| 1 | /* vfs_cluster.c 4.34 82/06/14 */ |
| 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 | int bioprintfs = 0; |
| 16 | |
| 17 | /* |
| 18 | * Read in (if necessary) the block and return a buffer pointer. |
| 19 | */ |
| 20 | struct buf * |
| 21 | bread(dev, blkno, size) |
| 22 | dev_t dev; |
| 23 | daddr_t blkno; |
| 24 | int size; |
| 25 | { |
| 26 | register struct buf *bp; |
| 27 | |
| 28 | bp = getblk(dev, blkno, size); |
| 29 | if (bp->b_flags&B_DONE) { |
| 30 | trace(TR_BREADHIT, dev, blkno); |
| 31 | return(bp); |
| 32 | } |
| 33 | bp->b_flags |= B_READ; |
| 34 | (*bdevsw[major(dev)].d_strategy)(bp); |
| 35 | trace(TR_BREADMISS, dev, blkno); |
| 36 | u.u_vm.vm_inblk++; /* pay for read */ |
| 37 | biowait(bp); |
| 38 | return(bp); |
| 39 | } |
| 40 | |
| 41 | /* |
| 42 | * Read in the block, like bread, but also start I/O on the |
| 43 | * read-ahead block (which is not allocated to the caller) |
| 44 | */ |
| 45 | struct buf * |
| 46 | breada(dev, blkno, size, rablkno, rasize) |
| 47 | dev_t dev; |
| 48 | daddr_t blkno; int size; |
| 49 | daddr_t rablkno; int rasize; |
| 50 | { |
| 51 | register struct buf *bp, *rabp; |
| 52 | |
| 53 | bp = NULL; |
| 54 | /* |
| 55 | * If the block isn't in core, then allocate |
| 56 | * a buffer and initiate i/o (getblk checks |
| 57 | * for a cache hit). |
| 58 | */ |
| 59 | if (!incore(dev, blkno)) { |
| 60 | bp = getblk(dev, blkno, size); |
| 61 | if ((bp->b_flags&B_DONE) == 0) { |
| 62 | bp->b_flags |= B_READ; |
| 63 | (*bdevsw[major(dev)].d_strategy)(bp); |
| 64 | trace(TR_BREADMISS, dev, blkno); |
| 65 | u.u_vm.vm_inblk++; /* pay for read */ |
| 66 | } else |
| 67 | trace(TR_BREADHIT, dev, blkno); |
| 68 | } |
| 69 | |
| 70 | /* |
| 71 | * If there's a read-ahead block, start i/o |
| 72 | * on it also (as above). |
| 73 | */ |
| 74 | if (rablkno && !incore(dev, rablkno)) { |
| 75 | rabp = getblk(dev, rablkno, rasize); |
| 76 | if (rabp->b_flags & B_DONE) { |
| 77 | brelse(rabp); |
| 78 | trace(TR_BREADHITRA, dev, blkno); |
| 79 | } else { |
| 80 | rabp->b_flags |= B_READ|B_ASYNC; |
| 81 | (*bdevsw[major(dev)].d_strategy)(rabp); |
| 82 | trace(TR_BREADMISSRA, dev, rablock); |
| 83 | u.u_vm.vm_inblk++; /* pay in advance */ |
| 84 | } |
| 85 | } |
| 86 | |
| 87 | /* |
| 88 | * If block was in core, let bread get it. |
| 89 | * If block wasn't in core, then the read was started |
| 90 | * above, and just wait for it. |
| 91 | */ |
| 92 | if (bp == NULL) |
| 93 | return (bread(dev, blkno, size)); |
| 94 | biowait(bp); |
| 95 | return (bp); |
| 96 | } |
| 97 | |
| 98 | /* |
| 99 | * Write the buffer, waiting for completion. |
| 100 | * Then release the buffer. |
| 101 | */ |
| 102 | bwrite(bp) |
| 103 | register struct buf *bp; |
| 104 | { |
| 105 | register flag; |
| 106 | |
| 107 | flag = bp->b_flags; |
| 108 | bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI | B_AGE); |
| 109 | if ((flag&B_DELWRI) == 0) |
| 110 | u.u_vm.vm_oublk++; /* noone paid yet */ |
| 111 | trace(TR_BWRITE, bp->b_dev, bp->b_blkno); |
