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/10.0/sys/geom/geom_io.c 252330 2013-06-28 03:51:20Z jeff $");
   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 #include <sys/vmem.h>
   53 
   54 #include <sys/errno.h>
   55 #include <geom/geom.h>
   56 #include <geom/geom_int.h>
   57 #include <sys/devicestat.h>
   58 
   59 #include <vm/uma.h>
   60 #include <vm/vm.h>
   61 #include <vm/vm_param.h>
   62 #include <vm/vm_kern.h>
   63 #include <vm/vm_page.h>
   64 #include <vm/vm_object.h>
   65 #include <vm/vm_extern.h>
   66 #include <vm/vm_map.h>
   67 
   68 static struct g_bioq g_bio_run_down;
   69 static struct g_bioq g_bio_run_up;
   70 static struct g_bioq g_bio_run_task;
   71 
   72 static u_int pace;
   73 static uma_zone_t       biozone;
   74 
   75 /*
   76  * The head of the list of classifiers used in g_io_request.
   77  * Use g_register_classifier() and g_unregister_classifier()
   78  * to add/remove entries to the list.
   79  * Classifiers are invoked in registration order.
   80  */
   81 static TAILQ_HEAD(g_classifier_tailq, g_classifier_hook)
   82     g_classifier_tailq = TAILQ_HEAD_INITIALIZER(g_classifier_tailq);
   83 
   84 #include <machine/atomic.h>
   85 
   86 static void
   87 g_bioq_lock(struct g_bioq *bq)
   88 {
   89 
   90         mtx_lock(&bq->bio_queue_lock);
   91 }
   92 
   93 static void
   94 g_bioq_unlock(struct g_bioq *bq)
   95 {
   96 
   97         mtx_unlock(&bq->bio_queue_lock);
   98 }
   99 
  100 #if 0
  101 static void
  102 g_bioq_destroy(struct g_bioq *bq)
  103 {
  104 
  105         mtx_destroy(&bq->bio_queue_lock);
  106 }
  107 #endif
  108 
  109 static void
  110 g_bioq_init(struct g_bioq *bq)
  111 {
  112 
  113         TAILQ_INIT(&bq->bio_queue);
  114         mtx_init(&bq->bio_queue_lock, "bio queue", NULL, MTX_DEF);
  115 }
  116 
  117 static struct bio *
  118 g_bioq_first(struct g_bioq *bq)
  119 {
  120         struct bio *bp;
  121 
  122         bp = TAILQ_FIRST(&bq->bio_queue);
  123         if (bp != NULL) {
  124                 KASSERT((bp->bio_flags & BIO_ONQUEUE),
  125                     ("Bio not on queue bp=%p target %p", bp, bq));
  126                 bp->bio_flags &= ~BIO_ONQUEUE;
  127                 TAILQ_REMOVE(&bq->bio_queue, bp, bio_queue);
  128                 bq->bio_queue_length--;
  129         }
  130         return (bp);
  131 }
  132 
  133 struct bio *
  134 g_new_bio(void)
  135 {
  136         struct bio *bp;
  137 
  138         bp = uma_zalloc(biozone, M_NOWAIT | M_ZERO);
  139 #ifdef KTR
  140         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  141                 struct stack st;
  142 
  143                 CTR1(KTR_GEOM, "g_new_bio(): %p", bp);
  144                 stack_save(&st);
  145                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  146         }
  147 #endif
  148         return (bp);
  149 }
  150 
  151 struct bio *
  152 g_alloc_bio(void)
  153 {
  154         struct bio *bp;
  155 
  156         bp = uma_zalloc(biozone, M_WAITOK | M_ZERO);
  157 #ifdef KTR
  158         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  159                 struct stack st;
  160 
  161                 CTR1(KTR_GEOM, "g_alloc_bio(): %p", bp);
  162                 stack_save(&st);
  163                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  164         }
  165 #endif
  166         return (bp);
  167 }
  168 
  169 void
  170 g_destroy_bio(struct bio *bp)
  171 {
  172 #ifdef KTR
  173         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  174                 struct stack st;
  175 
  176                 CTR1(KTR_GEOM, "g_destroy_bio(): %p", bp);
  177                 stack_save(&st);
  178                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  179         }
  180 #endif
  181         uma_zfree(biozone, bp);
  182 }
  183 
  184 struct bio *
  185 g_clone_bio(struct bio *bp)
  186 {
  187         struct bio *bp2;
  188 
  189         bp2 = uma_zalloc(biozone, M_NOWAIT | M_ZERO);
  190         if (bp2 != NULL) {
  191                 bp2->bio_parent = bp;
  192                 bp2->bio_cmd = bp->bio_cmd;
  193                 /*
  194                  *  BIO_ORDERED flag may be used by disk drivers to enforce
  195                  *  ordering restrictions, so this flag needs to be cloned.
