The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/geom/geom_io.c

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    1 /*-
    2  * Copyright (c) 2002 Poul-Henning Kamp
    3  * Copyright (c) 2002 Networks Associates Technology, Inc.
    4  * All rights reserved.
    5  *
    6  * This software was developed for the FreeBSD Project by Poul-Henning Kamp
    7  * and NAI Labs, the Security Research Division of Network Associates, Inc.
    8  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
    9  * DARPA CHATS research program.
   10  *
   11  * Redistribution and use in source and binary forms, with or without
   12  * modification, are permitted provided that the following conditions
   13  * are met:
   14  * 1. Redistributions of source code must retain the above copyright
   15  *    notice, this list of conditions and the following disclaimer.
   16  * 2. Redistributions in binary form must reproduce the above copyright
   17  *    notice, this list of conditions and the following disclaimer in the
   18  *    documentation and/or other materials provided with the distribution.
   19  * 3. The names of the authors may not be used to endorse or promote
   20  *    products derived from this software without specific prior written
   21  *    permission.
   22  *
   23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   33  * SUCH DAMAGE.
   34  */
   35 
   36 #include <sys/cdefs.h>
   37 __FBSDID("$FreeBSD: releng/8.3/sys/geom/geom_io.c 212939 2010-09-20 23:39:00Z gibbs $");
   38 
   39 #include <sys/param.h>
   40 #include <sys/systm.h>
   41 #include <sys/kernel.h>
   42 #include <sys/malloc.h>
   43 #include <sys/bio.h>
   44 #include <sys/ktr.h>
   45 #include <sys/proc.h>
   46 #include <sys/stack.h>
   47 
   48 #include <sys/errno.h>
   49 #include <geom/geom.h>
   50 #include <geom/geom_int.h>
   51 #include <sys/devicestat.h>
   52 
   53 #include <vm/uma.h>
   54 
   55 static struct g_bioq g_bio_run_down;
   56 static struct g_bioq g_bio_run_up;
   57 static struct g_bioq g_bio_run_task;
   58 
   59 static u_int pace;
   60 static uma_zone_t       biozone;
   61 
   62 /*
   63  * The head of the list of classifiers used in g_io_request.
   64  * Use g_register_classifier() and g_unregister_classifier()
   65  * to add/remove entries to the list.
   66  * Classifiers are invoked in registration order.
   67  */
   68 static TAILQ_HEAD(g_classifier_tailq, g_classifier_hook)
   69     g_classifier_tailq = TAILQ_HEAD_INITIALIZER(g_classifier_tailq);
   70 
   71 #include <machine/atomic.h>
   72 
   73 static void
   74 g_bioq_lock(struct g_bioq *bq)
   75 {
   76 
   77         mtx_lock(&bq->bio_queue_lock);
   78 }
   79 
   80 static void
   81 g_bioq_unlock(struct g_bioq *bq)
   82 {
   83 
   84         mtx_unlock(&bq->bio_queue_lock);
   85 }
   86 
   87 #if 0
   88 static void
   89 g_bioq_destroy(struct g_bioq *bq)
   90 {
   91 
   92         mtx_destroy(&bq->bio_queue_lock);
   93 }
   94 #endif
   95 
   96 static void
   97 g_bioq_init(struct g_bioq *bq)
   98 {
   99 
  100         TAILQ_INIT(&bq->bio_queue);
  101         mtx_init(&bq->bio_queue_lock, "bio queue", NULL, MTX_DEF);
  102 }
  103 
  104 static struct bio *
  105 g_bioq_first(struct g_bioq *bq)
  106 {
  107         struct bio *bp;
  108 
  109         bp = TAILQ_FIRST(&bq->bio_queue);
  110         if (bp != NULL) {
  111                 KASSERT((bp->bio_flags & BIO_ONQUEUE),
  112                     ("Bio not on queue bp=%p target %p", bp, bq));
  113                 bp->bio_flags &= ~BIO_ONQUEUE;
  114                 TAILQ_REMOVE(&bq->bio_queue, bp, bio_queue);
  115                 bq->bio_queue_length--;
  116         }
  117         return (bp);
  118 }
  119 
  120 struct bio *
  121 g_new_bio(void)
  122 {
  123         struct bio *bp;
  124 
  125         bp = uma_zalloc(biozone, M_NOWAIT | M_ZERO);