| 112 | if (bioprintfs) |
| 113 | printf("write %x blk %d count %d\n", bp->b_dev, bp->b_blkno, bp->b_bcount); |
| 114 | (*bdevsw[major(bp->b_dev)].d_strategy)(bp); |
| 115 | |
| 116 | /* |
| 117 | * If the write was synchronous, then await i/o completion. |
| 118 | * If the write was "delayed", then we put the buffer on |
| 119 | * the q of blocks awaiting i/o completion status. |
| 120 | * Otherwise, the i/o must be finished and we check for |
| 121 | * an error. |
| 122 | */ |
| 123 | if ((flag&B_ASYNC) == 0) { |
| 124 | biowait(bp); |
| 125 | brelse(bp); |
| 126 | } else if (flag & B_DELWRI) |
| 127 | bp->b_flags |= B_AGE; |
| 128 | else |
| 129 | geterror(bp); |
| 130 | } |
| 131 | |
| 132 | /* |
| 133 | * Release the buffer, marking it so that if it is grabbed |
| 134 | * for another purpose it will be written out before being |
| 135 | * given up (e.g. when writing a partial block where it is |
| 136 | * assumed that another write for the same block will soon follow). |
| 137 | * This can't be done for magtape, since writes must be done |
| 138 | * in the same order as requested. |
| 139 | */ |
| 140 | bdwrite(bp) |
| 141 | register struct buf *bp; |
| 142 | { |
| 143 | register int flags; |
| 144 | |
| 145 | if ((bp->b_flags&B_DELWRI) == 0) |
| 146 | u.u_vm.vm_oublk++; /* noone paid yet */ |
| 147 | flags = bdevsw[major(bp->b_dev)].d_flags; |
| 148 | if(flags & B_TAPE) |
| 149 | bawrite(bp); |
| 150 | else { |
| 151 | bp->b_flags |= B_DELWRI | B_DONE; |
| 152 | brelse(bp); |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | /* |
| 157 | * Release the buffer, start I/O on it, but don't wait for completion. |
| 158 | */ |
| 159 | bawrite(bp) |
| 160 | register struct buf *bp; |
| 161 | { |
| 162 | |
| 163 | bp->b_flags |= B_ASYNC; |
| 164 | bwrite(bp); |
| 165 | } |
| 166 | |
| 167 | /* |
| 168 | * Release the buffer, with no I/O implied. |
| 169 | */ |
| 170 | brelse(bp) |
| 171 | register struct buf *bp; |
| 172 | { |
| 173 | register struct buf *flist; |
| 174 | register s; |
| 175 | |
| 176 | /* |
| 177 | * If someone's waiting for the buffer, or |
| 178 | * is waiting for a buffer wake 'em up. |
| 179 | */ |
| 180 | if (bp->b_flags&B_WANTED) |
| 181 | wakeup((caddr_t)bp); |
| 182 | if (bfreelist[0].b_flags&B_WANTED) { |
| 183 | bfreelist[0].b_flags &= ~B_WANTED; |
| 184 | wakeup((caddr_t)bfreelist); |
| 185 | } |
| 186 | if (bp->b_flags&B_ERROR) |
| 187 | if (bp->b_flags & B_LOCKED) |
| 188 | bp->b_flags &= ~B_ERROR; /* try again later */ |
| 189 | else |
| 190 | bp->b_dev = NODEV; /* no assoc */ |
| 191 | |
| 192 | /* |
| 193 | * Stick the buffer back on a free list. |
| 194 | */ |
| 195 | s = spl6(); |
| 196 | if (bp->b_flags & (B_ERROR|B_INVAL)) { |
| 197 | /* block has no info ... put at front of most free list */ |
| 198 | flist = &bfreelist[BQUEUES-1]; |
| 199 | binsheadfree(bp, flist); |
| 200 | } else { |
| 201 | if (bp->b_flags & B_LOCKED) |
| 202 | flist = &bfreelist[BQ_LOCKED]; |
| 203 | else if (bp->b_flags & B_AGE) |
