vnd.c revision 1.36
1 /* $NetBSD: vnd.c,v 1.36 1997/05/25 19:37:36 pk Exp $ */ 2 3 /* 4 * Copyright (c) 1988 University of Utah. 5 * Copyright (c) 1990, 1993 6 * The Regents of the University of California. All rights reserved. 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: Utah $Hdr: vn.c 1.13 94/04/02$ 41 * 42 * @(#)vn.c 8.6 (Berkeley) 4/1/94 43 */ 44 45 /* 46 * Vnode disk driver. 47 * 48 * Block/character interface to a vnode. Allows one to treat a file 49 * as a disk (e.g. build a filesystem in it, mount it, etc.). 50 * 51 * NOTE 1: This uses the VOP_BMAP/VOP_STRATEGY interface to the vnode 52 * instead of a simple VOP_RDWR. We do this to avoid distorting the 53 * local buffer cache. 54 * 55 * NOTE 2: There is a security issue involved with this driver. 56 * Once mounted all access to the contents of the "mapped" file via 57 * the special file is controlled by the permissions on the special 58 * file, the protection of the mapped file is ignored (effectively, 59 * by using root credentials in all transactions). 60 * 61 * NOTE 3: Doesn't interact with leases, should it? 62 */ 63 64 #include <sys/param.h> 65 #include <sys/systm.h> 66 #include <sys/namei.h> 67 #include <sys/proc.h> 68 #include <sys/errno.h> 69 #include <sys/buf.h> 70 #include <sys/malloc.h> 71 #include <sys/ioctl.h> 72 #include <sys/disklabel.h> 73 #include <sys/device.h> 74 #include <sys/disk.h> 75 #include <sys/stat.h> 76 #include <sys/mount.h> 77 #include <sys/vnode.h> 78 #include <sys/file.h> 79 #include <sys/uio.h> 80 #include <sys/conf.h> 81 82 #include <miscfs/specfs/specdev.h> 83 84 #include <dev/vndioctl.h> 85 86 #ifdef DEBUG 87 int dovndcluster = 1; 88 int vnddebug = 0x00; 89 #define VDB_FOLLOW 0x01 90 #define VDB_INIT 0x02 91 #define VDB_IO 0x04 92 #endif 93 94 #define b_cylin b_resid 95 96 #define vndunit(x) DISKUNIT(x) 97 98 struct vndxfer { 99 struct buf *vx_bp; /* Pointer to parent buffer */ 100 int vx_error; 101 int vx_pending; /* # of pending aux buffers */ 102 }; 103 104 struct vndbuf { 105 struct buf vb_buf; 106 struct vndxfer *vb_xfer; 107 }; 108 109 #define getvndxfer() \ 110 ((struct vndxfer *)malloc(sizeof(struct vndxfer), M_DEVBUF, M_WAITOK)) 111 #define putvndxfer(vnx) \ 112 free((caddr_t)(vnx), M_DEVBUF) 113 #define getvndbuf() \ 114 ((struct vndbuf *)malloc(sizeof(struct vndbuf), M_DEVBUF, M_WAITOK)) 115 #define putvndbuf(vbp) \ 116 free((caddr_t)(vbp), M_DEVBUF) 117 118 struct vnd_softc { 119 int sc_flags; /* flags */ 120 size_t sc_size; /* size of vnd */ 121 struct vnode *sc_vp; /* vnode */ 122 struct ucred *sc_cred; /* credentials */ 123 int sc_maxactive; /* max # of active requests */ 124 struct buf sc_tab; /* transfer queue */ 125 char sc_xname[8]; /* XXX external name */ 126 struct disk sc_dkdev; /* generic disk device info */ 127 }; 128 