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  * Copyright (c) 2013 The FreeBSD Foundation
    5  * All rights reserved.
    6  *
    7  * This software was developed for the FreeBSD Project by Poul-Henning Kamp
    8  * and NAI Labs, the Security Research Division of Network Associates, Inc.
    9  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
   10  * DARPA CHATS research program.
   11  *
   12  * Portions of this software were developed by Konstantin Belousov
   13  * under sponsorship from the FreeBSD Foundation.
   14  *
   15  * Redistribution and use in source and binary forms, with or without
   16  * modification, are permitted provided that the following conditions
   17  * are met:
   18  * 1. Redistributions of source code must retain the above copyright
   19  *    notice, this list of conditions and the following disclaimer.
   20  * 2. Redistributions in binary form must reproduce the above copyright
   21  *    notice, this list of conditions and the following disclaimer in the
   22  *    documentation and/or other materials provided with the distribution.
   23  * 3. The names of the authors may not be used to endorse or promote
   24  *    products derived from this software without specific prior written
   25  *    permission.
   26  *
   27  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   37  * SUCH DAMAGE.
   38  */
   39 
   40 #include <sys/cdefs.h>
   41 __FBSDID("$FreeBSD: releng/9.2/sys/geom/geom_io.c 251920 2013-06-18 09:29:30Z mav $");
   42 
   43 #include <sys/param.h>
   44 #include <sys/systm.h>
   45 #include <sys/kernel.h>
   46 #include <sys/malloc.h>
   47 #include <sys/bio.h>
   48 #include <sys/ktr.h>
   49 #include <sys/proc.h>
   50 #include <sys/stack.h>
   51 #include <sys/sysctl.h>
   52 
   53 #include <sys/errno.h>
   54 #include <geom/geom.h>
   55 #include <geom/geom_int.h>
   56 #include <sys/devicestat.h>
   57 
   58 #include <vm/uma.h>
   59 #include <vm/vm.h>
   60 #include <vm/vm_param.h>
   61 #include <vm/vm_kern.h>
   62 #include <vm/vm_page.h>
   63 #include <vm/vm_object.h>
   64 #include <vm/vm_extern.h>
   65 #include <vm/vm_map.h>
   66 
   67 static struct g_bioq g_bio_run_down;
   68 static struct g_bioq g_bio_run_up;
   69 static struct g_bioq g_bio_run_task;
   70 
   71 static u_int pace;
   72 static uma_zone_t       biozone;
   73 
   74 /*
   75  * The head of the list of classifiers used in g_io_request.
   76  * Use g_register_classifier() and g_unregister_classifier()
   77  * to add/remove entries to the list.
   78  * Classifiers are invoked in registration order.
   79  */
   80 static TAILQ_HEAD(g_classifier_tailq, g_classifier_hook)
   81     g_classifier_tailq = TAILQ_HEAD_INITIALIZER(g_classifier_tailq);
   82 
   83 #include <machine/atomic.h>
   84 
   85 static void
   86 g_bioq_lock(struct g_bioq *bq)
   87 {
   88 
   89         mtx_lock(&bq->bio_queue_lock);
   90 }
   91 
   92 static void
   93 g_bioq_unlock(struct g_bioq *bq)
   94 {
   95 
   96         mtx_unlock(&bq->bio_queue_lock);
   97 }
   98 
   99 #if 0
  100 static void
  101 g_bioq_destroy(struct g_bioq *bq)
  102 {
  103 
  104         mtx_destroy(&bq->bio_queue_lock);
  105 }
  106 #endif
  107 
  108 static void
  109 g_bioq_init(struct g_bioq *bq)
  110 {
  111 
  112         TAILQ_INIT(&bq->bio_queue);
  113         mtx_init(&bq->bio_queue_lock, "bio queue", NULL, MTX_DEF);
  114 }
  115 
  116 static struct bio *
  117 g_bioq_first(struct g_bioq *bq)
  118 {
  119         struct bio *bp;
  120 
  121         bp = TAILQ_FIRST(&bq->bio_queue);
  122         if (bp != NULL) {
  123                 KASSERT((bp->bio_flags & BIO_ONQUEUE),
  124                     ("Bio not on queue bp=%p target %p", bp, bq));
  125                 bp->bio_flags &= ~BIO_ONQUEUE;
  126                 TAILQ_REMOVE(&bq->bio_queue, bp, bio_queue);
  127                 bq->bio_queue_length--;
  128         }
  129         return (bp);
  130 }
  131 
  132 struct bio *
  133 g_new_bio(void)
  134 {
  135         struct bio *bp;
  136 
  137         bp = uma_zalloc(biozone, M_NOWAIT | M_ZERO);
  138 #ifdef KTR
  139         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  140                 struct stack st;
  141 
  142                 CTR1(KTR_GEOM, "g_new_bio(): %p", bp);