  126 #ifdef KTR
  127         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  128                 struct stack st;
  129 
  130                 CTR1(KTR_GEOM, "g_new_bio(): %p", bp);
  131                 stack_save(&st);
  132                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  133         }
  134 #endif
  135         return (bp);
  136 }
  137 
  138 struct bio *
  139 g_alloc_bio(void)
  140 {
  141         struct bio *bp;
  142 
  143         bp = uma_zalloc(biozone, M_WAITOK | M_ZERO);
  144 #ifdef KTR
  145         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  146                 struct stack st;
  147 
  148                 CTR1(KTR_GEOM, "g_alloc_bio(): %p", bp);
  149                 stack_save(&st);
  150                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  151         }
  152 #endif
  153         return (bp);
  154 }
  155 
  156 void
  157 g_destroy_bio(struct bio *bp)
  158 {
  159 #ifdef KTR
  160         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  161                 struct stack st;
  162 
  163                 CTR1(KTR_GEOM, "g_destroy_bio(): %p", bp);
  164                 stack_save(&st);
  165                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  166         }
  167 #endif
  168         uma_zfree(biozone, bp);
  169 }
  170 
  171 struct bio *
  172 g_clone_bio(struct bio *bp)
  173 {
  174         struct bio *bp2;
  175 
  176         bp2 = uma_zalloc(biozone, M_NOWAIT | M_ZERO);
  177         if (bp2 != NULL) {
  178                 bp2->bio_parent = bp;
  179                 bp2->bio_cmd = bp->bio_cmd;
  180                 bp2->bio_length = bp->bio_length;
  181                 bp2->bio_offset = bp->bio_offset;
  182                 bp2->bio_data = bp->bio_data;
  183                 bp2->bio_attribute = bp->bio_attribute;
  184                 /* Inherit classification info from the parent */
  185                 bp2->bio_classifier1 = bp->bio_classifier1;
  186                 bp2->bio_classifier2 = bp->bio_classifier2;
  187                 bp->bio_children++;
  188         }
  189 #ifdef KTR
  190         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  191                 struct stack st;
  192 
  193                 CTR2(KTR_GEOM, "g_clone_bio(%p): %p", bp, bp2);
  194                 stack_save(&st);
  195                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  196         }
  197 #endif
  198         return(bp2);
  199 }
  200 
  201 struct bio *
  202 g_duplicate_bio(struct bio *bp)
  203 {
  204         struct bio *bp2;
  205 
  206         bp2 = uma_zalloc(biozone, M_WAITOK | M_ZERO);
  207         bp2->bio_parent = bp;
  208         bp2->bio_cmd = bp->bio_cmd;
  209         bp2->bio_length = bp->bio_length;
  210         bp2->bio_offset = bp->bio_offset;
  211         bp2->bio_data = bp->bio_data;
  212         bp2->bio_attribute = bp->bio_attribute;
  213         bp->bio_children++;
  214 #ifdef KTR
  215         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  216                 struct stack st;
  217 
  218                 CTR2(KTR_GEOM, "g_duplicate_bio(%p): %p", bp, bp2);
  219                 stack_save(&st);
  220                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  221         }
  222 #endif
  223         return(bp2);
  224 }
  225 
  226 void
  227 g_io_init()
  228 {
  229 
  230         g_bioq_init(&g_bio_run_down);
  231         g_bioq_init(&g_bio_run_up);
  232         g_bioq_init(&g_bio_run_task);
  233         biozone = uma_zcreate("g_bio", sizeof (struct bio),
  234             NULL, NULL,
  235             NULL, NULL,
  236             0, 0);
  237 }
  238 
  239 int
  240 g_io_getattr(const char *attr, struct g_consumer *cp, int *len, void *ptr)
  241 {
  242         struct bio *bp;
  243         int error;
  244 
  245         g_trace(G_T_BIO, "bio_getattr(%s)", attr);