129 /* sc_flags */ 130 #define VNF_ALIVE 0x01 131 #define VNF_INITED 0x02 132 #define VNF_WANTED 0x40 133 #define VNF_LOCKED 0x80 134 135 struct vnd_softc *vnd_softc; 136 int numvnd = 0; 137 138 /* called by main() at boot time */ 139 void vndattach __P((int)); 140 141 void vndclear __P((struct vnd_softc *)); 142 void vndstart __P((struct vnd_softc *)); 143 int vndsetcred __P((struct vnd_softc *, struct ucred *)); 144 void vndthrottle __P((struct vnd_softc *, struct vnode *)); 145 void vndiodone __P((struct buf *)); 146 void vndshutdown __P((void)); 147 148 static int vndlock __P((struct vnd_softc *)); 149 static void vndunlock __P((struct vnd_softc *)); 150 151 void 152 vndattach(num) 153 int num; 154 { 155 char *mem; 156 register u_long size; 157 158 if (num <= 0) 159 return; 160 size = num * sizeof(struct vnd_softc); 161 mem = malloc(size, M_DEVBUF, M_NOWAIT); 162 if (mem == NULL) { 163 printf("WARNING: no memory for vnode disks\n"); 164 return; 165 } 166 bzero(mem, size); 167 vnd_softc = (struct vnd_softc *)mem; 168 numvnd = num; 169 } 170 171 int 172 vndopen(dev, flags, mode, p) 173 dev_t dev; 174 int flags, mode; 175 struct proc *p; 176 { 177 int unit = vndunit(dev); 178 struct vnd_softc *sc; 179 int error = 0, part, pmask; 180 181 /* 182 * XXX Should support disklabels. 183 */ 184 185 #ifdef DEBUG 186 if (vnddebug & VDB_FOLLOW) 187 printf("vndopen(%x, %x, %x, %p)\n", dev, flags, mode, p); 188 #endif 189 if (unit >= numvnd) 190 return (ENXIO); 191 sc = &vnd_softc[unit]; 192 193 if ((error = vndlock(sc)) != 0) 194 return (error); 195 196 part = DISKPART(dev); 197 pmask = (1 << part); 198 199 /* Prevent our unit from being unconfigured while open. */ 200 switch (mode) { 201 case S_IFCHR: 202 sc->sc_dkdev.dk_copenmask |= pmask; 203 break; 204 205 case S_IFBLK: 206 sc->sc_dkdev.dk_bopenmask |= pmask; 207 break; 208 } 209 sc->sc_dkdev.dk_openmask = 210 sc->sc_dkdev.dk_copenmask | sc->sc_dkdev.dk_bopenmask; 211 212 vndunlock(sc); 213 return (0); 214 } 215 216 int 217 vndclose(dev, flags, mode, p) 218 dev_t dev; 219 int flags, mode; 220 struct proc *p; 221 { 222 int unit = vndunit(dev); 223 struct vnd_softc *sc; 224 int error = 0, part; 225 226 #ifdef DEBUG 227 if (vnddebug & VDB_FOLLOW) 228 printf("vndclose(%x, %x, %x, %p)\n", dev, flags, mode, p); 229 #endif 230 231 if (unit >= numvnd) 232 return (ENXIO); 233 sc = &vnd_softc[unit]; 234 235 if ((error = vndlock(sc)) != 0) 236 return (error); 237 238 part = DISKPART(dev); 239 240 /* ...that much closer to allowing unconfiguration... */ 241 switch (mode) { 242 case S_IFCHR: 243 sc->sc_dkdev.dk_copenmask &= ~(1 << part); 244 break; 245 246 case S_IFBLK: 247 sc->sc_dkdev.dk_bopenmask &= ~(1 << part); 248 break; 249 } 250 sc->sc_dkdev.dk_openmask = 251 sc->sc_dkdev.dk_copenmask | sc->sc_dkdev.dk_bopenmask; 252 253 vndunlock(sc); 254 return (0); 255 } 256 257 /* 258 * Break the request into bsize pieces and submit using VOP_BMAP/VOP_STRATEGY. 