src/vol/ihandle.c

   1 /*
   2  * Copyright 2000, International Business Machines Corporation and others.
   3  * All Rights Reserved.
   4  *
   5  * This software has been released under the terms of the IBM Public
   6  * License.  For details, see the LICENSE file in the top-level source
   7  * directory or online at http://www.openafs.org/dl/license10.html
   8  */
   9
  10 /*  ihandle.c   - file descriptor cacheing for Inode handles.           */
  11 /*                                                                      */
  12 /************************************************************************/
  13
  14 #include <afsconfig.h>
  15 #include <afs/param.h>
  16
  17 #include <roken.h>
  18
  19 #include <limits.h>
  20
  21 #ifdef HAVE_SYS_RESOURCE_H
  22 #include <sys/resource.h>
  23 #endif
  24
  25 #include <afs/opr.h>
  26 #ifdef AFS_PTHREAD_ENV
  27 # include <opr/lock.h>
  28 #endif
  29 #include <afs/afsint.h>
  30 #include <afs/afssyscalls.h>
  31 #include <afs/afsutil.h>
  32
  33 #include "nfs.h"
  34 #include "ihandle.h"
  35 #include "viceinode.h"
  36
  37 #ifdef AFS_PTHREAD_ENV
  38 pthread_once_t ih_glock_once = PTHREAD_ONCE_INIT;
  39 pthread_mutex_t ih_glock_mutex;
  40 #endif /* AFS_PTHREAD_ENV */
  41
  42 /* Linked list of available inode handles */
  43 IHandle_t *ihAvailHead;
  44 IHandle_t *ihAvailTail;
  45
  46 /* Linked list of available file descriptor handles */
  47 FdHandle_t *fdAvailHead;
  48 FdHandle_t *fdAvailTail;
  49
  50 /* Linked list of available stream descriptor handles */
  51 StreamHandle_t *streamAvailHead;
  52 StreamHandle_t *streamAvailTail;
  53
  54 /* LRU list for file descriptor handles */
  55 FdHandle_t *fdLruHead;
  56 FdHandle_t *fdLruTail;
  57
  58 int ih_Inited = 0;
  59 int ih_PkgDefaultsSet = 0;
  60
  61 /* Most of the servers use fopen/fdopen. Since the FILE structure
  62  * only has eight bits for the file descriptor, the cache size
  63  * has to be less than 256. The cache can be made larger as long
  64  * as you are sure you don't need fopen/fdopen. */
  65
  66 /* As noted in ihandle.h, the fileno member of FILE on most platforms
  67  * in 2008 is a 16- or 32-bit signed int. -Matt
  68  */
  69 int fdMaxCacheSize = 0;
  70 int fdCacheSize = 0;
  71
  72 /* Number of in use file descriptors */
  73 int fdInUseCount = 0;
  74
  75 /* Hash table for inode handles */
  76 IHashBucket_t ihashTable[I_HANDLE_HASH_SIZE];
  77
  78 static int _ih_release_r(IHandle_t * ihP);
  79
  80 /* start-time configurable I/O limits */
  81 ih_init_params vol_io_params;
  82
  83 void ih_PkgDefaults(void)
  84 {
  85     /* once */
  86     ih_PkgDefaultsSet = 1;
  87
  88     /* default to well-known values */
  89     vol_io_params.fd_handle_setaside = FD_HANDLE_SETASIDE;
  90
  91     /* initial fd cachesize.  the only one that will be used if
  92      * the application does not call ih_UseLargeCache().  set this
  93      * to a value representable in fileno member of the system's
  94      * FILE structure (or equivalent). */
  95     vol_io_params.fd_initial_cachesize = FD_DEFAULT_CACHESIZE;
  96
  97     /* fd cache size that will be used if/when ih_UseLargeCache()
  98      * is called */
  99     vol_io_params.fd_max_cachesize = FD_MAX_CACHESIZE;
 100
 101     vol_io_params.sync_behavior = IH_SYNC_ONCLOSE;
 102 }
 103
 104 int
 105 ih_SetSyncBehavior(const char *behavior)
 106 {
 107     int val;
 108
 109     if (strcmp(behavior, "always") == 0) {
 110         val = IH_SYNC_ALWAYS;
 111
 112     } else if (strcmp(behavior, "onclose") == 0) {
 113         val = IH_SYNC_ONCLOSE;
 114
 115     } else if (strcmp(behavior, "never") == 0) {
 116         val = IH_SYNC_NEVER;
 117
 118     } else {
 119         /* invalid behavior name */
 120         return -1;
 121     }
 122
 123     vol_io_params.sync_behavior = val;
 124     return 0;
 125 }
 126
 127 #ifdef AFS_PTHREAD_ENV
 128 /* Initialize the global ihandle mutex */
 129 void
 130 ih_glock_init(void)
 131 {
 132     opr_mutex_init(&ih_glock_mutex);
 133 }
 134 #endif /* AFS_PTHREAD_ENV */
 135
 136 /* Initialize the file descriptor cache */
 137 void
 138 ih_Initialize(void)
 139 {
 140     int i;
 141     opr_Assert(!ih_Inited);
 142     ih_Inited = 1;
 143     DLL_INIT_LIST(ihAvailHead, ihAvailTail);
 144     DLL_INIT_LIST(fdAvailHead, fdAvailTail);
 145     DLL_INIT_LIST(fdLruHead, fdLruTail);
 146     for (i = 0; i < I_HANDLE_HASH_SIZE; i++) {
 147         DLL_INIT_LIST(ihashTable[i].ihash_head, ihashTable[i].ihash_tail);
 148     }
 149 #if defined(AFS_NT40_ENV)
 150     fdMaxCacheSize = vol_io_params.fd_max_cachesize;
 151 #elif defined(AFS_SUN5_ENV) || defined(AFS_NBSD_ENV)
 152     {
 153         struct rlimit rlim;
 154         opr_Verify(getrlimit(RLIMIT_NOFILE, &rlim) == 0);
 155         rlim.rlim_cur = rlim.rlim_max;
 156         opr_Verify(setrlimit(RLIMIT_NOFILE, &rlim) == 0);
 157         fdMaxCacheSize = rlim.rlim_cur - vol_io_params.fd_handle_setaside;
 158 #ifdef AFS_NBSD_ENV
 159         /* XXX this is to avoid using up all system fd netbsd is
 160          * somewhat broken and have set maximum fd for a root process
 161          * to the same as system fd that is avaible, so if the
 162          * fileserver uses all up process fds, all system fd will be
 163          * used up too !
