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_fox.c

Version: -  FREEBSD  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-2  -  FREEBSD-11-1  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-4  -  FREEBSD-10-3  -  FREEBSD-10-2  -  FREEBSD-10-1  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-3  -  FREEBSD-9-2  -  FREEBSD-9-1  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-4  -  FREEBSD-8-3  -  FREEBSD-8-2  -  FREEBSD-8-1  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-4  -  FREEBSD-7-3  -  FREEBSD-7-2  -  FREEBSD-7-1  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-4  -  FREEBSD-6-3  -  FREEBSD-6-2  -  FREEBSD-6-1  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-5  -  FREEBSD-5-4  -  FREEBSD-5-3  -  FREEBSD-5-2  -  FREEBSD-5-1  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 2003 Poul-Henning Kamp
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 3. The names of the authors may not be used to endorse or promote
   14  *    products derived from this software without specific prior written
   15  *    permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  *
   29  * $FreeBSD: releng/8.3/sys/geom/geom_fox.c 199583 2009-11-20 15:27:52Z jhb $
   30  */
   31 
   32 /* This is a GEOM module for handling path selection for multi-path
   33  * storage devices.  It is named "fox" because it, like they, prefer
   34  * to have multiple exits to choose from.
   35  *
   36  */
   37 
   38 #include <sys/param.h>
   39 #include <sys/systm.h>
   40 #include <sys/kernel.h>
   41 #include <sys/conf.h>
   42 #include <sys/bio.h>
   43 #include <sys/malloc.h>
   44 #include <sys/lock.h>
   45 #include <sys/mutex.h>
   46 #include <sys/libkern.h>
   47 #include <sys/endian.h>
   48 #include <sys/md5.h>
   49 #include <sys/errno.h>
   50 #include <geom/geom.h>
   51 
   52 #define FOX_CLASS_NAME "FOX"
   53 #define FOX_MAGIC       "GEOM::FOX"
   54 
   55 struct g_fox_softc {
   56         off_t                   mediasize;
   57         u_int                   sectorsize;
   58         TAILQ_HEAD(, bio)       queue;
   59         struct mtx              lock;
   60         u_char                  magic[16];
   61         struct g_consumer       *path;
   62         struct g_consumer       *opath;
   63         int                     waiting;
   64         int                     cr, cw, ce;
   65 };
   66 
   67 /*
   68  * This function is called whenever we need to select a new path.
   69  */
   70 static void
   71 g_fox_select_path(void *arg, int flag)
   72 {
   73         struct g_geom *gp;
   74         struct g_fox_softc *sc;
   75         struct g_consumer *cp1;
   76         struct bio *bp;
   77         int error;
   78 
   79         g_topology_assert();
   80         if (flag == EV_CANCEL)
   81                 return;
   82         gp = arg;
   83         sc = gp->softc;
   84 
   85         if (sc->opath != NULL) {
   86                 /*
   87                  * First, close the old path entirely.
   88                  */
   89                 printf("Closing old path (%s) on fox (%s)\n",
   90                         sc->opath->provider->name, gp->name);
   91 
   92                 cp1 = LIST_NEXT(sc->opath, consumer);
   93 
   94                 g_access(sc->opath, -sc->cr, -sc->cw, -(sc->ce + 1));
   95 
   96                 /*
   97                  * The attempt to reopen it with a exclusive count
   98                  */
   99                 error = g_access(sc->opath, 0, 0, 1);
  100                 if (error) {
  101                         /*
  102                          * Ok, ditch this consumer, we can't use it.