259 * Note that this driver can only be used for swapping over NFS on the hp 260 * since nfs_strategy on the vax cannot handle u-areas and page tables. 261 */ 262 void 263 vndstrategy(bp) 264 register struct buf *bp; 265 { 266 int unit = vndunit(bp->b_dev); 267 register struct vnd_softc *vnd = &vnd_softc[unit]; 268 register struct vndbuf *nbp; 269 struct vndxfer *vnx; 270 register int bn, bsize, resid; 271 register caddr_t addr; 272 int sz, flags, error; 273 274 #ifdef DEBUG 275 if (vnddebug & VDB_FOLLOW) 276 printf("vndstrategy(%p): unit %d\n", bp, unit); 277 #endif 278 if ((vnd->sc_flags & VNF_INITED) == 0) { 279 bp->b_error = ENXIO; 280 bp->b_flags |= B_ERROR; 281 biodone(bp); 282 return; 283 } 284 bn = bp->b_blkno; 285 sz = howmany(bp->b_bcount, DEV_BSIZE); 286 bp->b_resid = bp->b_bcount; 287 if (bn < 0 || bn + sz > vnd->sc_size) { 288 if (bn != vnd->sc_size) { 289 bp->b_error = EINVAL; 290 bp->b_flags |= B_ERROR; 291 } 292 biodone(bp); 293 return; 294 } 295 bn = dbtob(bn); 296 bsize = vnd->sc_vp->v_mount->mnt_stat.f_iosize; 297 addr = bp->b_data; 298 flags = bp->b_flags | B_CALL; 299 300 /* Allocate a header for this transfer and link it to the buffer */ 301 vnx = getvndxfer(); 302 vnx->vx_error = 0; 303 vnx->vx_pending = 0; 304 vnx->vx_bp = bp; 305 306 for (resid = bp->b_resid; resid; resid -= sz) { 307 struct vnode *vp; 308 daddr_t nbn; 309 int off, s, nra; 310 311 nra = 0; 312 VOP_LOCK(vnd->sc_vp); 313 error = VOP_BMAP(vnd->sc_vp, bn / bsize, &vp, &nbn, &nra); 314 VOP_UNLOCK(vnd->sc_vp); 315 if (error == 0 && (long)nbn == -1) 316 error = EIO; 317 318 /* 319 * If there was an error or a hole in the file...punt. 320 * Note that we may have to wait for any operations 321 * that we have already fired off before releasing 322 * the buffer. 323 * 324 * XXX we could deal with holes here but it would be 325 * a hassle (in the write case). 326 */ 327 if (error) { 328 vnx->vx_error = error; 329 if (vnx->vx_pending == 0) { 330 bp->b_error = error; 331 bp->b_flags |= B_ERROR; 332 putvndxfer(vnx); 333 biodone(bp); 334 } 335 return; 336 } 337 338 #ifdef DEBUG 339 if (!dovndcluster) 340 nra = 0; 341 #endif 342 343 if ((off = bn % bsize) != 0) 344 sz = bsize - off; 345 else 346 sz = (1 + nra) * bsize; 347 if (resid < sz) 348 sz = resid; 349 #ifdef DEBUG 350 if (vnddebug & VDB_IO) 351 printf("vndstrategy: vp %p/%p bn %x/%x sz %x\n", 352 vnd->sc_vp, vp, bn, nbn, sz); 353 #endif 354 355 nbp = getvndbuf(); 356 nbp->vb_buf.b_flags = flags; 357 nbp->vb_buf.b_bcount = sz; 358 nbp->vb_buf.b_bufsize = bp->b_bufsize; 359 nbp->vb_buf.b_error = 0; 360 if (vp->v_type == VBLK || vp->v_type == VCHR) 361 nbp->vb_buf.b_dev = vp->v_rdev; 