  196                  *  BIO_UNMAPPED should be inherited, to properly indicate
  197                  *  which way the buffer is passed.
  198                  *  Other bio flags are not suitable for cloning.
  199                  */
  200                 bp2->bio_flags = bp->bio_flags & (BIO_ORDERED | BIO_UNMAPPED);
  201                 bp2->bio_length = bp->bio_length;
  202                 bp2->bio_offset = bp->bio_offset;
  203                 bp2->bio_data = bp->bio_data;
  204                 bp2->bio_ma = bp->bio_ma;
  205                 bp2->bio_ma_n = bp->bio_ma_n;
  206                 bp2->bio_ma_offset = bp->bio_ma_offset;
  207                 bp2->bio_attribute = bp->bio_attribute;
  208                 /* Inherit classification info from the parent */
  209                 bp2->bio_classifier1 = bp->bio_classifier1;
  210                 bp2->bio_classifier2 = bp->bio_classifier2;
  211                 bp->bio_children++;
  212         }
  213 #ifdef KTR
  214         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  215                 struct stack st;
  216 
  217                 CTR2(KTR_GEOM, "g_clone_bio(%p): %p", bp, bp2);
  218                 stack_save(&st);
  219                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  220         }
  221 #endif
  222         return(bp2);
  223 }
  224 
  225 struct bio *
  226 g_duplicate_bio(struct bio *bp)
  227 {
  228         struct bio *bp2;
  229 
  230         bp2 = uma_zalloc(biozone, M_WAITOK | M_ZERO);
  231         bp2->bio_flags = bp->bio_flags & BIO_UNMAPPED;
  232         bp2->bio_parent = bp;
  233         bp2->bio_cmd = bp->bio_cmd;
  234         bp2->bio_length = bp->bio_length;
  235         bp2->bio_offset = bp->bio_offset;
  236         bp2->bio_data = bp->bio_data;
  237         bp2->bio_ma = bp->bio_ma;
  238         bp2->bio_ma_n = bp->bio_ma_n;
  239         bp2->bio_ma_offset = bp->bio_ma_offset;
  240         bp2->bio_attribute = bp->bio_attribute;
  241         bp->bio_children++;
  242 #ifdef KTR
  243         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  244                 struct stack st;
  245 
  246                 CTR2(KTR_GEOM, "g_duplicate_bio(%p): %p", bp, bp2);
  247                 stack_save(&st);
  248                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  249         }
  250 #endif
  251         return(bp2);
  252 }
  253 
  254 void
  255 g_io_init()
  256 {
  257 
  258         g_bioq_init(&g_bio_run_down);
  259         g_bioq_init(&g_bio_run_up);
  260         g_bioq_init(&g_bio_run_task);
  261         biozone = uma_zcreate("g_bio", sizeof (struct bio),
  262             NULL, NULL,
  263             NULL, NULL,
  264             0, 0);
  265 }
  266 
  267 int
  268 g_io_getattr(const char *attr, struct g_consumer *cp, int *len, void *ptr)
  269 {
  270         struct bio *bp;
  271         int error;
  272 
  273         g_trace(G_T_BIO, "bio_getattr(%s)", attr);
  274         bp = g_alloc_bio();
  275         bp->bio_cmd = BIO_GETATTR;
  276         bp->bio_done = NULL;
  277         bp->bio_attribute = attr;
  278         bp->bio_length = *len;
  279         bp->bio_data = ptr;
  280         g_io_request(bp, cp);
  281         error = biowait(bp, "ggetattr");
  282         *len = bp->bio_completed;
  283         g_destroy_bio(bp);
  284         return (error);
  285 }
  286 
  287 int
  288 g_io_flush(struct g_consumer *cp)
  289 {
