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


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

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    1 /*-
    2  * Copyright (c) 2002 Poul-Henning Kamp
    3  * Copyright (c) 2002 Networks Associates Technology, Inc.
    4  * All rights reserved.
    5  *
    6  * This software was developed for the FreeBSD Project by Poul-Henning Kamp
    7  * and NAI Labs, the Security Research Division of Network Associates, Inc.
    8  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
    9  * DARPA CHATS research program.
   10  *
   11  * Redistribution and use in source and binary forms, with or without
   12  * modification, are permitted provided that the following conditions
   13  * are met:
   14  * 1. Redistributions of source code must retain the above copyright
   15  *    notice, this list of conditions and the following disclaimer.
   16  * 2. Redistributions in binary form must reproduce the above copyright
   17  *    notice, this list of conditions and the following disclaimer in the
   18  *    documentation and/or other materials provided with the distribution.
   19  * 3. The names of the authors may not be used to endorse or promote
   20  *    products derived from this software without specific prior written
   21  *    permission.
   22  *
   23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   33  * SUCH DAMAGE.
   34  */
   35 
   36 #include <sys/cdefs.h>
   37 __FBSDID("$FreeBSD: releng/6.3/sys/geom/geom_io.c 161961 2006-09-03 16:28:40Z pjd $");
   38 
   39 #include <sys/param.h>
   40 #include <sys/systm.h>
   41 #include <sys/kernel.h>
   42 #include <sys/malloc.h>
   43 #include <sys/bio.h>
   44 #include <sys/ktr.h>
   45 #include <sys/proc.h>
   46 
   47 #include <sys/errno.h>
   48 #include <geom/geom.h>
   49 #include <geom/geom_int.h>
   50 #include <sys/devicestat.h>
   51 
   52 #include <vm/uma.h>
   53 
   54 static struct g_bioq g_bio_run_down;
   55 static struct g_bioq g_bio_run_up;
   56 static struct g_bioq g_bio_run_task;
   57 
   58 static u_int pace;
   59 static uma_zone_t       biozone;
   60 
   61 #include <machine/atomic.h>
   62 
   63 static void
   64 g_bioq_lock(struct g_bioq *bq)
   65 {
   66 
   67         mtx_lock(&bq->bio_queue_lock);
   68 }
   69 
   70 static void
   71 g_bioq_unlock(struct g_bioq *bq)
   72 {
   73 
   74         mtx_unlock(&bq->bio_queue_lock);
   75 }
   76 
   77 #if 0
   78 static void
   79 g_bioq_destroy(struct g_bioq *bq)
   80 {
   81 
   82         mtx_destroy(&bq->bio_queue_lock);
   83 }
   84 #endif
   85 
   86 static void
   87 g_bioq_init(struct g_bioq *bq)
   88 {
   89 
   90         TAILQ_INIT(&bq->bio_queue);
   91         mtx_init(&bq->bio_queue_lock, "bio queue", NULL, MTX_DEF);
   92 }
   93 
   94 static struct bio *
   95 g_bioq_first(struct g_bioq *bq)
   96 {
   97         struct bio *bp;
   98 
   99         bp = TAILQ_FIRST(&bq->bio_queue);
  100         if (bp != NULL) {
  101                 KASSERT((bp->bio_flags & BIO_ONQUEUE),
  102                     ("Bio not on queue bp=%p target %p", bp, bq));
  103                 bp->bio_flags &= ~BIO_ONQUEUE;
  104                 TAILQ_REMOVE(&bq->bio_queue, bp, bio_queue);
  105                 bq->bio_queue_length--;
  106         }
  107         return (bp);
  108 }
  109 
  110 struct bio *
  111 g_new_bio(void)
  112 {
  113         struct bio *bp;
  114 
  115         bp = uma_zalloc(biozone, M_NOWAIT | M_ZERO);
  116         return (bp);
  117 }
  118 
  119 struct bio *
  120 g_alloc_bio(void)
  121 {
  122         struct bio *bp;
  123 
  124         bp = uma_zalloc(biozone, M_WAITOK | M_ZERO);
  125         return (bp);
  126 }
  127 
  128 void
  129 g_destroy_bio(struct bio *bp)
  130 {
  131 
  132         uma_zfree(biozone, bp);
  133 }
  134 
  135 struct bio *
  136 g_clone_bio(struct bio *bp)
  137 {
  138         struct bio *bp2;
  139 
