1 /* $NetBSD: uvm_vnode.c,v 1.89 2007/12/01 10:40:28 yamt 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 1.89 2007/12/01 10:40:28 yamt 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 #include <uvm/uvm_readahead.h> 76 77 /* 78 * functions 79 */ 80 81 static void uvn_detach(struct uvm_object *); 82 static int uvn_get(struct uvm_object *, voff_t, struct vm_page **, int *, 83 int, vm_prot_t, int, int); 84 static int uvn_put(struct uvm_object *, voff_t, voff_t, int); 85 static void uvn_reference(struct uvm_object *); 86 87 static int uvn_findpage(struct uvm_object *, voff_t, struct vm_page **, 88 int); 89 90 /* 91 * master pager structure 92 */ 93 94 const struct uvm_pagerops uvm_vnodeops = { 95 .pgo_reference = uvn_reference, 96 .pgo_detach = uvn_detach, 97 .pgo_get = uvn_get, 98 .pgo_put = uvn_put, 99 }; 100 101 /* 102 * the ops! 103 */ 104 105 /* 106 * uvn_reference 107 * 108 * duplicate a reference to a VM object. Note that the reference 109 * count must already be at least one (the passed in reference) so 110 * there is no chance of the uvn being killed or locked out here. 111 * 112 * => caller must call with object unlocked. 113 * => caller must be using the same accessprot as was used at attach time 114 */ 115 116 static void 117 uvn_reference(struct uvm_object *uobj) 118 { 119 VREF((struct vnode *)uobj); 120 } 121 122 123 /* 124 * uvn_detach 125 * 126 * remove a reference to a VM object. 127 * 128 * => caller must call with object unlocked and map locked. 129 */ 130 131 static void 132 uvn_detach(struct uvm_object *uobj) 133 { 134 vrele((struct vnode *)uobj); 135 } 136 137 /* 138 * uvn_put: flush page data to backing store. 139 * 140 * => object must be locked on entry! VOP_PUTPAGES must unlock it. 141 * => flags: PGO_SYNCIO -- use sync. I/O 142 * => note: caller must set PG_CLEAN and pmap_clear_modify (if needed) 143 */ 144 145 static int 146 uvn_put(struct uvm_object *uobj, voff_t offlo, voff_t offhi, int flags) 147 { 148 struct vnode *vp = (struct vnode *)uobj; 149 int error; 150 151 LOCK_ASSERT(simple_lock_held(&vp->v_interlock)); 152 error = VOP_PUTPAGES(vp, offlo, offhi, flags); 153 return error; 154 } 155 156 157 /* 158 * uvn_get: get pages (synchronously) from backing store 159 * 160 * => prefer map unlocked (not required) 161 * => object must be locked! we will _unlock_ it before starting any I/O. 162 * => flags: PGO_ALLPAGES: get all of the pages 163 * PGO_LOCKED: fault data structures are locked 164 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 165 * => NOTE: caller must check for released pages!! 166 */ 167 168 static int 169 uvn_get(struct uvm_object *uobj, voff_t offset, 170 struct vm_page **pps /* IN/OUT */, 171 int *npagesp /* IN (OUT if PGO_LOCKED)*/, 172 int centeridx, vm_prot_t access_type, int advice, int flags) 173 { 174 struct vnode *vp = (struct vnode *)uobj; 175 int error; 176 177 UVMHIST_FUNC("uvn_get"); UVMHIST_CALLED(ubchist); 178 179 UVMHIST_LOG(ubchist, "vp %p off 0x%x", vp, (int)offset, 0,0); 180 181 if ((access_type & VM_PROT_WRITE) == 0 && (flags & PGO_LOCKED) == 0) { 182 simple_unlock(&vp->v_interlock); 