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1.1 ! root 1: /* bio.c 4.23 81/07/25 */ ! 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: struct buf bfreelist[BQUEUES]; ! 38: struct buf bswlist, *bclnlist; ! 39: ! 40: #define BUFHSZ 63 ! 41: struct bufhd bufhash[BUFHSZ]; ! 42: #define BUFHASH(dev, dblkno) \ ! 43: ((struct buf *)&bufhash[((int)(dev)+(int)(dblkno)) % BUFHSZ]) ! 44: ! 45: /* ! 46: * Initialize hash links for buffers. ! 47: */ ! 48: bhinit() ! 49: { ! 50: register int i; ! 51: register struct bufhd *bp; ! 52: ! 53: for (bp = bufhash, i = 0; i < BUFHSZ; i++, bp++) ! 54: bp->b_forw = bp->b_back = (struct buf *)bp; ! 55: } ! 56: ! 57: /* #define DISKMON 1 */ ! 58: ! 59: #ifdef DISKMON ! 60: struct { ! 61: int nbuf; ! 62: long nread; ! 63: long nreada; ! 64: long ncache; ! 65: long nwrite; ! 66: long bufcount[64]; ! 67: } io_info; ! 68: #endif ! 69: ! 70: /* ! 71: * Swap IO headers - ! 72: * They contain the necessary information for the swap I/O. ! 73: * At any given time, a swap header can be in three ! 74: * different lists. When free it is in the free list, ! 75: * when allocated and the I/O queued, it is on the swap ! 76: * device list, and finally, if the operation was a dirty ! 77: * page push, when the I/O completes, it is inserted ! 78: * in a list of cleaned pages to be processed by the pageout daemon. ! 79: */ ! 80: struct buf *swbuf; ! 81: short *swsize; /* CAN WE JUST USE B_BCOUNT? */ ! 82: int *swpf; ! 83: ! 84: ! 85: #ifndef UNFAST ! 86: #define notavail(bp) \ ! 87: { \ ! 88: int s = spl6(); \ ! 89: (bp)->av_back->av_forw = (bp)->av_forw; \ ! 90: (bp)->av_forw->av_back = (bp)->av_back; \ ! 91: (bp)->b_flags |= B_BUSY; \ ! 92: splx(s); \ ! 93: } ! 94: #endif ! 95: ! 96: /* ! 97: * Read in (if necessary) the block and return a buffer pointer. ! 98: */ ! 99: struct buf * ! 100: bread(dev, blkno) ! 101: dev_t dev; ! 102: daddr_t blkno; ! 103: { ! 104: register struct buf *bp; ! 105: ! 106: bp = getblk(dev, blkno); ! 107: if (bp->b_flags&B_DONE) { ! 108: #ifdef TRACE ! 109: trace(TR_BREADHIT, dev, blkno); ! 110: #endif ! 111: #ifdef DISKMON ! 112: io_info.ncache++; ! 113: #endif ! 114: return(bp); ! 115: } ! 116: bp->b_flags |= B_READ; ! 117: bp->b_bcount = BSIZE; ! 118: (*bdevsw[major(dev)].d_strategy)(bp); ! 119: #ifdef TRACE ! 120: trace(TR_BREADMISS, dev, blkno); ! 121: #endif ! 122: #ifdef DISKMON ! 123: io_info.nread++; ! 124: #endif ! 125: u.u_vm.vm_inblk++; /* pay for read */ ! 126: iowait(bp); ! 127: return(bp); ! 128: } ! 129: ! 130: /* ! 131: * Read in the block, like bread, but also start I/O on the ! 132: * read-ahead block (which is not allocated to the caller) ! 133: */ ! 134: struct buf * ! 135: breada(dev, blkno, rablkno) ! 136: dev_t dev; ! 137: daddr_t blkno, rablkno; ! 138: { ! 139: register struct buf *bp, *rabp; ! 140: ! 141: bp = NULL; ! 142: if (!incore(dev, blkno)) { ! 143: bp = getblk(dev, blkno); ! 144: if ((bp->b_flags&B_DONE) == 0) { ! 145: bp->b_flags |= B_READ; ! 146: bp->b_bcount = BSIZE; ! 147: (*bdevsw[major(dev)].d_strategy)(bp); ! 