1 /* vfs_cluster.c 4.11 02/15/81 */ 2 3 #include "../h/param.h" 4 #include "../h/systm.h" 5 #include "../h/dir.h" 6 #include "../h/user.h" 7 #include "../h/buf.h" 8 #include "../h/conf.h" 9 #include "../h/proc.h" 10 #include "../h/seg.h" 11 #include "../h/pte.h" 12 #include "../h/vm.h" 13 #include "../h/trace.h" 14 15 /* 16 * The following several routines allocate and free 17 * buffers with various side effects. In general the 18 * arguments to an allocate routine are a device and 19 * a block number, and the value is a pointer to 20 * to the buffer header; the buffer is marked "busy" 21 * so that no one else can touch it. If the block was 22 * already in core, no I/O need be done; if it is 23 * already busy, the process waits until it becomes free. 24 * The following routines allocate a buffer: 25 * getblk 26 * bread 27 * breada 28 * baddr (if it is incore) 29 * Eventually the buffer must be released, possibly with the 30 * side effect of writing it out, by using one of 31 * bwrite 32 * bdwrite 33 * bawrite 34 * brelse 35 */ 36 37 #define BUFHSZ 63 38 struct bufhd bufhash[BUFHSZ]; 39 #define BUFHASH(dev, dblkno) \ 40 ((struct buf *)&bufhash[((int)(dev)+(int)(dblkno)) % BUFHSZ]) 41 42 /* 43 * Initialize hash links for buffers. 44 */ 45 bhinit() 46 { 47 register int i; 48 register struct bufhd *bp; 49 50 for (bp = bufhash, i = 0; i < BUFHSZ; i++, bp++) 51 bp->b_forw = bp->b_back = (struct buf *)bp; 52 } 53 54 /* #define DISKMON 1 */ 55 56 #ifdef DISKMON 57 struct { 58 int nbuf; 59 long nread; 60 long nreada; 61 long ncache; 62 long nwrite; 63 long bufcount[NBUF]; 64 } io_info; 65 #endif 66 67 /* 68 * Swap IO headers - 69 * They contain the necessary information for the swap I/O. 70 * At any given time, a swap header can be in three 71 * different lists. When free it is in the free list, 72 * when allocated and the I/O queued, it is on the swap 73 * device list, and finally, if the operation was a dirty 74 * page push, when the I/O completes, it is inserted 75 * in a list of cleaned pages to be processed by the pageout daemon. 76 */ 77 struct buf swbuf[NSWBUF]; 78 short swsize[NSWBUF]; /* CAN WE JUST USE B_BCOUNT? */ 79 int swpf[NSWBUF]; 80 81 82 #ifdef FASTVAX 83 #define notavail(bp) \ 84 { \ 85 int s = spl6(); \ 86 (bp)->av_back->av_forw = (bp)->av_forw; \ 87 (bp)->av_forw->av_back = (bp)->av_back; \ 88 (bp)->b_flags |= B_BUSY; \ 89 splx(s); \ 90 } 91 #endif 92 93 /* 94 * Read in (if necessary) the block and return a buffer pointer. 95 */ 96 struct buf * 97 bread(dev, blkno) 98 dev_t dev; 99 daddr_t blkno; 100 { 101 register struct buf *bp; 102 103 bp = getblk(dev, blkno); 104 if (bp->b_flags&B_DONE) { 105 #ifdef EPAWNJ 106 trace(TR_BREAD|TR_HIT, dev, blkno); 107 #endif 108 #ifdef DISKMON 109 io_info.ncache++; 110 #endif 111 return(bp); 112 } 113 bp->b_flags |= B_READ; 114 bp->b_bcount = BSIZE; 115 (*bdevsw[major(dev)].d_strategy)(bp); 116 #ifdef EPAWNJ 117 trace(TR_BREAD|TR_MISS, dev, blkno); 118 #endif 119 #ifdef DISKMON 120 io_info.nread++; 121 #endif 122 u.u_vm.vm_inblk++; /* pay for read */ 123 iowait(bp); 124 return(bp); 125 } 126 127 /* 128 * Read in the block, like bread, but also start I/O on the 129 * read-ahead block (which is not allocated to the caller) 130 */ 131 struct buf * 132 