  290         struct bio *bp;
  291         int error;
  292 
  293         g_trace(G_T_BIO, "bio_flush(%s)", cp->provider->name);
  294         bp = g_alloc_bio();
  295         bp->bio_cmd = BIO_FLUSH;
  296         bp->bio_flags |= BIO_ORDERED;
  297         bp->bio_done = NULL;
  298         bp->bio_attribute = NULL;
  299         bp->bio_offset = cp->provider->mediasize;
  300         bp->bio_length = 0;
  301         bp->bio_data = NULL;
  302         g_io_request(bp, cp);
  303         error = biowait(bp, "gflush");
  304         g_destroy_bio(bp);
  305         return (error);
  306 }
  307 
  308 static int
  309 g_io_check(struct bio *bp)
  310 {
  311         struct g_consumer *cp;
  312         struct g_provider *pp;
  313 
  314         cp = bp->bio_from;
  315         pp = bp->bio_to;
  316 
  317         /* Fail if access counters dont allow the operation */
  318         switch(bp->bio_cmd) {
  319         case BIO_READ:
  320         case BIO_GETATTR:
  321                 if (cp->acr == 0)
  322                         return (EPERM);
  323                 break;
  324         case BIO_WRITE:
  325         case BIO_DELETE:
  326         case BIO_FLUSH:
  327                 if (cp->acw == 0)
  328                         return (EPERM);
  329                 break;
  330         default:
  331                 return (EPERM);
  332         }
  333         /* if provider is marked for error, don't disturb. */
  334         if (pp->error)
  335                 return (pp->error);
  336         if (cp->flags & G_CF_ORPHAN)
  337                 return (ENXIO);
  338 
  339         switch(bp->bio_cmd) {
  340         case BIO_READ:
  341         case BIO_WRITE:
  342         case BIO_DELETE:
  343                 /* Zero sectorsize or mediasize is probably a lack of media. */
  344                 if (pp->sectorsize == 0 || pp->mediasize == 0)
  345                         return (ENXIO);
  346                 /* Reject I/O not on sector boundary */
  347                 if (bp->bio_offset % pp->sectorsize)
  348                         return (EINVAL);
  349                 /* Reject I/O not integral sector long */
  350                 if (bp->bio_length % pp->sectorsize)
  351                         return (EINVAL);
  352                 /* Reject requests before or past the end of media. */
  353                 if (bp->bio_offset < 0)
  354                         return (EIO);
  355                 if (bp->bio_offset > pp->mediasize)
  356                         return (EIO);
  357                 break;
  358         default:
  359                 break;
  360         }
  361         return (0);
  362 }
  363 
  364 /*
  365  * bio classification support.
  366  *
  367  * g_register_classifier() and g_unregister_classifier()
  368  * are used to add/remove a classifier from the list.
  369  * The list is protected using the g_bio_run_down lock,
  370  * because the classifiers are called in this path.
  371  *
  372  * g_io_request() passes bio's that are not already classified
  373  * (i.e. those with bio_classifier1 == NULL) to g_run_classifiers().
  374  * Classifiers can store their result in the two fields
  375  * bio_classifier1 and bio_classifier2.
  376  * A classifier that updates one of the fields should
  377  * return a non-zero value.
  378  * If no classifier updates the field, g_run_classifiers() sets
  379  * bio_classifier1 = BIO_NOTCLASSIFIED to avoid further calls.
