The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/geom/geom_io.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    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/10.4/sys/geom/geom_io.c 292348 2015-12-16 19:01:14Z ken $");
   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 int      g_io_transient_map_bio(struct bio *bp);
   69 
   70 static struct g_bioq g_bio_run_down;
   71 static struct g_bioq g_bio_run_up;
   72 static struct g_bioq g_bio_run_task;
   73 
   74 /*
   75  * Pace is a hint that we've had some trouble recently allocating
   76  * bios, so we should back off trying to send I/O down the stack
   77  * a bit to let the problem resolve. When pacing, we also turn
   78  * off direct dispatch to also reduce memory pressure from I/Os
   79  * there, at the expxense of some added latency while the memory
   80  * pressures exist. See g_io_schedule_down() for more details
   81  * and limitations.
   82  */
   83 static volatile u_int pace;
   84 
   85 static uma_zone_t       biozone;
   86 
   87 /*
   88  * The head of the list of classifiers used in g_io_request.
   89  * Use g_register_classifier() and g_unregister_classifier()
   90  * to add/remove entries to the list.
   91  * Classifiers are invoked in registration order.
   92  */
   93 static TAILQ_HEAD(g_classifier_tailq, g_classifier_hook)
   94     g_classifier_tailq = TAILQ_HEAD_INITIALIZER(g_classifier_tailq);
   95 
   96 #include <machine/atomic.h>
   97 
   98 static void
   99 g_bioq_lock(struct g_bioq *bq)
  100 {
  101 
  102         mtx_lock(&bq->bio_queue_lock);
  103 }
  104 
  105 static void
  106 g_bioq_unlock(struct g_bioq *bq)
  107 {
  108 
  109         mtx_unlock(&bq->bio_queue_lock);
  110 }
  111 
  112 #if 0
  113 static void
  114 g_bioq_destroy(struct g_bioq *bq)
  115 {
  116 
  117         mtx_destroy(&bq->bio_queue_lock);
  118 }
  119 #endif
  120 
  121 static void
  122 g_bioq_init(struct g_bioq *bq)
  123 {
  124 
  125         TAILQ_INIT(&bq->bio_queue);
  126         mtx_init(&bq->bio_queue_lock, "bio queue", NULL, MTX_DEF);
  127 }
  128 
  129 static struct bio *
  130 g_bioq_first(struct g_bioq *bq)
  131 {
  132         struct bio *bp;
  133 
  134         bp = TAILQ_FIRST(&bq->bio_queue);
  135         if (bp != NULL) {
  136                 KASSERT((bp->bio_flags & BIO_ONQUEUE),
  137                     ("Bio not on queue bp=%p target %p", bp, bq));
  138                 bp->bio_flags &= ~BIO_ONQUEUE;
  139                 TAILQ_REMOVE(&bq->bio_queue, bp, bio_queue);
  140                 bq->bio_queue_length--;
  141         }
  142         return (bp);
  143 }
  144 
  145 struct bio *
  146 g_new_bio(void)
  147 {
  148         struct bio *bp;
  149 
  150         bp = uma_zalloc(biozone, M_NOWAIT | M_ZERO);
  151 #ifdef KTR
  152         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  153                 struct stack st;
  154 
  155                 CTR1(KTR_GEOM, "g_new_bio(): %p", bp);
  156                 stack_save(&st);
  157                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  158         }
  159 #endif
  160         return (bp);
  161 }
  162 
  163 struct bio *
  164 g_alloc_bio(void)
  165 {
  166         struct bio *bp;
  167 
  168         bp = uma_zalloc(biozone, M_WAITOK | M_ZERO);
  169 #ifdef KTR
  170         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  171                 struct stack st;
  172 
  173                 CTR1(KTR_GEOM, "g_alloc_bio(): %p", bp);
  174                 stack_save(&st);
  175                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  176         }
  177 #endif
  178         return (bp);
  179 }
  180 
  181 void
  182 g_destroy_bio(struct bio *bp)
  183 {
  184 #ifdef KTR
  185         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  186                 struct stack st;
  187 
  188                 CTR1(KTR_GEOM, "g_destroy_bio(): %p", bp);
  189                 stack_save(&st);
  190                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  191         }
  192 #endif
  193         uma_zfree(biozone, bp);
  194 }
  195 
  196 struct bio *
  197 g_clone_bio(struct bio *bp)
  198 {
  199         struct bio *bp2;
  200 
  201         bp2 = uma_zalloc(biozone, M_NOWAIT | M_ZERO);
  202         if (bp2 != NULL) {
  203                 bp2->bio_parent = bp;
  204                 bp2->bio_cmd = bp->bio_cmd;
  205                 /*
  206                  *  BIO_ORDERED flag may be used by disk drivers to enforce
  207                  *  ordering restrictions, so this flag needs to be cloned.
  208                  *  BIO_UNMAPPED and BIO_VLIST should be inherited, to properly
  209                  *  indicate which way the buffer is passed.