breada(dev, blkno, rablkno) 133 dev_t dev; 134 daddr_t blkno, rablkno; 135 { 136 register struct buf *bp, *rabp; 137 138 bp = NULL; 139 if (!incore(dev, blkno)) { 140 bp = getblk(dev, blkno); 141 if ((bp->b_flags&B_DONE) == 0) { 142 bp->b_flags |= B_READ; 143 bp->b_bcount = BSIZE; 144 (*bdevsw[major(dev)].d_strategy)(bp); 145 #ifdef EPAWNJ 146 trace(TR_BREAD|TR_MISS, dev, blkno); 147 #endif 148 #ifdef DISKMON 149 io_info.nread++; 150 #endif 151 u.u_vm.vm_inblk++; /* pay for read */ 152 } 153 #ifdef EPAWNJ 154 else 155 trace(TR_BREAD|TR_HIT, dev, blkno); 156 #endif 157 } 158 if (rablkno && !incore(dev, rablkno)) { 159 rabp = getblk(dev, rablkno); 160 if (rabp->b_flags & B_DONE) { 161 brelse(rabp); 162 #ifdef EPAWNJ 163 trace(TR_BREAD|TR_HIT|TR_RA, dev, blkno); 164 #endif 165 } else { 166 rabp->b_flags |= B_READ|B_ASYNC; 167 rabp->b_bcount = BSIZE; 168 (*bdevsw[major(dev)].d_strategy)(rabp); 169 #ifdef EPAWNJ 170 trace(TR_BREAD|TR_MISS|TR_RA, dev, rablock); 171 #endif 172 #ifdef DISKMON 173 io_info.nreada++; 174 #endif 175 u.u_vm.vm_inblk++; /* pay in advance */ 176 } 177 } 178 if(bp == NULL) 179 return(bread(dev, blkno)); 180 iowait(bp); 181 return(bp); 182 } 183 184 /* 185 * Write the buffer, waiting for completion. 186 * Then release the buffer. 187 */ 188 bwrite(bp) 189 register struct buf *bp; 190 { 191 register flag; 192 193 flag = bp->b_flags; 194 bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI | B_AGE); 195 bp->b_bcount = BSIZE; 196 #ifdef DISKMON 197 io_info.nwrite++; 198 #endif 199 if ((flag&B_DELWRI) == 0) 200 u.u_vm.vm_oublk++; /* noone paid yet */ 201 #ifdef EPAWNJ 202 trace(TR_BWRITE, bp->b_dev, dbtofsb(bp->b_blkno)); 203 #endif 204 (*bdevsw[major(bp->b_dev)].d_strategy)(bp); 205 if ((flag&B_ASYNC) == 0) { 206 iowait(bp); 207 brelse(bp); 208 } else if (flag & B_DELWRI) 209 bp->b_flags |= B_AGE; 210 else 211 geterror(bp); 212 } 213 214 /* 215 * Release the buffer, marking it so that if it is grabbed 216 * for another purpose it will be written out before being 217 * given up (e.g. when writing a partial block where it is 218 * assumed that another write for the same block will soon follow). 219 * This can't be done for magtape, since writes must be done 220 * in the same order as requested. 221 */ 222 bdwrite(bp) 223 register struct buf *bp; 224 { 225 register int flags; 226 227 if ((bp->b_flags&B_DELWRI) == 0) 228 u.u_vm.vm_oublk++; /* noone paid yet */ 229 flags = bdevsw[major(bp->b_dev)].d_flags; 230 if(flags & B_TAPE) 231 bawrite(bp); 232 else { 233 bp->b_flags |= B_DELWRI | B_DONE; 234 brelse(bp); 235 } 236 } 237 238 /* 239 * Release the buffer, start I/O on it, but don't wait for completion. 240 */ 241 bawrite(bp) 242 register struct buf *bp; 243 { 244 245 bp->b_flags |= B_ASYNC; 246 bwrite(bp); 247 } 248 249 /* 250 * release the buffer, with no I/O implied. 