 164          *
 165          * Check for this better
 166          */
 167         fdMaxCacheSize /= 4;
 168 #endif
 169         fdMaxCacheSize = min(fdMaxCacheSize, vol_io_params.fd_max_cachesize);
 170         opr_Assert(fdMaxCacheSize > 0);
 171     }
 172 #elif defined(AFS_HPUX_ENV)
 173     /* Avoid problems with "UFSOpen: igetinode failed" panics on HPUX 11.0 */
 174     fdMaxCacheSize = 0;
 175 #else
 176     {
 177         long fdMax = max(sysconf(_SC_OPEN_MAX) - vol_io_params.fd_handle_setaside,
 178                                          0);
 179         fdMaxCacheSize = (int)min(fdMax, vol_io_params.fd_max_cachesize);
 180     }
 181 #endif
 182     fdCacheSize = min(fdMaxCacheSize, vol_io_params.fd_initial_cachesize);
 183 }
 184
 185 /* Make the file descriptor cache as big as possible. Don't this call
 186  * if the program uses fopen or fdopen, if fd_max_cachesize cannot be
 187  * represented in the fileno member of the system FILE structure (or
 188  * equivalent).
 189  */
 190 void
 191 ih_UseLargeCache(void)
 192 {
 193     IH_LOCK;
 194
 195     if (!ih_PkgDefaultsSet) {
 196         ih_PkgDefaults();
 197     }
 198
 199     if (!ih_Inited) {
 200         ih_Initialize();
 201     }
 202
 203     fdCacheSize = fdMaxCacheSize;
 204
 205     IH_UNLOCK;
 206 }
 207
 208 /* Allocate a chunk of inode handles */
 209 void
 210 iHandleAllocateChunk(void)
 211 {
 212     int i;
 213     IHandle_t *ihP;
 214
 215     opr_Assert(ihAvailHead == NULL);
 216     ihP = malloc(I_HANDLE_MALLOCSIZE * sizeof(IHandle_t));
 217     opr_Assert(ihP != NULL);
 218     for (i = 0; i < I_HANDLE_MALLOCSIZE; i++) {
 219         ihP[i].ih_refcnt = 0;
 220         DLL_INSERT_TAIL(&ihP[i], ihAvailHead, ihAvailTail, ih_next, ih_prev);
 221     }
 222 }
 223
 224 /* Initialize an inode handle */
 225 IHandle_t *
 226 ih_init(int dev, int vid, Inode ino)
 227 {
 228     int ihash = IH_HASH(dev, vid, ino);
 229     IHandle_t *ihP;
 230
 231     if (!ih_PkgDefaultsSet) {
 232         ih_PkgDefaults();
 233     }
 234
 235     IH_LOCK;
 236     if (!ih_Inited) {
 237         ih_Initialize();
 238     }
 239
 240     /* Do we already have a handle for this Inode? */
 241     for (ihP = ihashTable[ihash].ihash_head; ihP; ihP = ihP->ih_next) {
 242         if (ihP->ih_ino == ino && ihP->ih_vid == vid && ihP->ih_dev == dev) {
 243             ihP->ih_refcnt++;
 244             IH_UNLOCK;
 245             return ihP;
 246         }
 247     }
 248
 249     /* Allocate and initialize a new Inode handle */
 250     if (ihAvailHead == NULL) {
 251         iHandleAllocateChunk();
 252     }
 253     ihP = ihAvailHead;
 254     opr_Assert(ihP->ih_refcnt == 0);
 255     DLL_DELETE(ihP, ihAvailHead, ihAvailTail, ih_next, ih_prev);
 256     ihP->ih_dev = dev;
 257     ihP->ih_vid = vid;
 258     ihP->ih_ino = ino;
 259     ihP->ih_flags = 0;
 260     ihP->ih_synced = 0;
 261     ihP->ih_refcnt = 1;
 262     DLL_INIT_LIST(ihP->ih_fdhead, ihP->ih_fdtail);
 263     DLL_INSERT_TAIL(ihP, ihashTable[ihash].ihash_head,
 264                     ihashTable[ihash].ihash_tail, ih_next, ih_prev);
 265     IH_UNLOCK;
 266     return ihP;
 267 }
 268
 269 /* Copy an inode handle */
 270 IHandle_t *
 271 ih_copy(IHandle_t * ihP)
 272 {
 273     IH_LOCK;
 274     opr_Assert(ih_Inited);
 275     opr_Assert(ihP->ih_refcnt > 0);
 276     ihP->ih_refcnt++;
 277     IH_UNLOCK;
 278     return ihP;
 279 }
 280
 281 /* Allocate a chunk of file descriptor handles */
 282 void
 283 fdHandleAllocateChunk(void)
 284 {
 285     int i;
 286     FdHandle_t *fdP;
 287
 288     opr_Assert(fdAvailHead == NULL);
 289     fdP = malloc(FD_HANDLE_MALLOCSIZE * sizeof(FdHandle_t));
 290     opr_Assert(fdP != NULL);
 291     for (i = 0; i < FD_HANDLE_MALLOCSIZE; i++) {
 292         fdP[i].fd_status = FD_HANDLE_AVAIL;
 293         fdP[i].fd_refcnt = 0;
 294         fdP[i].fd_ih = NULL;
 295         fdP[i].fd_fd = INVALID_FD;
 296         fdP[i].fd_ihnext = NULL;
 297         fdP[i].fd_ihprev = NULL;
 298         DLL_INSERT_TAIL(&fdP[i], fdAvailHead, fdAvailTail, fd_next, fd_prev);
 299     }
 300 }
 301
 302 /* Allocate a chunk of stream handles */
 303 void
 304 streamHandleAllocateChunk(void)
 305 {
 306     int i;
 307     StreamHandle_t *streamP;
 308
 309     opr_Assert(streamAvailHead == NULL);
 310     streamP = (StreamHandle_t *)
 311         malloc(STREAM_HANDLE_MALLOCSIZE * sizeof(StreamHandle_t));
 312     opr_Assert(streamP != NULL);