  210                  *  Other bio flags are not suitable for cloning.
  211                  */
  212                 bp2->bio_flags = bp->bio_flags &
  213                     (BIO_ORDERED | BIO_UNMAPPED | BIO_VLIST);
  214                 bp2->bio_length = bp->bio_length;
  215                 bp2->bio_offset = bp->bio_offset;
  216                 bp2->bio_data = bp->bio_data;
  217                 bp2->bio_ma = bp->bio_ma;
  218                 bp2->bio_ma_n = bp->bio_ma_n;
  219                 bp2->bio_ma_offset = bp->bio_ma_offset;
  220                 bp2->bio_attribute = bp->bio_attribute;
  221                 /* Inherit classification info from the parent */
  222                 bp2->bio_classifier1 = bp->bio_classifier1;
  223                 bp2->bio_classifier2 = bp->bio_classifier2;
  224                 bp->bio_children++;
  225         }
  226 #ifdef KTR
  227         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  228                 struct stack st;
  229 
  230                 CTR2(KTR_GEOM, "g_clone_bio(%p): %p", bp, bp2);
  231                 stack_save(&st);
  232                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  233         }
  234 #endif
  235         return(bp2);
  236 }
  237 
  238 struct bio *
  239 g_duplicate_bio(struct bio *bp)
  240 {
  241         struct bio *bp2;
  242 
  243         bp2 = uma_zalloc(biozone, M_WAITOK | M_ZERO);
  244         bp2->bio_flags = bp->bio_flags & (BIO_UNMAPPED | BIO_VLIST);
  245         bp2->bio_parent = bp;
  246         bp2->bio_cmd = bp->bio_cmd;
  247         bp2->bio_length = bp->bio_length;
  248         bp2->bio_offset = bp->bio_offset;
  249         bp2->bio_data = bp->bio_data;
  250         bp2->bio_ma = bp->bio_ma;
  251         bp2->bio_ma_n = bp->bio_ma_n;
  252         bp2->bio_ma_offset = bp->bio_ma_offset;
  253         bp2->bio_attribute = bp->bio_attribute;
  254         bp->bio_children++;
  255 #ifdef KTR
  256         if ((KTR_COMPILE & KTR_GEOM) && (ktr_mask & KTR_GEOM)) {
  257                 struct stack st;
  258 
  259                 CTR2(KTR_GEOM, "g_duplicate_bio(%p): %p", bp, bp2);
  260                 stack_save(&st);
  261                 CTRSTACK(KTR_GEOM, &st, 3, 0);
  262         }
  263 #endif
  264         return(bp2);
  265 }
  266 
  267 void
  268 g_io_init()
  269 {
  270 
  271         g_bioq_init(&g_bio_run_down);
  272         g_bioq_init(&g_bio_run_up);
  273         g_bioq_init(&g_bio_run_task);
  274         biozone = uma_zcreate("g_bio", sizeof (struct bio),
  275             NULL, NULL,
  276             NULL, NULL,
  277             0, 0);
  278 }
  279 
  280 int
  281 g_io_getattr(const char *attr, struct g_consumer *cp, int *len, void *ptr)
  282 {
  283         struct bio *bp;
  284         int error;
  285 
  286         g_trace(G_T_BIO, "bio_getattr(%s)", attr);
  287         bp = g_alloc_bio();
  288         bp->bio_cmd = BIO_GETATTR;
  289         bp->bio_done = NULL;
  290         bp->bio_attribute = attr;
  291         bp->bio_length = *len;
  292         bp->bio_data = ptr;
  293         g_io_request(bp, cp);
  294         error = biowait(bp, "ggetattr");
  295         *len = bp->bio_completed;
  296         g_destroy_bio(bp);
  297         return (error);
  298 }
  299 
  300 int
  301 g_io_flush(struct g_consumer *cp)
  302 {
  303         struct bio *bp;
  304         int error;
  305 
  306         g_trace(G_T_BIO, "bio_flush(%s)", cp->provider->name);
  307         bp = g_alloc_bio();
  308         bp->bio_cmd = BIO_FLUSH;
  309         bp->bio_flags |= BIO_ORDERED;
  310         bp->bio_done = NULL;
  311         bp->bio_attribute = NULL;
  312         bp->bio_offset = cp->provider->mediasize;
  313         bp->bio_length = 0;
  314         bp->bio_data = NULL;
  315         g_io_request(bp, cp);
  316         error = biowait(bp, "gflush");
  317         g_destroy_bio(bp);
  318         return (error);
  319 }
  320 
  321 static int
  322 g_io_check(struct bio *bp)
  323 {
  324         struct g_consumer *cp;
  325         struct g_provider *pp;
  326         off_t excess;
  327         int error;
  328 
  329         cp = bp->bio_from;
  330         pp = bp->bio_to;
  331 
  332         /* Fail if access counters dont allow the operation */
  333         switch(bp->bio_cmd) {
  334         case BIO_READ:
  335         case BIO_GETATTR:
  336                 if (cp->acr == 0)
  337                         return (EPERM);
  338                 break;
  339         case BIO_WRITE:
  340         case BIO_DELETE:
  341         case BIO_FLUSH:
  342                 if (cp->acw == 0)
  343                         return (EPERM);
  344                 break;
  345         default:
  346                 return (EPERM);
  347         }
  348         /* if provider is marked for error, don't disturb. */
  349         if (pp->error)
  350                 return (pp->error);
  351         if (cp->flags & G_CF_ORPHAN)
  352                 return (ENXIO);
  353 
  354         switch(bp->bio_cmd) {
  355         case BIO_READ:
  356         case BIO_WRITE:
  357         case BIO_DELETE:
  358                 /* Zero sectorsize or mediasize is probably a lack of media. */
  359                 if (pp->sectorsize == 0 || pp->mediasize == 0)
  360                         return (ENXIO);
  361                 /* Reject I/O not on sector boundary */
  362                 if (bp->bio_offset % pp->sectorsize)
  363                         return (EINVAL);
  364                 /* Reject I/O not integral sector long */
  365                 if (bp->bio_length % pp->sectorsize)
  366                         return (EINVAL);
  367                 /* Reject requests before or past the end of media. */
  368                 if (bp->bio_offset < 0)
  369                         return (EIO);
  370                 if (bp->bio_offset > pp->mediasize)
  371                         return (EIO);
  372 
  373                 /* Truncate requests to the end of providers media. */
  374                 excess = bp->bio_offset + bp->bio_length;
  375                 if (excess > bp->bio_to->mediasize) {
  376                         KASSERT((bp->bio_flags & BIO_UNMAPPED) == 0 ||
  377                             round_page(bp->bio_ma_offset +
  378                             bp->bio_length) / PAGE_SIZE == bp->bio_ma_n,
  379                             ("excess bio %p too short", bp));
  380                         excess -= bp->bio_to->mediasize;
  381                         bp->bio_length -= excess;
  382                         if ((bp->bio_flags & BIO_UNMAPPED) != 0) {
  383                                 bp->bio_ma_n = round_page(bp->bio_ma_offset +
  384                                     bp->bio_length) / PAGE_SIZE;
  385                         }
  386                         if (excess > 0)
  387                                 CTR3(KTR_GEOM, "g_down truncated bio "
  388                                     "%p provider %s by %d", bp,
  389                                     bp->bio_to->name, excess);
  390                 }
  391 
  392                 /* Deliver zero length transfers right here. */
  393                 if (bp->bio_length == 0) {
  394                         CTR2(KTR_GEOM, "g_down terminated 0-length "
  395                             "bp %p provider %s", bp, bp->bio_to->name);
  396                         return (0);
  397                 }
  398 
  399                 if ((bp->bio_flags & BIO_UNMAPPED) != 0 &&
  400                     (bp->bio_to->flags & G_PF_ACCEPT_UNMAPPED) == 0 &&
  401                     (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE)) {
  402                         if ((error = g_io_transient_map_bio(bp)) >= 0)
  403                                 return (error);
  404                 }
  405                 break;
  406         default:
  407                 break;
  408         }
  409         return (EJUSTRETURN);
  410 }
  411 
  412 /*
  413  * bio classification support.
  414  *
  415  * g_register_classifier() and g_unregister_classifier()
  416  * are used to add/remove a classifier from the list.
  417  * The list is protected using the g_bio_run_down lock,
  418  * because the classifiers are called in this path.
  419  *
  420  * g_io_request() passes bio's that are not already classified
  421  * (i.e. those with bio_classifier1 == NULL) to g_run_classifiers().
  422  * Classifiers can store their result in the two fields
  423  * bio_classifier1 and bio_classifier2.
  424  * A classifier that updates one of the fields should
  425  * return a non-zero value.
  426  * If no classifier updates the field, g_run_classifiers() sets
  427  * bio_classifier1 = BIO_NOTCLASSIFIED to avoid further calls.