  246         bp = g_alloc_bio();
  247         bp->bio_cmd = BIO_GETATTR;
  248         bp->bio_done = NULL;
  249         bp->bio_attribute = attr;
  250         bp->bio_length = *len;
  251         bp->bio_data = ptr;
  252         g_io_request(bp, cp);
  253         error = biowait(bp, "ggetattr");
  254         *len = bp->bio_completed;
  255         g_destroy_bio(bp);
  256         return (error);
  257 }
  258 
  259 int
  260 g_io_flush(struct g_consumer *cp)
  261 {
  262         struct bio *bp;
  263         int error;
  264 
  265         g_trace(G_T_BIO, "bio_flush(%s)", cp->provider->name);
  266         bp = g_alloc_bio();
  267         bp->bio_cmd = BIO_FLUSH;
  268         bp->bio_flags |= BIO_ORDERED;
  269         bp->bio_done = NULL;
  270         bp->bio_attribute = NULL;
  271         bp->bio_offset = cp->provider->mediasize;
  272         bp->bio_length = 0;
  273         bp->bio_data = NULL;
  274         g_io_request(bp, cp);
  275         error = biowait(bp, "gflush");
  276         g_destroy_bio(bp);
  277         return (error);
  278 }
  279 
  280 static int
  281 g_io_check(struct bio *bp)
  282 {
  283         struct g_consumer *cp;
  284         struct g_provider *pp;
  285 
  286         cp = bp->bio_from;
  287         pp = bp->bio_to;
  288 
  289         /* Fail if access counters dont allow the operation */
  290         switch(bp->bio_cmd) {
  291         case BIO_READ:
  292         case BIO_GETATTR:
  293                 if (cp->acr == 0)
  294                         return (EPERM);
  295                 break;
  296         case BIO_WRITE:
  297         case BIO_DELETE:
  298         case BIO_FLUSH:
  299                 if (cp->acw == 0)
  300                         return (EPERM);
  301                 break;
  302         default:
  303                 return (EPERM);
  304         }
  305         /* if provider is marked for error, don't disturb. */
  306         if (pp->error)
  307                 return (pp->error);
  308 
  309         switch(bp->bio_cmd) {
  310         case BIO_READ:
  311         case BIO_WRITE:
  312         case BIO_DELETE:
  313                 /* Zero sectorsize or mediasize is probably a lack of media. */
  314                 if (pp->sectorsize == 0 || pp->mediasize == 0)
  315                         return (ENXIO);
  316                 /* Reject I/O not on sector boundary */
  317                 if (bp->bio_offset % pp->sectorsize)
  318                         return (EINVAL);
  319                 /* Reject I/O not integral sector long */
  320                 if (bp->bio_length % pp->sectorsize)
  321                         return (EINVAL);
  322                 /* Reject requests before or past the end of media. */
  323                 if (bp->bio_offset < 0)
  324                         return (EIO);
  325                 if (bp->bio_offset > pp->mediasize)
  326                         return (EIO);
  327                 break;
  328         default:
  329                 break;
  330         }
  331         return (0);
  332 }
  333 
  334 /*
  335  * bio classification support.
  336  *
  337  * g_register_classifier() and g_unregister_classifier()
  338  * are used to add/remove a classifier from the list.
  339  * The list is protected using the g_bio_run_down lock,
  340  * because the classifiers are called in this path.
  341  *
  342  * g_io_request() passes bio's that are not already classified
  343  * (i.e. those with bio_classifier1 == NULL) to g_run_classifiers().
  344  * Classifiers can store their result in the two fields
  345  * bio_classifier1 and bio_classifier2.
  346  * A classifier that updates one of the fields should
  347  * return a non-zero value.
  348  * If no classifier updates the field, g_run_classifiers() sets
  349  * bio_classifier1 = BIO_NOTCLASSIFIED to avoid further calls.