  380  */
  381 
  382 int
  383 g_register_classifier(struct g_classifier_hook *hook)
  384 {
  385 
  386         g_bioq_lock(&g_bio_run_down);
  387         TAILQ_INSERT_TAIL(&g_classifier_tailq, hook, link);
  388         g_bioq_unlock(&g_bio_run_down);
  389 
  390         return (0);
  391 }
  392 
  393 void
  394 g_unregister_classifier(struct g_classifier_hook *hook)
  395 {
  396         struct g_classifier_hook *entry;
  397 
  398         g_bioq_lock(&g_bio_run_down);
  399         TAILQ_FOREACH(entry, &g_classifier_tailq, link) {
  400                 if (entry == hook) {
  401                         TAILQ_REMOVE(&g_classifier_tailq, hook, link);
  402                         break;
  403                 }
  404         }
  405         g_bioq_unlock(&g_bio_run_down);
  406 }
  407 
  408 static void
  409 g_run_classifiers(struct bio *bp)
  410 {
  411         struct g_classifier_hook *hook;
  412         int classified = 0;
  413 
  414         TAILQ_FOREACH(hook, &g_classifier_tailq, link)
  415                 classified |= hook->func(hook->arg, bp);
  416 
  417         if (!classified)
  418                 bp->bio_classifier1 = BIO_NOTCLASSIFIED;
  419 }
  420 
  421 void
  422 g_io_request(struct bio *bp, struct g_consumer *cp)
  423 {
  424         struct g_provider *pp;
  425         int first;
  426 
  427         KASSERT(cp != NULL, ("NULL cp in g_io_request"));
  428         KASSERT(bp != NULL, ("NULL bp in g_io_request"));
  429         pp = cp->provider;
  430         KASSERT(pp != NULL, ("consumer not attached in g_io_request"));
  431 #ifdef DIAGNOSTIC
  432         KASSERT(bp->bio_driver1 == NULL,
  433             ("bio_driver1 used by the consumer (geom %s)", cp->geom->name));
  434         KASSERT(bp->bio_driver2 == NULL,
  435             ("bio_driver2 used by the consumer (geom %s)", cp->geom->name));
  436         KASSERT(bp->bio_pflags == 0,
  437             ("bio_pflags used by the consumer (geom %s)", cp->geom->name));
  438         /*
  439          * Remember consumer's private fields, so we can detect if they were
  440          * modified by the provider.
  441          */
  442         bp->_bio_caller1 = bp->bio_caller1;
  443         bp->_bio_caller2 = bp->bio_caller2;
  444         bp->_bio_cflags = bp->bio_cflags;
  445 #endif
  446 
  447         if (bp->bio_cmd & (BIO_READ|BIO_WRITE|BIO_GETATTR)) {
  448                 KASSERT(bp->bio_data != NULL,
  449                     ("NULL bp->data in g_io_request(cmd=%hhu)", bp->bio_cmd));
  450         }
  451         if (bp->bio_cmd & (BIO_DELETE|BIO_FLUSH)) {
  452                 KASSERT(bp->bio_data == NULL,
  453                     ("non-NULL bp->data in g_io_request(cmd=%hhu)",
  454                     bp->bio_cmd));
  455         }
  456         if (bp->bio_cmd & (BIO_READ|BIO_WRITE|BIO_DELETE)) {
  457                 KASSERT(bp->bio_offset % cp->provider->sectorsize == 0,
  458                     ("wrong offset %jd for sectorsize %u",
  459                     bp->bio_offset, cp->provider->sectorsize));
  460                 KASSERT(bp->bio_length % cp->provider->sectorsize == 0,
  461                     ("wrong length %jd for sectorsize %u",
  462                     bp->bio_length, cp->provider->sectorsize));
  463         }
  464 
  465         g_trace(G_T_BIO, "bio_request(%p) from %p(%s) to %p(%s) cmd %d",
  466             bp, cp, cp->geom->name, pp, pp->name, bp->bio_cmd);
  467 
  468         bp->bio_from = cp;
  469         bp->bio_to = pp;
  470         bp->bio_error = 0;
  471         bp->bio_completed = 0;
  472 
  473         KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
  474             ("Bio already on queue bp=%p", bp));
  475         bp->bio_flags |= BIO_ONQUEUE;
  476 
  477         if (g_collectstats)
  478                 binuptime(&bp->bio_t0);
  479         else
  480                 getbinuptime(&bp->bio_t0);
  481 
  482         /*
  483          * The statistics collection is lockless, as such, but we
  484          * can not update one instance of the statistics from more
  485          * than one thread at a time, so grab the lock first.
  486          *
  487          * We also use the lock to protect the list of classifiers.
