1 /* vfs_cluster.c 4.6 01/31/81 */ 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,blkno) \ 40 ((struct buf *)&bufhash[((int)dev+(int)blkno) % 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 struct buf *dp; 226 227 if ((bp->b_flags&B_DELWRI) == 0) 228 u.u_vm.vm_oublk++; /* noone paid yet */ 229 dp = bdevsw[major(bp->b_dev)].d_tab; 230 if(dp->b_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, blkno); 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 i, x; 333 register int dblkno = fsbtodb(blkno); 334 335 if ((unsigned)blkno >= 1 << (sizeof(int)*NBBY-PGSHIFT)) 336 blkno = 1 << ((sizeof(int)*NBBY-PGSHIFT) + 1); 337 dblkno = fsbtodb(blkno); 338 dp = BUFHASH(dev, dblkno); 339 loop: 340 (void) spl0(); 341 for (bp = dp->b_forw; bp != dp; bp = bp->b_forw) { 342 if (bp->b_blkno != dblkno || bp->b_dev != dev || 343 bp->b_flags&B_INVAL) 344 continue; 345 (void) spl6(); 346 if (bp->b_flags&B_BUSY) { 347 bp->b_flags |= B_WANTED; 348 sleep((caddr_t)bp, PRIBIO+1); 349 goto loop; 350 } 351 (void) spl0(); 352 #ifdef DISKMON 353 i = 0; 354 dp = bp->av_forw; 355 while ((dp->b_flags & B_HEAD) == 0) { 356 i++; 357 dp = dp->av_forw; 358 } 359 if (i<NBUF) 360 io_info.bufcount[i]++; 361 #endif 362 notavail(bp); 363 bp->b_flags |= B_CACHE; 364 return(bp); 365 } 366 if (major(dev) >= nblkdev) 367 panic("blkdev"); 368 (void) spl6(); 369 for (ep = &bfreelist[BQUEUES-1]; ep > bfreelist; ep--) 370 if (ep->av_forw != ep) 371 break; 372 if (ep == bfreelist) { /* no free blocks at all */ 373 ep->b_flags |= B_WANTED; 374 sleep((caddr_t)ep, PRIBIO+1); 375 goto loop; 376 } 377 (void) spl0(); 378 bp = ep->av_forw; 379 notavail(bp); 380 if (bp->b_flags & B_DELWRI) { 381 bp->b_flags |= B_ASYNC; 382 bwrite(bp); 383 goto loop; 384 } 385 #ifdef EPAWNJ 386 trace(TR_BRELSE, bp->b_dev, dbtofsb(bp->b_blkno)); 387 #endif 388 bp->b_flags = B_BUSY; 389 bp->b_back->b_forw = bp->b_forw; 390 bp->b_forw->b_back = bp->b_back; 391 bp->b_forw = dp->b_forw; 392 bp->b_back = dp; 393 dp->b_forw->b_back = bp; 394 dp->b_forw = bp; 395 bp->b_dev = dev; 396 bp->b_blkno = dblkno; 397 return(bp); 398 } 399 400 /* 401 * get an empty block, 402 * not assigned to any particular device 403 */ 404 struct buf * 405 geteblk() 406 { 407 register struct buf *bp, *dp; 408 409 loop: 410 (void) spl6(); 411 for (dp = &bfreelist[BQUEUES-1]; dp > bfreelist; dp--) 412 if (dp->av_forw != dp) 413 break; 414 if (dp == bfreelist) { /* no free blocks */ 415 dp->b_flags |= B_WANTED; 416 sleep((caddr_t)dp, PRIBIO+1); 417 goto loop; 418 } 419 (void) spl0(); 420 bp = dp->av_forw; 421 notavail(bp); 422 if (bp->b_flags & B_DELWRI) { 423 bp->b_flags |= B_ASYNC; 424 bwrite(bp); 425 goto loop; 426 } 427 #ifdef EPAWNJ 428 trace(TR_BRELSE, bp->b_dev, dbtofsb(bp->b_blkno)); 429 #endif 430 bp->b_flags = B_BUSY|B_INVAL; 431 bp->b_back->b_forw = bp->b_forw; 432 bp->b_forw->b_back = bp->b_back; 433 bp->b_forw = dp->b_forw; 434 bp->b_back = dp; 435 dp->b_forw->b_back = bp; 436 