| 204 | flist = &bfreelist[BQ_AGE]; |
| 205 | else |
| 206 | flist = &bfreelist[BQ_LRU]; |
| 207 | binstailfree(bp, flist); |
| 208 | } |
| 209 | bp->b_flags &= ~(B_WANTED|B_BUSY|B_ASYNC|B_AGE); |
| 210 | splx(s); |
| 211 | } |
| 212 | |
| 213 | /* |
| 214 | * See if the block is associated with some buffer |
| 215 | * (mainly to avoid getting hung up on a wait in breada) |
| 216 | */ |
| 217 | incore(dev, blkno) |
| 218 | dev_t dev; |
| 219 | daddr_t blkno; |
| 220 | { |
| 221 | register struct buf *bp; |
| 222 | register struct buf *dp; |
| 223 | |
| 224 | dp = BUFHASH(dev, blkno); |
| 225 | for (bp = dp->b_forw; bp != dp; bp = bp->b_forw) |
| 226 | if (bp->b_blkno == blkno && bp->b_dev == dev && |
| 227 | (bp->b_flags & B_INVAL) == 0) |
| 228 | return (1); |
| 229 | return (0); |
| 230 | } |
| 231 | |
| 232 | struct buf * |
| 233 | baddr(dev, blkno, size) |
| 234 | dev_t dev; |
| 235 | daddr_t blkno; |
| 236 | int size; |
| 237 | { |
| 238 | |
| 239 | if (incore(dev, blkno)) |
| 240 | return (bread(dev, blkno, size)); |
| 241 | return (0); |
| 242 | } |
| 243 | |
| 244 | /* |
| 245 | * Assign a buffer for the given block. If the appropriate |
| 246 | * block is already associated, return it; otherwise search |
| 247 | * for the oldest non-busy buffer and reassign it. |
| 248 | * |
| 249 | * We use splx here because this routine may be called |
| 250 | * on the interrupt stack during a dump, and we don't |
| 251 | * want to lower the ipl back to 0. |
| 252 | */ |
| 253 | struct buf * |
| 254 | getblk(dev, blkno, size) |
| 255 | dev_t dev; |
| 256 | daddr_t blkno; |
| 257 | int size; |
| 258 | { |
| 259 | register struct buf *bp, *dp, *ep; |
| 260 | int s; |
| 261 | |
| 262 | if ((unsigned)blkno >= 1 << (sizeof(int)*NBBY-PGSHIFT)) |
| 263 | blkno = 1 << ((sizeof(int)*NBBY-PGSHIFT) + 1); |
| 264 | /* |
| 265 | * Search the cache for the block. If we hit, but |
| 266 | * the buffer is in use for i/o, then we wait until |
| 267 | * the i/o has completed. |
| 268 | */ |
| 269 | dp = BUFHASH(dev, blkno); |
| 270 | loop: |
| 271 | for (bp = dp->b_forw; bp != dp; bp = bp->b_forw) { |
| 272 | if (bp->b_blkno != blkno || bp->b_dev != dev || |
| 273 | bp->b_flags&B_INVAL) |
| 274 | continue; |
| 275 | s = spl6(); |
| 276 | if (bp->b_flags&B_BUSY) { |
| 277 | bp->b_flags |= B_WANTED; |
| 278 | sleep((caddr_t)bp, PRIBIO+1); |
| 279 | splx(s); |
| 280 | goto loop; |
| 281 | } |
| 282 | splx(s); |
| 283 | notavail(bp); |
| 284 | if (brealloc(bp, size) == 0) |
| 285 | goto loop; |
| 286 | bp->b_flags |= B_CACHE; |
| 287 | return(bp); |
| 288 | } |
| 289 | if (major(dev) >= nblkdev) |
| 290 | panic("blkdev"); |
| 291 | /* |
| 292 | * Not found in the cache, select something from |
| 293 | * a free list. Preference is to LRU list, then AGE list. |
| 294 | */ |
| 295 | s = spl6(); |
| 296 | for (ep = &bfreelist[BQUEUES-1]; ep > bfreelist; ep--) |
| 297 | if (ep->av_forw != ep) |
| 298 | break; |
| 299 | if (ep == bfreelist) { /* no free blocks at all */ |
| 300 | ep->b_flags |= B_WANTED; |