183 vn_ra_allocctx(vp); 184 uvm_ra_request(vp->v_ractx, advice, uobj, offset, 185 *npagesp << PAGE_SHIFT); 186 simple_lock(&vp->v_interlock); 187 } 188 189 error = VOP_GETPAGES(vp, offset, pps, npagesp, centeridx, 190 access_type, advice, flags); 191 192 LOCK_ASSERT(((flags & PGO_LOCKED) != 0 && 193 simple_lock_held(&vp->v_interlock)) || 194 (flags & PGO_LOCKED) == 0); 195 return error; 196 } 197 198 199 /* 200 * uvn_findpages: 201 * return the page for the uobj and offset requested, allocating if needed. 202 * => uobj must be locked. 203 * => returned pages will be BUSY. 204 */ 205 206 int 207 uvn_findpages(struct uvm_object *uobj, voff_t offset, int *npagesp, 208 struct vm_page **pgs, int flags) 209 { 210 int i, count, found, npages, rv; 211 212 count = found = 0; 213 npages = *npagesp; 214 if (flags & UFP_BACKWARD) { 215 for (i = npages - 1; i >= 0; i--, offset -= PAGE_SIZE) { 216 rv = uvn_findpage(uobj, offset, &pgs[i], flags); 217 if (rv == 0) { 218 if (flags & UFP_DIRTYONLY) 219 break; 220 } else 221 found++; 222 count++; 223 } 224 } else { 225 for (i = 0; i < npages; i++, offset += PAGE_SIZE) { 226 rv = uvn_findpage(uobj, offset, &pgs[i], flags); 227 if (rv == 0) { 228 if (flags & UFP_DIRTYONLY) 229 break; 230 } else 231 found++; 232 count++; 233 } 234 } 235 *npagesp = count; 236 return (found); 237 } 238 239 static int 240 uvn_findpage(struct uvm_object *uobj, voff_t offset, struct vm_page **pgp, 241 int flags) 242 { 243 struct vm_page *pg; 244 bool dirty; 245 UVMHIST_FUNC("uvn_findpage"); UVMHIST_CALLED(ubchist); 246 UVMHIST_LOG(ubchist, "vp %p off 0x%lx", uobj, offset,0,0); 247 248 if (*pgp != NULL) { 249 UVMHIST_LOG(ubchist, "dontcare", 0,0,0,0); 250 return 0; 251 } 252 for (;;) { 253 /* look for an existing page */ 254 pg = uvm_pagelookup(uobj, offset); 255 256 /* nope? allocate one now */ 257 if (pg == NULL) { 258 if (flags & UFP_NOALLOC) { 259 UVMHIST_LOG(ubchist, "noalloc", 0,0,0,0); 260 return 0; 261 } 262 pg = uvm_pagealloc(uobj, offset, NULL, 0); 263 if (pg == NULL) { 264 if (flags & UFP_NOWAIT) { 265 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 266 return 0; 267 } 268 simple_unlock(&uobj->vmobjlock); 269 uvm_wait("uvn_fp1"); 270 simple_lock(&uobj->vmobjlock); 271 continue; 272 } 273 UVMHIST_LOG(ubchist, "alloced %p", pg,0,0,0); 274 break; 275 } else if (flags & UFP_NOCACHE) { 276 UVMHIST_LOG(ubchist, "nocache",0,0,0,0); 277 return 0; 278 } 279 280 /* page is there, see if we need to wait on it */ 281 if ((pg->flags & PG_BUSY) != 0) { 282 if (flags & UFP_NOWAIT) { 283 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 284 return 0; 285 } 286 pg->flags |= PG_WANTED; 287 UVMHIST_LOG(ubchist, "wait %p", pg,0,0,0); 288 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, 0, 289 "uvn_fp2", 0); 290 simple_lock(&uobj->vmobjlock); 291 continue; 292 } 293 294 /* skip PG_RDONLY pages if requested */ 295 if ((flags & UFP_NORDONLY) && (pg->flags & PG_RDONLY)) { 296 UVMHIST_LOG(ubchist, "nordonly",0,0,0,0); 297 return 0; 298 } 299 300 /* stop on clean pages if requested */ 301 if (flags & UFP_DIRTYONLY) { 302 dirty = pmap_clear_modify(pg) || 