148: #ifdef TRACE ! 149: trace(TR_BREADMISS, dev, blkno); ! 150: #endif ! 151: #ifdef DISKMON ! 152: io_info.nread++; ! 153: #endif ! 154: u.u_vm.vm_inblk++; /* pay for read */ ! 155: } ! 156: #ifdef TRACE ! 157: else ! 158: trace(TR_BREADHIT, dev, blkno); ! 159: #endif ! 160: } ! 161: if (rablkno && !incore(dev, rablkno)) { ! 162: rabp = getblk(dev, rablkno); ! 163: if (rabp->b_flags & B_DONE) { ! 164: brelse(rabp); ! 165: #ifdef TRACE ! 166: trace(TR_BREADHITRA, dev, blkno); ! 167: #endif ! 168: } else { ! 169: rabp->b_flags |= B_READ|B_ASYNC; ! 170: rabp->b_bcount = BSIZE; ! 171: (*bdevsw[major(dev)].d_strategy)(rabp); ! 172: #ifdef TRACE ! 173: trace(TR_BREADMISSRA, dev, rablock); ! 174: #endif ! 175: #ifdef DISKMON ! 176: io_info.nreada++; ! 177: #endif ! 178: u.u_vm.vm_inblk++; /* pay in advance */ ! 179: } ! 180: } ! 181: if(bp == NULL) ! 182: return(bread(dev, blkno)); ! 183: iowait(bp); ! 184: return(bp); ! 185: } ! 186: ! 187: /* ! 188: * Write the buffer, waiting for completion. ! 189: * Then release the buffer. ! 190: */ ! 191: bwrite(bp) ! 192: register struct buf *bp; ! 193: { ! 194: register flag; ! 195: ! 196: flag = bp->b_flags; ! 197: bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI | B_AGE); ! 198: bp->b_bcount = BSIZE; ! 199: #ifdef DISKMON ! 200: io_info.nwrite++; ! 201: #endif ! 202: if ((flag&B_DELWRI) == 0) ! 203: u.u_vm.vm_oublk++; /* noone paid yet */ ! 204: #ifdef TRACE ! 205: trace(TR_BWRITE, bp->b_dev, bp->b_blkno); ! 206: #endif ! 207: (*bdevsw[major(bp->b_dev)].d_strategy)(bp); ! 208: if ((flag&B_ASYNC) == 0) { ! 209: iowait(bp); ! 210: brelse(bp); ! 211: } else if (flag & B_DELWRI) ! 212: bp->b_flags |= B_AGE; ! 213: else ! 214: geterror(bp); ! 215: } ! 216: ! 217: /* ! 218: * Release the buffer, marking it so that if it is grabbed ! 219: * for another purpose it will be written out before being ! 220: * given up (e.g. when writing a partial block where it is ! 221: * assumed that another write for the same block will soon follow). ! 222: * This can't be done for magtape, since writes must be done ! 223: * in the same order as requested. ! 224: */ ! 225: bdwrite(bp) ! 226: register struct buf *bp; ! 227: { ! 228: register int flags; ! 229: ! 230: if ((bp->b_flags&B_DELWRI) == 0) ! 231: u.u_vm.vm_oublk++; /* noone paid yet */ ! 232: flags = bdevsw[major(bp->b_dev)].d_flags; ! 233: if(flags & B_TAPE) ! 234: bawrite(bp); ! 235: else { ! 236: bp->b_flags |= B_DELWRI | B_DONE; ! 237: brelse(bp); ! 238: } ! 239: } ! 240: ! 241: /* ! 242: * Release the buffer, start I/O on it, but don't wait for completion. ! 243: */ ! 244: bawrite(bp) ! 245: register struct buf *bp; ! 246: { ! 247: ! 248: bp->b_flags |= B_ASYNC; ! 249: bwrite(bp); ! 250: } ! 251: ! 252: /* ! 253: * release the buffer, with no I/O implied. ! 254: */ ! 255: brelse(bp) ! 256: register struct buf *bp; ! 257: { ! 258: register struct buf *flist; ! 259: register s; ! 260: ! 261: if (bp->b_flags&B_WANTED) ! 262: wakeup((caddr_t)bp); ! 263: if (bfreelist[0].b_flags&B_WANTED) { ! 