  143                 stack_save(&st);
  144                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  145         }
  146 #endif
  147         return (bp);
  148 }
  149 
  150 struct bio *
  151 g_alloc_bio(void)
  152 {
  153         struct bio *bp;
  154 
  155         bp = uma_zalloc(biozone, M_WAITOK | M_ZERO);
  156 #ifdef KTR
  157         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  158                 struct stack st;
  159 
  160                 CTR1(KTR_GEOM, "g_alloc_bio(): %p", bp);
  161                 stack_save(&st);
  162                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  163         }
  164 #endif
  165         return (bp);
  166 }
  167 
  168 void
  169 g_destroy_bio(struct bio *bp)
  170 {
  171 #ifdef KTR
  172         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  173                 struct stack st;
  174 
  175                 CTR1(KTR_GEOM, "g_destroy_bio(): %p", bp);
  176                 stack_save(&st);
  177                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  178         }
  179 #endif
  180         uma_zfree(biozone, bp);
  181 }
  182 
  183 struct bio *
  184 g_clone_bio(struct bio *bp)
  185 {
  186         struct bio *bp2;
  187 
  188         bp2 = uma_zalloc(biozone, M_NOWAIT | M_ZERO);
  189         if (bp2 != NULL) {
  190                 bp2->bio_parent = bp;
  191                 bp2->bio_cmd = bp->bio_cmd;
  192                 /*
  193                  *  BIO_ORDERED flag may be used by disk drivers to enforce
  194                  *  ordering restrictions, so this flag needs to be cloned.
  195                  *  BIO_UNMAPPED should be inherited, to properly indicate
  196                  *  which way the buffer is passed.
  197                  *  Other bio flags are not suitable for cloning.
  198                  */
  199                 bp2->bio_flags = bp->bio_flags & (BIO_ORDERED | BIO_UNMAPPED);
  200                 bp2->bio_length = bp->bio_length;
  201                 bp2->bio_offset = bp->bio_offset;
  202                 bp2->bio_data = bp->bio_data;
  203                 bp2->bio_ma = bp->bio_ma;
  204                 bp2->bio_ma_n = bp->bio_ma_n;
  205                 bp2->bio_ma_offset = bp->bio_ma_offset;
  206                 bp2->bio_attribute = bp->bio_attribute;
  207                 /* Inherit classification info from the parent */
  208                 bp2->bio_classifier1 = bp->bio_classifier1;
  209                 bp2->bio_classifier2 = bp->bio_classifier2;
  210                 bp->bio_children++;
  211         }
  212 #ifdef KTR
  213         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  214                 struct stack st;
  215 
  216                 CTR2(KTR_GEOM, "g_clone_bio(%p): %p", bp, bp2);
  217                 stack_save(&st);
  218                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  219         }
  220 #endif
  221         return(bp2);
  222 }
  223 
  224 struct bio *
  225 g_duplicate_bio(struct bio *bp)
  226 {
  227         struct bio *bp2;
  228 
  229         bp2 = uma_zalloc(biozone, M_WAITOK | M_ZERO);
  230         bp2->bio_flags = bp->bio_flags & BIO_UNMAPPED;
  231         bp2->bio_parent = bp;
  232         bp2->bio_cmd = bp->bio_cmd;
  233         bp2->bio_length = bp->bio_length;
  234         bp2->bio_offset = bp->bio_offset;
  235         bp2->bio_data = bp->bio_data;
  236         bp2->bio_ma = bp->bio_ma;
  237         bp2->bio_ma_n = bp->bio_ma_n;
  238         bp2->bio_ma_offset = bp->bio_ma_offset;
  239         bp2->bio_attribute = bp->bio_attribute;
  240         bp->bio_children++;
  241 #ifdef KTR
  242         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  243                 struct stack st;
  244 
  245                 CTR2(KTR_GEOM, "g_duplicate_bio(%p): %p", bp, bp2);
  246                 stack_save(&st);
  247                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  248         }
  249 #endif
  250         return(bp2);
  251 }
  252 
  253 void
  254 g_io_init()
  255 {
  256 
  257         g_bioq_init(&g_bio_run_down);
  258         g_bioq_init(&g_bio_run_up);
  259         g_bioq_init(&g_bio_run_task);
  260         biozone = uma_zcreate("g_bio", sizeof (struct bio),