  103                          */
  104                         printf("Drop old path (%s) on fox (%s)\n",
  105                                 sc->opath->provider->name, gp->name);
  106                         g_detach(sc->opath);
  107                         g_destroy_consumer(sc->opath);
  108                         if (LIST_EMPTY(&gp->consumer)) {
  109                                 /* No consumers left */
  110                                 g_wither_geom(gp, ENXIO);
  111                                 for (;;) {
  112                                         bp = TAILQ_FIRST(&sc->queue);
  113                                         if (bp == NULL)
  114                                                 break;
  115                                         TAILQ_REMOVE(&sc->queue, bp, bio_queue);
  116                                         bp->bio_error = ENXIO;
  117                                         g_std_done(bp);
  118                                 }
  119                                 return;
  120                         }
  121                 } else {
  122                         printf("Got e-bit on old path (%s) on fox (%s)\n",
  123                                 sc->opath->provider->name, gp->name);
  124                 }
  125                 sc->opath = NULL;
  126         } else {
  127                 cp1 = LIST_FIRST(&gp->consumer);
  128         }
  129         if (cp1 == NULL)
  130                 cp1 = LIST_FIRST(&gp->consumer);
  131         printf("Open new path (%s) on fox (%s)\n",
  132                 cp1->provider->name, gp->name);
  133         error = g_access(cp1, sc->cr, sc->cw, sc->ce);
  134         if (error) {
  135                 /*
  136                  * If we failed, we take another trip through here
  137                  */
  138                 printf("Open new path (%s) on fox (%s) failed, reselect.\n",
  139                         cp1->provider->name, gp->name);
  140                 sc->opath = cp1;
  141                 g_post_event(g_fox_select_path, gp, M_WAITOK, gp, NULL);
  142         } else {
  143                 printf("Open new path (%s) on fox (%s) succeeded\n",
  144                         cp1->provider->name, gp->name);
  145                 mtx_lock(&sc->lock);
  146                 sc->path = cp1;
  147                 sc->waiting = 0;
  148                 for (;;) {
  149                         bp = TAILQ_FIRST(&sc->queue);
  150                         if (bp == NULL)
  151                                 break;
  152                         TAILQ_REMOVE(&sc->queue, bp, bio_queue);
  153                         g_io_request(bp, sc->path);
  154                 }
  155                 mtx_unlock(&sc->lock);
  156         }
  157 }
  158 
  159 static void
  160 g_fox_orphan(struct g_consumer *cp)
  161 {
  162         struct g_geom *gp;
  163         struct g_fox_softc *sc;
  164         int error, mark;
  165 
  166         g_topology_assert();
  167         gp = cp->geom;
  168         sc = gp->softc;
  169         printf("Removing path (%s) from fox (%s)\n",
  170             cp->provider->name, gp->name);
  171         mtx_lock(&sc->lock);
  172         if (cp == sc->path) {
  173                 sc->opath = NULL;
  174                 sc->path = NULL;
  175                 sc->waiting = 1;
  176                 mark = 1;
  177         } else {
  178                 mark = 0;
  179         }
  180         mtx_unlock(&sc->lock);
  181             
  182         g_access(cp, -cp->acr, -cp->acw, -cp->ace);
  183         error = cp->provider->error;
  184         g_detach(cp);
  185         g_destroy_consumer(cp); 
  186         if (!LIST_EMPTY(&gp->consumer)) {
  187                 if (mark)
  188                         g_post_event(g_fox_select_path, gp, M_WAITOK, gp, NULL);
  189                 return;
  190         }
  191 
  192         mtx_destroy(&sc->lock);
  193         g_free(gp->softc);
  194         gp->softc = NULL;
  195         g_wither_geom(gp, ENXIO);
  196 }
  197 
  198 static void
  199 g_fox_done(struct bio *bp)
  200 {
  201         struct g_geom *gp;
  202         struct g_fox_softc *sc;
  203         int error;
  204 
  205         if (bp->bio_error == 0) {
  206                 g_std_done(bp);
  207                 return;
  208         }
  209         gp = bp->bio_from->geom;
  210         sc = gp->softc;
  211         if (bp->bio_from != sc->path) {
  212                 g_io_request(bp, sc->path);
  213                 return;
  214         }
  215         mtx_lock(&sc->lock);
  216         sc->opath = sc->path;
  217         sc->path = NULL;
  218         error = g_post_event(g_fox_select_path, gp, M_NOWAIT, gp, NULL);
  219         if (error) {
  220                 bp->bio_error = ENOMEM;
  221                 g_std_done(bp);
  222         } else {
  223                 sc->waiting = 1;
  224                 TAILQ_INSERT_TAIL(&sc->queue, bp, bio_queue);
  225         }
  226         mtx_unlock(&sc->lock);
  227 }
  228 
  229 static void
  230 g_fox_start(struct bio *bp)
  231 {
  232         struct g_geom *gp;
  233         struct bio *bp2;
  234         struct g_fox_softc *sc;
  235         int error;
  236 
  237         gp = bp->bio_to->geom;
  238         sc = gp->softc;
  239         if (sc == NULL) {
  240                 g_io_deliver(bp, ENXIO);
  241                 return;
  242         }
  243         switch(bp->bio_cmd) {
  244         case BIO_READ:
  245         case BIO_WRITE:
  246         case BIO_DELETE:
  247                 bp2 = g_clone_bio(bp);
  248                 if (bp2 == NULL) {
  249                         g_io_deliver(bp, ENOMEM);
  250                         break;
  251                 }
  252                 bp2->bio_offset += sc->sectorsize;
  253                 bp2->bio_done = g_fox_done;
  254                 mtx_lock(&sc->lock);
  255                 if (sc->path == NULL || !TAILQ_EMPTY(&sc->queue)) {
  256                         if (sc->waiting == 0) {
  257                                 error = g_post_event(g_fox_select_path, gp,
  258                                     M_NOWAIT, gp, NULL);
  259                                 if (error) {
  260                                         g_destroy_bio(bp2);
  261                                         bp2 = NULL;
  262                                         g_io_deliver(bp, error);
  263                                 } else {
  264                                         sc->waiting = 1;
  265                                 }
  266                         }
  267                         if (bp2 != NULL)
  268                                 TAILQ_INSERT_TAIL(&sc->queue, bp2,
  269                                     bio_queue);
  270                 } else {
  271                         g_io_request(bp2, sc->path);
  272                 }
  273                 mtx_unlock(&sc->lock);
  274                 break;
  275         default:
  276                 g_io_deliver(bp, EOPNOTSUPP);
  277                 break;
  278         }
  279         return;
  280 }
  281 
  282 static int
  283 g_fox_access(struct g_provider *pp, int dr, int dw, int de)
  284 {
  285         struct g_geom *gp;
  286         struct g_fox_softc *sc;
  287         struct g_consumer *cp1;
  288         int error;
  289 
  290         g_topology_assert();
  291         gp = pp->geom;
  292         sc = gp->softc;
  293         if (sc == NULL) {
  294                 if (dr <= 0 && dw <= 0 && de <= 0)
  295                         return (0);
  296                 else
  297                         return (ENXIO);
  298         }
  299 
  300         if (sc->cr == 0 && sc->cw == 0 && sc->ce == 0) {
  301                 /*
  302                  * First open, open all consumers with an exclusive bit
  303                  */
  304                 error = 0;
  305                 LIST_FOREACH(cp1, &gp->consumer, consumer) {
  306                         error = g_access(cp1, 0, 0, 1);
  307                         if (error) {
  308                                 printf("FOX: access(%s,0,0,1) = %d\n",
  309                                     cp1->provider->name, error);
  310                                 break;
  311                         }
  312                 }
  313                 if (error) {
  314                         LIST_FOREACH(cp1, &gp->consumer, consumer) {
  315                                 if (cp1->ace)
  316                                         g_access(cp1, 0, 0, -1);
  317                         }
  318                         return (error);
  319                 }
  320         }
  321         if (sc->path == NULL)
  322                 g_fox_select_path(gp, 0);
  323         if (sc->path == NULL)
  324                 error = ENXIO;
  325         else
  326                 error = g_access(sc->path, dr, dw, de);
  327         if (error == 0) {
  328                 sc->cr += dr;
  329                 sc->cw += dw;
  330                 sc->ce += de;
  331                 if (sc->cr == 0 && sc->cw == 0 && sc->ce == 0) {
  332                         /*
  333                          * Last close, remove e-bit on all consumers
  334                          */
  335                         LIST_FOREACH(cp1, &gp->consumer, consumer)
  336                                 g_access(cp1, 0, 0, -1);
  337                 }
  338         }
  339         return (error);
  340 }
  341 
  342 static struct g_geom *
  343 g_fox_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
  344 {
  345         struct g_geom *gp, *gp2;
  346         struct g_provider *pp2;
  347         struct g_consumer *cp, *cp2;
  348         struct g_fox_softc *sc, *sc2;
  349         int error;
  350         u_int sectorsize;
  351         u_char *buf;
  352 
  353         g_trace(G_T_TOPOLOGY, "fox_taste(%s, %s)", mp->name, pp->name);
  354         g_topology_assert();
  355         if (!strcmp(pp->geom->class->name, mp->name))
  356                 return (NULL);
  357         gp = g_new_geomf(mp, "%s.fox", pp->name);
  358         gp->softc = g_malloc(sizeof(struct g_fox_softc), M_WAITOK | M_ZERO);
  359         sc = gp->softc;
  360 
  361         cp = g_new_consumer(gp);
  362         g_attach(cp, pp);
  363         error = g_access(cp, 1, 0, 0);
  364         if (error) {
  365                 g_free(sc);
  366                 g_detach(cp);
  367                 g_destroy_consumer(cp); 
  368                 g_destroy_geom(gp);
  369                 return(NULL);
  370         }
  371         do {
  372                 sectorsize = cp->provider->sectorsize;
  373                 g_topology_unlock();
  374                 buf = g_read_data(cp, 0, sectorsize, NULL);
  375                 g_topology_lock();
  376                 if (buf == NULL)
  377                         break;
  378                 if (memcmp(buf, FOX_MAGIC, strlen(FOX_MAGIC)))
  379                         break;
  380 
  381                 /*
  382                  * First we need to see if this a new path for an existing fox.