264: bfreelist[0].b_flags &= ~B_WANTED; ! 265: wakeup((caddr_t)bfreelist); ! 266: } ! 267: if (bp->b_flags&B_ERROR) ! 268: if (bp->b_flags & B_LOCKED) ! 269: bp->b_flags &= ~B_ERROR; /* try again later */ ! 270: else ! 271: bp->b_dev = NODEV; /* no assoc */ ! 272: s = spl6(); ! 273: if (bp->b_flags & (B_ERROR|B_INVAL)) { ! 274: /* block has no info ... put at front of most free list */ ! 275: flist = &bfreelist[BQUEUES-1]; ! 276: flist->av_forw->av_back = bp; ! 277: bp->av_forw = flist->av_forw; ! 278: flist->av_forw = bp; ! 279: bp->av_back = flist; ! 280: } else { ! 281: if (bp->b_flags & B_LOCKED) ! 282: flist = &bfreelist[BQ_LOCKED]; ! 283: else if (bp->b_flags & B_AGE) ! 284: flist = &bfreelist[BQ_AGE]; ! 285: else ! 286: flist = &bfreelist[BQ_LRU]; ! 287: flist->av_back->av_forw = bp; ! 288: bp->av_back = flist->av_back; ! 289: flist->av_back = bp; ! 290: bp->av_forw = flist; ! 291: } ! 292: bp->b_flags &= ~(B_WANTED|B_BUSY|B_ASYNC|B_AGE); ! 293: splx(s); ! 294: } ! 295: ! 296: /* ! 297: * See if the block is associated with some buffer ! 298: * (mainly to avoid getting hung up on a wait in breada) ! 299: */ ! 300: incore(dev, blkno) ! 301: dev_t dev; ! 302: daddr_t blkno; ! 303: { ! 304: register struct buf *bp; ! 305: register struct buf *dp; ! 306: register int dblkno = fsbtodb(blkno); ! 307: ! 308: dp = BUFHASH(dev, dblkno); ! 309: for (bp = dp->b_forw; bp != dp; bp = bp->b_forw) ! 310: if (bp->b_blkno == dblkno && bp->b_dev == dev && ! 311: !(bp->b_flags & B_INVAL)) ! 312: return (1); ! 313: return (0); ! 314: } ! 315: ! 316: struct buf * ! 317: baddr(dev, blkno) ! 318: dev_t dev; ! 319: daddr_t blkno; ! 320: { ! 321: ! 322: if (incore(dev, blkno)) ! 323: return (bread(dev, blkno)); ! 324: return (0); ! 325: } ! 326: ! 327: /* ! 328: * Assign a buffer for the given block. If the appropriate ! 329: * block is already associated, return it; otherwise search ! 330: * for the oldest non-busy buffer and reassign it. ! 331: */ ! 332: struct buf * ! 333: getblk(dev, blkno) ! 334: dev_t dev; ! 335: daddr_t blkno; ! 336: { ! 337: register struct buf *bp, *dp, *ep; ! 338: register int dblkno = fsbtodb(blkno); ! 339: #ifdef DISKMON ! 340: register int i; ! 341: #endif ! 342: ! 343: if ((unsigned)blkno >= 1 << (sizeof(int)*NBBY-PGSHIFT)) ! 344: blkno = 1 << ((sizeof(int)*NBBY-PGSHIFT) + 1); ! 345: dblkno = fsbtodb(blkno); ! 346: dp = BUFHASH(dev, dblkno); ! 347: loop: ! 348: (void) spl0(); ! 349: for (bp = dp->b_forw; bp != dp; bp = bp->b_forw) { ! 350: if (bp->b_blkno != dblkno || bp->b_dev != dev || ! 351: bp->b_flags&B_INVAL) ! 352: continue; ! 353: (void) spl6(); ! 354: if (bp->b_flags&B_BUSY) { ! 355: bp->b_flags |= B_WANTED; ! 356: sleep((caddr_t)bp, PRIBIO+1); ! 357: goto loop; ! 358: } ! 359: (void) spl0(); ! 360: #ifdef DISKMON ! 361: i = 0; ! 362: dp = bp->av_forw; ! 363: while ((dp->b_flags & B_HEAD) == 0) { ! 364: i++; ! 365: dp = dp->av_forw; ! 366: } ! 367: if (i<64) ! 368: io_info.bufcount[i]++; ! 369: #endif ! 370: notavail(bp); ! 371: bp->b_flags |= B_CACHE; ! 