 313     for (i = 0; i < STREAM_HANDLE_MALLOCSIZE; i++) {
 314         streamP[i].str_fd = INVALID_FD;
 315         DLL_INSERT_TAIL(&streamP[i], streamAvailHead, streamAvailTail,
 316                         str_next, str_prev);
 317     }
 318 }
 319
 320 /*
 321  * Get a file descriptor handle given an Inode handle
 322  * Takes the given file descriptor, and creates a new FdHandle_t for it,
 323  * attached to the given IHandle_t. If fdLruHead is not NULL, fd can be
 324  * INVALID_FD, indicating that the caller failed to open the relevant file
 325  * because we had too many FDs open; ih_attachfd_r will then just evict/close
 326  * an existing fd in the cache, and return NULL. You must not call this
 327  * function with an invalid fd while fdLruHead is NULL; instead, error out.
 328  */
 329 static FdHandle_t *
 330 ih_attachfd_r(IHandle_t *ihP, FD_t fd)
 331 {
 332     FD_t closeFd;
 333     FdHandle_t *fdP;
 334
 335     /* If the given fd is invalid, we must have an available fd to close.
 336      * Otherwise, the caller must have realized this before calling
 337      * ih_attachfd_r and yielded an error before getting here. */
 338     opr_Assert(fd != INVALID_FD || fdLruHead != NULL);
 339
 340     /* fdCacheSize limits the size of the descriptor cache, but
 341      * we permit the number of open files to exceed fdCacheSize.
 342      * We only recycle open file descriptors when the number
 343      * of open files reaches the size of the cache */
 344     if ((fdInUseCount > fdCacheSize || fd == INVALID_FD)  && fdLruHead != NULL) {
 345         fdP = fdLruHead;
 346         opr_Assert(fdP->fd_status == FD_HANDLE_OPEN);
 347         DLL_DELETE(fdP, fdLruHead, fdLruTail, fd_next, fd_prev);
 348         DLL_DELETE(fdP, fdP->fd_ih->ih_fdhead, fdP->fd_ih->ih_fdtail,
 349                    fd_ihnext, fd_ihprev);
 350         closeFd = fdP->fd_fd;
 351         if (fd == INVALID_FD) {
 352             fdCacheSize--;          /* reduce in order to not run into here too often */
 353             DLL_INSERT_TAIL(fdP, fdAvailHead, fdAvailTail, fd_next, fd_prev);
 354             fdP->fd_status = FD_HANDLE_AVAIL;
 355             fdP->fd_ih = NULL;
 356             fdP->fd_fd = INVALID_FD;
 357             IH_UNLOCK;
 358             OS_CLOSE(closeFd);
 359             IH_LOCK;
 360             fdInUseCount -= 1;
 361             return NULL;
 362         }
 363     } else {
 364         if (fdAvailHead == NULL) {
 365             fdHandleAllocateChunk();
 366         }
 367         fdP = fdAvailHead;
 368         opr_Assert(fdP->fd_status == FD_HANDLE_AVAIL);
 369         DLL_DELETE(fdP, fdAvailHead, fdAvailTail, fd_next, fd_prev);
 370         closeFd = INVALID_FD;
 371     }
 372
 373     fdP->fd_status = FD_HANDLE_INUSE;
 374     fdP->fd_fd = fd;
 375     fdP->fd_ih = ihP;
 376     fdP->fd_refcnt++;
 377
 378     ihP->ih_refcnt++;
 379
 380     /* Add this handle to the Inode's list of open descriptors */
 381     DLL_INSERT_TAIL(fdP, ihP->ih_fdhead, ihP->ih_fdtail, fd_ihnext,
 382                     fd_ihprev);
 383
 384     if (closeFd != INVALID_FD) {
 385         IH_UNLOCK;
 386         OS_CLOSE(closeFd);
 387         IH_LOCK;
 388         fdInUseCount -= 1;
 389     }
 390
 391     return fdP;
 392 }
 393
 394 FdHandle_t *
 395 ih_attachfd(IHandle_t *ihP, FD_t fd)
 396 {
 397     FdHandle_t *fdP;
 398
 399     if (fd == INVALID_FD) {
 400         return NULL;
 401     }
 402
 403     IH_LOCK;
 404
 405     fdInUseCount += 1;
 406
 407     fdP = ih_attachfd_r(ihP, fd);
 408     opr_Assert(fdP);
 409
 410     IH_UNLOCK;
 411
 412     return fdP;
 413 }
 414
 415 /*
 416  * Get a file descriptor handle given an Inode handle
 417  */
 418 FdHandle_t *
 419 ih_open(IHandle_t * ihP)
 420 {
 421     FdHandle_t *fdP;
 422     FD_t fd;
 423
 424     if (!ihP)                   /* XXX should log here in the fileserver */
 425         return NULL;
 426
 427     IH_LOCK;
 428
 429     /* Do we already have an open file handle for this Inode? */
 430     for (fdP = ihP->ih_fdtail; fdP != NULL; fdP = fdP->fd_ihprev) {
 431         if (fdP->fd_status == FD_HANDLE_CLOSING) {
 432             /* The handle was open when an IH_REALLYCLOSE was issued, so we
 433              * cannot reuse it; it will be closed soon. */
 434             continue;
 435         }
 436 #ifndef AFS_IHANDLE_PIO_ENV
 437         /*
 438          * If we don't have positional i/o, don't try to share fds, since
 439          * we can't do so in a threadsafe way.
