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1.1 ! root 1: /* ! 2: * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. ! 3: * ! 4: * @APPLE_LICENSE_HEADER_START@ ! 5: * ! 6: * The contents of this file constitute Original Code as defined in and ! 7: * are subject to the Apple Public Source License Version 1.1 (the ! 8: * "License"). You may not use this file except in compliance with the ! 9: * License. Please obtain a copy of the License at ! 10: * http://www.apple.com/publicsource and read it before using this file. ! 11: * ! 12: * This Original Code and all software distributed under the License are ! 13: * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER ! 14: * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, ! 15: * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, ! 16: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the ! 17: * License for the specific language governing rights and limitations ! 18: * under the License. ! 19: * ! 20: * @APPLE_LICENSE_HEADER_END@ ! 21: */ ! 22: /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */ ! 23: /*- ! 24: * Copyright (c) 1994 Christopher G. Demetriou ! 25: * Copyright (c) 1982, 1986, 1989, 1993 ! 26: * The Regents of the University of California. All rights reserved. ! 27: * (c) UNIX System Laboratories, Inc. ! 28: * All or some portions of this file are derived from material licensed ! 29: * to the University of California by American Telephone and Telegraph ! 30: * Co. or Unix System Laboratories, Inc. and are reproduced herein with ! 31: * the permission of UNIX System Laboratories, Inc. ! 32: * ! 33: * Redistribution and use in source and binary forms, with or without ! 34: * modification, are permitted provided that the following conditions ! 35: * are met: ! 36: * 1. Redistributions of source code must retain the above copyright ! 37: * notice, this list of conditions and the following disclaimer. ! 38: * 2. Redistributions in binary form must reproduce the above copyright ! 39: * notice, this list of conditions and the following disclaimer in the ! 40: * documentation and/or other materials provided with the distribution. ! 41: * 3. All advertising materials mentioning features or use of this software ! 42: * must display the following acknowledgement: ! 43: * This product includes software developed by the University of ! 44: * California, Berkeley and its contributors. ! 45: * 4. Neither the name of the University nor the names of its contributors ! 46: * may be used to endorse or promote products derived from this software ! 47: * without specific prior written permission. ! 48: * ! 49: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ! 50: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE ! 51: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ! 52: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE ! 53: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL ! 54: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS ! 55: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) ! 56: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT ! 57: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY ! 58: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF ! 59: * SUCH DAMAGE. ! 60: * ! 61: * The NEXTSTEP Software License Agreement specifies the terms ! 62: * and conditions for redistribution. ! 63: * ! 64: * @(#)vfs_bio.c 8.6 (Berkeley) 1/11/94 ! 65: */ ! 66: ! 67: /* ! 68: * Some references: ! 69: * Bach: The Design of the UNIX Operating System (Prentice Hall, 1986) ! 70: * Leffler, et al.: The Design and Implementation of the 4.3BSD ! 71: * UNIX Operating System (Addison Welley, 1989) ! 72: */ ! 73: /* ! 74: * HISTORY ! 75: * 17-July-97 Umesh Vaishampayan ([email protected]) ! 76: * Eliminated multiple definition of buffers and buf which are defined in ! 77: * conf/param.c. ! 78: * Eliminated multiple definition of nbuf and bufpages which are defined ! 79: * in machdep/XXX/unix_startup.c ! 80: * ! 81: * 11-July-97 Umesh Vaishampayan ([email protected]) ! 