  350  */
  351 
  352 int
  353 g_register_classifier(struct g_classifier_hook *hook)
  354 {
  355 
  356         g_bioq_lock(&g_bio_run_down);
  357         TAILQ_INSERT_TAIL(&g_classifier_tailq, hook, link);
  358         g_bioq_unlock(&g_bio_run_down);
  359 
  360         return (0);
  361 }
  362 
  363 void
  364 g_unregister_classifier(struct g_classifier_hook *hook)
  365 {
  366         struct g_classifier_hook *entry;
  367 
  368         g_bioq_lock(&g_bio_run_down);
  369         TAILQ_FOREACH(entry, &g_classifier_tailq, link) {
  370                 if (entry == hook) {
  371                         TAILQ_REMOVE(&g_classifier_tailq, hook, link);
  372                         break;
  373                 }
  374         }
  375         g_bioq_unlock(&g_bio_run_down);
  376 }
  377 
  378 static void
  379 g_run_classifiers(struct bio *bp)
  380 {
  381         struct g_classifier_hook *hook;
  382         int classified = 0;
  383 
  384         TAILQ_FOREACH(hook, &g_classifier_tailq, link)
  385                 classified |= hook->func(hook->arg, bp);
  386 
  387         if (!classified)
  388                 bp->bio_classifier1 = BIO_NOTCLASSIFIED;
  389 }
  390 
  391 void
  392 g_io_request(struct bio *bp, struct g_consumer *cp)
  393 {
  394         struct g_provider *pp;
  395         int first;
  396 
  397         KASSERT(cp != NULL, ("NULL cp in g_io_request"));
  398         KASSERT(bp != NULL, ("NULL bp in g_io_request"));
  399         pp = cp->provider;
  400         KASSERT(pp != NULL, ("consumer not attached in g_io_request"));
  401 #ifdef DIAGNOSTIC
  402         KASSERT(bp->bio_driver1 == NULL,
  403             ("bio_driver1 used by the consumer (geom %s)", cp->geom->name));
  404         KASSERT(bp->bio_driver2 == NULL,
  405             ("bio_driver2 used by the consumer (geom %s)", cp->geom->name));
  406         KASSERT(bp->bio_pflags == 0,
  407             ("bio_pflags used by the consumer (geom %s)", cp->geom->name));
  408         /*
  409          * Remember consumer's private fields, so we can detect if they were
  410          * modified by the provider.
  411          */
  412         bp->_bio_caller1 = bp->bio_caller1;
  413         bp->_bio_caller2 = bp->bio_caller2;
  414         bp->_bio_cflags = bp->bio_cflags;
  415 #endif
  416 
  417         if (bp->bio_cmd & (BIO_READ|BIO_WRITE|BIO_GETATTR)) {
  418                 KASSERT(bp->bio_data != NULL,
  419                     ("NULL bp->data in g_io_request(cmd=%hhu)", bp->bio_cmd));
  420         }
  421         if (bp->bio_cmd & (BIO_DELETE|BIO_FLUSH)) {
  422                 KASSERT(bp->bio_data == NULL,
  423                     ("non-NULL bp->data in g_io_request(cmd=%hhu)",
  424                     bp->bio_cmd));
  425         }
  426         if (bp->bio_cmd & (BIO_READ|BIO_WRITE|BIO_DELETE)) {
  427                 KASSERT(bp->bio_offset % cp->provider->sectorsize == 0,
  428                     ("wrong offset %jd for sectorsize %u",
  429                     bp->bio_offset, cp->provider->sectorsize));
  430                 KASSERT(bp->bio_length % cp->provider->sectorsize == 0,
  431                     ("wrong length %jd for sectorsize %u",
  432                     bp->bio_length, cp->provider->sectorsize));
  433         }
  434 
  435         g_trace(G_T_BIO, "bio_request(%p) from %p(%s) to %p(%s) cmd %d",
  436             bp, cp, cp->geom->name, pp, pp->name, bp->bio_cmd);
  437 
  438         bp->bio_from = cp;
  439         bp->bio_to = pp;
  440         bp->bio_error = 0;
  441         bp->bio_completed = 0;
  442 
  443         KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
  444             ("Bio already on queue bp=%p", bp));
  445         bp->bio_flags |= BIO_ONQUEUE;
  446 
  447         binuptime(&bp->bio_t0);
  448 
  449         /*
  450          * The statistics collection is lockless, as such, but we
  451          * can not update one instance of the statistics from more
  452          * than one thread at a time, so grab the lock first.
  453          *
  454          * We also use the lock to protect the list of classifiers.