 440          */
 441         if (fdP->fd_status == FD_HANDLE_INUSE) {
 442             continue;
 443         }
 444         opr_Assert(fdP->fd_status == FD_HANDLE_OPEN);
 445 #else /* AFS_IHANDLE_PIO_ENV */
 446         opr_Assert(fdP->fd_status != FD_HANDLE_AVAIL);
 447 #endif /* AFS_IHANDLE_PIO_ENV */
 448
 449         fdP->fd_refcnt++;
 450         if (fdP->fd_status == FD_HANDLE_OPEN) {
 451             fdP->fd_status = FD_HANDLE_INUSE;
 452             DLL_DELETE(fdP, fdLruHead, fdLruTail, fd_next, fd_prev);
 453         }
 454         ihP->ih_refcnt++;
 455         IH_UNLOCK;
 456         return fdP;
 457     }
 458
 459     /*
 460      * Try to open the Inode, return NULL on error.
 461      */
 462     fdInUseCount += 1;
 463     IH_UNLOCK;
 464 ih_open_retry:
 465     fd = OS_IOPEN(ihP);
 466     IH_LOCK;
 467     if (fd == INVALID_FD && (errno != EMFILE || fdLruHead == NULL) ) {
 468         fdInUseCount -= 1;
 469         IH_UNLOCK;
 470         return NULL;
 471     }
 472
 473     fdP = ih_attachfd_r(ihP, fd);
 474     if (!fdP) {
 475         opr_Assert(fd == INVALID_FD);
 476         IH_UNLOCK;
 477         goto ih_open_retry;
 478     }
 479
 480     IH_UNLOCK;
 481
 482     return fdP;
 483 }
 484
 485 /*
 486  * Return a file descriptor handle to the cache
 487  */
 488 int
 489 fd_close(FdHandle_t * fdP)
 490 {
 491     IHandle_t *ihP;
 492
 493     if (!fdP)
 494         return 0;
 495
 496     IH_LOCK;
 497     opr_Assert(ih_Inited);
 498     opr_Assert(fdInUseCount > 0);
 499     opr_Assert(fdP->fd_status == FD_HANDLE_INUSE ||
 500                fdP->fd_status == FD_HANDLE_CLOSING);
 501
 502     ihP = fdP->fd_ih;
 503
 504     /* Call fd_reallyclose to really close the unused file handles if
 505      * the previous attempt to close (ih_reallyclose()) all file handles
 506      * failed (this is determined by checking the ihandle for the flag
 507      * IH_REALLY_CLOSED) or we have too many open files.
 508      */
 509     if (fdP->fd_status == FD_HANDLE_CLOSING ||
 510         ihP->ih_flags & IH_REALLY_CLOSED || fdInUseCount > fdCacheSize) {
 511         IH_UNLOCK;
 512         return fd_reallyclose(fdP);
 513     }
 514
 515     fdP->fd_refcnt--;
 516     if (fdP->fd_refcnt == 0) {
 517         /* Put this descriptor back into the cache */
 518         fdP->fd_status = FD_HANDLE_OPEN;
 519         DLL_INSERT_TAIL(fdP, fdLruHead, fdLruTail, fd_next, fd_prev);
 520     }
 521
 522     /* If this is not the only reference to the Inode then we can decrement
 523      * the reference count, otherwise we need to call ih_release.
 524      */
 525     if (ihP->ih_refcnt > 1)
 526         ihP->ih_refcnt--;
 527     else
 528         _ih_release_r(ihP);
 529
 530     IH_UNLOCK;
 531
 532     return 0;
 533 }
 534
 535 /*
 536  * Actually close the file descriptor handle and return it to
 537  * the free list.
 538  */
 539 int
 540 fd_reallyclose(FdHandle_t * fdP)
 541 {
 542     FD_t closeFd;
 543     IHandle_t *ihP;
 544
 545     if (!fdP)
 546         return 0;
 547
 548     IH_LOCK;
 549     opr_Assert(ih_Inited);
 550     opr_Assert(fdInUseCount > 0);
 551     opr_Assert(fdP->fd_status == FD_HANDLE_INUSE ||
 552                fdP->fd_status == FD_HANDLE_CLOSING);
 553
 554     ihP = fdP->fd_ih;
 555     closeFd = fdP->fd_fd;
 556     fdP->fd_refcnt--;
 557
 558     if (fdP->fd_refcnt == 0) {
 559         DLL_DELETE(fdP, ihP->ih_fdhead, ihP->ih_fdtail, fd_ihnext, fd_ihprev);
 560         DLL_INSERT_TAIL(fdP, fdAvailHead, fdAvailTail, fd_next, fd_prev);
 561
 562         fdP->fd_status = FD_HANDLE_AVAIL;
 563         fdP->fd_refcnt = 0;
 564         fdP->fd_ih = NULL;
 565         fdP->fd_fd = INVALID_FD;
 566     }
 567
 568     /* All the file descriptor handles have been closed; reset
 569      * the IH_REALLY_CLOSED flag indicating that ih_reallyclose
 570      * has completed its job.