| 301 | sleep((caddr_t)ep, PRIBIO+1); |
| 302 | splx(s); |
| 303 | goto loop; |
| 304 | } |
| 305 | splx(s); |
| 306 | bp = ep->av_forw; |
| 307 | notavail(bp); |
| 308 | if (bp->b_flags & B_DELWRI) { |
| 309 | bp->b_flags |= B_ASYNC; |
| 310 | bwrite(bp); |
| 311 | goto loop; |
| 312 | } |
| 313 | trace(TR_BRELSE, bp->b_dev, bp->b_blkno); |
| 314 | bp->b_flags = B_BUSY; |
| 315 | bfree(bp); |
| 316 | bremhash(bp); |
| 317 | binshash(bp, dp); |
| 318 | bp->b_dev = dev; |
| 319 | bp->b_blkno = blkno; |
| 320 | if (brealloc(bp, size) == 0) |
| 321 | goto loop; |
| 322 | return(bp); |
| 323 | } |
| 324 | |
| 325 | /* |
| 326 | * get an empty block, |
| 327 | * not assigned to any particular device |
| 328 | */ |
| 329 | struct buf * |
| 330 | geteblk(size) |
| 331 | int size; |
| 332 | { |
| 333 | register struct buf *bp, *dp; |
| 334 | int s; |
| 335 | |
| 336 | loop: |
| 337 | s = spl6(); |
| 338 | for (dp = &bfreelist[BQUEUES-1]; dp > bfreelist; dp--) |
| 339 | if (dp->av_forw != dp) |
| 340 | break; |
| 341 | if (dp == bfreelist) { /* no free blocks */ |
| 342 | dp->b_flags |= B_WANTED; |
| 343 | sleep((caddr_t)dp, PRIBIO+1); |
| 344 | goto loop; |
| 345 | } |
| 346 | splx(s); |
| 347 | bp = dp->av_forw; |
| 348 | notavail(bp); |
| 349 | if (bp->b_flags & B_DELWRI) { |
| 350 | bp->b_flags |= B_ASYNC; |
| 351 | bwrite(bp); |
| 352 | goto loop; |
| 353 | } |
| 354 | trace(TR_BRELSE, bp->b_dev, bp->b_blkno); |
| 355 | bp->b_flags = B_BUSY|B_INVAL; |
| 356 | bfree(bp); |
| 357 | bremhash(bp); |
| 358 | binshash(bp, dp); |
| 359 | bp->b_dev = (dev_t)NODEV; |
| 360 | if (brealloc(bp, size) == 0) |
| 361 | goto loop; |
| 362 | return(bp); |
| 363 | } |
| 364 | |
| 365 | /* |
| 366 | * Allocate space associated with a buffer. |
| 367 | */ |
| 368 | brealloc(bp, size) |
| 369 | register struct buf *bp; |
| 370 | int size; |
| 371 | { |
| 372 | daddr_t start, last; |
| 373 | register struct buf *ep; |
| 374 | struct buf *dp; |
| 375 | int s; |
| 376 | |
| 377 | /* |
| 378 | * First need to make sure that all overlaping previous I/O |
| 379 | * is dispatched with. |
| 380 | */ |
| 381 | if (size == bp->b_bcount) |
| 382 | return (1); |
| 383 | if (size < bp->b_bcount) { |
| 384 | if (bp->b_flags & B_DELWRI) { |
| 385 | bwrite(bp); |
| 386 | return (0); |
| 387 | } |
| 388 | if (bp->b_flags & B_LOCKED) |
| 389 | panic("brealloc"); |
| 390 | goto allocit; |
| 391 | } |
| 392 | bp->b_flags &= ~B_DONE; |
| 393 | if (bp->b_dev == NODEV) |
| 394 | goto allocit; |
| 395 | |
| 396 | /* |
| 397 | * Search cache for any buffers that overlap the one that we |
| 398 | * are trying to allocate. Overlapping buffers must be marked |
| 399 | * invalid, after being written out if they are dirty. (indicated |
| 400 | * by B_DELWRI) A disk block must be mapped by at most one buffer |
| 401 | * at any point in time. Care must be taken to avoid deadlocking |
| 402 | * when two buffer are trying to get the same set of disk blocks. |
| 403 | */ |
| 404 | start = bp->b_blkno; |