  455          */
  456         g_bioq_lock(&g_bio_run_down);
  457 
  458         if (!TAILQ_EMPTY(&g_classifier_tailq) && !bp->bio_classifier1)
  459                 g_run_classifiers(bp);
  460 
  461         if (g_collectstats & 1)
  462                 devstat_start_transaction(pp->stat, &bp->bio_t0);
  463         if (g_collectstats & 2)
  464                 devstat_start_transaction(cp->stat, &bp->bio_t0);
  465 
  466         pp->nstart++;
  467         cp->nstart++;
  468         first = TAILQ_EMPTY(&g_bio_run_down.bio_queue);
  469         TAILQ_INSERT_TAIL(&g_bio_run_down.bio_queue, bp, bio_queue);
  470         g_bio_run_down.bio_queue_length++;
  471         g_bioq_unlock(&g_bio_run_down);
  472 
  473         /* Pass it on down. */
  474         if (first)
  475                 wakeup(&g_wait_down);
  476 }
  477 
  478 void
  479 g_io_deliver(struct bio *bp, int error)
  480 {
  481         struct g_consumer *cp;
  482         struct g_provider *pp;
  483         int first;
  484 
  485         KASSERT(bp != NULL, ("NULL bp in g_io_deliver"));
  486         pp = bp->bio_to;
  487         KASSERT(pp != NULL, ("NULL bio_to in g_io_deliver"));
  488         cp = bp->bio_from;
  489         if (cp == NULL) {
  490                 bp->bio_error = error;
  491                 bp->bio_done(bp);
  492                 return;
  493         }
  494         KASSERT(cp != NULL, ("NULL bio_from in g_io_deliver"));
  495         KASSERT(cp->geom != NULL, ("NULL bio_from->geom in g_io_deliver"));
  496 #ifdef DIAGNOSTIC
  497         /*
  498          * Some classes - GJournal in particular - can modify bio's
  499          * private fields while the bio is in transit; G_GEOM_VOLATILE_BIO
  500          * flag means it's an expected behaviour for that particular geom.
  501          */
  502         if ((cp->geom->flags & G_GEOM_VOLATILE_BIO) == 0) {
  503                 KASSERT(bp->bio_caller1 == bp->_bio_caller1,
  504                     ("bio_caller1 used by the provider %s", pp->name));
  505                 KASSERT(bp->bio_caller2 == bp->_bio_caller2,
  506                     ("bio_caller2 used by the provider %s", pp->name));
  507                 KASSERT(bp->bio_cflags == bp->_bio_cflags,
  508                     ("bio_cflags used by the provider %s", pp->name));
  509         }
  510 #endif
  511         KASSERT(bp->bio_completed >= 0, ("bio_completed can't be less than 0"));
  512         KASSERT(bp->bio_completed <= bp->bio_length,
  513             ("bio_completed can't be greater than bio_length"));
  514 
  515         g_trace(G_T_BIO,
  516 "g_io_deliver(%p) from %p(%s) to %p(%s) cmd %d error %d off %jd len %jd",
  517             bp, cp, cp->geom->name, pp, pp->name, bp->bio_cmd, error,
  518             (intmax_t)bp->bio_offset, (intmax_t)bp->bio_length);
  519 
  520         KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
  521             ("Bio already on queue bp=%p", bp));
  522 
  523         /*
  524          * XXX: next two doesn't belong here
  525          */
  526         bp->bio_bcount = bp->bio_length;
  527         bp->bio_resid = bp->bio_bcount - bp->bio_completed;
  528 
  529         /*
  530          * The statistics collection is lockless, as such, but we
  531          * can not update one instance of the statistics from more
  532          * than one thread at a time, so grab the lock first.
  533          */
  534         g_bioq_lock(&g_bio_run_up);
  535         if (g_collectstats & 1)
  536                 devstat_end_transaction_bio(pp->stat, bp);
  537         if (g_collectstats & 2)
  538                 devstat_end_transaction_bio(cp->stat, bp);
  539 
  540         cp->nend++;
  541         pp->nend++;
  542         if (error != ENOMEM) {
  543                 bp->bio_error = error;
  544                 first = TAILQ_EMPTY(&g_bio_run_up.bio_queue);
  545                 TAILQ_INSERT_TAIL(&g_bio_run_up.bio_queue, bp, bio_queue);
  546                 bp->bio_flags |= BIO_ONQUEUE;
  547                 g_bio_run_up.bio_queue_length++;
  548                 g_bioq_unlock(&g_bio_run_up);
  549                 if (first)
  550                         wakeup(&g_wait_up);
  551                 return;
  552         }
  553         g_bioq_unlock(&g_bio_run_up);
  554 
  555         if (bootverbose)
  556                 printf("ENOMEM %p on %p(%s)\n", bp, pp, pp->name);
  557         bp->bio_children = 0;
  558         bp->bio_inbed = 0;
  559         g_io_request(bp, cp);
  560         pace++;
  561         return;
  562 }
  563 
  564 void
  565 g_io_schedule_down(struct thread *tp __unused)
  566 {
  567         struct bio *bp;
  568         off_t excess;
  569         int error;
  570 
  571         for(;;) {
  572                 g_bioq_lock(&g_bio_run_down);
  573                 bp = g_bioq_first(&g_bio_run_down);
  574                 if (bp == NULL) {
  575                         CTR0(KTR_GEOM, "g_down going to sleep");
  576                         msleep(&g_wait_down, &g_bio_run_down.bio_queue_lock,
  577                             PRIBIO | PDROP, "-", 0);
  578                         continue;
  579                 }
  580                 CTR0(KTR_GEOM, "g_down has work to do");
  581                 g_bioq_unlock(&g_bio_run_down);
  582                 if (pace > 0) {
  583                         CTR1(KTR_GEOM, "g_down pacing self (pace %d)", pace);
  584                         pause("g_down", hz/10);
  585                         pace--;
  586                 }
  587                 error = g_io_check(bp);
  588                 if (error) {
  589                         CTR3(KTR_GEOM, "g_down g_io_check on bp %p provider "
  590                             "%s returned %d", bp, bp->bio_to->name, error);
  591                         g_io_deliver(bp, error);
  592                         continue;
  593                 }
  594                 CTR2(KTR_GEOM, "g_down processing bp %p provider %s", bp,
  595                     bp->bio_to->name);
  596                 switch (bp->bio_cmd) {
  597                 case BIO_READ:
  598                 case BIO_WRITE:
  599                 case BIO_DELETE:
  600                         /* Truncate requests to the end of providers media. */
  601                         /*
  602                          * XXX: What if we truncate because of offset being
  603                          * bad, not length?