  261             NULL, NULL,
  262             NULL, NULL,
  263             0, 0);
  264 }
  265 
  266 int
  267 g_io_getattr(const char *attr, struct g_consumer *cp, int *len, void *ptr)
  268 {
  269         struct bio *bp;
  270         int error;
  271 
  272         g_trace(G_T_BIO, "bio_getattr(%s)", attr);
  273         bp = g_alloc_bio();
  274         bp->bio_cmd = BIO_GETATTR;
  275         bp->bio_done = NULL;
  276         bp->bio_attribute = attr;
  277         bp->bio_length = *len;
  278         bp->bio_data = ptr;
  279         g_io_request(bp, cp);
  280         error = biowait(bp, "ggetattr");
  281         *len = bp->bio_completed;
  282         g_destroy_bio(bp);
  283         return (error);
  284 }
  285 
  286 int
  287 g_io_flush(struct g_consumer *cp)
  288 {
  289         struct bio *bp;
  290         int error;
  291 
  292         g_trace(G_T_BIO, "bio_flush(%s)", cp->provider->name);
  293         bp = g_alloc_bio();
  294         bp->bio_cmd = BIO_FLUSH;
  295         bp->bio_flags |= BIO_ORDERED;
  296         bp->bio_done = NULL;
  297         bp->bio_attribute = NULL;
  298         bp->bio_offset = cp->provider->mediasize;
  299         bp->bio_length = 0;
  300         bp->bio_data = NULL;
  301         g_io_request(bp, cp);
  302         error = biowait(bp, "gflush");
  303         g_destroy_bio(bp);
  304         return (error);
  305 }
  306 
  307 static int
  308 g_io_check(struct bio *bp)
  309 {
  310         struct g_consumer *cp;
  311         struct g_provider *pp;
  312 
  313         cp = bp->bio_from;
  314         pp = bp->bio_to;
  315 
  316         /* Fail if access counters dont allow the operation */
  317         switch(bp->bio_cmd) {
  318         case BIO_READ:
  319         case BIO_GETATTR:
  320                 if (cp->acr == 0)
  321                         return (EPERM);
  322                 break;
  323         case BIO_WRITE:
  324         case BIO_DELETE:
  325         case BIO_FLUSH:
  326                 if (cp->acw == 0)
  327                         return (EPERM);
  328                 break;
  329         default:
  330                 return (EPERM);
  331         }
  332         /* if provider is marked for error, don't disturb. */
  333         if (pp->error)
  334                 return (pp->error);
  335         if (cp->flags & G_CF_ORPHAN)
  336                 return (ENXIO);
  337 
  338         switch(bp->bio_cmd) {
  339         case BIO_READ:
  340         case BIO_WRITE:
  341         case BIO_DELETE:
  342                 /* Zero sectorsize or mediasize is probably a lack of media. */
  343                 if (pp->sectorsize == 0 || pp->mediasize == 0)
  344                         return (ENXIO);
  345                 /* Reject I/O not on sector boundary */
  346                 if (bp->bio_offset % pp->sectorsize)
  347                         return (EINVAL);
  348                 /* Reject I/O not integral sector long */
  349                 if (bp->bio_length % pp->sectorsize)
  350                         return (EINVAL);
  351                 /* Reject requests before or past the end of media. */
  352                 if (bp->bio_offset < 0)
  353                         return (EIO);
  354                 if (bp->bio_offset > pp->mediasize)
  355                         return (EIO);
  356                 break;
  357         default:
  358                 break;
  359         }
  360         return (0);
  361 }
  362 
  363 /*
  364  * bio classification support.
  365  *
  366  * g_register_classifier() and g_unregister_classifier()
  367  * are used to add/remove a classifier from the list.
  368  * The list is protected using the g_bio_run_down lock,
  369  * because the classifiers are called in this path.
  370  *
  371  * g_io_request() passes bio's that are not already classified
  372  * (i.e. those with bio_classifier1 == NULL) to g_run_classifiers().
  373  * Classifiers can store their result in the two fields
  374  * bio_classifier1 and bio_classifier2.
  375  * A classifier that updates one of the fields should
  376  * return a non-zero value.
  377  * If no classifier updates the field, g_run_classifiers() sets
  378  * bio_classifier1 = BIO_NOTCLASSIFIED to avoid further calls.