82: * Defined global variables for use when tracing is turned on. ! 83: */ ! 84: ! 85: #include <mach_nbc.h> ! 86: #include <sys/param.h> ! 87: #include <sys/systm.h> ! 88: #include <sys/proc.h> ! 89: #include <sys/buf.h> ! 90: #include <sys/vnode.h> ! 91: #include <sys/mount.h> ! 92: #include <sys/trace.h> ! 93: #include <sys/malloc.h> ! 94: #include <sys/resourcevar.h> ! 95: #include <miscfs/specfs/specdev.h> ! 96: ! 97: extern void reassignbuf(struct buf *, struct vnode *); ! 98: ! 99: extern int nbuf; /* The number of buffer headers */ ! 100: extern int niobuf; ! 101: extern struct buf *buf; /* The buffer headers. */ ! 102: extern char *buffers; /* The buffer contents. */ ! 103: extern int bufpages; /* Number of memory pages in the buffer pool. */ ! 104: struct buf *swbuf; /* Swap I/O buffer headers. */ ! 105: int nswbuf; /* Number of swap I/O buffer headers. */ ! 106: struct buf bswlist; /* Head of swap I/O buffer headers free list. */ ! 107: struct buf *bclnlist;/* Head of cleaned page list. */ ! 108: ! 109: #if TRACE ! 110: struct proc *traceproc; ! 111: int tracewhich, tracebuf[TRCSIZ]; ! 112: u_int tracex; ! 113: char traceflags[TR_NFLAGS]; ! 114: #endif /* TRACE */ ! 115: ! 116: /* Macros to clear/set/test flags. */ ! 117: #define SET(t, f) (t) |= (f) ! 118: #define CLR(t, f) (t) &= ~(f) ! 119: #define ISSET(t, f) ((t) & (f)) ! 120: ! 121: /* ! 122: * Definitions for the buffer hash lists. ! 123: */ ! 124: #define BUFHASH(dvp, lbn) \ ! 125: (&bufhashtbl[((long)(dvp) / sizeof(*(dvp)) + (int)(lbn)) & bufhash]) ! 126: LIST_HEAD(bufhashhdr, buf) *bufhashtbl, invalhash; ! 127: u_long bufhash; ! 128: ! 129: /* ! 130: * Insq/Remq for the buffer hash lists. ! 131: */ ! 132: #define binshash(bp, dp) LIST_INSERT_HEAD(dp, bp, b_hash) ! 133: #define bremhash(bp) LIST_REMOVE(bp, b_hash) ! 134: ! 135: /* ! 136: * Definitions for the buffer free lists. ! 137: */ ! 138: #define BQUEUES 4 /* number of free buffer queues */ ! 139: ! 140: #define BQ_LOCKED 0 /* super-blocks &c */ ! 141: #define BQ_LRU 1 /* lru, useful buffers */ ! 142: #define BQ_AGE 2 /* rubbish */ ! 143: #define BQ_EMPTY 3 /* buffer headers with no memory */ ! 144: ! 145: TAILQ_HEAD(ioqueue, buf) iobufqueue; ! 146: TAILQ_HEAD(bqueues, buf) bufqueues[BQUEUES]; ! 147: int needbuffer; ! 148: ! 149: /* ! 150: * Insq/Remq for the buffer free lists. ! 151: */ ! 152: #define binsheadfree(bp, dp) do { \ ! 153: TAILQ_INSERT_HEAD(dp, bp, b_freelist); \ ! 154: (bp)->b_timestamp = time.tv_sec; \ ! 155: } while (0) ! 156: ! 157: #define binstailfree(bp, dp) do { \ ! 158: TAILQ_INSERT_TAIL(dp, bp, b_freelist); \ ! 159: (bp)->b_timestamp = time.tv_sec; \ ! 160: } while (0) ! 161: ! 162: ! 163: /* Time in seconds before a buf on a list is considered as a stale buf */ ! 164: #define LRU_IS_STALE 120 /* default value for the LRU */ ! 165: #define AGE_IS_STALE 60 /* default value for the AGE */ ! 166: ! 167: int lru_is_stale = LRU_IS_STALE; ! 168: int age_is_stale = AGE_IS_STALE; ! 169: ! 170: ! 171: ! 172: void ! 173: bremfree(bp) ! 174: struct buf *bp; ! 175: { ! 176: struct bqueues *dp = NULL; ! 177: ! 178: /* ! 179: * We only calculate the head of the freelist when removing ! 180: * the last element of the list as that is the only time that ! 181: * it is needed (e.g. to reset the tail pointer). ! 182: * ! 183: * NB: This makes an assumption about how tailq's are implemented. ! 184: */ ! 185: if (bp->b_freelist.tqe_next == NULL) { ! 186: for (dp = bufqueues; dp < &bufqueues[BQUEUES]; dp++) ! 187: if (dp->tqh_last == &bp->b_freelist.tqe_next) ! 188: break; ! 189: if (dp == &bufqueues[BQUEUES]) ! 190: panic("bremfree: lost tail"); ! 191: } ! 192: TAILQ_REMOVE(dp, bp, b_freelist); ! 193: bp->b_timestamp = 0; ! 194: } ! 195: ! 196: /* ! 197: * Initialize buffers and hash links for buffers. ! 198: */ ! 199: void ! 200: bufinit() ! 201: { ! 202: register struct buf *bp; ! 203: struct bqueues *dp; ! 204: register int i; ! 205: int base, residual; ! 206: ! 207: for (dp = bufqueues; dp < &bufqueues[BQUEUES]; dp++) ! 