  604                          */
  605                         excess = bp->bio_offset + bp->bio_length;
  606                         if (excess > bp->bio_to->mediasize) {
  607                                 excess -= bp->bio_to->mediasize;
  608                                 bp->bio_length -= excess;
  609                                 if (excess > 0)
  610                                         CTR3(KTR_GEOM, "g_down truncated bio "
  611                                             "%p provider %s by %d", bp,
  612                                             bp->bio_to->name, excess);
  613                         }
  614                         /* Deliver zero length transfers right here. */
  615                         if (bp->bio_length == 0) {
  616                                 g_io_deliver(bp, 0);
  617                                 CTR2(KTR_GEOM, "g_down terminated 0-length "
  618                                     "bp %p provider %s", bp, bp->bio_to->name);
  619                                 continue;
  620                         }
  621                         break;
  622                 default:
  623                         break;
  624                 }
  625                 THREAD_NO_SLEEPING();
  626                 CTR4(KTR_GEOM, "g_down starting bp %p provider %s off %ld "
  627                     "len %ld", bp, bp->bio_to->name, bp->bio_offset,
  628                     bp->bio_length);
  629                 bp->bio_to->geom->start(bp);
  630                 THREAD_SLEEPING_OK();
  631         }
  632 }
  633 
  634 void
  635 bio_taskqueue(struct bio *bp, bio_task_t *func, void *arg)
  636 {
  637         bp->bio_task = func;
  638         bp->bio_task_arg = arg;
  639         /*
  640          * The taskqueue is actually just a second queue off the "up"
  641          * queue, so we use the same lock.
  642          */
  643         g_bioq_lock(&g_bio_run_up);
  644         KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
  645             ("Bio already on queue bp=%p target taskq", bp));
  646         bp->bio_flags |= BIO_ONQUEUE;
  647         TAILQ_INSERT_TAIL(&g_bio_run_task.bio_queue, bp, bio_queue);
  648         g_bio_run_task.bio_queue_length++;
  649         wakeup(&g_wait_up);
  650         g_bioq_unlock(&g_bio_run_up);
  651 }
  652 
  653 
  654 void
  655 g_io_schedule_up(struct thread *tp __unused)
  656 {
  657         struct bio *bp;
  658         for(;;) {
  659                 g_bioq_lock(&g_bio_run_up);
  660                 bp = g_bioq_first(&g_bio_run_task);
  661                 if (bp != NULL) {
  662                         g_bioq_unlock(&g_bio_run_up);
  663                         THREAD_NO_SLEEPING();
  664                         CTR1(KTR_GEOM, "g_up processing task bp %p", bp);
  665                         bp->bio_task(bp->bio_task_arg);
  666                         THREAD_SLEEPING_OK();
  667                         continue;
  668                 }
  669                 bp = g_bioq_first(&g_bio_run_up);
  670                 if (bp != NULL) {
  671                         g_bioq_unlock(&g_bio_run_up);
  672                         THREAD_NO_SLEEPING();
  673                         CTR4(KTR_GEOM, "g_up biodone bp %p provider %s off "
  674                             "%jd len %ld", bp, bp->bio_to->name,
  675                             bp->bio_offset, bp->bio_length);
  676                         biodone(bp);
  677                         THREAD_SLEEPING_OK();
  678                         continue;
  679                 }
  680                 CTR0(KTR_GEOM, "g_up going to sleep");
  681                 msleep(&g_wait_up, &g_bio_run_up.bio_queue_lock,
  682                     PRIBIO | PDROP, "-", 0);
  683         }
  684 }
  685 