  379  */
  380 
  381 int
  382 g_register_classifier(struct g_classifier_hook *hook)
  383 {
  384 
  385         g_bioq_lock(&g_bio_run_down);
  386         TAILQ_INSERT_TAIL(&g_classifier_tailq, hook, link);
  387         g_bioq_unlock(&g_bio_run_down);
  388 
  389         return (0);
  390 }
  391 
  392 void
  393 g_unregister_classifier(struct g_classifier_hook *hook)
  394 {
  395         struct g_classifier_hook *entry;
  396 
  397         g_bioq_lock(&g_bio_run_down);
  398         TAILQ_FOREACH(entry, &g_classifier_tailq, link) {
  399                 if (entry == hook) {
  400                         TAILQ_REMOVE(&g_classifier_tailq, hook, link);
  401                         break;
  402                 }
  403         }
  404         g_bioq_unlock(&g_bio_run_down);
  405 }
  406 
  407 static void
  408 g_run_classifiers(struct bio *bp)
  409 {
  410         struct g_classifier_hook *hook;
  411         int classified = 0;
  412 
  413         TAILQ_FOREACH(hook, &g_classifier_tailq, link)
  414                 classified |= hook->func(hook->arg, bp);
  415 
  416         if (!classified)
  417                 bp->bio_classifier1 = BIO_NOTCLASSIFIED;
  418 }
  419 
  420 void
  421 g_io_request(struct bio *bp, struct g_consumer *cp)
  422 {
  423         struct g_provider *pp;
  424         int first;
  425 
  426         KASSERT(cp != NULL, ("NULL cp in g_io_request"));
  427         KASSERT(bp != NULL, ("NULL bp in g_io_request"));
  428         pp = cp->provider;
  429         KASSERT(pp != NULL, ("consumer not attached in g_io_request"));
  430 #ifdef DIAGNOSTIC
  431         KASSERT(bp->bio_driver1 == NULL,
  432             ("bio_driver1 used by the consumer (geom %s)", cp->geom->name));
  433         KASSERT(bp->bio_driver2 == NULL,
  434             ("bio_driver2 used by the consumer (geom %s)", cp->geom->name));
  435         KASSERT(bp->bio_pflags == 0,
  436             ("bio_pflags used by the consumer (geom %s)", cp->geom->name));
  437         /*
  438          * Remember consumer's private fields, so we can detect if they were
  439          * modified by the provider.
  440          */
  441         bp->_bio_caller1 = bp->bio_caller1;
  442         bp->_bio_caller2 = bp->bio_caller2;
  443         bp->_bio_cflags = bp->bio_cflags;
  444 #endif
  445 
  446         if (bp->bio_cmd & (BIO_READ|BIO_WRITE|BIO_GETATTR)) {
  447                 KASSERT(bp->bio_data != NULL,
  448                     ("NULL bp->data in g_io_request(cmd=%hhu)", bp->bio_cmd));
  449         }
  450         if (bp->bio_cmd & (BIO_DELETE|BIO_FLUSH)) {
  451                 KASSERT(bp->bio_data == NULL,
  452                     ("non-NULL bp->data in g_io_request(cmd=%hhu)",
  453                     bp->bio_cmd));
  454         }
  455         if (bp->bio_cmd & (BIO_READ|BIO_WRITE|BIO_DELETE)) {
  456                 KASSERT(bp->bio_offset % cp->provider->sectorsize == 0,
  457                     ("wrong offset %jd for sectorsize %u",
  458                     bp->bio_offset, cp->provider->sectorsize));
  459                 KASSERT(bp->bio_length % cp->provider->sectorsize == 0,
  460                     ("wrong length %jd for sectorsize %u",
  461                     bp->bio_length, cp->provider->sectorsize));
  462         }
  463 
  464         g_trace(G_T_BIO, "bio_request(%p) from %p(%s) to %p(%s) cmd %d",
  465             bp, cp, cp->geom->name, pp, pp->name, bp->bio_cmd);
  466 
  467         bp->bio_from = cp;
  468         bp->bio_to = pp;
  469         bp->bio_error = 0;
  470         bp->bio_completed = 0;
  471 
  472         KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
  473             ("Bio already on queue bp=%p", bp));
  474         bp->bio_flags |= BIO_ONQUEUE;
  475 
  476         if (g_collectstats)
  477                 binuptime(&bp->bio_t0);
  478         else
  479                 getbinuptime(&bp->bio_t0);
  480 
  481         /*
  482          * The statistics collection is lockless, as such, but we
  483          * can not update one instance of the statistics from more
  484          * than one thread at a time, so grab the lock first.
  485          *
  486          * We also use the lock to protect the list of classifiers.