251 */ 252 brelse(bp) 253 register struct buf *bp; 254 { 255 register struct buf *flist; 256 register s; 257 258 if (bp->b_flags&B_WANTED) 259 wakeup((caddr_t)bp); 260 if (bfreelist[0].b_flags&B_WANTED) { 261 bfreelist[0].b_flags &= ~B_WANTED; 262 wakeup((caddr_t)bfreelist); 263 } 264 if ((bp->b_flags&B_ERROR) && bp->b_dev != NODEV) 265 bp->b_dev = NODEV; /* no assoc. on error */ 266 s = spl6(); 267 if (bp->b_flags & (B_ERROR|B_INVAL)) { 268 /* block has no info ... put at front of most free list */ 269 flist = &bfreelist[BQUEUES-1]; 270 flist->av_forw->av_back = bp; 271 bp->av_forw = flist->av_forw; 272 flist->av_forw = bp; 273 bp->av_back = flist; 274 } else { 275 if (bp->b_flags & B_LOCKED) 276 flist = &bfreelist[BQ_LOCKED]; 277 else if (bp->b_flags & B_AGE) 278 flist = &bfreelist[BQ_AGE]; 279 else 280 flist = &bfreelist[BQ_LRU]; 281 flist->av_back->av_forw = bp; 282 bp->av_back = flist->av_back; 283 flist->av_back = bp; 284 bp->av_forw = flist; 285 } 286 bp->b_flags &= ~(B_WANTED|B_BUSY|B_ASYNC|B_AGE); 287 splx(s); 288 } 289 290 /* 291 * See if the block is associated with some buffer 292 * (mainly to avoid getting hung up on a wait in breada) 293 */ 294 incore(dev, blkno) 295 dev_t dev; 296 daddr_t blkno; 297 { 298 register struct buf *bp; 299 register struct buf *dp; 300 register int dblkno = fsbtodb(blkno); 301 302 dp = BUFHASH(dev, dblkno); 303 for (bp = dp->b_forw; bp != dp; bp = bp->b_forw) 304 if (bp->b_blkno == dblkno && bp->b_dev == dev && 305 !(bp->b_flags & B_INVAL)) 306 return (1); 307 return (0); 308 } 309 310 struct buf * 311 baddr(dev, blkno) 312 dev_t dev; 313 daddr_t blkno; 314 { 315 316 if (incore(dev, blkno)) 317 return (bread(dev, blkno)); 318 return (0); 319 } 320 321 /* 322 * Assign a buffer for the given block. If the appropriate 323 * block is already associated, return it; otherwise search 324 * for the oldest non-busy buffer and reassign it. 325 */ 326 struct buf * 327 getblk(dev, blkno) 328 dev_t dev; 329 daddr_t blkno; 330 { 331 register struct buf *bp, *dp, *ep; 332 register int dblkno = fsbtodb(blkno); 333 #ifdef DISKMON 334 register int i; 335 #endif 336 337 if ((unsigned)blkno >= 1 << (sizeof(int)*NBBY-PGSHIFT)) 338 blkno = 1 << ((sizeof(int)*NBBY-PGSHIFT) + 1); 339 dblkno = fsbtodb(blkno); 340 dp = BUFHASH(dev, dblkno); 341 loop: 342 (void) spl0(); 343 for (bp = dp->b_forw; bp != dp; bp = bp->b_forw) { 344 if (bp->b_blkno != dblkno || bp->b_dev != dev || 345 bp->b_flags&B_INVAL) 346 continue; 347 (void) spl6(); 348 if (bp->b_flags&B_BUSY) { 349 bp->b_flags |= B_WANTED; 350 sleep((caddr_t)bp, PRIBIO+1); 351 goto loop; 352 } 353 (void) spl0(); 354 #ifdef DISKMON 355 i = 0; 356 dp = bp->av_forw; 357 while ((dp->b_flags & B_HEAD) == 0) { 358 i++; 359 dp = dp->av_forw; 360 } 361 if (i<NBUF) 362 io_info.bufcount[i]++; 363 #endif 364 notavail(bp); 365 bp->b_flags |= B_CACHE; 366 return(bp); 367 } 368 if (major(dev) >= nblkdev) 369 panic("blkdev"); 370 (void) spl6(); 371 for (ep = &bfreelist[BQUEUES-1]; ep > bfreelist; ep--) 372 if (ep->av_forw != ep) 373 break; 374 if (ep == bfreelist) { /* no free blocks at all */ 375 ep->b_flags |= B_WANTED; 376 sleep((caddr_t)ep, PRIBIO+1); 377 goto loop; 378 } 379 (void) spl0(); 380 bp = ep->av_forw; 381 notavail(bp); 382 if (bp->b_flags & B_DELWRI) { 383 bp->b_flags |= B_ASYNC; 384 bwrite(bp); 385 goto loop; 386 } 387 #ifdef EPAWNJ 388 trace(TR_BRELSE, bp->b_dev, dbtofsb(bp->b_blkno)); 389 #endif 390 bp->b_flags = B_BUSY; 391 bp->b_back->b_forw = bp->b_forw; 392 bp->b_forw->b_back = bp->b_back; 393 bp->b_forw = dp->b_forw; 394 bp->b_back = dp; 395 dp->b_forw->b_back = bp; 396 dp->b_forw = bp; 397 bp->b_dev = dev; 398 bp->b_blkno = dblkno; 399 return(bp); 400 } 401 402 /* 403 * get an empty block, 404 * not assigned to any particular device 405 */ 406 struct buf * 407 geteblk() 408 { 409 register struct buf *bp, *dp; 410 411 loop: 412 (void) spl6(); 413 for (dp = &bfreelist[BQUEUES-1]; dp > bfreelist; dp--) 414 if (dp->av_forw != dp) 415 break; 416 if (dp == bfreelist) { /* no free blocks */ 417 dp->b_flags |= B_WANTED; 418 sleep((caddr_t)dp, PRIBIO+1); 419 goto loop; 420 } 421 (void) spl0(); 422 bp = dp->av_forw; 423 notavail(bp); 424 if (bp->b_flags & B_DELWRI) { 425 bp->b_flags |= B_ASYNC; 426 bwrite(bp); 427 goto loop; 428 } 429 #ifdef EPAWNJ 430 trace(TR_BRELSE, bp->b_dev, dbtofsb(bp->b_blkno)); 431 #endif 432 bp->b_flags = B_BUSY|B_INVAL; 433 bp->b_back->b_forw = bp->b_forw; 434 bp->b_forw->b_back = bp->b_back; 435 bp->b_forw = dp->b_forw; 436 bp->b_back = dp; 437 dp->b_forw->b_back = bp; 438 dp->b_forw = bp; 439 bp->b_dev = (dev_t)NODEV; 440 return(bp); 441 } 442 443 /* 444 * Wait for I/O completion on the buffer; return errors 445 * to the user. 446 */ 447 iowait(bp) 448 register struct buf *bp; 449 { 450 451 (void) spl6(); 452 while ((bp->b_flags&B_DONE)==0) 453 sleep((caddr_t)bp, PRIBIO); 454 (void) spl0(); 455 geterror(bp); 456 } 457 458 #ifndef FASTVAX 459 /* 460 * Unlink a buffer from the available list and mark it busy. 461 * (internal interface) 462 */ 463 notavail(bp) 464 register struct buf *bp; 465 { 466 register s; 467 468 s = spl6(); 469 bp->av_back->av_forw = bp->av_forw; 470 bp->av_forw->av_back = bp->av_back; 471 bp->b_flags |= B_BUSY; 472 splx(s); 473 } 474 #endif 475 476 /* 477 * Mark I/O complete on a buffer. If the header 478 * indicates a dirty page push completion, the 479 * header is inserted into the ``cleaned'' list 480 * to be processed by the pageout daemon. Otherwise 481 * release it if I/O is asynchronous, and wake 482 * up anyone waiting for it. 483 */ 484 iodone(bp) 485 register struct buf *bp; 486 { 487 register int s; 488 489 if (bp->b_flags & B_DONE) 490 panic("dup iodone"); 491 bp->b_flags |= B_DONE; 492 if (bp->b_flags & B_DIRTY) { 493 if (bp->b_flags & B_ERROR) 494 panic("IO err in push"); 495 s = spl6(); 496 cnt.v_pgout++; 497 bp->av_forw = bclnlist; 498 bp->b_bcount = swsize[bp - swbuf]; 499 bp->b_pfcent = swpf[bp - swbuf]; 500 bclnlist = bp; 501 if (bswlist.b_flags & B_WANTED) 502 wakeup((caddr_t)&proc[2]); 503 splx(s); 504 return; 505 } 506 if (bp->b_flags&B_ASYNC) 507 brelse(bp); 508 else { 509 bp->b_flags &= ~B_WANTED; 510 wakeup((caddr_t)bp); 511 } 512 } 513 514 /* 515 * Zero the core associated with a buffer. 516 */ 517 clrbuf(bp) 518 struct buf *bp; 519 { 520 register *p; 521 register c; 522 523 p = bp->b_un.b_words; 524 c = BSIZE/sizeof(int); 525 do 526 *p++ = 0; 527 while (--c); 528 bp->b_resid = 0; 529 } 530 531 /* 532 * swap I/O - 533 * 534 * If the flag indicates a dirty page push initiated 535 * by the pageout daemon, we map the page into the i th 536 * virtual page of process 2 (the daemon itself) where i is 537 * the index of the swap header that has been allocated. 538 * We simply initialize the header and queue the I/O but 539 * do not wait for completion. When the I/O completes, 540 * iodone() will link the header to a list of cleaned 541 * pages to be processed by the pageout daemon. 