| 405 | last = start + (size / DEV_BSIZE) - 1; |
| 406 | dp = BUFHASH(bp->b_dev, bp->b_blkno); |
| 407 | loop: |
| 408 | for (ep = dp->b_forw; ep != dp; ep = ep->b_forw) { |
| 409 | if (ep == bp || ep->b_dev != bp->b_dev || (ep->b_flags&B_INVAL)) |
| 410 | continue; |
| 411 | /* look for overlap */ |
| 412 | if (ep->b_bcount == 0 || ep->b_blkno > last || |
| 413 | ep->b_blkno + (ep->b_bcount / DEV_BSIZE) <= start) |
| 414 | continue; |
| 415 | if (bioprintfs) |
| 416 | if (ep->b_flags&B_BUSY) |
| 417 | printf("sleeping on:dev 0x%x, blks %d-%d, flg 0%o allocing dev 0x%x, blks %d-%d, flg 0%o\n", |
| 418 | ep->b_dev, ep->b_blkno, ep->b_blkno + (ep->b_bcount / DEV_BSIZE) - 1, |
| 419 | ep->b_flags, bp->b_dev, start, last, bp->b_flags); |
| 420 | s = spl6(); |
| 421 | if (ep->b_flags&B_BUSY) { |
| 422 | ep->b_flags |= B_WANTED; |
| 423 | sleep((caddr_t)ep, PRIBIO+1); |
| 424 | (void) splx(s); |
| 425 | goto loop; |
| 426 | } |
| 427 | (void) splx(s); |
| 428 | notavail(ep); |
| 429 | if (ep->b_flags & B_DELWRI) { |
| 430 | if (bioprintfs) |
| 431 | printf("DELWRI:dev 0x%x, blks %d-%d, flg 0%o allocing dev 0x%x, blks %d-%d, flg 0%o\n", |
| 432 | ep->b_dev, ep->b_blkno, ep->b_blkno + (ep->b_bcount / DEV_BSIZE) - 1, |
| 433 | ep->b_flags, bp->b_dev, start, last, bp->b_flags); |
| 434 | bwrite(ep); |
| 435 | goto loop; |
| 436 | } |
| 437 | ep->b_flags |= B_INVAL; |
| 438 | brelse(ep); |
| 439 | } |
| 440 | allocit: |
| 441 | /* |
| 442 | * Here the buffer is already available, so all we |
| 443 | * need to do is set the size. Someday a better memory |
| 444 | * management scheme will be implemented. |
| 445 | */ |
| 446 | bp->b_bcount = size; |
| 447 | return (1); |
| 448 | } |
| 449 | |
| 450 | /* |
| 451 | * Release space associated with a buffer. |
| 452 | */ |
| 453 | bfree(bp) |
| 454 | struct buf *bp; |
| 455 | { |
| 456 | /* |
| 457 | * Here the buffer does not change, so all we |
| 458 | * need to do is set the size. Someday a better memory |
| 459 | * management scheme will be implemented. |
| 460 | */ |
| 461 | bp->b_bcount = 0; |
| 462 | } |
| 463 | |
| 464 | /* |
| 465 | * Wait for I/O completion on the buffer; return errors |
| 466 | * to the user. |
| 467 | */ |
| 468 | biowait(bp) |
| 469 | register struct buf *bp; |
| 470 | { |
| 471 | int s; |
| 472 | |
| 473 | s = spl6(); |
| 474 | while ((bp->b_flags&B_DONE)==0) |
| 475 | sleep((caddr_t)bp, PRIBIO); |
| 476 | splx(s); |
| 477 | geterror(bp); |
| 478 | } |
| 479 | |
| 480 | /* |
| 481 | * Mark I/O complete on a buffer. If the header |
| 482 | * indicates a dirty page push completion, the |
| 483 | * header is inserted into the ``cleaned'' list |
| 484 | * to be processed by the pageout daemon. Otherwise |
| 485 | * release it if I/O is asynchronous, and wake |
| 486 | * up anyone waiting for it. |
| 487 | */ |
| 488 | biodone(bp) |
| 489 | register struct buf *bp; |
| 490 | { |
| 491 | register int s; |
| 492 | |
| 493 | if (bp->b_flags & B_DONE) |
| 494 | panic("dup biodone"); |