208: TAILQ_INIT(dp); ! 209: bufhashtbl = hashinit(nbuf, M_CACHE, &bufhash); ! 210: base = bufpages / nbuf; ! 211: residual = bufpages % nbuf; ! 212: for (i = 0; i < nbuf; i++) { ! 213: bp = &buf[i]; ! 214: bzero((char *)bp, sizeof *bp); ! 215: bp->b_dev = NODEV; ! 216: bp->b_rcred = NOCRED; ! 217: bp->b_wcred = NOCRED; ! 218: bp->b_vnbufs.le_next = NOLIST; ! 219: bp->b_data = buffers + i * MAXBSIZE; ! 220: if (i < residual) ! 221: bp->b_bufsize = (base + 1) * CLBYTES; ! 222: else ! 223: bp->b_bufsize = base * CLBYTES; ! 224: bp->b_flags = B_INVAL; ! 225: dp = bp->b_bufsize ? &bufqueues[BQ_AGE] : &bufqueues[BQ_EMPTY]; ! 226: binsheadfree(bp, dp); ! 227: binshash(bp, &invalhash); ! 228: } ! 229: base = (int )(buffers + (i * MAXBSIZE)); ! 230: ! 231: for (; i < nbuf + niobuf; i++) { ! 232: bp = &buf[i]; ! 233: bzero((char *)bp, sizeof *bp); ! 234: bp->b_dev = NODEV; ! 235: bp->b_rcred = NOCRED; ! 236: bp->b_wcred = NOCRED; ! 237: bp->b_vnbufs.le_next = NOLIST; ! 238: bp->b_data = (char *)base; ! 239: bp->b_bufsize = 0; ! 240: bp->b_flags = B_INVAL; ! 241: binsheadfree(bp, &iobufqueue); ! 242: ! 243: base += MAXPHYSIO; ! 244: } ! 245: } ! 246: ! 247: __inline struct buf * ! 248: bio_doread(vp, blkno, size, cred, async) ! 249: struct vnode *vp; ! 250: daddr_t blkno; ! 251: int size; ! 252: struct ucred *cred; ! 253: int async; ! 254: { ! 255: register struct buf *bp; ! 256: struct proc *p = current_proc(); ! 257: ! 258: bp = getblk(vp, blkno, size, 0, 0); ! 259: ! 260: /* ! 261: * If buffer does not have data valid, start a read. ! 262: * Note that if buffer is B_INVAL, getblk() won't return it. ! 263: * Therefore, it's valid if it's I/O has completed or been delayed. ! 264: */ ! 265: if (!ISSET(bp->b_flags, (B_DONE | B_DELWRI))) { ! 266: /* Start I/O for the buffer (keeping credentials). */ ! 267: SET(bp->b_flags, B_READ | async); ! 268: if (cred != NOCRED && bp->b_rcred == NOCRED) { ! 269: crhold(cred); ! 270: bp->b_rcred = cred; ! 271: } ! 272: VOP_STRATEGY(bp); ! 273: ! 274: trace(TR_BREADMISS, pack(vp, size), blkno); ! 275: ! 276: /* Pay for the read. */ ! 277: if (p && p->p_stats) ! 278: p->p_stats->p_ru.ru_inblock++; /* XXX */ ! 279: } else if (async) { ! 280: brelse(bp); ! 281: } ! 282: ! 283: trace(TR_BREADHIT, pack(vp, size), blkno); ! 284: ! 285: return (bp); ! 286: } ! 287: ! 288: /* ! 289: * Read a disk block. ! 290: * This algorithm described in Bach (p.54). ! 291: */ ! 292: int ! 293: bread(vp, blkno, size, cred, bpp) ! 294: struct vnode *vp; ! 295: daddr_t blkno; ! 296: int size; ! 297: struct ucred *cred; ! 298: struct buf **bpp; ! 299: { ! 300: register struct buf *bp; ! 301: ! 302: /* Get buffer for block. */ ! 303: bp = *bpp = bio_doread(vp, blkno, size, cred, 0); ! 304: ! 305: /* Wait for the read to complete, and return result. */ ! 306: return (biowait(bp)); ! 307: } ! 308: ! 309: /* ! 310: * Read-ahead multiple disk blocks. The first is sync, the rest async. ! 311: * Trivial modification to the breada algorithm presented in Bach (p.55). ! 312: */ ! 313: int ! 314: breadn(vp, blkno, size, rablks, rasizes, nrablks, cred, bpp) ! 315: struct vnode *vp; ! 316: daddr_t blkno; int size; ! 317: daddr_t rablks[]; int rasizes[]; ! 318: int nrablks; ! 319: struct ucred *cred; ! 320: struct buf **bpp; ! 321: { ! 322: register struct buf *bp; ! 323: int i; ! 324: ! 325: bp = *bpp = bio_doread(vp, blkno, size, cred, 0); ! 326: ! 327: /* ! 328: * For each of the read-ahead blocks, start a read, if necessary. ! 329: */ ! 330: for (i = 0; i < nrablks; i++) { ! 331: /* If it's in the cache, just go on to next one. */ ! 332: if (incore(vp, rablks[i])) ! 333: continue; ! 334: ! 335: /* Get a buffer for the read-ahead block */ ! 336: (void) bio_doread(vp, rablks[i], rasizes[i], cred, B_ASYNC); ! 337: } ! 338: ! 339: /* Otherwise, we had to start a read for it; wait until it's valid. */ ! 340: return (biowait(bp)); ! 341: } ! 342: ! 343: /* ! 344: * Read with single-block read-ahead. Defined in Bach (p.55), but ! 345: * implemented as a call to breadn(). ! 