542 */ 543 swap(p, dblkno, addr, nbytes, rdflg, flag, dev, pfcent) 544 struct proc *p; 545 swblk_t dblkno; 546 caddr_t addr; 547 int flag, nbytes; 548 dev_t dev; 549 unsigned pfcent; 550 { 551 register struct buf *bp; 552 register int c; 553 int p2dp; 554 register struct pte *dpte, *vpte; 555 556 (void) spl6(); 557 while (bswlist.av_forw == NULL) { 558 bswlist.b_flags |= B_WANTED; 559 sleep((caddr_t)&bswlist, PSWP+1); 560 } 561 bp = bswlist.av_forw; 562 bswlist.av_forw = bp->av_forw; 563 (void) spl0(); 564 565 bp->b_flags = B_BUSY | B_PHYS | rdflg | flag; 566 if ((bp->b_flags & (B_DIRTY|B_PGIN)) == 0) 567 if (rdflg == B_READ) 568 sum.v_pswpin += btoc(nbytes); 569 else 570 sum.v_pswpout += btoc(nbytes); 571 bp->b_proc = p; 572 if (flag & B_DIRTY) { 573 p2dp = ((bp - swbuf) * CLSIZE) * KLMAX; 574 dpte = dptopte(&proc[2], p2dp); 575 vpte = vtopte(p, btop(addr)); 576 for (c = 0; c < nbytes; c += NBPG) { 577 if (vpte->pg_pfnum == 0 || vpte->pg_fod) 578 panic("swap bad pte"); 579 *dpte++ = *vpte++; 580 } 581 bp->b_un.b_addr = (caddr_t)ctob(p2dp); 582 } else 583 bp->b_un.b_addr = addr; 584 while (nbytes > 0) { 585 c = imin(ctob(120), nbytes); 586 bp->b_bcount = c; 587 bp->b_blkno = dblkno; 588 bp->b_dev = dev; 589 if (flag & B_DIRTY) { 590 swpf[bp - swbuf] = pfcent; 591 swsize[bp - swbuf] = nbytes; 592 } 593 (*bdevsw[major(dev)].d_strategy)(bp); 594 if (flag & B_DIRTY) { 595 if (c < nbytes) 596 panic("big push"); 597 return; 598 } 599 (void) spl6(); 600 while((bp->b_flags&B_DONE)==0) 601 sleep((caddr_t)bp, PSWP); 602 (void) spl0(); 603 bp->b_un.b_addr += c; 604 bp->b_flags &= ~B_DONE; 605 if (bp->b_flags & B_ERROR) { 606 if ((flag & (B_UAREA|B_PAGET)) || rdflg == B_WRITE) 607 panic("hard IO err in swap"); 608 swkill(p, (char *)0); 609 } 610 nbytes -= c; 611 dblkno += btoc(c); 612 } 613 (void) spl6(); 614 bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_PAGET|B_UAREA|B_DIRTY); 615 bp->av_forw = bswlist.av_forw; 616 bswlist.av_forw = bp; 617 if (bswlist.b_flags & B_WANTED) { 618 bswlist.b_flags &= ~B_WANTED; 619 wakeup((caddr_t)&bswlist); 620 wakeup((caddr_t)&proc[2]); 621 } 622 (void) spl0(); 623 } 624 625 /* 626 * If rout == 0 then killed on swap error, else 627 * rout is the name of the routine where we ran out of 628 * swap space. 629 */ 630 swkill(p, rout) 631 struct proc *p; 632 char *rout; 633 { 634 635 printf("%d: ", p->p_pid); 636 if (rout) 637 printf("out of swap space in %s\n", rout); 638 else 639 printf("killed on swap error\n"); 640 /* 641 * To be sure no looping (e.g. in vmsched trying to 642 * swap out) mark process locked in core (as though 643 * done by user) after killing it so noone will try 644 * to swap it out. 645 */ 646 psignal(p, SIGKILL); 647 p->p_flag |= SULOCK; 648 } 649 650 /* 651 * make sure all write-behind blocks 652 * on dev (or NODEV for all) 653 * are flushed out. 654 * (from umount and update) 655 */ 656 bflush(dev) 657 dev_t dev; 658 { 659 register struct buf *bp; 660 register struct buf *flist; 661 662 loop: 663 (void) spl6(); 664 for (flist = bfreelist; flist < &bfreelist[BQUEUES]; flist++) 665 for (bp = flist->av_forw; bp != flist; bp = bp->av_forw) { 666 if (bp->b_flags&B_DELWRI && (dev == NODEV||dev==bp->b_dev)) { 667 bp->b_flags |= B_ASYNC; 668 notavail(bp); 669 bwrite(bp); 