  428  */
  429 
  430 int
  431 g_register_classifier(struct g_classifier_hook *hook)
  432 {
  433 
  434         g_bioq_lock(&g_bio_run_down);
  435         TAILQ_INSERT_TAIL(&g_classifier_tailq, hook, link);
  436         g_bioq_unlock(&g_bio_run_down);
  437 
  438         return (0);
  439 }
  440 
  441 void
  442 g_unregister_classifier(struct g_classifier_hook *hook)
  443 {
  444         struct g_classifier_hook *entry;
  445 
  446         g_bioq_lock(&g_bio_run_down);
  447         TAILQ_FOREACH(entry, &g_classifier_tailq, link) {
  448                 if (entry == hook) {
  449                         TAILQ_REMOVE(&g_classifier_tailq, hook, link);
  450                         break;
  451                 }
  452         }
  453         g_bioq_unlock(&g_bio_run_down);
  454 }
  455 
  456 static void
  457 g_run_classifiers(struct bio *bp)
  458 {
  459         struct g_classifier_hook *hook;
  460         int classified = 0;
  461 
  462         TAILQ_FOREACH(hook, &g_classifier_tailq, link)
  463                 classified |= hook->func(hook->arg, bp);
  464 
  465         if (!classified)
  466                 bp->bio_classifier1 = BIO_NOTCLASSIFIED;
  467 }
  468 
  469 void
  470 g_io_request(struct bio *bp, struct g_consumer *cp)
  471 {
  472         struct g_provider *pp;
  473         struct mtx *mtxp;
  474         int direct, error, first;
  475 
  476         KASSERT(cp != NULL, ("NULL cp in g_io_request"));
  477         KASSERT(bp != NULL, ("NULL bp in g_io_request"));
  478         pp = cp->provider;
  479         KASSERT(pp != NULL, ("consumer not attached in g_io_request"));
  480 #ifdef DIAGNOSTIC
  481         KASSERT(bp->bio_driver1 == NULL,
  482             ("bio_driver1 used by the consumer (geom %s)", cp->geom->name));
  483         KASSERT(bp->bio_driver2 == NULL,
  484             ("bio_driver2 used by the consumer (geom %s)", cp->geom->name));
  485         KASSERT(bp->bio_pflags == 0,
  486             ("bio_pflags used by the consumer (geom %s)", cp->geom->name));
  487         /*
  488          * Remember consumer's private fields, so we can detect if they were
  489          * modified by the provider.
  490          */
  491         bp->_bio_caller1 = bp->bio_caller1;
  492         bp->_bio_caller2 = bp->bio_caller2;
  493         bp->_bio_cflags = bp->bio_cflags;
  494 #endif
  495 
  496         if (bp->bio_cmd & (BIO_READ|BIO_WRITE|BIO_GETATTR)) {
  497                 KASSERT(bp->bio_data != NULL,
  498                     ("NULL bp->data in g_io_request(cmd=%hhu)", bp->bio_cmd));
  499         }
  500         if (bp->bio_cmd & (BIO_DELETE|BIO_FLUSH)) {
  501                 KASSERT(bp->bio_data == NULL,
  502                     ("non-NULL bp->data in g_io_request(cmd=%hhu)",
  503                     bp->bio_cmd));
  504         }
  505         if (bp->bio_cmd & (BIO_READ|BIO_WRITE|BIO_DELETE)) {
  506                 KASSERT(bp->bio_offset % cp->provider->sectorsize == 0,
  507                     ("wrong offset %jd for sectorsize %u",
  508                     bp->bio_offset, cp->provider->sectorsize));
  509                 KASSERT(bp->bio_length % cp->provider->sectorsize == 0,
  510                     ("wrong length %jd for sectorsize %u",
  511                     bp->bio_length, cp->provider->sectorsize));
  512         }
  513 
  514         g_trace(G_T_BIO, "bio_request(%p) from %p(%s) to %p(%s) cmd %d",
  515             bp, cp, cp->geom->name, pp, pp->name, bp->bio_cmd);
  516 
  517         bp->bio_from = cp;
  518         bp->bio_to = pp;
  519         bp->bio_error = 0;
  520         bp->bio_completed = 0;
  521 
  522         KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
  523             ("Bio already on queue bp=%p", bp));
  524         if ((g_collectstats & G_STATS_CONSUMERS) != 0 ||
  525             ((g_collectstats & G_STATS_PROVIDERS) != 0 && pp->stat != NULL))
  526                 binuptime(&bp->bio_t0);
  527         else
  528                 getbinuptime(&bp->bio_t0);
  529 
  530 #ifdef GET_STACK_USAGE
  531         direct = (cp->flags & G_CF_DIRECT_SEND) != 0 &&
  532             (pp->flags & G_PF_DIRECT_RECEIVE) != 0 &&
  533             !g_is_geom_thread(curthread) &&
  534             ((pp->flags & G_PF_ACCEPT_UNMAPPED) != 0 ||
  535             (bp->bio_flags & BIO_UNMAPPED) == 0 || THREAD_CAN_SLEEP()) &&
  536             pace == 0;
  537         if (direct) {
  538                 /* Block direct execution if less then half of stack left. */
  539                 size_t  st, su;
  540                 GET_STACK_USAGE(st, su);
  541                 if (su * 2 > st)
  542                         direct = 0;
  543         }
  544 #else
  545         direct = 0;
  546 #endif
  547 
  548         if (!TAILQ_EMPTY(&g_classifier_tailq) && !bp->bio_classifier1) {
  549                 g_bioq_lock(&g_bio_run_down);
  550                 g_run_classifiers(bp);
  551                 g_bioq_unlock(&g_bio_run_down);
  552         }
  553 
  554         /*
  555          * The statistics collection is lockless, as such, but we
  556          * can not update one instance of the statistics from more
  557          * than one thread at a time, so grab the lock first.