  140         bp2 = uma_zalloc(biozone, M_NOWAIT | M_ZERO);
  141         if (bp2 != NULL) {
  142                 bp2->bio_parent = bp;
  143                 bp2->bio_cmd = bp->bio_cmd;
  144                 bp2->bio_length = bp->bio_length;
  145                 bp2->bio_offset = bp->bio_offset;
  146                 bp2->bio_data = bp->bio_data;
  147                 bp2->bio_attribute = bp->bio_attribute;
  148                 bp->bio_children++;
  149         }
  150         return(bp2);
  151 }
  152 
  153 struct bio *
  154 g_duplicate_bio(struct bio *bp)
  155 {
  156         struct bio *bp2;
  157 
  158         bp2 = uma_zalloc(biozone, M_WAITOK | M_ZERO);
  159         bp2->bio_parent = bp;
  160         bp2->bio_cmd = bp->bio_cmd;
  161         bp2->bio_length = bp->bio_length;
  162         bp2->bio_offset = bp->bio_offset;
  163         bp2->bio_data = bp->bio_data;
  164         bp2->bio_attribute = bp->bio_attribute;
  165         bp->bio_children++;
  166         return(bp2);
  167 }
  168 
  169 void
  170 g_io_init()
  171 {
  172 
  173         g_bioq_init(&g_bio_run_down);
  174         g_bioq_init(&g_bio_run_up);
  175         g_bioq_init(&g_bio_run_task);
  176         biozone = uma_zcreate("g_bio", sizeof (struct bio),
  177             NULL, NULL,
  178             NULL, NULL,
  179             0, 0);
  180 }
  181 
  182 int
  183 g_io_getattr(const char *attr, struct g_consumer *cp, int *len, void *ptr)
  184 {
  185         struct bio *bp;
  186         int error;
  187 
  188         g_trace(G_T_BIO, "bio_getattr(%s)", attr);
  189         bp = g_alloc_bio();
  190         bp->bio_cmd = BIO_GETATTR;
  191         bp->bio_done = NULL;
  192         bp->bio_attribute = attr;
  193         bp->bio_length = *len;
  194         bp->bio_data = ptr;
  195         g_io_request(bp, cp);
  196         error = biowait(bp, "ggetattr");
  197         *len = bp->bio_completed;
  198         g_destroy_bio(bp);
  199         return (error);
  200 }
  201 
  202 static int
  203 g_io_check(struct bio *bp)
  204 {
  205         struct g_consumer *cp;
  206         struct g_provider *pp;
  207 
  208         cp = bp->bio_from;
  209         pp = bp->bio_to;
  210 
  211         /* Fail if access counters dont allow the operation */
  212         switch(bp->bio_cmd) {
  213         case BIO_READ:
  214         case BIO_GETATTR:
  215                 if (cp->acr == 0)
  216                         return (EPERM);
  217                 break;
  218         case BIO_WRITE:
  219         case BIO_DELETE:
  220                 if (cp->acw == 0)
  221                         return (EPERM);
  222                 break;
  223         default:
  224                 return (EPERM);
  225         }
  226         /* if provider is marked for error, don't disturb. */
  227         if (pp->error)
  228                 return (pp->error);
  229 
  230         switch(bp->bio_cmd) {
  231         case BIO_READ:
  232         case BIO_WRITE:
  233         case BIO_DELETE:
  234                 /* Zero sectorsize is a probably lack of media */
  235                 if (pp->sectorsize == 0)
  236                         return (ENXIO);
  237                 /* Reject I/O not on sector boundary */
  238                 if (bp->bio_offset % pp->sectorsize)
  239                         return (EINVAL);
  240                 /* Reject I/O not integral sector long */
  241                 if (bp->bio_length % pp->sectorsize)
  242                         return (EINVAL);
  243                 /* Reject requests before or past the end of media. */
  244                 if (bp->bio_offset < 0)
  245                         return (EIO);
  246                 if (bp->bio_offset > pp->mediasize)
  247                         return (EIO);
  248                 break;
  249         default:
  250                 break;
  251         }
  252         return (0);
  253 }
  254 
  255 void
  256 g_io_request(struct bio *bp, struct g_consumer *cp)
