| 1 | /* vfs_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 | } |