346: * XXX for compatibility with old file systems. ! 347: */ ! 348: int ! 349: breada(vp, blkno, size, rablkno, rabsize, cred, bpp) ! 350: struct vnode *vp; ! 351: daddr_t blkno; int size; ! 352: daddr_t rablkno; int rabsize; ! 353: struct ucred *cred; ! 354: struct buf **bpp; ! 355: { ! 356: ! 357: return (breadn(vp, blkno, size, &rablkno, &rabsize, 1, cred, bpp)); ! 358: } ! 359: ! 360: /* ! 361: * Block write. Described in Bach (p.56) ! 362: */ ! 363: int ! 364: bwrite(bp) ! 365: struct buf *bp; ! 366: { ! 367: int rv, sync, wasdelayed; ! 368: struct proc *p = current_proc(); ! 369: ! 370: /* Remember buffer type, to switch on it later. */ ! 371: sync = !ISSET(bp->b_flags, B_ASYNC); ! 372: wasdelayed = ISSET(bp->b_flags, B_DELWRI); ! 373: CLR(bp->b_flags, (B_READ | B_DONE | B_ERROR | B_DELWRI)); ! 374: ! 375: if (!sync) { ! 376: /* ! 377: * If not synchronous, pay for the I/O operation and make ! 378: * sure the buf is on the correct vnode queue. We have ! 379: * to do this now, because if we don't, the vnode may not ! 380: * be properly notified that its I/O has completed. ! 381: */ ! 382: if (wasdelayed) ! 383: reassignbuf(bp, bp->b_vp); ! 384: else ! 385: if (p && p->p_stats) ! 386: p->p_stats->p_ru.ru_oublock++; /* XXX */ ! 387: } ! 388: ! 389: trace(TR_BWRITE, pack(bp->b_vp, bp->b_bcount), bp->b_lblkno); ! 390: ! 391: /* Initiate disk write. Make sure the appropriate party is charged. */ ! 392: SET(bp->b_flags, B_WRITEINPROG); ! 393: bp->b_vp->v_numoutput++; ! 394: VOP_STRATEGY(bp); ! 395: ! 396: if (sync) { ! 397: /* ! 398: * If I/O was synchronous, wait for it to complete. ! 399: */ ! 400: rv = biowait(bp); ! 401: ! 402: /* ! 403: * Pay for the I/O operation, if it's not been paid for, and ! 404: * make sure it's on the correct vnode queue. (async operatings ! 405: * were payed for above.) ! 406: */ ! 407: if (wasdelayed) ! 408: reassignbuf(bp, bp->b_vp); ! 409: else ! 410: if (p && p->p_stats) ! 411: p->p_stats->p_ru.ru_oublock++; /* XXX */ ! 412: ! 413: /* Release the buffer. */ ! 414: brelse(bp); ! 415: ! 416: return (rv); ! 417: } else { ! 418: return (0); ! 419: } ! 420: } ! 421: ! 422: int ! 423: vn_bwrite(ap) ! 424: struct vop_bwrite_args *ap; ! 425: { ! 426: ! 427: return (bwrite(ap->a_bp)); ! 428: } ! 429: ! 430: /* ! 431: * Delayed write. ! 432: * ! 433: * The buffer is marked dirty, but is not queued for I/O. ! 434: * This routine should be used when the buffer is expected ! 435: * to be modified again soon, typically a small write that ! 436: * partially fills a buffer. ! 437: * ! 438: * NB: magnetic tapes cannot be delayed; they must be ! 439: * written in the order that the writes are requested. ! 440: * ! 441: * Described in Leffler, et al. (pp. 208-213). ! 442: */ ! 443: void ! 444: bdwrite(bp) ! 445: struct buf *bp; ! 446: { ! 447: struct proc *p = current_proc(); ! 448: ! 449: /* ! 450: * If the block hasn't been seen before: ! 451: * (1) Mark it as having been seen, ! 452: * (2) Charge for the write. ! 453: * (3) Make sure it's on its vnode's correct block list, ! 454: */ ! 455: if (!ISSET(bp->b_flags, B_DELWRI)) { ! 456: SET(bp->b_flags, B_DELWRI); ! 457: if (p && p->p_stats) ! 458: p->p_stats->p_ru.ru_oublock++; /* XXX */ ! 459: reassignbuf(bp, bp->b_vp); ! 460: } ! 461: ! 462: /* If this is a tape block, write it the block now. */ ! 463: if (ISSET(bp->b_flags, B_TAPE)) { ! 464: bwrite(bp); ! 465: return; ! 466: } ! 467: ! 468: /* Otherwise, the "write" is done, so mark and release the buffer. */ ! 469: SET(bp->b_flags, B_DONE); ! 470: brelse(bp); ! 471: } ! 472: ! 473: /* ! 474: * Asynchronous block write; just an asynchronous bwrite(). ! 475: */ ! 476: void ! 477: bawrite(bp) ! 478: struct buf *bp; ! 479: { ! 480: ! 481: SET(bp->b_flags, B_ASYNC); ! 482: VOP_BWRITE(bp); ! 483: } ! 484: ! 485: /* ! 486: * Release a buffer on to the free lists. ! 487: * Described in Bach (p. 46). ! 488: */ ! 489: void ! 490: brelse(bp) ! 491: struct buf *bp; ! 492: { ! 493: struct bqueues *bufq; ! 494: int s; ! 495: ! 496: trace(TR_BRELSE, pack(bp->b_vp, bp->b_bufsize), bp->b_lblkno); ! 