372: return(bp); ! 373: } ! 374: if (major(dev) >= nblkdev) ! 375: panic("blkdev"); ! 376: (void) spl6(); ! 377: for (ep = &bfreelist[BQUEUES-1]; ep > bfreelist; ep--) ! 378: if (ep->av_forw != ep) ! 379: break; ! 380: if (ep == bfreelist) { /* no free blocks at all */ ! 381: ep->b_flags |= B_WANTED; ! 382: sleep((caddr_t)ep, PRIBIO+1); ! 383: goto loop; ! 384: } ! 385: (void) spl0(); ! 386: bp = ep->av_forw; ! 387: notavail(bp); ! 388: if (bp->b_flags & B_DELWRI) { ! 389: bp->b_flags |= B_ASYNC; ! 390: bwrite(bp); ! 391: goto loop; ! 392: } ! 393: #ifdef TRACE ! 394: trace(TR_BRELSE, bp->b_dev, bp->b_blkno); ! 395: #endif ! 396: bp->b_flags = B_BUSY; ! 397: bp->b_back->b_forw = bp->b_forw; ! 398: bp->b_forw->b_back = bp->b_back; ! 399: bp->b_forw = dp->b_forw; ! 400: bp->b_back = dp; ! 401: dp->b_forw->b_back = bp; ! 402: dp->b_forw = bp; ! 403: bp->b_dev = dev; ! 404: bp->b_blkno = dblkno; ! 405: return(bp); ! 406: } ! 407: ! 408: /* ! 409: * get an empty block, ! 410: * not assigned to any particular device ! 411: */ ! 412: struct buf * ! 413: geteblk() ! 414: { ! 415: register struct buf *bp, *dp; ! 416: ! 417: loop: ! 418: (void) spl6(); ! 419: for (dp = &bfreelist[BQUEUES-1]; dp > bfreelist; dp--) ! 420: if (dp->av_forw != dp) ! 421: break; ! 422: if (dp == bfreelist) { /* no free blocks */ ! 423: dp->b_flags |= B_WANTED; ! 424: sleep((caddr_t)dp, PRIBIO+1); ! 425: goto loop; ! 426: } ! 427: (void) spl0(); ! 428: bp = dp->av_forw; ! 429: notavail(bp); ! 430: if (bp->b_flags & B_DELWRI) { ! 431: bp->b_flags |= B_ASYNC; ! 432: bwrite(bp); ! 433: goto loop; ! 434: } ! 435: #ifdef TRACE ! 436: trace(TR_BRELSE, bp->b_dev, bp->b_blkno); ! 437: #endif ! 438: bp->b_flags = B_BUSY|B_INVAL; ! 439: bp->b_back->b_forw = bp->b_forw; ! 440: bp->b_forw->b_back = bp->b_back; ! 441: bp->b_forw = dp->b_forw; ! 442: bp->b_back = dp; ! 443: dp->b_forw->b_back = bp; ! 444: dp->b_forw = bp; ! 445: bp->b_dev = (dev_t)NODEV; ! 446: return(bp); ! 447: } ! 448: ! 449: /* ! 450: * Wait for I/O completion on the buffer; return errors ! 451: * to the user. ! 452: */ ! 453: iowait(bp) ! 454: register struct buf *bp; ! 455: { ! 456: ! 457: (void) spl6(); ! 458: while ((bp->b_flags&B_DONE)==0) ! 459: sleep((caddr_t)bp, PRIBIO); ! 460: (void) spl0(); ! 461: geterror(bp); ! 462: } ! 463: ! 464: #ifdef UNFAST ! 465: /* ! 466: * Unlink a buffer from the available list and mark it busy. ! 467: * (internal interface) ! 468: */ ! 469: notavail(bp) ! 470: register struct buf *bp; ! 471: { ! 472: register s; ! 473: ! 474: s = spl6(); ! 475: bp->av_back->av_forw = bp->av_forw; ! 476: bp->av_forw->av_back = bp->av_back; ! 477: bp->b_flags |= B_BUSY; ! 478: splx(s); ! 479: } ! 480: #endif ! 481: ! 482: /* ! 483: * Mark I/O complete on a buffer. If the header ! 484: * indicates a dirty page push completion, the ! 485: * header is inserted into the ``cleaned'' list ! 486: * to be processed by the pageout daemon. Otherwise ! 487: * release it if I/O is asynchronous, and wake ! 488: * up anyone waiting for it. ! 489: */ ! 