303 (pg->flags & PG_CLEAN) == 0; 304 pg->flags |= PG_CLEAN; 305 if (!dirty) { 306 UVMHIST_LOG(ubchist, "dirtonly", 0,0,0,0); 307 return 0; 308 } 309 } 310 311 /* mark the page BUSY and we're done. */ 312 pg->flags |= PG_BUSY; 313 UVM_PAGE_OWN(pg, "uvn_findpage"); 314 UVMHIST_LOG(ubchist, "found %p", pg,0,0,0); 315 break; 316 } 317 *pgp = pg; 318 return 1; 319 } 320 321 /* 322 * uvm_vnp_setsize: grow or shrink a vnode uobj 323 * 324 * grow => just update size value 325 * shrink => toss un-needed pages 326 * 327 * => we assume that the caller has a reference of some sort to the 328 * vnode in question so that it will not be yanked out from under 329 * us. 330 */ 331 332 void 333 uvm_vnp_setsize(struct vnode *vp, voff_t newsize) 334 { 335 struct uvm_object *uobj = &vp->v_uobj; 336 voff_t pgend = round_page(newsize); 337 voff_t oldsize; 338 UVMHIST_FUNC("uvm_vnp_setsize"); UVMHIST_CALLED(ubchist); 339 340 simple_lock(&uobj->vmobjlock); 341 UVMHIST_LOG(ubchist, "vp %p old 0x%x new 0x%x", 342 vp, vp->v_size, newsize, 0); 343 344 /* 345 * now check if the size has changed: if we shrink we had better 346 * toss some pages... 347 */ 348 349 KASSERT(newsize != VSIZENOTSET); 350 KASSERT(vp->v_size <= vp->v_writesize); 351 KASSERT(vp->v_size == vp->v_writesize || 352 newsize == vp->v_writesize || newsize <= vp->v_size); 353 354 oldsize = vp->v_writesize; 355 KASSERT(oldsize != VSIZENOTSET || pgend > oldsize); 356 357 if (oldsize > pgend) { 358 (void) uvn_put(uobj, pgend, 0, PGO_FREE | PGO_SYNCIO); 359 simple_lock(&uobj->vmobjlock); 360 } 361 vp->v_size = vp->v_writesize = newsize; 362 simple_unlock(&uobj->vmobjlock); 363 } 364 365 void 366 uvm_vnp_setwritesize(struct vnode *vp, voff_t newsize) 367 { 368 369 simple_lock(&vp->v_interlock); 370 KASSERT(newsize != VSIZENOTSET); 371 KASSERT(vp->v_size != VSIZENOTSET); 372 KASSERT(vp->v_writesize != VSIZENOTSET); 373 KASSERT(vp->v_size <= vp->v_writesize); 374 KASSERT(vp->v_size <= newsize); 375 vp->v_writesize = newsize; 376 simple_unlock(&vp->v_interlock); 377 } 378 379 /* 380 * uvm_vnp_zerorange: set a range of bytes in a file to zero. 381 */ 382 383 void 384 uvm_vnp_zerorange(struct vnode *vp, off_t off, size_t len) 385 { 386 void *win; 387 int flags; 388 389 /* 390 * XXXUBC invent kzero() and use it 391 */ 392 393 while (len) { 394 vsize_t bytelen = len; 395 396 win = ubc_alloc(&vp->v_uobj, off, &bytelen, UVM_ADV_NORMAL, 397 UBC_WRITE); 398 memset(win, 0, bytelen); 399 flags = UBC_WANT_UNMAP(vp) ? UBC_UNMAP : 0; 400 ubc_release(win, flags); 401 402 off += bytelen; 403 len -= bytelen; 404 } 405 } 406 407 bool 408 uvn_text_p(struct uvm_object *uobj) 409 { 410 struct vnode *vp = (struct vnode *)uobj; 411 412 return (vp->v_iflag & VI_EXECMAP) != 0; 413 } 414 415 bool 416 uvn_clean_p(struct uvm_object *uobj) 417 { 418 struct vnode *vp = (struct vnode *)uobj; 419 420 return (vp->v_iflag & VI_ONWORKLST) == 0; 421 } 422 423 bool 424 uvn_needs_writefault_p(struct uvm_object *uobj) 425 { 426 struct vnode *vp = (struct vnode *)uobj; 427 428 return uvn_clean_p(uobj) || 429 (vp->v_iflag & (VI_WRMAP|VI_WRMAPDIRTY)) == VI_WRMAP; 430 } 431