362 else 363 nbp->vb_buf.b_dev = NODEV; 364 nbp->vb_buf.b_data = addr; 365 nbp->vb_buf.b_blkno = nbn + btodb(off); 366 nbp->vb_buf.b_proc = bp->b_proc; 367 nbp->vb_buf.b_iodone = vndiodone; 368 nbp->vb_buf.b_vp = vp; 369 nbp->vb_buf.b_rcred = vnd->sc_cred; /* XXX crdup? */ 370 nbp->vb_buf.b_wcred = vnd->sc_cred; /* XXX crdup? */ 371 if (bp->b_dirtyend == 0) { 372 nbp->vb_buf.b_dirtyoff = 0; 373 nbp->vb_buf.b_dirtyend = sz; 374 } else { 375 nbp->vb_buf.b_dirtyoff = 376 max(0, bp->b_dirtyoff - (bp->b_bcount - resid)); 377 nbp->vb_buf.b_dirtyend = 378 min(sz, 379 max(0, bp->b_dirtyend - (bp->b_bcount-resid))); 380 } 381 if (bp->b_validend == 0) { 382 nbp->vb_buf.b_validoff = 0; 383 nbp->vb_buf.b_validend = sz; 384 } else { 385 nbp->vb_buf.b_validoff = 386 max(0, bp->b_validoff - (bp->b_bcount - resid)); 387 nbp->vb_buf.b_validend = 388 min(sz, 389 max(0, bp->b_validend - (bp->b_bcount-resid))); 390 } 391 392 nbp->vb_xfer = vnx; 393 vnx->vx_pending++; 394 395 /* 396 * Just sort by block number 397 */ 398 nbp->vb_buf.b_cylin = nbp->vb_buf.b_blkno; 399 s = splbio(); 400 disksort(&vnd->sc_tab, &nbp->vb_buf); 401 if (vnd->sc_tab.b_active < vnd->sc_maxactive) { 402 vnd->sc_tab.b_active++; 403 vndstart(vnd); 404 } 405 splx(s); 406 bn += sz; 407 addr += sz; 408 } 409 } 410 411 /* 412 * Feed requests sequentially. 413 * We do it this way to keep from flooding NFS servers if we are connected 414 * to an NFS file. This places the burden on the client rather than the 415 * server. 416 */ 417 void 418 vndstart(vnd) 419 register struct vnd_softc *vnd; 420 { 421 register struct buf *bp; 422 423 /* 424 * Dequeue now since lower level strategy routine might 425 * queue using same links 426 */ 427 bp = vnd->sc_tab.b_actf; 428 vnd->sc_tab.b_actf = bp->b_actf; 429 #ifdef DEBUG 430 if (vnddebug & VDB_IO) 431 printf("vndstart(%ld): bp %p vp %p blkno %x addr %p cnt %lx\n", 432 (long) (vnd-vnd_softc), bp, bp->b_vp, bp->b_blkno, 433 bp->b_data, bp->b_bcount); 434 #endif 435 436 /* Instrumentation. */ 437 disk_busy(&vnd->sc_dkdev); 438 439 if ((bp->b_flags & B_READ) == 0) 440 bp->b_vp->v_numoutput++; 441 VOP_STRATEGY(bp); 442 } 443 444 void 445 vndiodone(bp) 446 struct buf *bp; 447 { 448 register struct vndbuf *vbp = (struct vndbuf *) bp; 449 register struct vndxfer *vnx = (struct vndxfer *)vbp->vb_xfer; 450 register struct buf *pbp = vnx->vx_bp; 451 register struct vnd_softc *vnd = &vnd_softc[vndunit(pbp->b_dev)]; 452 int s, resid; 453 454 s = splbio(); 455 #ifdef DEBUG 456 if (vnddebug & VDB_IO) 457 printf("vndiodone(%ld): vbp %p vp %p blkno %x addr %p cnt %lx\n", 458 (long) (vnd-vnd_softc), vbp, vbp->vb_buf.b_vp, 459 vbp->vb_buf.b_blkno, vbp->vb_buf.b_data, 460 vbp->vb_buf.b_bcount); 461 #endif 462 463 resid = vbp->vb_buf.b_bcount - vbp->vb_buf.b_resid; 464 pbp->b_resid -= resid; 465 disk_unbusy(&vnd->sc_dkdev, resid); 466 vnx->vx_pending--; 467 468 if (vbp->vb_buf.b_error) { 469 #ifdef DEBUG 470 if (vnddebug & VDB_IO) 471 printf("vndiodone: vbp %p error %d\n", vbp, 472 vbp->vb_buf.b_error); 473 #endif 474 vnx->vx_error = vbp->vb_buf.b_error; 475 } 476 putvndbuf(vbp); 477 478 /* 479 * Wrap up this transaction if it has run to completion or, in 480 * case of an error, when all auxiliary buffers have returned. 481 */ 482 if (pbp->b_resid == 0 || (vnx->vx_error && vnx->vx_pending == 0)) { 483 484 if (vnx->vx_error != 0) { 485 pbp->b_flags |= B_ERROR; 486 pbp->b_error = vnx->vx_error; 487 } 488 putvndxfer(vnx); 489 #ifdef DEBUG 490 if (vnddebug & VDB_IO) 491 printf("vndiodone: pbp %p iodone\n", pbp); 492 #endif 493 biodone(pbp); 494 } 495 496 if (vnd->sc_tab.b_actf) 497 vndstart(vnd); 498 else 499 vnd->sc_tab.b_active--; 500 splx(s); 501 } 502 503 /* ARGSUSED */ 504 int 505 vndread(dev, uio, flags) 506 dev_t dev; 507 struct uio *uio; 508 int flags; 509 { 510 int unit = vndunit(dev); 511 struct vnd_softc *sc; 512 513 #ifdef DEBUG 514 if (vnddebug & VDB_FOLLOW) 515 printf("vndread(%x, %p)\n", dev, uio); 516 #endif 517 518 if (unit >= numvnd) 519 return (ENXIO); 520 sc = &vnd_softc[unit]; 521 522 if ((sc->sc_flags & VNF_INITED) == 0) 523 return (ENXIO); 524 525 return (physio(vndstrategy, NULL, dev, B_READ, minphys, uio)); 526 } 527 528 /* ARGSUSED */ 529 int 530 vndwrite(dev, uio, flags) 531 dev_t dev; 532 struct uio *uio; 533 int flags; 534 { 535 int unit = vndunit(dev); 536 struct vnd_softc *sc; 537 538 #ifdef DEBUG 539 if (vnddebug & VDB_FOLLOW) 540 printf("vndwrite(%x, %p)\n", dev, uio); 541 #endif 542 543 if (unit >= numvnd) 544 return (ENXIO); 545 sc = &vnd_softc[unit]; 546 547 if ((sc->sc_flags & VNF_INITED) == 0) 548 return (ENXIO); 549 550 return (physio(vndstrategy, NULL, dev, B_WRITE, minphys, uio)); 551 } 552 553 /* ARGSUSED */ 554 int 555 vndioctl(dev, cmd, data, flag, p) 556 dev_t dev; 557 u_long cmd; 558 caddr_t data; 559 int flag; 560 struct proc *p; 561 { 562 int unit = vndunit(dev); 563 register struct vnd_softc *vnd; 564 struct vnd_ioctl *vio; 565 struct vattr vattr; 566 struct nameidata nd; 567 int error, part, pmask; 568 569 #ifdef DEBUG 570 if (vnddebug & VDB_FOLLOW) 571 printf("vndioctl(%x, %lx, %p, %x, %p): unit %d\n", 572 dev, cmd, data, flag, p, unit); 573 #endif 574 error = suser(p->p_ucred, &p->p_acflag); 575 if (error) 576 return (error); 577 if (unit >= numvnd) 578 return (ENXIO); 579 580 vnd = &vnd_softc[unit]; 581 vio = (struct vnd_ioctl *)data; 582 switch (cmd) { 583 584 case VNDIOCSET: 585 if (vnd->sc_flags & VNF_INITED) 586 return (EBUSY); 587 588 if ((error = vndlock(vnd)) != 0) 589 return (error); 590 591 /* 592 * Always open for read and write. 