490: iodone(bp) ! 491: register struct buf *bp; ! 492: { ! 493: register int s; ! 494: ! 495: if (bp->b_flags & B_DONE) ! 496: panic("dup iodone"); ! 497: bp->b_flags |= B_DONE; ! 498: if (bp->b_flags & B_DIRTY) { ! 499: if (bp->b_flags & B_ERROR) ! 500: panic("IO err in push"); ! 501: s = spl6(); ! 502: bp->av_forw = bclnlist; ! 503: bp->b_bcount = swsize[bp - swbuf]; ! 504: bp->b_pfcent = swpf[bp - swbuf]; ! 505: cnt.v_pgout++; ! 506: cnt.v_pgpgout += bp->b_bcount / NBPG; ! 507: bclnlist = bp; ! 508: if (bswlist.b_flags & B_WANTED) ! 509: wakeup((caddr_t)&proc[2]); ! 510: splx(s); ! 511: return; ! 512: } ! 513: if (bp->b_flags&B_ASYNC) ! 514: brelse(bp); ! 515: else { ! 516: bp->b_flags &= ~B_WANTED; ! 517: wakeup((caddr_t)bp); ! 518: } ! 519: } ! 520: ! 521: /* ! 522: * Zero the core associated with a buffer. ! 523: */ ! 524: clrbuf(bp) ! 525: struct buf *bp; ! 526: { ! 527: register *p; ! 528: register c; ! 529: ! 530: p = bp->b_un.b_words; ! 531: c = BSIZE/sizeof(int); ! 532: do ! 533: *p++ = 0; ! 534: while (--c); ! 535: bp->b_resid = 0; ! 536: } ! 537: ! 538: /* ! 539: * swap I/O - ! 540: * ! 541: * If the flag indicates a dirty page push initiated ! 542: * by the pageout daemon, we map the page into the i th ! 543: * virtual page of process 2 (the daemon itself) where i is ! 544: * the index of the swap header that has been allocated. ! 545: * We simply initialize the header and queue the I/O but ! 546: * do not wait for completion. When the I/O completes, ! 547: * iodone() will link the header to a list of cleaned ! 548: * pages to be processed by the pageout daemon. ! 549: */ ! 550: swap(p, dblkno, addr, nbytes, rdflg, flag, dev, pfcent) ! 551: struct proc *p; ! 552: swblk_t dblkno; ! 553: caddr_t addr; ! 554: int flag, nbytes; ! 555: dev_t dev; ! 556: unsigned pfcent; ! 557: { ! 558: register struct buf *bp; ! 559: register int c; ! 560: int p2dp; ! 561: register struct pte *dpte, *vpte; ! 562: ! 563: (void) spl6(); ! 564: while (bswlist.av_forw == NULL) { ! 565: bswlist.b_flags |= B_WANTED; ! 566: sleep((caddr_t)&bswlist, PSWP+1); ! 567: } ! 568: bp = bswlist.av_forw; ! 569: bswlist.av_forw = bp->av_forw; ! 570: (void) spl0(); ! 571: ! 572: bp->b_flags = B_BUSY | B_PHYS | rdflg | flag; ! 573: if ((bp->b_flags & (B_DIRTY|B_PGIN)) == 0) ! 574: if (rdflg == B_READ) ! 575: sum.v_pswpin += btoc(nbytes); ! 576: else ! 577: sum.v_pswpout += btoc(nbytes); ! 578: bp->b_proc = p; ! 579: if (flag & B_DIRTY) { ! 580: p2dp = ((bp - swbuf) * CLSIZE) * KLMAX; ! 581: dpte = dptopte(&proc[2], p2dp); ! 582: vpte = vtopte(p, btop(addr)); ! 583: for (c = 0; c < nbytes; c += NBPG) { ! 584: if (vpte->pg_pfnum == 0 || vpte->pg_fod) ! 585: panic("swap bad pte"); ! 586: *dpte++ = *vpte++; ! 587: } ! 588: bp->b_un.b_addr = (caddr_t)ctob(p2dp); ! 589: } else ! 590: bp->b_un.b_addr = addr; ! 591: while (nbytes > 0) { ! 592: c = imin(ctob(120), nbytes); ! 593: bp->b_bcount = c; ! 594: bp->b_blkno = dblkno; ! 595: bp->b_dev = dev; ! 596: if (flag & B_DIRTY) { ! 597: swpf[bp - swbuf] = pfcent; ! 