497: ! 498: /* Wake up any processes waiting for any buffer to become free. */ ! 499: if (needbuffer) { ! 500: needbuffer = 0; ! 501: wakeup(&needbuffer); ! 502: } ! 503: ! 504: /* Wake up any proceeses waiting for _this_ buffer to become free. */ ! 505: if (ISSET(bp->b_flags, B_WANTED)) { ! 506: CLR(bp->b_flags, B_WANTED); ! 507: wakeup(bp); ! 508: } ! 509: ! 510: /* Block disk interrupts. */ ! 511: s = splbio(); ! 512: ! 513: /* ! 514: * Determine which queue the buffer should be on, then put it there. ! 515: */ ! 516: ! 517: /* If it's locked, don't report an error; try again later. */ ! 518: if (ISSET(bp->b_flags, (B_LOCKED|B_ERROR)) == (B_LOCKED|B_ERROR)) ! 519: CLR(bp->b_flags, B_ERROR); ! 520: ! 521: /* If it's not cacheable, or an error, mark it invalid. */ ! 522: if (ISSET(bp->b_flags, (B_NOCACHE|B_ERROR))) ! 523: SET(bp->b_flags, B_INVAL); ! 524: ! 525: if ((bp->b_bufsize <= 0) || ISSET(bp->b_flags, B_INVAL)) { ! 526: /* ! 527: * If it's invalid or empty, dissociate it from its vnode ! 528: * and put on the head of the appropriate queue. ! 529: */ ! 530: if (bp->b_vp) ! 531: brelvp(bp); ! 532: CLR(bp->b_flags, B_DELWRI); ! 533: if (bp->b_bufsize <= 0) ! 534: /* no data */ ! 535: bufq = &bufqueues[BQ_EMPTY]; ! 536: else ! 537: /* invalid data */ ! 538: bufq = &bufqueues[BQ_AGE]; ! 539: binsheadfree(bp, bufq); ! 540: } else { ! 541: /* ! 542: * It has valid data. Put it on the end of the appropriate ! 543: * queue, so that it'll stick around for as long as possible. ! 544: */ ! 545: if (ISSET(bp->b_flags, B_LOCKED)) ! 546: /* locked in core */ ! 547: bufq = &bufqueues[BQ_LOCKED]; ! 548: else if (ISSET(bp->b_flags, B_AGE)) ! 549: /* stale but valid data */ ! 550: bufq = &bufqueues[BQ_AGE]; ! 551: else ! 552: /* valid data */ ! 553: bufq = &bufqueues[BQ_LRU]; ! 554: binstailfree(bp, bufq); ! 555: } ! 556: ! 557: /* Unlock the buffer. */ ! 558: CLR(bp->b_flags, (B_AGE | B_ASYNC | B_BUSY | B_NOCACHE)); ! 559: ! 560: /* Allow disk interrupts. */ ! 561: splx(s); ! 562: } ! 563: ! 564: /* ! 565: * Determine if a block is in the cache. ! 566: * Just look on what would be its hash chain. If it's there, return ! 567: * a pointer to it, unless it's marked invalid. If it's marked invalid, ! 568: * we normally don't return the buffer, unless the caller explicitly ! 569: * wants us to. ! 570: */ ! 571: struct buf * ! 572: incore(vp, blkno) ! 573: struct vnode *vp; ! 574: daddr_t blkno; ! 575: { ! 576: struct buf *bp; ! 577: ! 578: bp = BUFHASH(vp, blkno)->lh_first; ! 579: ! 580: /* Search hash chain */ ! 581: for (; bp != NULL; bp = bp->b_hash.le_next) { ! 582: if (bp->b_lblkno == blkno && bp->b_vp == vp && ! 583: !ISSET(bp->b_flags, B_INVAL)) ! 584: return (bp); ! 585: } ! 586: ! 587: return (0); ! 588: } ! 589: ! 590: /* ! 591: * Get a block of requested size that is associated with ! 592: * a given vnode and block offset. If it is found in the ! 593: * block cache, mark it as having been found, make it busy ! 594: * and return it. Otherwise, return an empty block of the ! 595: * correct size. It is up to the caller to insure that the ! 596: * cached blocks be of the correct size. ! 597: */ ! 598: struct buf * ! 599: getblk(vp, blkno, size, slpflag, slptimeo) ! 600: register struct vnode *vp; ! 601: daddr_t blkno; ! 602: int size, slpflag, slptimeo; ! 603: { ! 604: struct buf *bp; ! 605: int s, err; ! 606: ! 607: start: ! 608: s = splbio(); ! 609: if (bp = incore(vp, blkno)) { /* XXX NFS VOP_BWRITE foolishness */ ! 610: if (ISSET(bp->b_flags, B_BUSY)) { ! 611: SET(bp->b_flags, B_WANTED); ! 612: err = tsleep(bp, slpflag | (PRIBIO + 1), "getblk", ! 613: slptimeo); ! 614: splx(s); ! 615: if (err) ! 616: return (NULL); ! 617: goto start; ! 618: } ! 619: SET(bp->b_flags, (B_BUSY | B_CACHE)); ! 620: bremfree(bp); ! 621: splx(s); ! 622: allocbuf(bp, size); ! 623: } else { ! 624: splx(s); ! 625: if ((bp = getnewbuf(slpflag, slptimeo)) == NULL) ! 626: goto start; ! 627: binshash(bp, BUFHASH(vp, blkno)); ! 628: allocbuf(bp, size); ! 