  488          */
  489         g_bioq_lock(&g_bio_run_down);
  490 
  491         if (!TAILQ_EMPTY(&g_classifier_tailq) && !bp->bio_classifier1)
  492                 g_run_classifiers(bp);
  493 
  494         if (g_collectstats & 1)
  495                 devstat_start_transaction(pp->stat, &bp->bio_t0);
  496         if (g_collectstats & 2)
  497                 devstat_start_transaction(cp->stat, &bp->bio_t0);
  498 
  499         pp->nstart++;
  500         cp->nstart++;
  501         first = TAILQ_EMPTY(&g_bio_run_down.bio_queue);
  502         TAILQ_INSERT_TAIL(&g_bio_run_down.bio_queue, bp, bio_queue);
  503         g_bio_run_down.bio_queue_length++;
  504         g_bioq_unlock(&g_bio_run_down);
  505 
  506         /* Pass it on down. */
  507         if (first)
  508                 wakeup(&g_wait_down);
  509 }
  510 
  511 void
  512 g_io_deliver(struct bio *bp, int error)
  513 {
  514         struct g_consumer *cp;
  515         struct g_provider *pp;
  516         int first;
  517 
  518         KASSERT(bp != NULL, ("NULL bp in g_io_deliver"));
  519         pp = bp->bio_to;
  520         KASSERT(pp != NULL, ("NULL bio_to in g_io_deliver"));
  521         cp = bp->bio_from;
  522         if (cp == NULL) {
  523                 bp->bio_error = error;
  524                 bp->bio_done(bp);
  525                 return;
  526         }
  527         KASSERT(cp != NULL, ("NULL bio_from in g_io_deliver"));
  528         KASSERT(cp->geom != NULL, ("NULL bio_from->geom in g_io_deliver"));
  529 #ifdef DIAGNOSTIC
  530         /*
  531          * Some classes - GJournal in particular - can modify bio's
  532          * private fields while the bio is in transit; G_GEOM_VOLATILE_BIO
  533          * flag means it's an expected behaviour for that particular geom.
  534          */
  535         if ((cp->geom->flags & G_GEOM_VOLATILE_BIO) == 0) {
  536                 KASSERT(bp->bio_caller1 == bp->_bio_caller1,
  537                     ("bio_caller1 used by the provider %s", pp->name));
  538                 KASSERT(bp->bio_caller2 == bp->_bio_caller2,
  539                     ("bio_caller2 used by the provider %s", pp->name));
  540                 KASSERT(bp->bio_cflags == bp->_bio_cflags,
  541                     ("bio_cflags used by the provider %s", pp->name));
  542         }
  543 #endif
  544         KASSERT(bp->bio_completed >= 0, ("bio_completed can't be less than 0"));
  545         KASSERT(bp->bio_completed <= bp->bio_length,
  546             ("bio_completed can't be greater than bio_length"));
  547 
  548         g_trace(G_T_BIO,
  549 "g_io_deliver(%p) from %p(%s) to %p(%s) cmd %d error %d off %jd len %jd",
  550             bp, cp, cp->geom->name, pp, pp->name, bp->bio_cmd, error,
  551             (intmax_t)bp->bio_offset, (intmax_t)bp->bio_length);
  552 
  553         KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
  554             ("Bio already on queue bp=%p", bp));
  555 
  556         /*
  557          * XXX: next two doesn't belong here
  558          */
  559         bp->bio_bcount = bp->bio_length;
  560         bp->bio_resid = bp->bio_bcount - bp->bio_completed;
  561 
  562         /*
  563          * The statistics collection is lockless, as such, but we
  564          * can not update one instance of the statistics from more
  565          * than one thread at a time, so grab the lock first.
  566          */
  567         g_bioq_lock(&g_bio_run_up);
  568         if (g_collectstats & 1)
  569                 devstat_end_transaction_bio(pp->stat, bp);
  570         if (g_collectstats & 2)
  571                 devstat_end_transaction_bio(cp->stat, bp);
  572 
  573         cp->nend++;
  574         pp->nend++;
  575         if (error != ENOMEM) {
  576                 bp->bio_error = error;
  577                 first = TAILQ_EMPTY(&g_bio_run_up.bio_queue);
  578                 TAILQ_INSERT_TAIL(&g_bio_run_up.bio_queue, bp, bio_queue);
  579                 bp->bio_flags |= BIO_ONQUEUE;
  580                 g_bio_run_up.bio_queue_length++;
  581                 g_bioq_unlock(&g_bio_run_up);
  582                 if (first)
  583                         wakeup(&g_wait_up);
  584                 return;
  585         }
  586         g_bioq_unlock(&g_bio_run_up);
  587 
  588         if (bootverbose)
  589                 printf("ENOMEM %p on %p(%s)\n", bp, pp, pp->name);
  590         bp->bio_children = 0;
  591         bp->bio_inbed = 0;
  592         bp->bio_driver1 = NULL;
  593         bp->bio_driver2 = NULL;
  594         bp->bio_pflags = 0;
  595         g_io_request(bp, cp);
  596         pace++;
  597         return;
  598 }
  599 
  600 SYSCTL_DECL(_kern_geom);
  601 
  602 static long transient_maps;