593 * This is probably bogus, but it lets vn_open() 594 * weed out directories, sockets, etc. so we don't 595 * have to worry about them. 596 */ 597 NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, vio->vnd_file, p); 598 if ((error = vn_open(&nd, FREAD|FWRITE, 0)) != 0) { 599 vndunlock(vnd); 600 return(error); 601 } 602 error = VOP_GETATTR(nd.ni_vp, &vattr, p->p_ucred, p); 603 if (error) { 604 VOP_UNLOCK(nd.ni_vp); 605 (void) vn_close(nd.ni_vp, FREAD|FWRITE, p->p_ucred, p); 606 vndunlock(vnd); 607 return(error); 608 } 609 VOP_UNLOCK(nd.ni_vp); 610 vnd->sc_vp = nd.ni_vp; 611 vnd->sc_size = btodb(vattr.va_size); /* note truncation */ 612 if ((error = vndsetcred(vnd, p->p_ucred)) != 0) { 613 (void) vn_close(nd.ni_vp, FREAD|FWRITE, p->p_ucred, p); 614 vndunlock(vnd); 615 return(error); 616 } 617 vndthrottle(vnd, vnd->sc_vp); 618 vio->vnd_size = dbtob(vnd->sc_size); 619 vnd->sc_flags |= VNF_INITED; 620 #ifdef DEBUG 621 if (vnddebug & VDB_INIT) 622 printf("vndioctl: SET vp %p size %lx\n", 623 vnd->sc_vp, (unsigned long) vnd->sc_size); 624 #endif 625 626 /* Attach the disk. */ 627 bzero(vnd->sc_xname, sizeof(vnd->sc_xname)); /* XXX */ 628 sprintf(vnd->sc_xname, "vnd%d", unit); /* XXX */ 629 vnd->sc_dkdev.dk_name = vnd->sc_xname; 630 disk_attach(&vnd->sc_dkdev); 631 632 vndunlock(vnd); 633 634 break; 635 636 case VNDIOCCLR: 637 if ((vnd->sc_flags & VNF_INITED) == 0) 638 return (ENXIO); 639 640 if ((error = vndlock(vnd)) != 0) 641 return (error); 642 643 /* 644 * Don't unconfigure if any other partitions are open 645 * or if both the character and block flavors of this 646 * partition are open. 647 */ 648 part = DISKPART(dev); 649 pmask = (1 << part); 650 if ((vnd->sc_dkdev.dk_openmask & ~pmask) || 651 ((vnd->sc_dkdev.dk_bopenmask & pmask) && 652 (vnd->sc_dkdev.dk_copenmask & pmask))) { 653 vndunlock(vnd); 654 return (EBUSY); 655 } 656 657 vndclear(vnd); 658 #ifdef DEBUG 659 if (vnddebug & VDB_INIT) 660 printf("vndioctl: CLRed\n"); 661 #endif 662 663 /* Detatch the disk. */ 664 disk_detach(&vnd->sc_dkdev); 665 666 vndunlock(vnd); 667 668 break; 669 670 /* 671 * XXX Should support disklabels. 672 */ 673 674 default: 675 return(ENOTTY); 676 } 677 678 return (0); 679 } 680 681 /* 682 * Duplicate the current processes' credentials. Since we are called only 683 * as the result of a SET ioctl and only root can do that, any future access 684 * to this "disk" is essentially as root. Note that credentials may change 685 * if some other uid can write directly to the mapped file (NFS). 