629: bp->b_blkno = bp->b_lblkno = blkno; ! 630: s = splbio(); ! 631: bgetvp(vp, bp); ! 632: splx(s); ! 633: } ! 634: return (bp); ! 635: } ! 636: ! 637: /* ! 638: * Get an empty, disassociated buffer of given size. ! 639: */ ! 640: struct buf * ! 641: geteblk(size) ! 642: int size; ! 643: { ! 644: struct buf *bp; ! 645: ! 646: while ((bp = getnewbuf(0, 0)) == 0) ! 647: ; ! 648: SET(bp->b_flags, B_INVAL); ! 649: binshash(bp, &invalhash); ! 650: allocbuf(bp, size); ! 651: ! 652: return (bp); ! 653: } ! 654: ! 655: /* ! 656: * Expand or contract the actual memory allocated to a buffer. ! 657: * ! 658: * If the buffer shrinks, data is lost, so it's up to the ! 659: * caller to have written it out *first*; this routine will not ! 660: * start a write. If the buffer grows, it's the callers ! 661: * responsibility to fill out the buffer's additional contents. ! 662: */ ! 663: int ! 664: allocbuf(bp, size) ! 665: struct buf *bp; ! 666: int size; ! 667: { ! 668: struct buf *nbp; ! 669: vm_size_t desired_size; ! 670: int s; ! 671: ! 672: desired_size = roundup(size, CLBYTES); ! 673: if (desired_size > MAXBSIZE) ! 674: panic("allocbuf: buffer larger than MAXBSIZE requested"); ! 675: ! 676: if (bp->b_bufsize == desired_size) ! 677: goto out; ! 678: ! 679: /* ! 680: * If the buffer is smaller than the desired size, we need to snarf ! 681: * it from other buffers. Get buffers (via getnewbuf()), and ! 682: * steal their pages. ! 683: */ ! 684: while (bp->b_bufsize < desired_size) { ! 685: int amt; ! 686: ! 687: /* find a buffer */ ! 688: while ((nbp = getnewbuf(0, 0)) == NULL) ! 689: ; ! 690: SET(nbp->b_flags, B_INVAL); ! 691: binshash(nbp, &invalhash); ! 692: ! 693: /* and steal its pages, up to the amount we need */ ! 694: amt = min(nbp->b_bufsize, (desired_size - bp->b_bufsize)); ! 695: pagemove((nbp->b_data + nbp->b_bufsize - amt), ! 696: bp->b_data + bp->b_bufsize, amt); ! 697: bp->b_bufsize += amt; ! 698: nbp->b_bufsize -= amt; ! 699: ! 700: /* reduce transfer count if we stole some data */ ! 701: if (nbp->b_bcount > nbp->b_bufsize) ! 702: nbp->b_bcount = nbp->b_bufsize; ! 703: ! 704: #if DIAGNOSTIC ! 705: if (nbp->b_bufsize < 0) ! 706: panic("allocbuf: negative bufsize"); ! 707: #endif ! 708: ! 709: brelse(nbp); ! 710: } ! 711: ! 712: /* ! 713: * If we want a buffer smaller than the current size, ! 714: * shrink this buffer. Grab a buf head from the EMPTY queue, ! 715: * move a page onto it, and put it on front of the AGE queue. ! 716: * If there are no free buffer headers, leave the buffer alone. ! 717: */ ! 718: if (bp->b_bufsize > desired_size) { ! 719: s = splbio(); ! 720: if ((nbp = bufqueues[BQ_EMPTY].tqh_first) == NULL) { ! 721: /* No free buffer head */ ! 722: splx(s); ! 723: goto out; ! 724: } ! 725: bremfree(nbp); ! 726: SET(nbp->b_flags, B_BUSY); ! 727: splx(s); ! 728: ! 729: /* move the page to it and note this change */ ! 730: pagemove(bp->b_data + desired_size, ! 731: nbp->b_data, bp->b_bufsize - desired_size); ! 732: nbp->b_bufsize = bp->b_bufsize - desired_size; ! 733: bp->b_bufsize = desired_size; ! 734: nbp->b_bcount = 0; ! 735: SET(nbp->b_flags, B_INVAL); ! 736: ! 737: /* release the newly-filled buffer and leave */ ! 738: brelse(nbp); ! 739: } ! 740: ! 741: out: ! 742: bp->b_bcount = size; ! 743: } ! 744: ! 745: /* ! 746: * Find a buffer which is available for use. ! 747: * Select something from a free list. ! 748: * Preference is to AGE list, then LRU list. ! 749: */ ! 750: struct buf * ! 751: getnewbuf(slpflag, slptimeo) ! 752: int slpflag, slptimeo; ! 753: { ! 754: register struct buf *bp; ! 755: register struct buf *lru_bp; ! 756: register struct buf *age_bp; ! 757: register int age_time, lru_time; ! 758: int s; ! 759: struct ucred *cred; ! 760: ! 761: start: ! 762: s = splbio(); ! 763: ! 764: age_bp = bufqueues[BQ_AGE].tqh_first; ! 765: lru_bp = bufqueues[BQ_LRU].tqh_first; ! 766: ! 767: if (age_bp == NULL && lru_bp == NULL) { ! 768: /* wait for a free buffer of any kind */ ! 769: needbuffer = 1; ! 770: tsleep(&needbuffer, slpflag|(PRIBIO+1), "getnewbuf", slptimeo); ! 