  558          */
  559         mtxp = mtx_pool_find(mtxpool_sleep, pp);
  560         mtx_lock(mtxp);
  561         if (g_collectstats & G_STATS_PROVIDERS)
  562                 devstat_start_transaction(pp->stat, &bp->bio_t0);
  563         if (g_collectstats & G_STATS_CONSUMERS)
  564                 devstat_start_transaction(cp->stat, &bp->bio_t0);
  565         pp->nstart++;
  566         cp->nstart++;
  567         mtx_unlock(mtxp);
  568 
  569         if (direct) {
  570                 error = g_io_check(bp);
  571                 if (error >= 0) {
  572                         CTR3(KTR_GEOM, "g_io_request g_io_check on bp %p "
  573                             "provider %s returned %d", bp, bp->bio_to->name,
  574                             error);
  575                         g_io_deliver(bp, error);
  576                         return;
  577                 }
  578                 bp->bio_to->geom->start(bp);
  579         } else {
  580                 g_bioq_lock(&g_bio_run_down);
  581                 first = TAILQ_EMPTY(&g_bio_run_down.bio_queue);
  582                 TAILQ_INSERT_TAIL(&g_bio_run_down.bio_queue, bp, bio_queue);
  583                 bp->bio_flags |= BIO_ONQUEUE;
  584                 g_bio_run_down.bio_queue_length++;
  585                 g_bioq_unlock(&g_bio_run_down);
  586                 /* Pass it on down. */
  587                 if (first)
  588                         wakeup(&g_wait_down);
  589         }
  590 }
  591 
  592 void
  593 g_io_deliver(struct bio *bp, int error)
  594 {
  595         struct bintime now;
  596         struct g_consumer *cp;
  597         struct g_provider *pp;
  598         struct mtx *mtxp;
  599         int direct, first;
  600 
  601         KASSERT(bp != NULL, ("NULL bp in g_io_deliver"));
  602         pp = bp->bio_to;
  603         KASSERT(pp != NULL, ("NULL bio_to in g_io_deliver"));
  604         cp = bp->bio_from;
  605         if (cp == NULL) {
  606                 bp->bio_error = error;
  607                 bp->bio_done(bp);
  608                 return;
  609         }
  610         KASSERT(cp != NULL, ("NULL bio_from in g_io_deliver"));
  611         KASSERT(cp->geom != NULL, ("NULL bio_from->geom in g_io_deliver"));
  612 #ifdef DIAGNOSTIC
  613         /*
  614          * Some classes - GJournal in particular - can modify bio's
  615          * private fields while the bio is in transit; G_GEOM_VOLATILE_BIO
  616          * flag means it's an expected behaviour for that particular geom.
  617          */
  618         if ((cp->geom->flags & G_GEOM_VOLATILE_BIO) == 0) {
  619                 KASSERT(bp->bio_caller1 == bp->_bio_caller1,
  620                     ("bio_caller1 used by the provider %s", pp->name));
  621                 KASSERT(bp->bio_caller2 == bp->_bio_caller2,
  622                     ("bio_caller2 used by the provider %s", pp->name));
  623                 KASSERT(bp->bio_cflags == bp->_bio_cflags,
  624                     ("bio_cflags used by the provider %s", pp->name));
  625         }
  626 #endif
  627         KASSERT(bp->bio_completed >= 0, ("bio_completed can't be less than 0"));
  628         KASSERT(bp->bio_completed <= bp->bio_length,
  629             ("bio_completed can't be greater than bio_length"));
  630 
  631         g_trace(G_T_BIO,
  632 "g_io_deliver(%p) from %p(%s) to %p(%s) cmd %d error %d off %jd len %jd",
  633             bp, cp, cp->geom->name, pp, pp->name, bp->bio_cmd, error,
  634             (intmax_t)bp->bio_offset, (intmax_t)bp->bio_length);
  635 
  636         KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
  637             ("Bio already on queue bp=%p", bp));
  638 
  639         /*
  640          * XXX: next two doesn't belong here
  641          */
  642         bp->bio_bcount = bp->bio_length;
  643         bp->bio_resid = bp->bio_bcount - bp->bio_completed;
  644 
  645 #ifdef GET_STACK_USAGE
  646         direct = (pp->flags & G_PF_DIRECT_SEND) &&
  647                  (cp->flags & G_CF_DIRECT_RECEIVE) &&
  648                  !g_is_geom_thread(curthread);
  649         if (direct) {
  650                 /* Block direct execution if less then half of stack left. */
  651                 size_t  st, su;
  652                 GET_STACK_USAGE(st, su);
  653                 if (su * 2 > st)
  654                         direct = 0;
  655         }
  656 #else
  657         direct = 0;
  658 #endif
  659 
  660         /*
  661          * The statistics collection is lockless, as such, but we
  662          * can not update one instance of the statistics from more
  663          * than one thread at a time, so grab the lock first.