 571      */
 572     if (!ihP->ih_fdhead) {
 573         ihP->ih_flags &= ~IH_REALLY_CLOSED;
 574     } else {
 575         FdHandle_t *lfdP, *next;
 576         int clear = 1;
 577         for (lfdP = ihP->ih_fdhead; lfdP != NULL; lfdP = next) {
 578             next = lfdP->fd_ihnext;
 579             osi_Assert(lfdP->fd_ih == ihP);
 580             if (lfdP->fd_status != FD_HANDLE_CLOSING) {
 581                 clear = 0;
 582                 break;
 583             }
 584         }
 585         /* no *future* fd should be subjected to this */
 586         if (clear)
 587             ihP->ih_flags &= ~IH_REALLY_CLOSED;
 588     }
 589
 590     if (fdP->fd_refcnt == 0) {
 591         IH_UNLOCK;
 592         OS_CLOSE(closeFd);
 593         IH_LOCK;
 594         fdInUseCount -= 1;
 595     }
 596
 597     /* If this is not the only reference to the Inode then we can decrement
 598      * the reference count, otherwise we need to call ih_release. */
 599     if (ihP->ih_refcnt > 1)
 600         ihP->ih_refcnt--;
 601     else
 602         _ih_release_r(ihP);
 603
 604     IH_UNLOCK;
 605
 606     return 0;
 607 }
 608
 609 /* Enable buffered I/O on a file descriptor */
 610 StreamHandle_t *
 611 stream_fdopen(FD_t fd)
 612 {
 613     StreamHandle_t *streamP;
 614
 615     IH_LOCK;
 616     if (streamAvailHead == NULL) {
 617         streamHandleAllocateChunk();
 618     }
 619     streamP = streamAvailHead;
 620     DLL_DELETE(streamP, streamAvailHead, streamAvailTail, str_next, str_prev);
 621     IH_UNLOCK;
 622     streamP->str_fd = fd;
 623     streamP->str_buflen = 0;
 624     streamP->str_bufoff = 0;
 625     streamP->str_fdoff = 0;
 626     streamP->str_error = 0;
 627     streamP->str_eof = 0;
 628     streamP->str_direction = STREAM_DIRECTION_NONE;
 629     return streamP;
 630 }
 631
 632 /* Open a file for buffered I/O */
 633 StreamHandle_t *
 634 stream_open(const char *filename, const char *mode)
 635 {
 636     FD_t fd = INVALID_FD;
 637
 638     if (strcmp(mode, "r") == 0) {
 639         fd = OS_OPEN(filename, O_RDONLY, 0);
 640     } else if (strcmp(mode, "r+") == 0) {
 641         fd = OS_OPEN(filename, O_RDWR, 0);
 642     } else if (strcmp(mode, "w") == 0) {
 643         fd = OS_OPEN(filename, O_WRONLY | O_TRUNC | O_CREAT, 0);
 644     } else if (strcmp(mode, "w+") == 0) {
 645         fd = OS_OPEN(filename, O_RDWR | O_TRUNC | O_CREAT, 0);
 646     } else if (strcmp(mode, "a") == 0) {
 647         fd = OS_OPEN(filename, O_WRONLY | O_APPEND | O_CREAT, 0);
 648     } else if (strcmp(mode, "a+") == 0) {
 649         fd = OS_OPEN(filename, O_RDWR | O_APPEND | O_CREAT, 0);
 650     } else {
 651         opr_abort();            /* not implemented */
 652     }
 653
 654     if (fd == INVALID_FD) {
 655         return NULL;
 656     }
 657     return stream_fdopen(fd);
 658 }
 659
 660 /* fread for buffered I/O handles */
 661 afs_sfsize_t
 662 stream_read(void *ptr, afs_fsize_t size, afs_fsize_t nitems,
 663             StreamHandle_t * streamP)
 664 {
 665     afs_fsize_t nbytes, bytesRead, bytesToRead;
 666     char *p;
 667
 668     /* Need to seek before changing direction */
 669     if (streamP->str_direction == STREAM_DIRECTION_NONE) {
 670         streamP->str_direction = STREAM_DIRECTION_READ;
 671         streamP->str_bufoff = 0;
 672         streamP->str_buflen = 0;
 673     } else {
 674         opr_Assert(streamP->str_direction == STREAM_DIRECTION_READ);
 675     }
 676
 677     bytesRead = 0;
 678     nbytes = size * nitems;
 679     p = (char *)ptr;
 680     while (nbytes > 0 && !streamP->str_eof) {
 681         if (streamP->str_buflen == 0) {
 682             streamP->str_bufoff = 0;
 683             streamP->str_buflen =
 684                 OS_PREAD(streamP->str_fd, streamP->str_buffer,
 685                         STREAM_HANDLE_BUFSIZE, streamP->str_fdoff);
 686             if (streamP->str_buflen < 0) {
 687                 streamP->str_error = errno;
 688                 streamP->str_buflen = 0;
 689                 bytesRead = 0;
 690                 break;
 691             } else if (streamP->str_buflen == 0) {
 692                 streamP->str_eof = 1;
 693                 break;
 694             }
 695             streamP->str_fdoff += streamP->str_buflen;
 696         }
 697
 698         bytesToRead = nbytes;
 699         if (bytesToRead > streamP->str_buflen) {
 700             bytesToRead = streamP->str_buflen;
 701         }
 702         memcpy(p, streamP->str_buffer + streamP->str_bufoff, bytesToRead);
 703         p += bytesToRead;
 704         streamP->str_bufoff += bytesToRead;
 705         streamP->str_buflen -= bytesToRead;