  257 {
  258         struct g_provider *pp;
  259 
  260         KASSERT(cp != NULL, ("NULL cp in g_io_request"));
  261         KASSERT(bp != NULL, ("NULL bp in g_io_request"));
  262         KASSERT(bp->bio_data != NULL, ("NULL bp->data in g_io_request"));
  263         pp = cp->provider;
  264         KASSERT(pp != NULL, ("consumer not attached in g_io_request"));
  265 
  266         if (bp->bio_cmd & (BIO_READ|BIO_WRITE|BIO_DELETE)) {
  267                 KASSERT(bp->bio_offset % cp->provider->sectorsize == 0,
  268                     ("wrong offset %jd for sectorsize %u",
  269                     bp->bio_offset, cp->provider->sectorsize));
  270                 KASSERT(bp->bio_length % cp->provider->sectorsize == 0,
  271                     ("wrong length %jd for sectorsize %u",
  272                     bp->bio_length, cp->provider->sectorsize));
  273         }
  274 
  275         g_trace(G_T_BIO, "bio_request(%p) from %p(%s) to %p(%s) cmd %d",
  276             bp, cp, cp->geom->name, pp, pp->name, bp->bio_cmd);
  277 
  278         bp->bio_from = cp;
  279         bp->bio_to = pp;
  280         bp->bio_error = 0;
  281         bp->bio_completed = 0;
  282 
  283         KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
  284             ("Bio already on queue bp=%p", bp));
  285         bp->bio_flags |= BIO_ONQUEUE;
  286 
  287         binuptime(&bp->bio_t0);
  288 
  289         /*
  290          * The statistics collection is lockless, as such, but we
  291          * can not update one instance of the statistics from more
  292          * than one thread at a time, so grab the lock first.
  293          */
  294         g_bioq_lock(&g_bio_run_down);
  295         if (g_collectstats & 1)
  296                 devstat_start_transaction(pp->stat, &bp->bio_t0);
  297         if (g_collectstats & 2)
  298                 devstat_start_transaction(cp->stat, &bp->bio_t0);
  299 
  300         pp->nstart++;
  301         cp->nstart++;
  302         TAILQ_INSERT_TAIL(&g_bio_run_down.bio_queue, bp, bio_queue);
  303         g_bio_run_down.bio_queue_length++;
  304         g_bioq_unlock(&g_bio_run_down);
  305 
  306         /* Pass it on down. */
  307         wakeup(&g_wait_down);
  308 }
  309 
  310 void
  311 g_io_deliver(struct bio *bp, int error)
  312 {
  313         struct g_consumer *cp;
  314         struct g_provider *pp;
  315 
  316         KASSERT(bp != NULL, ("NULL bp in g_io_deliver"));
  317         pp = bp->bio_to;
  318         KASSERT(pp != NULL, ("NULL bio_to in g_io_deliver"));
  319         cp = bp->bio_from;
  320         if (cp == NULL) {
  321                 bp->bio_error = error;
  322                 bp->bio_done(bp);
  323                 return;
  324         }
  325         KASSERT(cp != NULL, ("NULL bio_from in g_io_deliver"));
  326         KASSERT(cp->geom != NULL, ("NULL bio_from->geom in g_io_deliver"));
  327         KASSERT(bp->bio_completed >= 0, ("bio_completed can't be less than 0"));
  328         KASSERT(bp->bio_completed <= bp->bio_length,
  329             ("bio_completed can't be greater than bio_length"));
  330 
  331         g_trace(G_T_BIO,
  332 "g_io_deliver(%p) from %p(%s) to %p(%s) cmd %d error %d off %jd len %jd",
  333             bp, cp, cp->geom->name, pp, pp->name, bp->bio_cmd, error,
  334             (intmax_t)bp->bio_offset, (intmax_t)bp->bio_length);
  335 
  336         KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
  337             ("Bio already on queue bp=%p", bp));
  338 
  339         /*
  340          * XXX: next two doesn't belong here
  341          */
  342         bp->bio_bcount = bp->bio_length;
  343         bp->bio_resid = bp->bio_bcount - bp->bio_completed;
  344 
  345         /*
  346          * The statistics collection is lockless, as such, but we
  347          * can not update one instance of the statistics from more
  348          * than one thread at a time, so grab the lock first.