  664          */
  665         if ((g_collectstats & G_STATS_CONSUMERS) != 0 ||
  666             ((g_collectstats & G_STATS_PROVIDERS) != 0 && pp->stat != NULL))
  667                 binuptime(&now);
  668         mtxp = mtx_pool_find(mtxpool_sleep, cp);
  669         mtx_lock(mtxp);
  670         if (g_collectstats & G_STATS_PROVIDERS)
  671                 devstat_end_transaction_bio_bt(pp->stat, bp, &now);
  672         if (g_collectstats & G_STATS_CONSUMERS)
  673                 devstat_end_transaction_bio_bt(cp->stat, bp, &now);
  674         cp->nend++;
  675         pp->nend++;
  676         mtx_unlock(mtxp);
  677 
  678         if (error != ENOMEM) {
  679                 bp->bio_error = error;
  680                 if (direct) {
  681                         biodone(bp);
  682                 } else {
  683                         g_bioq_lock(&g_bio_run_up);
  684                         first = TAILQ_EMPTY(&g_bio_run_up.bio_queue);
  685                         TAILQ_INSERT_TAIL(&g_bio_run_up.bio_queue, bp, bio_queue);
  686                         bp->bio_flags |= BIO_ONQUEUE;
  687                         g_bio_run_up.bio_queue_length++;
  688                         g_bioq_unlock(&g_bio_run_up);
  689                         if (first)
  690                                 wakeup(&g_wait_up);
  691                 }
  692                 return;
  693         }
  694 
  695         if (bootverbose)
  696                 printf("ENOMEM %p on %p(%s)\n", bp, pp, pp->name);
  697         bp->bio_children = 0;
  698         bp->bio_inbed = 0;
  699         bp->bio_driver1 = NULL;
  700         bp->bio_driver2 = NULL;
  701         bp->bio_pflags = 0;
  702         g_io_request(bp, cp);
  703         pace = 1;
  704         return;
  705 }
  706 
  707 SYSCTL_DECL(_kern_geom);
  708 
  709 static long transient_maps;
  710 SYSCTL_LONG(_kern_geom, OID_AUTO, transient_maps, CTLFLAG_RD,
  711     &transient_maps, 0,
  712     "Total count of the transient mapping requests");
  713 u_int transient_map_retries = 10;
  714 SYSCTL_UINT(_kern_geom, OID_AUTO, transient_map_retries, CTLFLAG_RW,
  715     &transient_map_retries, 0,
  716     "Max count of retries used before giving up on creating transient map");
  717 int transient_map_hard_failures;
  718 SYSCTL_INT(_kern_geom, OID_AUTO, transient_map_hard_failures, CTLFLAG_RD,
  719     &transient_map_hard_failures, 0,
  720     "Failures to establish the transient mapping due to retry attempts "
  721     "exhausted");
  722 int transient_map_soft_failures;
  723 SYSCTL_INT(_kern_geom, OID_AUTO, transient_map_soft_failures, CTLFLAG_RD,
  724     &transient_map_soft_failures, 0,
  725     "Count of retried failures to establish the transient mapping");
  726 int inflight_transient_maps;
  727 SYSCTL_INT(_kern_geom, OID_AUTO, inflight_transient_maps, CTLFLAG_RD,
  728     &inflight_transient_maps, 0,
  729     "Current count of the active transient maps");
  730 
  731 static int
  732 g_io_transient_map_bio(struct bio *bp)
  733 {
  734         vm_offset_t addr;
  735         long size;
  736         u_int retried;
  737 
  738         KASSERT(unmapped_buf_allowed, ("unmapped disabled"));
  739 
  740         size = round_page(bp->bio_ma_offset + bp->bio_length);
  741         KASSERT(size / PAGE_SIZE == bp->bio_ma_n, ("Bio too short %p", bp));
  742         addr = 0;
  743         retried = 0;
  744         atomic_add_long(&transient_maps, 1);
  745 retry:
  746         if (vmem_alloc(transient_arena, size, M_BESTFIT | M_NOWAIT, &addr)) {
  747                 if (transient_map_retries != 0 &&
  748                     retried >= transient_map_retries) {
  749                         CTR2(KTR_GEOM, "g_down cannot map bp %p provider %s",
  750                             bp, bp->bio_to->name);
  751                         atomic_add_int(&transient_map_hard_failures, 1);
  752                         return (EDEADLK/* XXXKIB */);
  753                 } else {
  754                         /*
  755                          * Naive attempt to quisce the I/O to get more
  756                          * in-flight requests completed and defragment
  757                          * the transient_arena.