 706         bytesRead += bytesToRead;
 707         nbytes -= bytesToRead;
 708     }
 709
 710     return (bytesRead / size);
 711 }
 712
 713 /* fwrite for buffered I/O handles */
 714 afs_sfsize_t
 715 stream_write(void *ptr, afs_fsize_t size, afs_fsize_t nitems,
 716              StreamHandle_t * streamP)
 717 {
 718     char *p;
 719     afs_sfsize_t rc;
 720     afs_fsize_t nbytes, bytesWritten, bytesToWrite;
 721
 722     /* Need to seek before changing direction */
 723     if (streamP->str_direction == STREAM_DIRECTION_NONE) {
 724         streamP->str_direction = STREAM_DIRECTION_WRITE;
 725         streamP->str_bufoff = 0;
 726         streamP->str_buflen = STREAM_HANDLE_BUFSIZE;
 727     } else {
 728         opr_Assert(streamP->str_direction == STREAM_DIRECTION_WRITE);
 729     }
 730
 731     nbytes = size * nitems;
 732     bytesWritten = 0;
 733     p = (char *)ptr;
 734     while (nbytes > 0) {
 735         if (streamP->str_buflen == 0) {
 736             rc = OS_PWRITE(streamP->str_fd, streamP->str_buffer,
 737                           STREAM_HANDLE_BUFSIZE, streamP->str_fdoff);
 738             if (rc < 0) {
 739                 streamP->str_error = errno;
 740                 bytesWritten = 0;
 741                 break;
 742             }
 743             streamP->str_fdoff += rc;
 744             streamP->str_bufoff = 0;
 745             streamP->str_buflen = STREAM_HANDLE_BUFSIZE;
 746         }
 747
 748         bytesToWrite = nbytes;
 749         if (bytesToWrite > streamP->str_buflen) {
 750             bytesToWrite = streamP->str_buflen;
 751         }
 752         memcpy(streamP->str_buffer + streamP->str_bufoff, p, bytesToWrite);
 753         p += bytesToWrite;
 754         streamP->str_bufoff += bytesToWrite;
 755         streamP->str_buflen -= bytesToWrite;
 756         bytesWritten += bytesToWrite;
 757         nbytes -= bytesToWrite;
 758     }
 759
 760     return (bytesWritten / size);
 761 }
 762
 763 /* fseek for buffered I/O handles */
 764 int
 765 stream_aseek(StreamHandle_t * streamP, afs_foff_t offset)
 766 {
 767     ssize_t rc;
 768     int retval = 0;
 769
 770     if (streamP->str_direction == STREAM_DIRECTION_WRITE
 771         && streamP->str_bufoff > 0) {
 772         rc = OS_PWRITE(streamP->str_fd, streamP->str_buffer,
 773                       streamP->str_bufoff, streamP->str_fdoff);
 774         if (rc < 0) {
 775             streamP->str_error = errno;
 776             retval = -1;
 777         }
 778     }
 779     streamP->str_fdoff = offset;
 780     streamP->str_bufoff = 0;
 781     streamP->str_buflen = 0;
 782     streamP->str_eof = 0;
 783     streamP->str_direction = STREAM_DIRECTION_NONE;
 784     return retval;
 785 }
 786
 787 /* fflush for buffered I/O handles */
 788 int
 789 stream_flush(StreamHandle_t * streamP)
 790 {
 791     ssize_t rc;
 792     int retval = 0;
 793
 794     if (streamP->str_direction == STREAM_DIRECTION_WRITE
 795         && streamP->str_bufoff > 0) {
 796         rc = OS_PWRITE(streamP->str_fd, streamP->str_buffer,
 797                       streamP->str_bufoff, streamP->str_fdoff);
 798         if (rc < 0) {
 799             streamP->str_error = errno;
 800             retval = -1;
 801         } else {
 802             streamP->str_fdoff += rc;
 803         }
 804         streamP->str_bufoff = 0;
 805         streamP->str_buflen = STREAM_HANDLE_BUFSIZE;
 806     }
 807
 808     return retval;
 809 }
 810
 811 /* Free a buffered I/O handle */
 812 int
 813 stream_close(StreamHandle_t * streamP, int reallyClose)
 814 {
 815     ssize_t rc;
 816     int retval = 0;
 817
 818     opr_Assert(streamP != NULL);
 819     if (streamP->str_direction == STREAM_DIRECTION_WRITE
 820         && streamP->str_bufoff > 0) {
 821         rc = OS_PWRITE(streamP->str_fd, streamP->str_buffer,
 822                       streamP->str_bufoff, streamP->str_fdoff);
 823         if (rc < 0) {
 824             retval = -1;
 825         } else {
 826             streamP->str_fdoff += rc;
 827         }
 828     }
 829     if (reallyClose) {
 830         rc = OS_CLOSE(streamP->str_fd);
 831         if (rc < 0) {
 832             retval = -1;
 833         }
 834     }
 835     streamP->str_fd = INVALID_FD;
 836
 837     IH_LOCK;
 838     DLL_INSERT_TAIL(streamP, streamAvailHead, streamAvailTail,
 839                     str_next, str_prev);
 840     IH_UNLOCK;
 841     return retval;
 842 }
 843
 844 /* Close all unused file descriptors associated with the inode
 845  * handle. Called with IH_LOCK held. May drop and reacquire
 846  * IH_LOCK. Sets the IH_REALLY_CLOSED flag in the inode handle
 847  * if it fails to close all file handles.