598: swsize[bp - swbuf] = nbytes; ! 599: } ! 600: #ifdef TRACE ! 601: trace(TR_SWAPIO, dev, bp->b_blkno); ! 602: #endif ! 603: (*bdevsw[major(dev)].d_strategy)(bp); ! 604: if (flag & B_DIRTY) { ! 605: if (c < nbytes) ! 606: panic("big push"); ! 607: return; ! 608: } ! 609: (void) spl6(); ! 610: while((bp->b_flags&B_DONE)==0) ! 611: sleep((caddr_t)bp, PSWP); ! 612: (void) spl0(); ! 613: bp->b_un.b_addr += c; ! 614: bp->b_flags &= ~B_DONE; ! 615: if (bp->b_flags & B_ERROR) { ! 616: if ((flag & (B_UAREA|B_PAGET)) || rdflg == B_WRITE) ! 617: panic("hard IO err in swap"); ! 618: swkill(p, (char *)0); ! 619: } ! 620: nbytes -= c; ! 621: dblkno += btoc(c); ! 622: } ! 623: (void) spl6(); ! 624: bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_PAGET|B_UAREA|B_DIRTY); ! 625: bp->av_forw = bswlist.av_forw; ! 626: bswlist.av_forw = bp; ! 627: if (bswlist.b_flags & B_WANTED) { ! 628: bswlist.b_flags &= ~B_WANTED; ! 629: wakeup((caddr_t)&bswlist); ! 630: wakeup((caddr_t)&proc[2]); ! 631: } ! 632: (void) spl0(); ! 633: } ! 634: ! 635: /* ! 636: * If rout == 0 then killed on swap error, else ! 637: * rout is the name of the routine where we ran out of ! 638: * swap space. ! 639: */ ! 640: swkill(p, rout) ! 641: struct proc *p; ! 642: char *rout; ! 643: { ! 644: char *mesg; ! 645: ! 646: printf("pid %d: ", p->p_pid); ! 647: if (rout) ! 648: printf(mesg = "killed due to no swap space\n"); ! 649: else ! 650: printf(mesg = "killed on swap error\n"); ! 651: uprintf("sorry, pid %d was %s", p->p_pid, mesg); ! 652: /* ! 653: * To be sure no looping (e.g. in vmsched trying to ! 654: * swap out) mark process locked in core (as though ! 655: * done by user) after killing it so noone will try ! 656: * to swap it out. ! 657: */ ! 658: psignal(p, SIGKILL); ! 659: p->p_flag |= SULOCK; ! 660: } ! 661: ! 662: /* ! 663: * make sure all write-behind blocks ! 664: * on dev (or NODEV for all) ! 665: * are flushed out. ! 666: * (from umount and update) ! 667: */ ! 668: bflush(dev) ! 669: dev_t dev; ! 670: { ! 671: register struct buf *bp; ! 672: register struct buf *flist; ! 673: ! 674: loop: ! 675: (void) spl6(); ! 676: for (flist = bfreelist; flist < &bfreelist[BQUEUES]; flist++) ! 677: for (bp = flist->av_forw; bp != flist; bp = bp->av_forw) { ! 678: if (bp->b_flags&B_DELWRI && (dev == NODEV||dev==bp->b_dev)) { ! 679: bp->b_flags |= B_ASYNC; ! 680: notavail(bp); ! 681: bwrite(bp); ! 682: goto loop; ! 683: } ! 684: } ! 685: (void) spl0(); ! 686: } ! 687: ! 688: /* ! 689: * Raw I/O. The arguments are ! 690: * The strategy routine for the device ! 691: * A buffer, which will always be a special buffer ! 692: * header owned exclusively by the device for this purpose ! 693: * The device number ! 694: * Read/write flag ! 695: * Essentially all the work is computing physical addresses and ! 696: * validating them. ! 697: * If the user has the proper access privilidges, the process is ! 698: * marked 'delayed unlock' and the pages involved in the I/O are ! 699: * faulted and locked. After the completion of the I/O, the above pages ! 