  686 void *
  687 g_read_data(struct g_consumer *cp, off_t offset, off_t length, int *error)
  688 {
  689         struct bio *bp;
  690         void *ptr;
  691         int errorc;
  692 
  693         KASSERT(length > 0 && length >= cp->provider->sectorsize &&
  694             length <= MAXPHYS, ("g_read_data(): invalid length %jd",
  695             (intmax_t)length));
  696 
  697         bp = g_alloc_bio();
  698         bp->bio_cmd = BIO_READ;
  699         bp->bio_done = NULL;
  700         bp->bio_offset = offset;
  701         bp->bio_length = length;
  702         ptr = g_malloc(length, M_WAITOK);
  703         bp->bio_data = ptr;
  704         g_io_request(bp, cp);
  705         errorc = biowait(bp, "gread");
  706         if (error != NULL)
  707                 *error = errorc;
  708         g_destroy_bio(bp);
  709         if (errorc) {
  710                 g_free(ptr);
  711                 ptr = NULL;
  712         }
  713         return (ptr);
  714 }
  715 
  716 int
  717 g_write_data(struct g_consumer *cp, off_t offset, void *ptr, off_t length)
  718 {
  719         struct bio *bp;
  720         int error;
  721 
  722         KASSERT(length > 0 && length >= cp->provider->sectorsize &&
  723             length <= MAXPHYS, ("g_write_data(): invalid length %jd",
  724             (intmax_t)length));
  725 
  726         bp = g_alloc_bio();
  727         bp->bio_cmd = BIO_WRITE;
  728         bp->bio_done = NULL;
  729         bp->bio_offset = offset;
  730         bp->bio_length = length;
  731         bp->bio_data = ptr;
  732         g_io_request(bp, cp);
  733         error = biowait(bp, "gwrite");
  734         g_destroy_bio(bp);
  735         return (error);
  736 }
  737 
  738 int
  739 g_delete_data(struct g_consumer *cp, off_t offset, off_t length)
  740 {
  741         struct bio *bp;
  742         int error;
  743 
  744         KASSERT(length > 0 && length >= cp->provider->sectorsize,
  745             ("g_delete_data(): invalid length %jd", (intmax_t)length));
  746 
  747         bp = g_alloc_bio();
  748         bp->bio_cmd = BIO_DELETE;
  749         bp->bio_done = NULL;
  750         bp->bio_offset = offset;
  751         bp->bio_length = length;
  752         bp->bio_data = NULL;
  753         g_io_request(bp, cp);
  754         error = biowait(bp, "gdelete");
  755         g_destroy_bio(bp);
  756         return (error);
  757 }
  758 
  759 void
  760 g_print_bio(struct bio *bp)
  761 {
  762         const char *pname, *cmd = NULL;
  763 
  764         if (bp->bio_to != NULL)
  765                 pname = bp->bio_to->name;
  766         else
  767                 pname = "[unknown]";
  768 
  769         switch (bp->bio_cmd) {
  770         case BIO_GETATTR:
  771                 cmd = "GETATTR";
  772                 printf("%s[%s(attr=%s)]", pname, cmd, bp->bio_attribute);
  773                 return;
  774         case BIO_FLUSH:
  775                 cmd = "FLUSH";
  776                 printf("%s[%s]", pname, cmd);
  777                 return;
  778         case BIO_READ:
  779                 cmd = "READ";
  780         case BIO_WRITE:
  781                 if (cmd == NULL)
  782                         cmd = "WRITE";
  783         case BIO_DELETE:
  784                 if (cmd == NULL)
  785                         cmd = "DELETE";
  786                 printf("%s[%s(offset=%jd, length=%jd)]", pname, cmd,
  787                     (intmax_t)bp->bio_offset, (intmax_t)bp->bio_length);
  788                 return;
  789         default:
  790                 cmd = "UNKNOWN";
  791                 printf("%s[%s()]", pname, cmd);
  792                 return;
  793         }
  794         /* NOTREACHED */
  795 }

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