670 goto loop; 671 } 672 } 673 (void) spl0(); 674 } 675 676 /* 677 * Raw I/O. The arguments are 678 * The strategy routine for the device 679 * A buffer, which will always be a special buffer 680 * header owned exclusively by the device for this purpose 681 * The device number 682 * Read/write flag 683 * Essentially all the work is computing physical addresses and 684 * validating them. 685 * If the user has the proper access privilidges, the process is 686 * marked 'delayed unlock' and the pages involved in the I/O are 687 * faulted and locked. After the completion of the I/O, the above pages 688 * are unlocked. 689 */ 690 physio(strat, bp, dev, rw, mincnt) 691 int (*strat)(); 692 register struct buf *bp; 693 unsigned (*mincnt)(); 694 { 695 register int c; 696 char *a; 697 698 if (useracc(u.u_base,u.u_count,rw==B_READ?B_WRITE:B_READ) == NULL) { 699 u.u_error = EFAULT; 700 return; 701 } 702 (void) spl6(); 703 while (bp->b_flags&B_BUSY) { 704 bp->b_flags |= B_WANTED; 705 sleep((caddr_t)bp, PRIBIO+1); 706 } 707 bp->b_error = 0; 708 bp->b_proc = u.u_procp; 709 bp->b_un.b_addr = u.u_base; 710 while (u.u_count != 0 && bp->b_error==0) { 711 bp->b_flags = B_BUSY | B_PHYS | rw; 712 bp->b_dev = dev; 713 bp->b_blkno = u.u_offset >> PGSHIFT; 714 bp->b_bcount = u.u_count; 715 (*mincnt)(bp); 716 c = bp->b_bcount; 717 u.u_procp->p_flag |= SPHYSIO; 718 vslock(a = bp->b_un.b_addr, c); 719 (*strat)(bp); 720 (void) spl6(); 721 while ((bp->b_flags&B_DONE) == 0) 722 sleep((caddr_t)bp, PRIBIO); 723 vsunlock(a, c, rw); 724 u.u_procp->p_flag &= ~SPHYSIO; 725 if (bp->b_flags&B_WANTED) 726 wakeup((caddr_t)bp); 727 (void) spl0(); 728 bp->b_un.b_addr += c; 729 u.u_count -= c; 730 u.u_offset += c; 731 } 732 bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS); 733 u.u_count = bp->b_resid; 734 geterror(bp); 735 } 736 737 /*ARGSUSED*/ 738 unsigned 739 minphys(bp) 740 struct buf *bp; 741 { 742 743 if (bp->b_bcount > 60 * 1024) 744 bp->b_bcount = 60 * 1024; 745 } 746 747 /* 748 * Pick up the device's error number and pass it to the user; 749 * if there is an error but the number is 0 set a generalized 750 * code. Actually the latter is always true because devices 751 * don't yet return specific errors. 752 */ 753 geterror(bp) 754 register struct buf *bp; 755 { 756 757 if (bp->b_flags&B_ERROR) 758 if ((u.u_error = bp->b_error)==0) 759 u.u_error = EIO; 760 } 761 762 /* 763 * Invalidate in core blocks belonging to closed or umounted filesystem 764 * 765 * This is not nicely done at all - the buffer ought to be removed from the 766 * hash chains & have its dev/blkno fields clobbered, but unfortunately we 767 * can't do that here, as it is quite possible that the block is still 768 * being used for i/o. Eventually, all disc drivers should be forced to 769 * have a close routine, which ought ensure that the queue is empty, then 770 * properly flush the queues. Until that happy day, this suffices for 771 * correctness. ... kre 772 */ 773 binval(dev) 774 dev_t dev; 775 { 776 register struct buf *bp; 777 register struct bufhd *hp; 778 #define dp ((struct buf *)hp) 779 780 for (hp = bufhash; hp < &bufhash[BUFHSZ]; hp++) 781 for (bp = dp->b_forw; bp != dp; bp = bp->b_forw) 782 if (bp->b_dev == dev) 783 bp->b_flags |= B_INVAL; 784 } 785