  383                  */
  384                 LIST_FOREACH(gp2, &mp->geom, geom) {
  385                         sc2 = gp2->softc;
  386                         if (sc2 == NULL)
  387                                 continue;
  388                         if (memcmp(buf + 16, sc2->magic, sizeof sc2->magic))
  389                                 continue;
  390                         break;
  391                 }
  392                 if (gp2 != NULL) {
  393                         /*
  394                          * It was.  Create a new consumer for that fox,
  395                          * attach it, and if the fox is open, open this
  396                          * path with an exclusive count of one.
  397                          */
  398                         printf("Adding path (%s) to fox (%s)\n",
  399                             pp->name, gp2->name);
  400                         cp2 = g_new_consumer(gp2);
  401                         g_attach(cp2, pp);
  402                         pp2 = LIST_FIRST(&gp2->provider);
  403                         if (pp2->acr > 0 || pp2->acw > 0 || pp2->ace > 0) {
  404                                 error = g_access(cp2, 0, 0, 1);
  405                                 if (error) {
  406                                         /*
  407                                          * This is bad, or more likely,
  408                                          * the user is doing something stupid
  409                                          */
  410                                         printf(
  411         "WARNING: New path (%s) to fox(%s) not added: %s\n%s",
  412                                             cp2->provider->name, gp2->name,
  413         "Could not get exclusive bit.",
  414         "WARNING: This indicates a risk of data inconsistency."
  415                                         );
  416                                         g_detach(cp2);
  417                                         g_destroy_consumer(cp2);
  418                                 }
  419                         }
  420                         break;
  421                 }
  422                 printf("Creating new fox (%s)\n", pp->name);
  423                 sc->path = cp;
  424                 memcpy(sc->magic, buf + 16, sizeof sc->magic);
  425                 pp2 = g_new_providerf(gp, "%s", gp->name);
  426                 pp2->mediasize = sc->mediasize = pp->mediasize - pp->sectorsize;
  427                 pp2->sectorsize = sc->sectorsize = pp->sectorsize;
  428 printf("fox %s lock %p\n", gp->name, &sc->lock);
  429 
  430                 mtx_init(&sc->lock, "fox queue", NULL, MTX_DEF);
  431                 TAILQ_INIT(&sc->queue);
  432                 g_error_provider(pp2, 0);
  433         } while (0);
  434         if (buf != NULL)
  435                 g_free(buf);
  436         g_access(cp, -1, 0, 0);
  437 
  438         if (!LIST_EMPTY(&gp->provider))
  439                 return (gp);
  440 
  441         g_free(gp->softc);
  442         g_detach(cp);
  443         g_destroy_consumer(cp);
  444         g_destroy_geom(gp);
  445         return (NULL);
  446 }
  447 
  448 static int
  449 g_fox_destroy_geom(struct gctl_req *req, struct g_class *mp, struct g_geom *gp)
  450 {
  451         struct g_fox_softc *sc;
  452 
  453         g_topology_assert();
  454         sc = gp->softc;
  455         mtx_destroy(&sc->lock);
  456         g_free(gp->softc);
  457         gp->softc = NULL;
  458         g_wither_geom(gp, ENXIO);
  459         return (0);
  460 }
  461 
  462 static struct g_class g_fox_class       = {
  463         .name = FOX_CLASS_NAME,
  464         .version = G_VERSION,
  465         .taste = g_fox_taste,
  466         .destroy_geom = g_fox_destroy_geom,
  467         .start = g_fox_start,
  468         .spoiled = g_fox_orphan,
  469         .orphan = g_fox_orphan,
  470         .access= g_fox_access,
  471 };
  472 
  473 DECLARE_GEOM_CLASS(g_fox_class, g_fox);

Cache object: a05ebb266cbb410e566d60659d460f14


[ 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.