  758                          */
  759                         CTR3(KTR_GEOM, "g_down retrymap bp %p provider %s r %d",
  760                             bp, bp->bio_to->name, retried);
  761                         pause("g_d_tra", hz / 10);
  762                         retried++;
  763                         atomic_add_int(&transient_map_soft_failures, 1);
  764                         goto retry;
  765                 }
  766         }
  767         atomic_add_int(&inflight_transient_maps, 1);
  768         pmap_qenter((vm_offset_t)addr, bp->bio_ma, OFF_TO_IDX(size));
  769         bp->bio_data = (caddr_t)addr + bp->bio_ma_offset;
  770         bp->bio_flags |= BIO_TRANSIENT_MAPPING;
  771         bp->bio_flags &= ~BIO_UNMAPPED;
  772         return (EJUSTRETURN);
  773 }
  774 
  775 void
  776 g_io_schedule_down(struct thread *tp __unused)
  777 {
  778         struct bio *bp;
  779         int error;
  780 
  781         for(;;) {
  782                 g_bioq_lock(&g_bio_run_down);
  783                 bp = g_bioq_first(&g_bio_run_down);
  784                 if (bp == NULL) {
  785                         CTR0(KTR_GEOM, "g_down going to sleep");
  786                         msleep(&g_wait_down, &g_bio_run_down.bio_queue_lock,
  787                             PRIBIO | PDROP, "-", 0);
  788                         continue;
  789                 }
  790                 CTR0(KTR_GEOM, "g_down has work to do");
  791                 g_bioq_unlock(&g_bio_run_down);
  792                 if (pace != 0) {
  793                         /*
  794                          * There has been at least one memory allocation
  795                          * failure since the last I/O completed. Pause 1ms to
  796                          * give the system a chance to free up memory. We only
  797                          * do this once because a large number of allocations
  798                          * can fail in the direct dispatch case and there's no
  799                          * relationship between the number of these failures and
  800                          * the length of the outage. If there's still an outage,
  801                          * we'll pause again and again until it's
  802                          * resolved. Older versions paused longer and once per
  803                          * allocation failure. This was OK for a single threaded
  804                          * g_down, but with direct dispatch would lead to max of
  805                          * 10 IOPs for minutes at a time when transient memory
  806                          * issues prevented allocation for a batch of requests
  807                          * from the upper layers.
  808                          *
  809                          * XXX This pacing is really lame. It needs to be solved
  810                          * by other methods. This is OK only because the worst
  811                          * case scenario is so rare. In the worst case scenario
  812                          * all memory is tied up waiting for I/O to complete
  813                          * which can never happen since we can't allocate bios
  814                          * for that I/O.
  815                          */
  816                         CTR0(KTR_GEOM, "g_down pacing self");
  817                         pause("g_down", min(hz/1000, 1));
  818                         pace = 0;
  819                 }
  820                 CTR2(KTR_GEOM, "g_down processing bp %p provider %s", bp,
  821                     bp->bio_to->name);
  822                 error = g_io_check(bp);
  823                 if (error >= 0) {
  824                         CTR3(KTR_GEOM, "g_down g_io_check on bp %p provider "
  825                             "%s returned %d", bp, bp->bio_to->name, error);
  826                         g_io_deliver(bp, error);
  827                         continue;
  828                 }
  829                 THREAD_NO_SLEEPING();
  830                 CTR4(KTR_GEOM, "g_down starting bp %p provider %s off %ld "
  831                     "len %ld", bp, bp->bio_to->name, bp->bio_offset,
  832                     bp->bio_length);
  833                 bp->bio_to->geom->start(bp);
  834                 THREAD_SLEEPING_OK();
  835         }
  836 }
  837 
  838 void
  839 bio_taskqueue(struct bio *bp, bio_task_t *func, void *arg)
  840 {
  841         bp->bio_task = func;
  842         bp->bio_task_arg = arg;
  843         /*
  844          * The taskqueue is actually just a second queue off the "up"
  845          * queue, so we use the same lock.