  487          */
  488         g_bioq_lock(&g_bio_run_down);
  489 
  490         if (!TAILQ_EMPTY(&g_classifier_tailq) && !bp->bio_classifier1)
  491                 g_run_classifiers(bp);
  492 
  493         if (g_collectstats & 1)
  494                 devstat_start_transaction(pp->stat, &bp->bio_t0);
  495         if (g_collectstats & 2)
  496                 devstat_start_transaction(cp->stat, &bp->bio_t0);
  497 
  498         pp->nstart++;
  499         cp->nstart++;
  500         first = TAILQ_EMPTY(&g_bio_run_down.bio_queue);
  501         TAILQ_INSERT_TAIL(&g_bio_run_down.bio_queue, bp, bio_queue);
  502         g_bio_run_down.bio_queue_length++;
  503         g_bioq_unlock(&g_bio_run_down);
  504 
  505         /* Pass it on down. */
  506         if (first)
  507                 wakeup(&g_wait_down);
  508 }
  509 
  510 void
  511 g_io_deliver(struct bio *bp, int error)
  512 {
  513         struct g_consumer *cp;
  514         struct g_provider *pp;
  515         int first;
  516 
  517         KASSERT(bp != NULL, ("NULL bp in g_io_deliver"));
  518         pp = bp->bio_to;
  519         KASSERT(pp != NULL, ("NULL bio_to in g_io_deliver"));
  520         cp = bp->bio_from;
  521         if (cp == NULL) {
  522                 bp->bio_error = error;
  523                 bp->bio_done(bp);
  524                 return;
  525         }
  526         KASSERT(cp != NULL, ("NULL bio_from in g_io_deliver"));
  527         KASSERT(cp->geom != NULL, ("NULL bio_from->geom in g_io_deliver"));
  528 #ifdef DIAGNOSTIC
  529         /*
  530          * Some classes - GJournal in particular - can modify bio's
  531          * private fields while the bio is in transit; G_GEOM_VOLATILE_BIO
  532          * flag means it's an expected behaviour for that particular geom.
  533          */
  534         if ((cp->geom->flags & G_GEOM_VOLATILE_BIO) == 0) {
  535                 KASSERT(bp->bio_caller1 == bp->_bio_caller1,
  536                     ("bio_caller1 used by the provider %s", pp->name));
  537                 KASSERT(bp->bio_caller2 == bp->_bio_caller2,
  538                     ("bio_caller2 used by the provider %s", pp->name));
  539                 KASSERT(bp->bio_cflags == bp->_bio_cflags,
  540                     ("bio_cflags used by the provider %s", pp->name));
  541         }
  542 #endif
  543         KASSERT(bp->bio_completed >= 0, ("bio_completed can't be less than 0"));
  544         KASSERT(bp->bio_completed <= bp->bio_length,
  545             ("bio_completed can't be greater than bio_length"));
  546 
  547         g_trace(G_T_BIO,
  548 "g_io_deliver(%p) from %p(%s) to %p(%s) cmd %d error %d off %jd len %jd",
  549             bp, cp, cp->geom->name, pp, pp->name, bp->bio_cmd, error,
  550             (intmax_t)bp->bio_offset, (intmax_t)bp->bio_length);
  551 
  552         KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
  553             ("Bio already on queue bp=%p", bp));
  554 
  555         /*
  556          * XXX: next two doesn't belong here
  557          */
  558         bp->bio_bcount = bp->bio_length;
  559         bp->bio_resid = bp->bio_bcount - bp->bio_completed;
  560 
  561         /*
  562          * The statistics collection is lockless, as such, but we
  563          * can not update one instance of the statistics from more
  564          * than one thread at a time, so grab the lock first.
  565          */
  566         g_bioq_lock(&g_bio_run_up);
  567         if (g_collectstats & 1)
  568                 devstat_end_transaction_bio(pp->stat, bp);
  569         if (g_collectstats & 2)
  570                 devstat_end_transaction_bio(cp->stat, bp);
  571 
  572         cp->nend++;
  573         pp->nend++;
  574         if (error != ENOMEM) {
  575                 bp->bio_error = error;
  576                 first = TAILQ_EMPTY(&g_bio_run_up.bio_queue);
  577                 TAILQ_INSERT_TAIL(&g_bio_run_up.bio_queue, bp, bio_queue);
  578                 bp->bio_flags |= BIO_ONQUEUE;
  579                 g_bio_run_up.bio_queue_length++;
  580                 g_bioq_unlock(&g_bio_run_up);
  581                 if (first)
  582                         wakeup(&g_wait_up);
  583                 return;
  584         }
  585         g_bioq_unlock(&g_bio_run_up);
  586 
  587         if (bootverbose)
  588                 printf("ENOMEM %p on %p(%s)\n", bp, pp, pp->name);
  589         bp->bio_children = 0;
  590         bp->bio_inbed = 0;
  591         bp->bio_driver1 = NULL;
  592         bp->bio_driver2 = NULL;
  593         bp->bio_pflags = 0;
  594         g_io_request(bp, cp);
  595         pace++;
  596         return;
  597 }
  598 
  599 SYSCTL_DECL(_kern_geom);
  600 
  601 static long transient_maps;
  602 SYSCTL_LONG(_kern_geom, OID_AUTO, transient_maps, CTLFLAG_RD,
  603     &transient_maps, 0,
  604     "Total count of the transient mapping requests");
  605 u_int transient_map_retries = 10;
  606 SYSCTL_UINT(_kern_geom, OID_AUTO, transient_map_retries, CTLFLAG_RW,
  607     &transient_map_retries, 0,
  608     "Max count of retries used before giving up on creating transient map");
  609 int transient_map_hard_failures;