  603 SYSCTL_LONG(_kern_geom, OID_AUTO, transient_maps, CTLFLAG_RD,
  604     &transient_maps, 0,
  605     "Total count of the transient mapping requests");
  606 u_int transient_map_retries = 10;
  607 SYSCTL_UINT(_kern_geom, OID_AUTO, transient_map_retries, CTLFLAG_RW,
  608     &transient_map_retries, 0,
  609     "Max count of retries used before giving up on creating transient map");
  610 int transient_map_hard_failures;
  611 SYSCTL_INT(_kern_geom, OID_AUTO, transient_map_hard_failures, CTLFLAG_RD,
  612     &transient_map_hard_failures, 0,
  613     "Failures to establish the transient mapping due to retry attempts "
  614     "exhausted");
  615 int transient_map_soft_failures;
  616 SYSCTL_INT(_kern_geom, OID_AUTO, transient_map_soft_failures, CTLFLAG_RD,
  617     &transient_map_soft_failures, 0,
  618     "Count of retried failures to establish the transient mapping");
  619 int inflight_transient_maps;
  620 SYSCTL_INT(_kern_geom, OID_AUTO, inflight_transient_maps, CTLFLAG_RD,
  621     &inflight_transient_maps, 0,
  622     "Current count of the active transient maps");
  623 
  624 static int
  625 g_io_transient_map_bio(struct bio *bp)
  626 {
  627         vm_offset_t addr;
  628         long size;
  629         u_int retried;
  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         if (vmem_alloc(transient_arena, size, M_BESTFIT | M_NOWAIT, &addr)) {
  640                 if (transient_map_retries != 0 &&
  641                     retried >= transient_map_retries) {
  642                         g_io_deliver(bp, EDEADLK/* XXXKIB */);
  643                         CTR2(KTR_GEOM, "g_down cannot map bp %p provider %s",
  644                             bp, bp->bio_to->name);
  645                         atomic_add_int(&transient_map_hard_failures, 1);
  646                         return (1);
  647                 } else {
  648                         /*
  649                          * Naive attempt to quisce the I/O to get more
  650                          * in-flight requests completed and defragment
  651                          * the transient_arena.
  652                          */
  653                         CTR3(KTR_GEOM, "g_down retrymap bp %p provider %s r %d",
  654                             bp, bp->bio_to->name, retried);
  655                         pause("g_d_tra", hz / 10);
  656                         retried++;
  657                         atomic_add_int(&transient_map_soft_failures, 1);
  658                         goto retry;
  659                 }
  660         }
  661         atomic_add_int(&inflight_transient_maps, 1);
  662         pmap_qenter((vm_offset_t)addr, bp->bio_ma, OFF_TO_IDX(size));
  663         bp->bio_data = (caddr_t)addr + bp->bio_ma_offset;
  664         bp->bio_flags |= BIO_TRANSIENT_MAPPING;
  665         bp->bio_flags &= ~BIO_UNMAPPED;
  666         return (0);
  667 }
  668 
  669 void
  670 g_io_schedule_down(struct thread *tp __unused)
  671 {
  672         struct bio *bp;
  673         off_t excess;
  674         int error;
  675 
  676         for(;;) {
  677                 g_bioq_lock(&g_bio_run_down);
  678                 bp = g_bioq_first(&g_bio_run_down);
  679                 if (bp == NULL) {
  680                         CTR0(KTR_GEOM, "g_down going to sleep");
  681                         msleep(&g_wait_down, &g_bio_run_down.bio_queue_lock,
  682                             PRIBIO | PDROP, "-", 0);
  683                         continue;
  684                 }
  685                 CTR0(KTR_GEOM, "g_down has work to do");
  686                 g_bioq_unlock(&g_bio_run_down);
  687                 if (pace > 0) {
  688                         CTR1(KTR_GEOM, "g_down pacing self (pace %d)", pace);
  689                         pause("g_down", hz/10);
  690                         pace--;
  691                 }
  692                 error = g_io_check(bp);
  693                 if (error) {
  694                         CTR3(KTR_GEOM, "g_down g_io_check on bp %p provider "
  695                             "%s returned %d", bp, bp->bio_to->name, error);
  696                         g_io_deliver(bp, error);
  697                         continue;
  698                 }
  699                 CTR2(KTR_GEOM, "g_down processing bp %p provider %s", bp,
  700                     bp->bio_to->name);
  701                 switch (bp->bio_cmd) {
  702                 case BIO_READ:
  703                 case BIO_WRITE:
  704                 case BIO_DELETE:
  705                         /* Truncate requests to the end of providers media. */
  706                         /*
  707                          * XXX: What if we truncate because of offset being
  708                          * bad, not length?