  846          */
  847         g_bioq_lock(&g_bio_run_up);
  848         KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
  849             ("Bio already on queue bp=%p target taskq", bp));
  850         bp->bio_flags |= BIO_ONQUEUE;
  851         TAILQ_INSERT_TAIL(&g_bio_run_task.bio_queue, bp, bio_queue);
  852         g_bio_run_task.bio_queue_length++;
  853         wakeup(&g_wait_up);
  854         g_bioq_unlock(&g_bio_run_up);
  855 }
  856 
  857 
  858 void
  859 g_io_schedule_up(struct thread *tp __unused)
  860 {
  861         struct bio *bp;
  862         for(;;) {
  863                 g_bioq_lock(&g_bio_run_up);
  864                 bp = g_bioq_first(&g_bio_run_task);
  865                 if (bp != NULL) {
  866                         g_bioq_unlock(&g_bio_run_up);
  867                         THREAD_NO_SLEEPING();
  868                         CTR1(KTR_GEOM, "g_up processing task bp %p", bp);
  869                         bp->bio_task(bp->bio_task_arg);
  870                         THREAD_SLEEPING_OK();
  871                         continue;
  872                 }
  873                 bp = g_bioq_first(&g_bio_run_up);
  874                 if (bp != NULL) {
  875                         g_bioq_unlock(&g_bio_run_up);
  876                         THREAD_NO_SLEEPING();
  877                         CTR4(KTR_GEOM, "g_up biodone bp %p provider %s off "
  878                             "%jd len %ld", bp, bp->bio_to->name,
  879                             bp->bio_offset, bp->bio_length);
  880                         biodone(bp);
  881                         THREAD_SLEEPING_OK();
  882                         continue;
  883                 }
  884                 CTR0(KTR_GEOM, "g_up going to sleep");
  885                 msleep(&g_wait_up, &g_bio_run_up.bio_queue_lock,
  886                     PRIBIO | PDROP, "-", 0);
  887         }
  888 }
  889 
  890 void *
  891 g_read_data(struct g_consumer *cp, off_t offset, off_t length, int *error)
  892 {
  893         struct bio *bp;
  894         void *ptr;
  895         int errorc;
  896 
  897         KASSERT(length > 0 && length >= cp->provider->sectorsize &&
  898             length <= MAXPHYS, ("g_read_data(): invalid length %jd",
  899             (intmax_t)length));
  900 
  901         bp = g_alloc_bio();
  902         bp->bio_cmd = BIO_READ;
  903         bp->bio_done = NULL;
  904         bp->bio_offset = offset;
  905         bp->bio_length = length;
  906         ptr = g_malloc(length, M_WAITOK);
  907         bp->bio_data = ptr;
  908         g_io_request(bp, cp);
  909         errorc = biowait(bp, "gread");
  910         if (error != NULL)
  911                 *error = errorc;
  912         g_destroy_bio(bp);
  913         if (errorc) {
  914                 g_free(ptr);
  915                 ptr = NULL;
  916         }
  917         return (ptr);
  918 }
  919 
  920 int
  921 g_write_data(struct g_consumer *cp, off_t offset, void *ptr, off_t length)
  922 {
  923         struct bio *bp;
  924         int error;
  925 
  926         KASSERT(length > 0 && length >= cp->provider->sectorsize &&
  927             length <= MAXPHYS, ("g_write_data(): invalid length %jd",
  928             (intmax_t)length));
  929 
  930         bp = g_alloc_bio();
  931         bp->bio_cmd = BIO_WRITE;
  932         bp->bio_done = NULL;
  933         bp->bio_offset = offset;
  934         bp->bio_length = length;
  935         bp->bio_data = ptr;
  936         g_io_request(bp, cp);
  937         error = biowait(bp, "gwrite");
  938         g_destroy_bio(bp);
  939         return (error);
  940 }
  941 
  942 int
  943 g_delete_data(struct g_consumer *cp, off_t offset, off_t length)
  944 {
  945         struct bio *bp;
  946         int error;
  947 
  948         KASSERT(length > 0 && length >= cp->provider->sectorsize,
  949             ("g_delete_data(): invalid length %jd", (intmax_t)length));
  950 
  951         bp = g_alloc_bio();
  952         bp->bio_cmd = BIO_DELETE;
  953         bp->bio_done = NULL;
  954         bp->bio_offset = offset;
  955         bp->bio_length = length;
  956         bp->bio_data = NULL;
  957         g_io_request(bp, cp);
  958         error = biowait(bp, "gdelete");
  959         g_destroy_bio(bp);
  960         return (error);
  961 }
  962 
  963 void
  964 g_print_bio(struct bio *bp)
  965 {
  966         const char *pname, *cmd = NULL;
  967 
  968         if (bp->bio_to != NULL)
  969                 pname = bp->bio_to->name;
  970         else
  971                 pname = "[unknown]";
  972 
  973         switch (bp->bio_cmd) {
  974         case BIO_GETATTR:
  975                 cmd = "GETATTR";
  976                 printf("%s[%s(attr=%s)]", pname, cmd, bp->bio_attribute);
  977                 return;
  978         case BIO_FLUSH:
  979                 cmd = "FLUSH";
  980                 printf("%s[%s]", pname, cmd);
  981                 return;
  982         case BIO_READ:
  983                 cmd = "READ";
  984                 break;
  985         case BIO_WRITE:
  986                 cmd = "WRITE";
  987                 break;
  988         case BIO_DELETE:
  989                 cmd = "DELETE";
  990                 break;
  991         default:
  992                 cmd = "UNKNOWN";
  993                 printf("%s[%s()]", pname, cmd);
  994                 return;
  995         }
  996         printf("%s[%s(offset=%jd, length=%jd)]", pname, cmd,
  997             (intmax_t)bp->bio_offset, (intmax_t)bp->bio_length);
  998 }

Cache object: d6f79702beed5591c16b17036d44b16f


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.