  610 SYSCTL_INT(_kern_geom, OID_AUTO, transient_map_hard_failures, CTLFLAG_RD,
  611     &transient_map_hard_failures, 0,
  612     "Failures to establish the transient mapping due to retry attempts "
  613     "exhausted");
  614 int transient_map_soft_failures;
  615 SYSCTL_INT(_kern_geom, OID_AUTO, transient_map_soft_failures, CTLFLAG_RD,
  616     &transient_map_soft_failures, 0,
  617     "Count of retried failures to establish the transient mapping");
  618 int inflight_transient_maps;
  619 SYSCTL_INT(_kern_geom, OID_AUTO, inflight_transient_maps, CTLFLAG_RD,
  620     &inflight_transient_maps, 0,
  621     "Current count of the active transient maps");
  622 
  623 static int
  624 g_io_transient_map_bio(struct bio *bp)
  625 {
  626         vm_offset_t addr;
  627         long size;
  628         u_int retried;
  629         int rv;
  630 
  631         KASSERT(unmapped_buf_allowed, ("unmapped disabled"));
  632 
  633         size = round_page(bp->bio_ma_offset + bp->bio_length);
  634         KASSERT(size / PAGE_SIZE == bp->bio_ma_n, ("Bio too short %p", bp));
  635         addr = 0;
  636         retried = 0;
  637         atomic_add_long(&transient_maps, 1);
  638 retry:
  639         vm_map_lock(bio_transient_map);
  640         if (vm_map_findspace(bio_transient_map, vm_map_min(bio_transient_map),
  641             size, &addr)) {
  642                 vm_map_unlock(bio_transient_map);
  643                 if (transient_map_retries != 0 &&
  644                     retried >= transient_map_retries) {
  645                         g_io_deliver(bp, EDEADLK/* XXXKIB */);
  646                         CTR2(KTR_GEOM, "g_down cannot map bp %p provider %s",
  647                             bp, bp->bio_to->name);
  648                         atomic_add_int(&transient_map_hard_failures, 1);
  649                         return (1);
  650                 } else {
  651                         /*
  652                          * Naive attempt to quisce the I/O to get more
  653                          * in-flight requests completed and defragment
  654                          * the bio_transient_map.
  655                          */
  656                         CTR3(KTR_GEOM, "g_down retrymap bp %p provider %s r %d",
  657                             bp, bp->bio_to->name, retried);
  658                         pause("g_d_tra", hz / 10);
  659                         retried++;
  660                         atomic_add_int(&transient_map_soft_failures, 1);
  661                         goto retry;
  662                 }
  663         }
  664         rv = vm_map_insert(bio_transient_map, NULL, 0, addr, addr + size,
  665             VM_PROT_RW, VM_PROT_RW, MAP_NOFAULT);
  666         KASSERT(rv == KERN_SUCCESS,
  667             ("vm_map_insert(bio_transient_map) rv %d %jx %lx",
  668             rv, (uintmax_t)addr, size));
  669         vm_map_unlock(bio_transient_map);
  670         atomic_add_int(&inflight_transient_maps, 1);
  671         pmap_qenter((vm_offset_t)addr, bp->bio_ma, OFF_TO_IDX(size));
  672         bp->bio_data = (caddr_t)addr + bp->bio_ma_offset;
  673         bp->bio_flags |= BIO_TRANSIENT_MAPPING;
  674         bp->bio_flags &= ~BIO_UNMAPPED;
  675         return (0);
  676 }
  677 
  678 void
  679 g_io_schedule_down(struct thread *tp __unused)
  680 {
  681         struct bio *bp;
  682         off_t excess;
  683         int error;
  684 
  685         for(;;) {
  686                 g_bioq_lock(&g_bio_run_down);
  687                 bp = g_bioq_first(&g_bio_run_down);
  688                 if (bp == NULL) {
  689                         CTR0(KTR_GEOM, "g_down going to sleep");
  690                         msleep(&g_wait_down, &g_bio_run_down.bio_queue_lock,
  691                             PRIBIO | PDROP, "-", 0);
  692                         continue;
  693                 }
  694                 CTR0(KTR_GEOM, "g_down has work to do");
  695                 g_bioq_unlock(&g_bio_run_down);
  696                 if (pace > 0) {
  697                         CTR1(KTR_GEOM, "g_down pacing self (pace %d)", pace);
  698                         pause("g_down", hz/10);
  699                         pace--;
  700                 }
  701                 error = g_io_check(bp);
  702                 if (error) {
  703                         CTR3(KTR_GEOM, "g_down g_io_check on bp %p provider "
  704                             "%s returned %d", bp, bp->bio_to->name, error);
  705                         g_io_deliver(bp, error);
  706                         continue;
  707                 }
  708                 CTR2(KTR_GEOM, "g_down processing bp %p provider %s", bp,
  709                     bp->bio_to->name);
  710                 switch (bp->bio_cmd) {
  711                 case BIO_READ:
  712                 case BIO_WRITE:
  713                 case BIO_DELETE:
  714                         /* Truncate requests to the end of providers media. */
  715                         /*
  716                          * XXX: What if we truncate because of offset being
  717                          * bad, not length?