  709                          */
  710                         excess = bp->bio_offset + bp->bio_length;
  711                         if (excess > bp->bio_to->mediasize) {
  712                                 KASSERT((bp->bio_flags & BIO_UNMAPPED) == 0 ||
  713                                     round_page(bp->bio_ma_offset +
  714                                     bp->bio_length) / PAGE_SIZE == bp->bio_ma_n,
  715                                     ("excess bio %p too short", bp));
  716                                 excess -= bp->bio_to->mediasize;
  717                                 bp->bio_length -= excess;
  718                                 if ((bp->bio_flags & BIO_UNMAPPED) != 0) {
  719                                         bp->bio_ma_n = round_page(
  720                                             bp->bio_ma_offset +
  721                                             bp->bio_length) / PAGE_SIZE;
  722                                 }
  723                                 if (excess > 0)
  724                                         CTR3(KTR_GEOM, "g_down truncated bio "
  725                                             "%p provider %s by %d", bp,
  726                                             bp->bio_to->name, excess);
  727                         }
  728                         /* Deliver zero length transfers right here. */
  729                         if (bp->bio_length == 0) {
  730                                 g_io_deliver(bp, 0);
  731                                 CTR2(KTR_GEOM, "g_down terminated 0-length "
  732                                     "bp %p provider %s", bp, bp->bio_to->name);
  733                                 continue;
  734                         }
  735                         break;
  736                 default:
  737                         break;
  738                 }
  739                 if ((bp->bio_flags & BIO_UNMAPPED) != 0 &&
  740                     (bp->bio_to->flags & G_PF_ACCEPT_UNMAPPED) == 0 &&
  741                     (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE)) {
  742                         if (g_io_transient_map_bio(bp))
  743                                 continue;
  744                 }
  745                 THREAD_NO_SLEEPING();
  746                 CTR4(KTR_GEOM, "g_down starting bp %p provider %s off %ld "
  747                     "len %ld", bp, bp->bio_to->name, bp->bio_offset,
  748                     bp->bio_length);
  749                 bp->bio_to->geom->start(bp);
  750                 THREAD_SLEEPING_OK();
  751         }
  752 }
  753 
  754 void
  755 bio_taskqueue(struct bio *bp, bio_task_t *func, void *arg)
  756 {
  757         bp->bio_task = func;
  758         bp->bio_task_arg = arg;
  759         /*
  760          * The taskqueue is actually just a second queue off the "up"
  761          * queue, so we use the same lock.
  762          */
  763         g_bioq_lock(&g_bio_run_up);
  764         KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
  765             ("Bio already on queue bp=%p target taskq", bp));
  766         bp->bio_flags |= BIO_ONQUEUE;
  767         TAILQ_INSERT_TAIL(&g_bio_run_task.bio_queue, bp, bio_queue);
  768         g_bio_run_task.bio_queue_length++;
  769         wakeup(&g_wait_up);
  770         g_bioq_unlock(&g_bio_run_up);
  771 }
  772 
  773 
  774 void
  775 g_io_schedule_up(struct thread *tp __unused)
  776 {
  777         struct bio *bp;
  778         for(;;) {
  779                 g_bioq_lock(&g_bio_run_up);
  780                 bp = g_bioq_first(&g_bio_run_task);
  781                 if (bp != NULL) {
  782                         g_bioq_unlock(&g_bio_run_up);
  783                         THREAD_NO_SLEEPING();
  784                         CTR1(KTR_GEOM, "g_up processing task bp %p", bp);
  785                         bp->bio_task(bp->bio_task_arg);
  786                         THREAD_SLEEPING_OK();
  787                         continue;
  788                 }
  789                 bp = g_bioq_first(&g_bio_run_up);
  790                 if (bp != NULL) {
  791                         g_bioq_unlock(&g_bio_run_up);
  792                         THREAD_NO_SLEEPING();
  793                         CTR4(KTR_GEOM, "g_up biodone bp %p provider %s off "