  349          */
  350         g_bioq_lock(&g_bio_run_up);
  351         if (g_collectstats & 1)
  352                 devstat_end_transaction_bio(pp->stat, bp);
  353         if (g_collectstats & 2)
  354                 devstat_end_transaction_bio(cp->stat, bp);
  355 
  356         cp->nend++;
  357         pp->nend++;
  358         if (error != ENOMEM) {
  359                 bp->bio_error = error;
  360                 TAILQ_INSERT_TAIL(&g_bio_run_up.bio_queue, bp, bio_queue);
  361                 bp->bio_flags |= BIO_ONQUEUE;
  362                 g_bio_run_up.bio_queue_length++;
  363                 g_bioq_unlock(&g_bio_run_up);
  364                 wakeup(&g_wait_up);
  365                 return;
  366         }
  367         g_bioq_unlock(&g_bio_run_up);
  368 
  369         if (bootverbose)
  370                 printf("ENOMEM %p on %p(%s)\n", bp, pp, pp->name);
  371         bp->bio_children = 0;
  372         bp->bio_inbed = 0;
  373         g_io_request(bp, cp);
  374         pace++;
  375         return;
  376 }
  377 
  378 void
  379 g_io_schedule_down(struct thread *tp __unused)
  380 {
  381         struct bio *bp;
  382         off_t excess;
  383         int error;
  384 
  385         for(;;) {
  386                 g_bioq_lock(&g_bio_run_down);
  387                 bp = g_bioq_first(&g_bio_run_down);
  388                 if (bp == NULL) {
  389                         CTR0(KTR_GEOM, "g_down going to sleep");
  390                         msleep(&g_wait_down, &g_bio_run_down.bio_queue_lock,
  391                             PRIBIO | PDROP, "-", hz/10);
  392                         continue;
  393                 }
  394                 CTR0(KTR_GEOM, "g_down has work to do");
  395                 g_bioq_unlock(&g_bio_run_down);
  396                 if (pace > 0) {
  397                         CTR1(KTR_GEOM, "g_down pacing self (pace %d)", pace);
  398                         msleep(&error, NULL, PRIBIO, "g_down", hz/10);
  399                         pace--;
  400                 }
  401                 error = g_io_check(bp);
  402                 if (error) {
  403                         CTR3(KTR_GEOM, "g_down g_io_check on bp %p provider "
  404                             "%s returned %d", bp, bp->bio_to->name, error);
  405                         g_io_deliver(bp, error);
  406                         continue;
  407                 }
  408                 CTR2(KTR_GEOM, "g_down processing bp %p provider %s", bp,
  409                     bp->bio_to->name);
  410                 switch (bp->bio_cmd) {
  411                 case BIO_READ:
  412                 case BIO_WRITE:
  413                 case BIO_DELETE:
  414                         /* Truncate requests to the end of providers media. */
  415                         /*
  416                          * XXX: What if we truncate because of offset being
  417                          * bad, not length?
  418                          */
  419                         excess = bp->bio_offset + bp->bio_length;
  420                         if (excess > bp->bio_to->mediasize) {
  421                                 excess -= bp->bio_to->mediasize;
  422                                 bp->bio_length -= excess;
  423                                 if (excess > 0)
  424                                         CTR3(KTR_GEOM, "g_down truncated bio "
  425                                             "%p provider %s by %d", bp,
  426                                             bp->bio_to->name, excess);
  427                         }
  428                         /* Deliver zero length transfers right here. */
  429                         if (bp->bio_length == 0) {
  430                                 g_io_deliver(bp, 0);
  431                                 CTR2(KTR_GEOM, "g_down terminated 0-length "
  432                                     "bp %p provider %s", bp, bp->bio_to->name);
  433                                 continue;
  434                         }
  435                         break;
  436                 default:
  437                         break;
  438                 }
  439                 THREAD_NO_SLEEPING();
  440                 CTR4(KTR_GEOM, "g_down starting bp %p provider %s off %ld "
  441                     "len %ld", bp, bp->bio_to->name, bp->bio_offset,
  442                     bp->bio_length);
  443                 bp->bio_to->geom->start(bp);
  444                 THREAD_SLEEPING_OK();
  445         }
  446 }
  447 
  448 void
  449 bio_taskqueue(struct bio *bp, bio_task_t *func, void *arg)
  450 {
  451         bp->bio_task = func;
  452         bp->bio_task_arg = arg;
  453         /*
  454          * The taskqueue is actually just a second queue off the "up"
  455          * queue, so we use the same lock.