 848  */
 849 static int
 850 ih_fdclose(IHandle_t * ihP)
 851 {
 852     int closeCount, closedAll;
 853     FdHandle_t *fdP, *head, *tail, *next;
 854
 855     opr_Assert(ihP->ih_refcnt > 0);
 856
 857     closedAll = 1;
 858     DLL_INIT_LIST(head, tail);
 859     ihP->ih_flags &= ~IH_REALLY_CLOSED;
 860
 861     /*
 862      * Remove the file descriptors for this Inode from the LRU queue
 863      * and the IHandle queue and put them on a temporary queue so we
 864      * can drop the lock before we close the files.
 865      */
 866     for (fdP = ihP->ih_fdhead; fdP != NULL; fdP = next) {
 867         next = fdP->fd_ihnext;
 868         opr_Assert(fdP->fd_ih == ihP);
 869         opr_Assert(fdP->fd_status == FD_HANDLE_OPEN
 870                || fdP->fd_status == FD_HANDLE_INUSE
 871                || fdP->fd_status == FD_HANDLE_CLOSING);
 872         if (fdP->fd_status == FD_HANDLE_OPEN) {
 873             /* Note that FdHandle_t's do not count against the parent
 874              * IHandle_t ref count when they are FD_HANDLE_OPEN. So, we don't
 875              * need to dec the parent IHandle_t ref count for each one we pull
 876              * off here. */
 877             DLL_DELETE(fdP, ihP->ih_fdhead, ihP->ih_fdtail, fd_ihnext,
 878                        fd_ihprev);
 879             DLL_DELETE(fdP, fdLruHead, fdLruTail, fd_next, fd_prev);
 880             DLL_INSERT_TAIL(fdP, head, tail, fd_next, fd_prev);
 881         } else {
 882             closedAll = 0;
 883             fdP->fd_status = FD_HANDLE_CLOSING;
 884             ihP->ih_flags |= IH_REALLY_CLOSED;
 885         }
 886     }
 887
 888     /* If the ihandle reference count is 1, we should have
 889      * closed all file descriptors.
 890      */
 891     if (ihP->ih_refcnt == 1 || closedAll) {
 892         opr_Assert(closedAll);
 893         opr_Assert(!ihP->ih_fdhead);
 894         opr_Assert(!ihP->ih_fdtail);
 895     }
 896
 897     if (head == NULL) {
 898         return 0;               /* No file descriptors closed */
 899     }
 900
 901     IH_UNLOCK;
 902     /*
 903      * Close the file descriptors
 904      */
 905     closeCount = 0;
 906     for (fdP = head; fdP != NULL; fdP = fdP->fd_next) {
 907         OS_CLOSE(fdP->fd_fd);
 908         fdP->fd_status = FD_HANDLE_AVAIL;
 909         fdP->fd_refcnt = 0;
 910         fdP->fd_fd = INVALID_FD;
 911         fdP->fd_ih = NULL;
 912         closeCount++;
 913     }
 914
 915     IH_LOCK;
 916     opr_Assert(fdInUseCount >= closeCount);
 917     fdInUseCount -= closeCount;
 918
 919     /*
 920      * Append the temporary queue to the list of available descriptors
 921      */
 922     if (fdAvailHead == NULL) {
 923         fdAvailHead = head;
 924         fdAvailTail = tail;
 925     } else {
 926         fdAvailTail->fd_next = head;
 927         head->fd_prev = fdAvailTail;
 928         fdAvailTail = tail;
 929     }
 930
 931     return 0;
 932 }
 933
 934 /* Close all cached file descriptors for this inode. */
 935 int
 936 ih_reallyclose(IHandle_t * ihP)
 937 {
 938     if (!ihP)
 939         return 0;
 940
 941     IH_LOCK;
 942     ihP->ih_refcnt++;   /* must not disappear over unlock */
 943     if (ihP->ih_synced) {
 944         FdHandle_t *fdP;
 945         opr_Assert(vol_io_params.sync_behavior != IH_SYNC_ALWAYS);
 946         opr_Assert(vol_io_params.sync_behavior != IH_SYNC_NEVER);
 947         ihP->ih_synced = 0;
 948         IH_UNLOCK;
 949
 950         fdP = IH_OPEN(ihP);
 951         if (fdP) {
 952             OS_SYNC(fdP->fd_fd);
 953             FDH_CLOSE(fdP);
 954         }
 955
 956         IH_LOCK;
 957     }
 958
 959     opr_Assert(ihP->ih_refcnt > 0);
 960
 961     ih_fdclose(ihP);
 962
 963     if (ihP->ih_refcnt > 1)
 964         ihP->ih_refcnt--;
 965     else
 966         _ih_release_r(ihP);
 967
 968     IH_UNLOCK;
 969     return 0;
 970 }
 971
 972 /* Release an Inode handle. All cached file descriptors for this
 973  * inode are closed when the last reference to this handle is released
 974  */
 975 static int
 976 _ih_release_r(IHandle_t * ihP)
 977 {
 978     int ihash;
 979
 980     if (!ihP)
 981         return 0;
 982
 983     opr_Assert(ihP->ih_refcnt > 0);
 984
 985     if (ihP->ih_refcnt > 1) {