dp->b_forw = bp; 437 bp->b_dev = (dev_t)NODEV; 438 bp->b_hlink = -1; 439 return(bp); 440 } 441 442 /* 443 * Wait for I/O completion on the buffer; return errors 444 * to the user. 445 */ 446 iowait(bp) 447 register struct buf *bp; 448 { 449 450 (void) spl6(); 451 while ((bp->b_flags&B_DONE)==0) 452 sleep((caddr_t)bp, PRIBIO); 453 (void) spl0(); 454 geterror(bp); 455 } 456 457 #ifndef FASTVAX 458 /* 459 * Unlink a buffer from the available list and mark it busy. 460 * (internal interface) 461 */ 462 notavail(bp) 463 register struct buf *bp; 464 { 465 register s; 466 467 s = spl6(); 468 bp->av_back->av_forw = bp->av_forw; 469 bp->av_forw->av_back = bp->av_back; 470 bp->b_flags |= B_BUSY; 471 splx(s); 472 } 473 #endif 474 475 /* 476 * Mark I/O complete on a buffer. If the header 477 * indicates a dirty page push completion, the 478 * header is inserted into the ``cleaned'' list 479 * to be processed by the pageout daemon. Otherwise 480 * release it if I/O is asynchronous, and wake 481 * up anyone waiting for it. 482 */ 483 iodone(bp) 484 register struct buf *bp; 485 { 486 register int s; 487 488 if (bp->b_flags & B_DONE) 489 panic("dup iodone"); 490 bp->b_flags |= B_DONE; 491 if (bp->b_flags & B_DIRTY) { 492 if (bp->b_flags & B_ERROR) 493 panic("IO err in push"); 494 s = spl6(); 495 cnt.v_pgout++; 496 bp->av_forw = bclnlist; 497 bp->b_bcount = swsize[bp - swbuf]; 498 bp->b_pfcent = swpf[bp - swbuf]; 499 bclnlist = bp; 500 if (bswlist.b_flags & B_WANTED) 501 wakeup((caddr_t)&proc[2]); 502 splx(s); 503 return; 504 } 505 if (bp->b_flags&B_ASYNC) 506 brelse(bp); 507 else { 508 bp->b_flags &= ~B_WANTED; 509 wakeup((caddr_t)bp); 510 } 511 } 512 513 /* 514 * Zero the core associated with a buffer. 515 */ 516 clrbuf(bp) 517 struct buf *bp; 518 { 519 register *p; 520 register c; 521 522 p = bp->b_un.b_words; 523 c = BSIZE/sizeof(int); 524 do 525 *p++ = 0; 526 while (--c); 527 bp->b_resid = 0; 528 } 529 530 /* 531 * swap I/O - 532 * 533 * If the flag indicates a dirty page push initiated 534 * by the pageout daemon, we map the page into the i th 535 * virtual page of process 2 (the daemon itself) where i is 536 * the index of the swap header that has been allocated. 537 * We simply initialize the header and queue the I/O but 538 * do not wait for completion. When the I/O completes, 539 * iodone() will link the header to a list of cleaned 540 * pages to be processed by the pageout daemon. 541 */ 542 swap(p, dblkno, addr, nbytes, rdflg, flag, dev, pfcent) 543 struct proc *p; 544 swblk_t dblkno; 545 caddr_t addr; 546 int flag, nbytes; 547 dev_t dev; 548 unsigned pfcent; 549 { 550 register struct buf *bp; 551 register int c; 552 int p2dp; 553 register struct pte *dpte, *vpte; 554 555 (void) spl6(); 556 while (bswlist.av_forw == NULL) { 557 bswlist.b_flags |= B_WANTED; 558 sleep((caddr_t)&bswlist, PSWP+1); 559 } 560 bp = bswlist.av_forw; 561 bswlist.av_forw = bp->av_forw; 562 (void) spl0(); 563 564 bp->b_flags = B_BUSY | B_PHYS | rdflg | flag; 565 if ((bp->b_flags & (B_DIRTY|B_PGIN)) == 0) 566 if (rdflg == B_READ) 567 sum.v_pswpin += btoc(nbytes); 568 else 569 sum.v_pswpout += btoc(nbytes); 570 bp->b_proc = p; 571 if (flag & B_DIRTY) { 572 p2dp = ((bp - swbuf) * CLSIZE) * KLMAX; 573 dpte = dptopte(&proc[2], p2dp); 574 vpte = vtopte(p, btop(addr)); 575 for (c = 0; c < nbytes; c += NBPG) { 576 if (vpte->pg_pfnum == 0 || vpte->pg_fod) 577 panic("swap bad pte"); 578 *dpte++ = *vpte++; 579 } 580 bp->b_un.b_addr = (caddr_t)ctob(p2dp); 581 } else 582 bp->b_un.b_addr = addr; 583 while (nbytes > 0) { 584 c = imin(ctob(120), nbytes); 585 bp->b_bcount = c; 586 bp->b_blkno = dblkno; 587 bp->b_dev = dev; 588 if (flag & B_DIRTY) { 589 swpf[bp - swbuf] = pfcent; 590 swsize[bp - swbuf] = nbytes; 591 } 592 (*bdevsw[major(dev)].d_strategy)(bp); 593 if (flag & B_DIRTY) { 594 if (c < nbytes) 595 panic("big push"); 596 return; 597 } 598 (void) spl6(); 599 while((bp->b_flags&B_DONE)==0) 600 sleep((caddr_t)bp, PSWP); 601 (void) spl0(); 602 bp->b_un.b_addr += c; 603 bp->b_flags &= ~B_DONE; 604 if (bp->b_flags & B_ERROR) { 605 if ((flag & (B_UAREA|B_PAGET)) || rdflg == B_WRITE) 606 panic("hard IO err in swap"); 607 swkill(p, (char *)0); 608 } 609 nbytes -= c; 610 dblkno += btoc(c); 611 } 612 (void) spl6(); 613 bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_PAGET|B_UAREA|B_DIRTY); 614 bp->av_forw = bswlist.av_forw; 615 bswlist.av_forw = bp; 616 if (bswlist.b_flags & B_WANTED) { 617 bswlist.b_flags &= ~B_WANTED; 618 wakeup((caddr_t)&bswlist); 619 wakeup((caddr_t)&proc[2]); 620 } 621 (void) spl0(); 622 } 623 624 /* 625 * If rout == 0 then killed on swap error, else 626 * rout is the name of the routine where we ran out of 627 * swap space. 628 */ 629 swkill(p, rout) 630 struct proc *p; 631 char *rout; 632 { 633 634 printf("%d: ", p->p_pid); 635 if (rout) 636 printf("out of swap space in %s\n", rout); 637 else 638 printf("killed on swap error\n"); 639 /* 640 * To be sure no looping (e.g. in vmsched trying to 641 * swap out) mark process locked in core (as though 642 * done by user) after killing it so noone will try 643 * to swap it out. 644 */ 645 psignal(p, SIGKILL); 646 p->p_flag |= SULOCK; 647 } 648 649 /* 650 * make sure all write-behind blocks 651 * on dev (or NODEV for all) 652 * are flushed out. 653 * (from umount and update) 654 */ 655 bflush(dev) 656 dev_t dev; 657 { 658 register struct buf *bp; 659 register struct buf *flist; 660 661 loop: 662 (void) spl6(); 663 for (flist = bfreelist; flist < &bfreelist[BQUEUES]; flist++) 664 for (bp = flist->av_forw; bp != flist; bp = bp->av_forw) { 665 if (bp->b_flags&B_DELWRI && (dev == NODEV||dev==bp->b_dev)) { 666 bp->b_flags |= B_ASYNC; 667 notavail(bp); 668 bwrite(bp); 669 goto loop; 670 } 671 } 672 (void) spl0(); 673 } 674 675 /* 676 * Raw I/O. The arguments are 677 * The strategy routine for the device 678 * A buffer, which will always be a special buffer 679 * header owned exclusively by the device for this purpose 680 * The device number 681 * Read/write flag 682 * Essentially all the work is computing physical addresses and 683 * validating them. 684 * If the user has the proper access privilidges, the process is 685 * marked 'delayed unlock' and the pages involved in the I/O are 686 * faulted and locked. After the completion of the I/O, the above pages 687 * are unlocked. 