  456          */
  457         g_bioq_lock(&g_bio_run_up);
  458         KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
  459             ("Bio already on queue bp=%p target taskq", bp));
  460         bp->bio_flags |= BIO_ONQUEUE;
  461         TAILQ_INSERT_TAIL(&g_bio_run_task.bio_queue, bp, bio_queue);
  462         g_bio_run_task.bio_queue_length++;
  463         wakeup(&g_wait_up);
  464         g_bioq_unlock(&g_bio_run_up);
  465 }
  466 
  467 
  468 void
  469 g_io_schedule_up(struct thread *tp __unused)
  470 {
  471         struct bio *bp;
  472         for(;;) {
  473                 g_bioq_lock(&g_bio_run_up);
  474                 bp = g_bioq_first(&g_bio_run_task);
  475                 if (bp != NULL) {
  476                         g_bioq_unlock(&g_bio_run_up);
  477                         THREAD_NO_SLEEPING();
  478                         CTR1(KTR_GEOM, "g_up processing task bp %p", bp);
  479                         bp->bio_task(bp->bio_task_arg);
  480                         THREAD_SLEEPING_OK();
  481                         continue;
  482                 }
  483                 bp = g_bioq_first(&g_bio_run_up);
  484                 if (bp != NULL) {
  485                         g_bioq_unlock(&g_bio_run_up);
  486                         THREAD_NO_SLEEPING();
  487                         CTR4(KTR_GEOM, "g_up biodone bp %p provider %s off "
  488                             "%ld len %ld", bp, bp->bio_to->name,
  489                             bp->bio_offset, bp->bio_length);
  490                         biodone(bp);
  491                         THREAD_SLEEPING_OK();
  492                         continue;
  493                 }
  494                 CTR0(KTR_GEOM, "g_up going to sleep");
  495                 msleep(&g_wait_up, &g_bio_run_up.bio_queue_lock,
  496                     PRIBIO | PDROP, "-", hz/10);
  497         }
  498 }
  499 
  500 void *
  501 g_read_data(struct g_consumer *cp, off_t offset, off_t length, int *error)
  502 {
  503         struct bio *bp;
  504         void *ptr;
  505         int errorc;
  506 
  507         KASSERT(length > 0 && length >= cp->provider->sectorsize &&
  508             length <= MAXPHYS, ("g_read_data(): invalid length %jd",
  509             (intmax_t)length));
  510 
  511         bp = g_alloc_bio();
  512         bp->bio_cmd = BIO_READ;
  513         bp->bio_done = NULL;
  514         bp->bio_offset = offset;
  515         bp->bio_length = length;
  516         ptr = g_malloc(length, M_WAITOK);
  517         bp->bio_data = ptr;
  518         g_io_request(bp, cp);
  519         errorc = biowait(bp, "gread");
  520         if (error != NULL)
  521                 *error = errorc;
  522         g_destroy_bio(bp);
  523         if (errorc) {
  524                 g_free(ptr);
  525                 ptr = NULL;
  526         }
  527         return (ptr);
  528 }
  529 
  530 int
  531 g_write_data(struct g_consumer *cp, off_t offset, void *ptr, off_t length)
  532 {
  533         struct bio *bp;
  534         int error;
  535 
  536         KASSERT(length > 0 && length >= cp->provider->sectorsize &&
  537             length <= MAXPHYS, ("g_write_data(): invalid length %jd",
  538             (intmax_t)length));
  539 
  540         bp = g_alloc_bio();
  541         bp->bio_cmd = BIO_WRITE;
  542         bp->bio_done = NULL;
  543         bp->bio_offset = offset;
  544         bp->bio_length = length;
  545         bp->bio_data = ptr;
  546         g_io_request(bp, cp);
  547         error = biowait(bp, "gwrite");
  548         g_destroy_bio(bp);
  549         return (error);
  550 }
  551 
  552 void
  553 g_print_bio(struct bio *bp)
  554 {
  555         const char *pname, *cmd = NULL;
  556 
  557         if (bp->bio_to != NULL)
  558                 pname = bp->bio_to->name;
  559         else
  560                 pname = "[unknown]";
  561 
  562         switch (bp->bio_cmd) {
  563         case BIO_GETATTR:
  564                 cmd = "GETATTR";
  565                 printf("%s[%s(attr=%s)]", pname, cmd, bp->bio_attribute);
  566                 return;
  567         case BIO_READ:
  568                 cmd = "READ";
  569         case BIO_WRITE:
  570                 if (cmd == NULL)
  571                         cmd = "WRITE";
  572         case BIO_DELETE:
  573                 if (cmd == NULL)
  574                         cmd = "DELETE";
  575                 printf("%s[%s(offset=%jd, length=%jd)]", pname, cmd,
  576                     (intmax_t)bp->bio_offset, (intmax_t)bp->bio_length);
  577                 return;
  578         default:
  579                 cmd = "UNKNOWN";
  580                 printf("%s[%s()]", pname, cmd);
  581                 return;
  582         }
  583         /* NOTREACHED */
  584 }

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