 461 } 462 463 /* 464 * uvm_vnp_zerorange: set a range of bytes in a file to zero. 465 */ 466 467 void 468 uvm_vnp_zerorange(struct vnode *vp, off_t off, size_t len) 469 { 470 void *win; 471 int flags; 472 473 /* 474 * XXXUBC invent kzero() and use it 475 */ 476 477 while (len) { 478 vsize_t bytelen = len; 479 480 win = ubc_alloc(&vp->v_uobj, off, &bytelen, UBC_WRITE); 481 memset(win, 0, bytelen); 482 flags = UBC_WANT_UNMAP(vp) ? UBC_UNMAP : 0; 483 ubc_release(win, flags); 484 485 off += bytelen; 486 len -= bytelen; 487 } 488 } 489