771: splx(s); ! 772: return (0); ! 773: } ! 774: if (age_bp == NULL) ! 775: bp = lru_bp; ! 776: else if (lru_bp == NULL) ! 777: bp = age_bp; ! 778: else { ! 779: if (((age_time = (time.tv_sec - age_bp->b_timestamp)) < 0) || ! 780: ((lru_time = (time.tv_sec - lru_bp->b_timestamp)) < 0)) { ! 781: /* time was set backwards */ ! 782: bp = age_bp; ! 783: /* ! 784: * we should probably re-timestamp eveything in the queues ! 785: * at this point with the current time ! 786: */ ! 787: } else { ! 788: if (lru_time >= lru_is_stale && age_time < age_is_stale) ! 789: bp = lru_bp; ! 790: else ! 791: bp = age_bp; ! 792: } ! 793: } ! 794: bremfree(bp); ! 795: ! 796: /* Buffer is no longer on free lists. */ ! 797: SET(bp->b_flags, B_BUSY); ! 798: splx(s); ! 799: ! 800: /* If buffer was a delayed write, start it, and go back to the top. */ ! 801: if (ISSET(bp->b_flags, B_DELWRI)) { ! 802: bawrite (bp); ! 803: goto start; ! 804: } ! 805: ! 806: trace(TR_BRELSE, pack(bp->b_vp, bp->b_bufsize), bp->b_lblkno); ! 807: ! 808: /* disassociate us from our vnode, if we had one... */ ! 809: s = splbio(); ! 810: if (bp->b_vp) ! 811: brelvp(bp); ! 812: splx(s); ! 813: ! 814: /* clear out various other fields */ ! 815: bp->b_flags = B_BUSY; ! 816: bp->b_dev = NODEV; ! 817: bp->b_blkno = bp->b_lblkno = 0; ! 818: bp->b_iodone = 0; ! 819: bp->b_error = 0; ! 820: bp->b_resid = 0; ! 821: bp->b_bcount = 0; ! 822: bp->b_dirtyoff = bp->b_dirtyend = 0; ! 823: bp->b_validoff = bp->b_validend = 0; ! 824: ! 825: /* nuke any credentials we were holding */ ! 826: cred = bp->b_rcred; ! 827: if (cred != NOCRED) { ! 828: bp->b_rcred = NOCRED; ! 829: crfree(cred); ! 830: } ! 831: cred = bp->b_wcred; ! 832: if (cred != NOCRED) { ! 833: bp->b_wcred = NOCRED; ! 834: crfree(cred); ! 835: } ! 836: ! 837: bremhash(bp); ! 838: return (bp); ! 839: } ! 840: ! 841: /* ! 842: * Wait for operations on the buffer to complete. ! 843: * When they do, extract and return the I/O's error value. ! 844: */ ! 845: int ! 846: biowait(bp) ! 847: struct buf *bp; ! 848: { ! 849: int s; ! 850: ! 851: s = splbio(); ! 852: while (!ISSET(bp->b_flags, B_DONE)) ! 853: tsleep(bp, PRIBIO + 1, "biowait", 0); ! 854: splx(s); ! 855: ! 856: /* check for interruption of I/O (e.g. via NFS), then errors. */ ! 857: if (ISSET(bp->b_flags, B_EINTR)) { ! 858: CLR(bp->b_flags, B_EINTR); ! 859: return (EINTR); ! 860: } else if (ISSET(bp->b_flags, B_ERROR)) ! 861: return (bp->b_error ? bp->b_error : EIO); ! 862: else ! 863: return (0); ! 864: } ! 865: ! 866: /* ! 867: * Mark I/O complete on a buffer. ! 868: * ! 869: * If a callback has been requested, e.g. the pageout ! 870: * daemon, do so. Otherwise, awaken waiting processes. ! 871: * ! 872: * [ Leffler, et al., says on p.247: ! 873: * "This routine wakes up the blocked process, frees the buffer ! 874: * for an asynchronous write, or, for a request by the pagedaemon ! 875: * process, invokes a procedure specified in the buffer structure" ] ! 876: * ! 877: * In real life, the pagedaemon (or other system processes) wants ! 878: * to do async stuff to, and doesn't want the buffer brelse()'d. ! 879: * (for swap pager, that puts swap buffers on the free lists (!!!), ! 880: * for the vn device, that puts malloc'd buffers on the free lists!) ! 881: */ ! 882: void ! 883: biodone(bp) ! 884: struct buf *bp; ! 885: { ! 886: boolean_t funnel_state; ! 887: ! 888: funnel_state = thread_set_funneled(TRUE); ! 889: if (ISSET(bp->b_flags, B_DONE)) ! 890: panic("biodone already"); ! 891: SET(bp->b_flags, B_DONE); /* note that it's done */ ! 892: ! 893: if (!ISSET(bp->b_flags, B_READ) && !ISSET(bp->b_flags, B_RAW)) /* wake up reader */ ! 894: vwakeup(bp); ! 895: ! 896: if (ISSET(bp->b_flags, B_CALL)) { /* if necessary, call out */ ! 897: CLR(bp->b_flags, B_CALL); /* but note callout done */ ! 898: (*bp->b_iodone)(bp); ! 899: } else if (ISSET(bp->b_flags, B_ASYNC)) /* if async, release it */ ! 900: brelse(bp); ! 901: else { /* or just wakeup the buffer */ ! 902: CLR(bp->b_flags, B_WANTED); ! 903: wakeup(bp); ! 