  718                          */
  719                         excess = bp->bio_offset + bp->bio_length;
  720                         if (excess > bp->bio_to->mediasize) {
  721                                 KASSERT((bp->bio_flags & BIO_UNMAPPED) == 0 ||
  722                                     round_page(bp->bio_ma_offset +
  723                                     bp->bio_length) / PAGE_SIZE == bp->bio_ma_n,
  724                                     ("excess bio %p too short", bp));
  725                                 excess -= bp->bio_to->mediasize;
  726                                 bp->bio_length -= excess;
  727                                 if ((bp->bio_flags & BIO_UNMAPPED) != 0) {
  728                                         bp->bio_ma_n = round_page(
  729                                             bp->bio_ma_offset +
  730                                             bp->bio_length) / PAGE_SIZE;
  731                                 }
  732                                 if (excess > 0)
  733                                         CTR3(KTR_GEOM, "g_down truncated bio "
  734                                             "%p provider %s by %d", bp,
  735                                             bp->bio_to->name, excess);
  736                         }
  737                         /* Deliver zero length transfers right here. */
  738                         if (bp->bio_length == 0) {
  739                                 g_io_deliver(bp, 0);
  740                                 CTR2(KTR_GEOM, "g_down terminated 0-length "
  741                                     "bp %p provider %s", bp, bp->bio_to->name);
  742                                 continue;
  743                         }
  744                         break;
  745                 default:
  746                         break;
  747                 }
  748                 if ((bp->bio_flags & BIO_UNMAPPED) != 0 &&
  749                     (bp->bio_to->flags & G_PF_ACCEPT_UNMAPPED) == 0 &&
  750                     (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE)) {
  751                         if (g_io_transient_map_bio(bp))
  752                                 continue;
  753                 }
  754                 THREAD_NO_SLEEPING();
  755                 CTR4(KTR_GEOM, "g_down starting bp %p provider %s off %ld "
  756                     "len %ld", bp, bp->bio_to->name, bp->bio_offset,
  757                     bp->bio_length);
  758                 bp->bio_to->geom->start(bp);
  759                 THREAD_SLEEPING_OK();
  760         }
  761 }
  762 
  763 void
  764 bio_taskqueue(struct bio *bp, bio_task_t *func, void *arg)
  765 {
  766         bp->bio_task = func;
  767         bp->bio_task_arg = arg;
  768         /*
  769          * The taskqueue is actually just a second queue off the "up"
  770          * queue, so we use the same lock.