688 */ 689 physio(strat, bp, dev, rw, mincnt) 690 int (*strat)(); 691 register struct buf *bp; 692 unsigned (*mincnt)(); 693 { 694 register int c; 695 char *a; 696 697 if (useracc(u.u_base,u.u_count,rw==B_READ?B_WRITE:B_READ) == NULL) { 698 u.u_error = EFAULT; 699 return; 700 } 701 (void) spl6(); 702 while (bp->b_flags&B_BUSY) { 703 bp->b_flags |= B_WANTED; 704 sleep((caddr_t)bp, PRIBIO+1); 705 } 706 bp->b_error = 0; 707 bp->b_proc = u.u_procp; 708 bp->b_un.b_addr = u.u_base; 709 while (u.u_count != 0 && bp->b_error==0) { 710 bp->b_flags = B_BUSY | B_PHYS | rw; 711 bp->b_dev = dev; 712 bp->b_blkno = u.u_offset >> PGSHIFT; 713 bp->b_bcount = u.u_count; 714 (*mincnt)(bp); 715 c = bp->b_bcount; 716 u.u_procp->p_flag |= SPHYSIO; 717 vslock(a = bp->b_un.b_addr, c); 718 (*strat)(bp); 719 (void) spl6(); 720 while ((bp->b_flags&B_DONE) == 0) 721 sleep((caddr_t)bp, PRIBIO); 722 vsunlock(a, c, rw); 723 u.u_procp->p_flag &= ~SPHYSIO; 724 if (bp->b_flags&B_WANTED) 725 wakeup((caddr_t)bp); 726 (void) spl0(); 727 bp->b_un.b_addr += c; 728 u.u_count -= c; 729 u.u_offset += c; 730 } 731 bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS); 732 u.u_count = bp->b_resid; 733 geterror(bp); 734 } 735 736 /*ARGSUSED*/ 737 unsigned 738 minphys(bp) 739 struct buf *bp; 740 { 741 742 if (bp->b_bcount > 60 * 1024) 743 bp->b_bcount = 60 * 1024; 744 } 745 746 /* 747 * Pick up the device's error number and pass it to the user; 748 * if there is an error but the number is 0 set a generalized 749 * code. Actually the latter is always true because devices 750 * don't yet return specific errors. 751 */ 752 geterror(bp) 753 register struct buf *bp; 754 { 755 756 if (bp->b_flags&B_ERROR) 757 if ((u.u_error = bp->b_error)==0) 758 u.u_error = EIO; 759 } 760 761 /* 762 * Invalidate in core blocks belonging to closed or umounted filesystem 763 * 764 * This is not nicely done at all - the buffer ought to be removed from the 765 * hash chains & have its dev/blkno fields clobbered, but unfortunately we 766 * can't do that here, as it is quite possible that the block is still 767 * being used for i/o. Eventually, all disc drivers should be forced to 768 * have a close routine, which ought ensure that the queue is empty, then 769 * properly flush the queues. Until that happy day, this suffices for 770 * correctness. ... kre 771 */ 772 binval(dev) 773 dev_t dev; 774 { 775 register struct buf *bp, *dp; 776 777 dp = bdevsw[major(dev)].d_tab; 778 for (bp = dp->b_forw; bp != dp; bp = bp->b_forw) 779 if (bp->b_dev == dev) 780 bp->b_flags |= B_INVAL; 781 } 782