700: * are unlocked. ! 701: */ ! 702: physio(strat, bp, dev, rw, mincnt) ! 703: int (*strat)(); ! 704: register struct buf *bp; ! 705: unsigned (*mincnt)(); ! 706: { ! 707: register int c; ! 708: char *a; ! 709: ! 710: if (useracc(u.u_base,u.u_count,rw==B_READ?B_WRITE:B_READ) == NULL) { ! 711: u.u_error = EFAULT; ! 712: return; ! 713: } ! 714: (void) spl6(); ! 715: while (bp->b_flags&B_BUSY) { ! 716: bp->b_flags |= B_WANTED; ! 717: sleep((caddr_t)bp, PRIBIO+1); ! 718: } ! 719: bp->b_error = 0; ! 720: bp->b_proc = u.u_procp; ! 721: bp->b_un.b_addr = u.u_base; ! 722: while (u.u_count != 0) { ! 723: bp->b_flags = B_BUSY | B_PHYS | rw; ! 724: bp->b_dev = dev; ! 725: bp->b_blkno = u.u_offset >> PGSHIFT; ! 726: bp->b_bcount = u.u_count; ! 727: (*mincnt)(bp); ! 728: c = bp->b_bcount; ! 729: u.u_procp->p_flag |= SPHYSIO; ! 730: vslock(a = bp->b_un.b_addr, c); ! 731: (*strat)(bp); ! 732: (void) spl6(); ! 733: while ((bp->b_flags&B_DONE) == 0) ! 734: sleep((caddr_t)bp, PRIBIO); ! 735: vsunlock(a, c, rw); ! 736: u.u_procp->p_flag &= ~SPHYSIO; ! 737: if (bp->b_flags&B_WANTED) ! 738: wakeup((caddr_t)bp); ! 739: (void) spl0(); ! 740: bp->b_un.b_addr += c; ! 741: u.u_count -= c; ! 742: u.u_offset += c; ! 743: if (bp->b_flags&B_ERROR) ! 744: break; ! 745: } ! 746: bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS); ! 747: u.u_count = bp->b_resid; ! 748: geterror(bp); ! 749: } ! 750: ! 751: /*ARGSUSED*/ ! 752: unsigned ! 753: minphys(bp) ! 754: struct buf *bp; ! 755: { ! 756: ! 757: if (bp->b_bcount > 60 * 1024) ! 758: bp->b_bcount = 60 * 1024; ! 759: } ! 760: ! 761: /* ! 762: * Pick up the device's error number and pass it to the user; ! 763: * if there is an error but the number is 0 set a generalized ! 764: * code. Actually the latter is always true because devices ! 765: * don't yet return specific errors. ! 766: */ ! 767: geterror(bp) ! 768: register struct buf *bp; ! 769: { ! 770: ! 771: if (bp->b_flags&B_ERROR) ! 772: if ((u.u_error = bp->b_error)==0) ! 773: u.u_error = EIO; ! 774: } ! 775: ! 776: /* ! 777: * Invalidate in core blocks belonging to closed or umounted filesystem ! 778: * ! 779: * This is not nicely done at all - the buffer ought to be removed from the ! 780: * hash chains & have its dev/blkno fields clobbered, but unfortunately we ! 781: * can't do that here, as it is quite possible that the block is still ! 782: * being used for i/o. Eventually, all disc drivers should be forced to ! 783: * have a close routine, which ought ensure that the queue is empty, then ! 784: * properly flush the queues. Until that happy day, this suffices for ! 785: * correctness. ... kre ! 786: */ ! 787: binval(dev) ! 788: dev_t dev; ! 789: { ! 790: register struct buf *bp; ! 791: register struct bufhd *hp; ! 792: #define dp ((struct buf *)hp) ! 793: ! 794: for (hp = bufhash; hp < &bufhash[BUFHSZ]; hp++) ! 795: for (bp = dp->b_forw; bp != dp; bp = bp->b_forw) ! 796: if (bp->b_dev == dev) ! 797: bp->b_flags |= B_INVAL; ! 798: }
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