904: } ! 905: (void) thread_set_funneled(funnel_state); ! 906: } ! 907: ! 908: /* ! 909: * Return a count of buffers on the "locked" queue. ! 910: */ ! 911: int ! 912: count_lock_queue() ! 913: { ! 914: register struct buf *bp; ! 915: register int n = 0; ! 916: ! 917: for (bp = bufqueues[BQ_LOCKED].tqh_first; bp; ! 918: bp = bp->b_freelist.tqe_next) ! 919: n++; ! 920: return (n); ! 921: } ! 922: ! 923: #if MACH_NBC ! 924: #include <ufs/ufs/quota.h> ! 925: #include <ufs/ufs/inode.h> ! 926: ! 927: #define btodevblk(b) ((b) / devBlocksize) ! 928: void ! 929: blkflush(struct vnode *vp, daddr_t blkno, vm_size_t size) ! 930: { ! 931: register struct buf *ep, *nbp; ! 932: daddr_t start, last; ! 933: int s,err; ! 934: struct inode *ip= VTOI(vp); ! 935: int devBlocksize=1024; ! 936: ! 937: #if 1 ! 938: VOP_DEVBLOCKSIZE(ip->i_devvp, &devBlocksize); ! 939: #endif ! 940: ! 941: ! 942: start = blkno; ! 943: last = start + btodb(size, devBlocksize) - 1; ! 944: loop: ! 945: for(ep = vp->v_dirtyblkhd.lh_first; ep; ep = nbp) { ! 946: nbp = ep->b_vnbufs.le_next; ! 947: if (ep->b_vp != vp || ISSET(ep->b_flags, B_INVAL)) ! 948: continue; ! 949: /* look for overlap */ ! 950: if (ep->b_bcount == 0 || ep->b_blkno > last || ! 951: ep->b_blkno + btodevblk(ep->b_bcount) <= start) ! 952: continue; ! 953: s = splbio(); ! 954: if (ISSET(ep->b_flags, B_BUSY)) { ! 955: SET(ep->b_flags, B_WANTED); ! 956: err = tsleep(ep, (PRIBIO + 1), "blkflush", ! 957: 0); ! 958: splx(s); ! 959: goto loop; ! 960: } ! 961: if(ISSET(ep->b_flags, B_DELWRI)) { ! 962: bremfree(ep); ! 963: SET(ep->b_flags, B_BUSY); ! 964: (void) splx(s); ! 965: bwrite(ep); ! 966: goto loop; ! 967: } ! 968: (void) splx(s); ! 969: } ! 970: ! 971: } ! 972: #endif /* MACH_NBC */ ! 973: #if DIAGNOSTIC ! 974: /* ! 975: * Print out statistics on the current allocation of the buffer pool. ! 976: * Can be enabled to print out on every ``sync'' by setting "syncprt" ! 977: * in vfs_syscalls.c using sysctl. ! 978: */ ! 979: void ! 980: vfs_bufstats() ! 981: { ! 982: int s, i, j, count; ! 983: register struct buf *bp; ! 984: register struct bqueues *dp; ! 985: int counts[MAXBSIZE/CLBYTES+1]; ! 986: static char *bname[BQUEUES] = { "LOCKED", "LRU", "AGE", "EMPTY" }; ! 987: ! 988: for (dp = bufqueues, i = 0; dp < &bufqueues[BQUEUES]; dp++, i++) { ! 989: count = 0; ! 990: for (j = 0; j <= MAXBSIZE/CLBYTES; j++) ! 991: counts[j] = 0; ! 992: s = splbio(); ! 993: for (bp = dp->tqh_first; bp; bp = bp->b_freelist.tqe_next) { ! 994: counts[bp->b_bufsize/CLBYTES]++; ! 995: count++; ! 996: } ! 997: splx(s); ! 998: printf("%s: total-%d", bname[i], count); ! 999: for (j = 0; j <= MAXBSIZE/CLBYTES; j++) ! 1000: if (counts[j] != 0) ! 1001: printf(", %d-%d", j * CLBYTES, counts[j]); ! 1002: printf("\n"); ! 1003: } ! 1004: } ! 1005: #endif /* DIAGNOSTIC */ ! 1006: ! 1007: ! 1008: struct buf * ! 1009: alloc_io_buf(vp) ! 1010: struct vnode *vp; ! 1011: { register struct buf *bp; ! 1012: int s; ! 1013: ! 1014: s = splbio(); ! 1015: ! 1016: if ((bp = iobufqueue.tqh_first) == NULL) { ! 1017: splx(s); ! 1018: return (NULL); ! 1019: } ! 1020: TAILQ_REMOVE(&iobufqueue, bp, b_freelist); ! 1021: bp->b_timestamp = 0; ! 1022: ! 1023: /* clear out various fields */ ! 1024: bp->b_flags = (B_BUSY | B_RAW); ! 1025: bp->b_blkno = bp->b_lblkno = 0; ! 1026: bp->b_iodone = 0; ! 1027: bp->b_error = 0; ! 1028: bp->b_resid = 0; ! 1029: bp->b_bcount = 0; ! 1030: bp->b_bufsize = 0; ! 1031: bp->b_vp = vp; ! 1032: ! 1033: if (vp->v_type == VBLK || vp->v_type == VCHR) ! 1034: bp->b_dev = vp->v_rdev; ! 1035: else ! 1036: bp->b_dev = NODEV; ! 1037: splx(s); ! 1038: ! 1039: return (bp); ! 1040: } ! 1041: ! 1042: void ! 1043: free_io_buf(bp) ! 1044: struct buf *bp; ! 1045: { ! 1046: int s; ! 1047: ! 1048: s = splbio(); ! 1049: /* ! 1050: * put buffer back on the head of the iobufqueue ! 1051: */ ! 1052: bp->b_vp = NULL; ! 1053: bp->b_flags = B_INVAL; ! 1054: ! 1055: binsheadfree(bp, &iobufqueue); ! 1056: ! 1057: splx(s); ! 1058: }
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