  771          */
  772         g_bioq_lock(&g_bio_run_up);
  773         KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
  774             ("Bio already on queue bp=%p target taskq", bp));
  775         bp->bio_flags |= BIO_ONQUEUE;
  776         TAILQ_INSERT_TAIL(&g_bio_run_task.bio_queue, bp, bio_queue);
  777         g_bio_run_task.bio_queue_length++;
  778         wakeup(&g_wait_up);
  779         g_bioq_unlock(&g_bio_run_up);
  780 }
  781 
  782 
  783 void
  784 g_io_schedule_up(struct thread *tp __unused)
  785 {
  786         struct bio *bp;
  787         for(;;) {
  788                 g_bioq_lock(&g_bio_run_up);
  789                 bp = g_bioq_first(&g_bio_run_task);
  790                 if (bp != NULL) {
  791                         g_bioq_unlock(&g_bio_run_up);
  792                         THREAD_NO_SLEEPING();
  793                         CTR1(KTR_GEOM, "g_up processing task bp %p", bp);
  794                         bp->bio_task(bp->bio_task_arg);
  795                         THREAD_SLEEPING_OK();
  796                         continue;
  797                 }
  798                 bp = g_bioq_first(&g_bio_run_up);
  799                 if (bp != NULL) {
  800                         g_bioq_unlock(&g_bio_run_up);
  801                         THREAD_NO_SLEEPING();
  802                         CTR4(KTR_GEOM, "g_up biodone bp %p provider %s off "
  803                             "%jd len %ld", bp, bp->bio_to->name,
  804                             bp->bio_offset, bp->bio_length);
  805                         biodone(bp);
  806                         THREAD_SLEEPING_OK();
  807                         continue;
  808                 }
  809                 CTR0(KTR_GEOM, "g_up going to sleep");
  810                 msleep(&g_wait_up, &g_bio_run_up.bio_queue_lock,
  811                     PRIBIO | PDROP, "-", 0);
  812         }
  813 }
  814 
  815 void *
  816 g_read_data(struct g_consumer *cp, off_t offset, off_t length, int *error)
  817 {
  818         struct bio *bp;
  819         void *ptr;
  820         int errorc;
  821 
  822         KASSERT(length > 0 && length >= cp->provider->sectorsize &&
  823             length <= MAXPHYS, ("g_read_data(): invalid length %jd",
  824             (intmax_t)length));
  825 
  826         bp = g_alloc_bio();
  827         bp->bio_cmd = BIO_READ;
  828         bp->bio_done = NULL;
  829         bp->bio_offset = offset;
  830         bp->bio_length = length;
  831         ptr = g_malloc(length, M_WAITOK);
  832         bp->bio_data = ptr;
  833         g_io_request(bp, cp);
  834         errorc = biowait(bp, "gread");
  835         if (error != NULL)
  836                 *error = errorc;
  837         g_destroy_bio(bp);
  838         if (errorc) {
  839                 g_free(ptr);
  840                 ptr = NULL;
  841         }
  842         return (ptr);
  843 }
  844 
  845 int
  846 g_write_data(struct g_consumer *cp, off_t offset, void *ptr, off_t length)
  847 {
  848         struct bio *bp;
  849         int error;
  850 
  851         KASSERT(length > 0 && length >= cp->provider->sectorsize &&
  852             length <= MAXPHYS, ("g_write_data(): invalid length %jd",
  853             (intmax_t)length));
  854 
  855         bp = g_alloc_bio();
  856         bp->bio_cmd = BIO_WRITE;
  857         bp->bio_done = NULL;
  858         bp->bio_offset = offset;
  859         bp->bio_length = length;
  860         bp->bio_data = ptr;
  861         g_io_request(bp, cp);
  862         error = biowait(bp, "gwrite");
  863         g_destroy_bio(bp);
  864         return (error);
  865 }
  866 
  867 int
  868 g_delete_data(struct g_consumer *cp, off_t offset, off_t length)
  869 {
  870         struct bio *bp;
  871         int error;
  872 
  873         KASSERT(length > 0 && length >= cp->provider->sectorsize,
  874             ("g_delete_data(): invalid length %jd", (intmax_t)length));
  875 
  876         bp = g_alloc_bio();
  877         bp->bio_cmd = BIO_DELETE;
  878         bp->bio_done = NULL;
  879         bp->bio_offset = offset;
  880         bp->bio_length = length;
  881         bp->bio_data = NULL;
  882         g_io_request(bp, cp);
  883         error = biowait(bp, "gdelete");
  884         g_destroy_bio(bp);
  885         return (error);
  886 }
  887 
  888 void
  889 g_print_bio(struct bio *bp)
  890 {
  891         const char *pname, *cmd = NULL;
  892 
  893         if (bp->bio_to != NULL)
  894                 pname = bp->bio_to->name;
  895         else
  896                 pname = "[unknown]";
  897 
  898         switch (bp->bio_cmd) {
  899         case BIO_GETATTR:
  900                 cmd = "GETATTR";
  901                 printf("%s[%s(attr=%s)]", pname, cmd, bp->bio_attribute);
  902                 return;
  903         case BIO_FLUSH:
  904                 cmd = "FLUSH";
  905                 printf("%s[%s]", pname, cmd);
  906                 return;
  907         case BIO_READ:
  908                 cmd = "READ";
  909                 break;
  910         case BIO_WRITE:
  911                 cmd = "WRITE";
  912                 break;
  913         case BIO_DELETE:
  914                 cmd = "DELETE";
  915                 break;
  916         default:
  917                 cmd = "UNKNOWN";
  918                 printf("%s[%s()]", pname, cmd);
  919                 return;
  920         }
  921         printf("%s[%s(offset=%jd, length=%jd)]", pname, cmd,
  922             (intmax_t)bp->bio_offset, (intmax_t)bp->bio_length);
  923 }

Cache object: c58603bf49601e716716ba8063241229


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