686 */ 687 int 688 vndsetcred(vnd, cred) 689 register struct vnd_softc *vnd; 690 struct ucred *cred; 691 { 692 struct uio auio; 693 struct iovec aiov; 694 char *tmpbuf; 695 int error; 696 697 vnd->sc_cred = crdup(cred); 698 tmpbuf = malloc(DEV_BSIZE, M_TEMP, M_WAITOK); 699 700 /* XXX: Horrible kludge to establish credentials for NFS */ 701 aiov.iov_base = tmpbuf; 702 aiov.iov_len = min(DEV_BSIZE, dbtob(vnd->sc_size)); 703 auio.uio_iov = &aiov; 704 auio.uio_iovcnt = 1; 705 auio.uio_offset = 0; 706 auio.uio_rw = UIO_READ; 707 auio.uio_segflg = UIO_SYSSPACE; 708 auio.uio_resid = aiov.iov_len; 709 VOP_LOCK(vnd->sc_vp); 710 error = VOP_READ(vnd->sc_vp, &auio, 0, vnd->sc_cred); 711 VOP_UNLOCK(vnd->sc_vp); 712 713 free(tmpbuf, M_TEMP); 714 return (error); 715 } 716 717 /* 718 * Set maxactive based on FS type 719 */ 720 void 721 vndthrottle(vnd, vp) 722 register struct vnd_softc *vnd; 723 struct vnode *vp; 724 { 725 #ifdef NFS 726 extern int (**nfsv2_vnodeop_p) __P((void *)); 727 728 if (vp->v_op == nfsv2_vnodeop_p) 729 vnd->sc_maxactive = 2; 730 else 731 #endif 732 vnd->sc_maxactive = 8; 733 734 if (vnd->sc_maxactive < 1) 735 vnd->sc_maxactive = 1; 736 } 737 738 void 739 vndshutdown() 740 { 741 register struct vnd_softc *vnd; 742 743 for (vnd = &vnd_softc[0]; vnd < &vnd_softc[numvnd]; vnd++) 744 if (vnd->sc_flags & VNF_INITED) 745 vndclear(vnd); 746 } 747 748 void 749 vndclear(vnd) 750 register struct vnd_softc *vnd; 751 { 752 register struct vnode *vp = vnd->sc_vp; 753 struct proc *p = curproc; /* XXX */ 754 755 #ifdef DEBUG 756 if (vnddebug & VDB_FOLLOW) 757 printf("vndclear(%p): vp %p\n", vnd, vp); 758 #endif 759 vnd->sc_flags &= ~VNF_INITED; 760 if (vp == (struct vnode *)0) 761 panic("vndioctl: null vp"); 762 (void) vn_close(vp, FREAD|FWRITE, vnd->sc_cred, p); 763 crfree(vnd->sc_cred); 764 vnd->sc_vp = (struct vnode *)0; 765 vnd->sc_cred = (struct ucred *)0; 766 vnd->sc_size = 0; 767 } 768 769 int 770 vndsize(dev) 771 dev_t dev; 772 { 773 int unit = vndunit(dev); 774 register struct vnd_softc *vnd = &vnd_softc[unit]; 775 776 if (unit >= numvnd || (vnd->sc_flags & VNF_INITED) == 0) 777 return(-1); 778 return(vnd->sc_size); 779 } 780 781 int 782 vnddump(dev, blkno, va, size) 783 dev_t dev; 784 daddr_t blkno; 785 caddr_t va; 786 size_t size; 787 { 788 789 /* Not implemented. */ 790 return ENXIO; 791 } 792 793 /* 794 * Wait interruptibly for an exclusive lock. 795 * 796 * XXX 797 * Several drivers do this; it should be abstracted and made MP-safe. 798 */ 799 static int 800 vndlock(sc) 801 struct vnd_softc *sc; 802 { 803 int error; 804 805 while ((sc->sc_flags & VNF_LOCKED) != 0) { 806 sc->sc_flags |= VNF_WANTED; 807 if ((error = tsleep(sc, PRIBIO | PCATCH, "vndlck", 0)) != 0) 808 return (error); 809 } 810 sc->sc_flags |= VNF_LOCKED; 811 return (0); 812 } 813 814 /* 815 * Unlock and wake up any waiters. 816 */ 817 static void 818 vndunlock(sc) 819 struct vnd_softc *sc; 820 { 821 822 sc->sc_flags &= ~VNF_LOCKED; 823 if ((sc->sc_flags & VNF_WANTED) != 0) { 824 sc->sc_flags &= ~VNF_WANTED; 825 wakeup(sc); 826 } 827 } 828
Indexes created Mon Sep 29 21:09:56 GMT 2025