 986         ihP->ih_refcnt--;
 987         return 0;
 988     }
 989
 990     ihash = IH_HASH(ihP->ih_dev, ihP->ih_vid, ihP->ih_ino);
 991     DLL_DELETE(ihP, ihashTable[ihash].ihash_head,
 992                ihashTable[ihash].ihash_tail, ih_next, ih_prev);
 993
 994     ih_fdclose(ihP);
 995
 996     ihP->ih_refcnt--;
 997
 998     DLL_INSERT_TAIL(ihP, ihAvailHead, ihAvailTail, ih_next, ih_prev);
 999
1000     return 0;
1001 }
1002
1003 /* Release an Inode handle. All cached file descriptors for this
1004  * inode are closed when the last reference to this handle is released
1005  */
1006 int
1007 ih_release(IHandle_t * ihP)
1008 {
1009     int ret;
1010
1011     if (!ihP)
1012         return 0;
1013
1014     IH_LOCK;
1015     ret = _ih_release_r(ihP);
1016     IH_UNLOCK;
1017     return ret;
1018 }
1019
1020 /* Sync an inode to disk if its handle isn't NULL */
1021 int
1022 ih_condsync(IHandle_t * ihP)
1023 {
1024     int code;
1025     FdHandle_t *fdP;
1026
1027     if (!ihP)
1028         return 0;
1029
1030     fdP = IH_OPEN(ihP);
1031     if (fdP == NULL)
1032         return -1;
1033
1034     code = FDH_SYNC(fdP);
1035     FDH_CLOSE(fdP);
1036
1037     return code;
1038 }
1039
1040 /*************************************************************************
1041  * OS specific support routines.
1042  *************************************************************************/
1043 #ifndef AFS_NAMEI_ENV
1044 Inode
1045 ih_icreate(IHandle_t * ih, int dev, char *part, Inode nI, int p1, int p2,
1046            int p3, int p4)
1047 {
1048     Inode ino;
1049 #ifdef  AFS_3DISPARES
1050     /* See viceinode.h */
1051     if (p2 == INODESPECIAL) {
1052         int tp = p3;
1053         p3 = p4;
1054         p4 = tp;
1055     }
1056 #endif
1057     ino = ICREATE(dev, part, nI, p1, p2, p3, p4);
1058     return ino;
1059 }
1060 #endif /* AFS_NAMEI_ENV */
1061
1062 #if defined(AFS_NT40_ENV) || !defined(AFS_NAMEI_ENV)
1063 /* Unix namei implements its own more efficient IH_CREATE_INIT; this wrapper
1064  * is for everyone else */
1065 IHandle_t *
1066 ih_icreate_init(IHandle_t *lh, int dev, char *part, Inode nearInode,
1067                 afs_uint32 p1, afs_uint32 p2, afs_uint32 p3, afs_uint32 p4)
1068 {
1069     IHandle_t *ihP;
1070     Inode ino = IH_CREATE(lh, dev, part, nearInode, p1, p2, p3, p4);
1071     if (!VALID_INO(ino)) {
1072         return NULL;
1073     }
1074     IH_INIT(ihP, dev, p1, ino);
1075     return ihP;
1076 }
1077 #endif
1078
1079 afs_sfsize_t
1080 ih_size(FD_t fd)
1081 {
1082 #ifdef AFS_NT40_ENV
1083     LARGE_INTEGER size;
1084     if (!GetFileSizeEx(fd, &size))
1085         return -1;
1086     return size.QuadPart;
1087 #else
1088     struct afs_stat_st status;
1089     if (afs_fstat(fd, &status) < 0)
1090         return -1;
1091     return status.st_size;
1092 #endif
1093 }
1094
1095 #ifndef AFS_IHANDLE_PIO_ENV
1096 ssize_t
1097 ih_pread(int fd, void * buf, size_t count, afs_foff_t offset)
1098 {
1099         afs_foff_t code;
1100         code = OS_SEEK(fd, offset, 0);
1101         if (code < 0)
1102             return code;
1103         return OS_READ(fd, buf, count);
1104 }
1105
1106 ssize_t
1107 ih_pwrite(int fd, const void * buf, size_t count, afs_foff_t offset)
1108 {
1109         afs_foff_t code;
1110         code = OS_SEEK(fd, offset, 0);
1111         if (code < 0)
1112             return code;
1113         return OS_WRITE(fd, buf, count);
1114 }
1115 #endif /* !AFS_IHANDLE_PIO_ENV */
1116
1117 #ifndef AFS_NT40_ENV
1118 int
1119 ih_isunlinked(int fd)
1120 {
1121     struct afs_stat_st status;
1122     if (afs_fstat(fd, &status) < 0) {
1123         return -1;
1124     }
1125     if (status.st_nlink < 1) {
1126         return 1;
1127     }
1128     return 0;
1129 }
1130 #endif /* !AFS_NT40_ENV */
1131
1132 int
1133 ih_fdsync(FdHandle_t *fdP)
1134 {
1135     switch (vol_io_params.sync_behavior) {
1136     case IH_SYNC_ALWAYS:
1137         return OS_SYNC(fdP->fd_fd);
1138     case IH_SYNC_ONCLOSE:
1139         if (fdP->fd_ih) {
1140             fdP->fd_ih->ih_synced = 1;
1141             return 0;
1142         }
1143         return 1;
1144     case IH_SYNC_NEVER:
1145         return 0;
1146     default:
1147         opr_Assert(0);
1148     }
1149 }