  794                             "%jd len %ld", bp, bp->bio_to->name,
  795                             bp->bio_offset, bp->bio_length);
  796                         biodone(bp);
  797                         THREAD_SLEEPING_OK();
  798                         continue;
  799                 }
  800                 CTR0(KTR_GEOM, "g_up going to sleep");
  801                 msleep(&g_wait_up, &g_bio_run_up.bio_queue_lock,
  802                     PRIBIO | PDROP, "-", 0);
  803         }
  804 }
  805 
  806 void *
  807 g_read_data(struct g_consumer *cp, off_t offset, off_t length, int *error)
  808 {
  809         struct bio *bp;
  810         void *ptr;
  811         int errorc;
  812 
  813         KASSERT(length > 0 && length >= cp->provider->sectorsize &&
  814             length <= MAXPHYS, ("g_read_data(): invalid length %jd",
  815             (intmax_t)length));
  816 
  817         bp = g_alloc_bio();
  818         bp->bio_cmd = BIO_READ;
  819         bp->bio_done = NULL;
  820         bp->bio_offset = offset;
  821         bp->bio_length = length;
  822         ptr = g_malloc(length, M_WAITOK);
  823         bp->bio_data = ptr;
  824         g_io_request(bp, cp);
  825         errorc = biowait(bp, "gread");
  826         if (error != NULL)
  827                 *error = errorc;
  828         g_destroy_bio(bp);
  829         if (errorc) {
  830                 g_free(ptr);
  831                 ptr = NULL;
  832         }
  833         return (ptr);
  834 }
  835 
  836 int
  837 g_write_data(struct g_consumer *cp, off_t offset, void *ptr, off_t length)
  838 {
  839         struct bio *bp;
  840         int error;
  841 
  842         KASSERT(length > 0 && length >= cp->provider->sectorsize &&
  843             length <= MAXPHYS, ("g_write_data(): invalid length %jd",
  844             (intmax_t)length));
  845 
  846         bp = g_alloc_bio();
  847         bp->bio_cmd = BIO_WRITE;
  848         bp->bio_done = NULL;
  849         bp->bio_offset = offset;
  850         bp->bio_length = length;
  851         bp->bio_data = ptr;
  852         g_io_request(bp, cp);
  853         error = biowait(bp, "gwrite");
  854         g_destroy_bio(bp);
  855         return (error);
  856 }
  857 
  858 int
  859 g_delete_data(struct g_consumer *cp, off_t offset, off_t length)
  860 {
  861         struct bio *bp;
  862         int error;
  863 
  864         KASSERT(length > 0 && length >= cp->provider->sectorsize,
  865             ("g_delete_data(): invalid length %jd", (intmax_t)length));
  866 
  867         bp = g_alloc_bio();
  868         bp->bio_cmd = BIO_DELETE;
  869         bp->bio_done = NULL;
  870         bp->bio_offset = offset;
  871         bp->bio_length = length;
  872         bp->bio_data = NULL;
  873         g_io_request(bp, cp);
  874         error = biowait(bp, "gdelete");
  875         g_destroy_bio(bp);
  876         return (error);
  877 }
  878 
  879 void
  880 g_print_bio(struct bio *bp)
  881 {
  882         const char *pname, *cmd = NULL;
  883 
  884         if (bp->bio_to != NULL)
  885                 pname = bp->bio_to->name;
  886         else
  887                 pname = "[unknown]";
  888 
  889         switch (bp->bio_cmd) {
  890         case BIO_GETATTR:
  891                 cmd = "GETATTR";
  892                 printf("%s[%s(attr=%s)]", pname, cmd, bp->bio_attribute);
  893                 return;
  894         case BIO_FLUSH:
  895                 cmd = "FLUSH";
  896                 printf("%s[%s]", pname, cmd);
  897                 return;
  898         case BIO_READ:
  899                 cmd = "READ";
  900                 break;
  901         case BIO_WRITE:
  902                 cmd = "WRITE";
  903                 break;
  904         case BIO_DELETE:
  905                 cmd = "DELETE";
  906                 break;
  907         default:
  908                 cmd = "UNKNOWN";
  909                 printf("%s[%s()]", pname, cmd);
  910                 return;
  911         }
  912         printf("%s[%s(offset=%jd, length=%jd)]", pname, cmd,
  913             (intmax_t)bp->bio_offset, (intmax_t)bp->bio_length);
  914 }

Cache object: 4657b97499df43a676f1665383126edd


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