| 495 | bp->b_flags |= B_DONE; |
| 496 | if (bp->b_flags & B_DIRTY) { |
| 497 | if (bp->b_flags & B_ERROR) |
| 498 | panic("IO err in push"); |
| 499 | s = spl6(); |
| 500 | bp->av_forw = bclnlist; |
| 501 | bp->b_bcount = swsize[bp - swbuf]; |
| 502 | bp->b_pfcent = swpf[bp - swbuf]; |
| 503 | cnt.v_pgout++; |
| 504 | cnt.v_pgpgout += bp->b_bcount / NBPG; |
| 505 | bclnlist = bp; |
| 506 | if (bswlist.b_flags & B_WANTED) |
| 507 | wakeup((caddr_t)&proc[2]); |
| 508 | splx(s); |
| 509 | return; |
| 510 | } |
| 511 | if (bp->b_flags&B_ASYNC) |
| 512 | brelse(bp); |
| 513 | else { |
| 514 | bp->b_flags &= ~B_WANTED; |
| 515 | wakeup((caddr_t)bp); |
| 516 | } |
| 517 | } |
| 518 | |
| 519 | /* |
| 520 | * make sure all write-behind blocks |
| 521 | * on dev (or NODEV for all) |
| 522 | * are flushed out. |
| 523 | * (from umount and update) |
| 524 | * (and temporarily pagein) |
| 525 | */ |
| 526 | bflush(dev) |
| 527 | dev_t dev; |
| 528 | { |
| 529 | register struct buf *bp; |
| 530 | register struct buf *flist; |
| 531 | int s; |
| 532 | |
| 533 | loop: |
| 534 | s = spl6(); |
| 535 | for (flist = bfreelist; flist < &bfreelist[BQUEUES]; flist++) |
| 536 | for (bp = flist->av_forw; bp != flist; bp = bp->av_forw) { |
| 537 | if ((bp->b_flags & B_DELWRI) == 0) |
| 538 | continue; |
| 539 | if (dev == NODEV || dev == bp->b_dev) { |
| 540 | bp->b_flags |= B_ASYNC; |
| 541 | notavail(bp); |
| 542 | bwrite(bp); |
| 543 | goto loop; |
| 544 | } |
| 545 | } |
| 546 | splx(s); |
| 547 | } |
| 548 | |
| 549 | /* |
| 550 | * Pick up the device's error number and pass it to the user; |
| 551 | * if there is an error but the number is 0 set a generalized |
| 552 | * code. Actually the latter is always true because devices |
| 553 | * don't yet return specific errors. |
| 554 | */ |
| 555 | geterror(bp) |
| 556 | register struct buf *bp; |
| 557 | { |
| 558 | |
| 559 | if (bp->b_flags&B_ERROR) |
| 560 | if ((u.u_error = bp->b_error)==0) |
| 561 | u.u_error = EIO; |
| 562 | } |
| 563 | |
| 564 | /* |
| 565 | * Invalidate in core blocks belonging to closed or umounted filesystem |
| 566 | * |
| 567 | * This is not nicely done at all - the buffer ought to be removed from the |
| 568 | * hash chains & have its dev/blkno fields clobbered, but unfortunately we |
| 569 | * can't do that here, as it is quite possible that the block is still |
| 570 | * being used for i/o. Eventually, all disc drivers should be forced to |
| 571 | * have a close routine, which ought ensure that the queue is empty, then |
| 572 | * properly flush the queues. Until that happy day, this suffices for |
| 573 | * correctness. ... kre |
| 574 | */ |
| 575 | binval(dev) |
| 576 | dev_t dev; |
| 577 | { |
| 578 | register struct buf *bp; |
| 579 | register struct bufhd *hp; |
| 580 | #define dp ((struct buf *)hp) |
| 581 | |
| 582 | for (hp = bufhash; hp < &bufhash[BUFHSZ]; hp++) |
| 583 | for (bp = dp->b_forw; bp != dp; bp = bp->b_forw) |
| 584 | if (bp->b_dev == dev) |
| 585 | bp->b_flags |= B_INVAL; |
| 586 | } |