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

     /*-
      * Copyright (c) 2002 Poul-Henning Kamp
      * Copyright (c) 2002 Networks Associates Technology, Inc.
      * All rights reserved.
      *
      * This software was developed for the FreeBSD Project by Poul-Henning Kamp
      * and NAI Labs, the Security Research Division of Network Associates, Inc.
      * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
      * DARPA CHATS research program.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. The names of the authors may not be used to endorse or promote
     *    products derived from this software without specific prior written
     *    permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/5.2/sys/geom/geom_dev.c 121253 2003-10-19 19:06:54Z phk $");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/malloc.h>
    #include <sys/kernel.h>
    #include <sys/conf.h>
    #include <sys/bio.h>
    #include <sys/lock.h>
    #include <sys/mutex.h>
    #include <sys/errno.h>
    #include <sys/time.h>
    #include <sys/disk.h>
    #include <sys/fcntl.h>
    #include <sys/limits.h>
    #include <geom/geom.h>
    #include <geom/geom_int.h>
    
    static d_open_t         g_dev_open;
    static d_close_t        g_dev_close;
    static d_strategy_t     g_dev_strategy;
    static d_ioctl_t        g_dev_ioctl;
    
    static struct cdevsw g_dev_cdevsw = {
            .d_open =       g_dev_open,
            .d_close =      g_dev_close,
            .d_read =       physread,
            .d_write =      physwrite,
            .d_ioctl =      g_dev_ioctl,
            .d_strategy =   g_dev_strategy,
            .d_name =       "g_dev",
            .d_maj =        GEOM_MAJOR,
            .d_flags =      D_DISK | D_TRACKCLOSE | D_NOGIANT,
    };
    
    static g_taste_t g_dev_taste;
    static g_orphan_t g_dev_orphan;
    
    static struct g_class g_dev_class       = {
            .name = "DEV",
            .taste = g_dev_taste,
    };
    
    void
    g_dev_print(void)
    {
            struct g_geom *gp;
            char const *p = "";
    
            LIST_FOREACH(gp, &g_dev_class.geom, geom) {
                    printf("%s%s", p, gp->name);
                    p = " ";
            }
            printf("\n");
    }
    
    /*
     * XXX: This is disgusting and wrong in every way imaginable:  The only reason
     * XXX: we have a clone function is because of the root-mount hack we currently
     * XXX: employ.  An improvment would be to unregister this cloner once we know
     * XXX: we no longer need it.  Ideally, root-fs would be mounted through DEVFS
     * XXX: eliminating the need for this hack.
     */
   static void
   g_dev_clone(void *arg __unused, char *name, int namelen __unused, dev_t *dev)
   {
           struct g_geom *gp;
   
           if (*dev != NODEV)
                   return;
   
           g_waitidle();
   
           /* g_topology_lock(); */
           LIST_FOREACH(gp, &g_dev_class.geom, geom) {
                   if (strcmp(gp->name, name))
                           continue;
                   *dev = gp->softc;
                   g_trace(G_T_TOPOLOGY, "g_dev_clone(%s) = %p", name, *dev);
                   return;
           }
           /* g_topology_unlock(); */
           return;
   }
   
   static void
   g_dev_register_cloner(void *foo __unused)
   {
           static int once;
   
           /* XXX: why would this happen more than once ?? */
           if (!once) {
                   EVENTHANDLER_REGISTER(dev_clone, g_dev_clone, 0, 1000);
                   once++;
           }
   }
   
   SYSINIT(geomdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE,g_dev_register_cloner,NULL);
   
   struct g_provider *
   g_dev_getprovider(dev_t dev)
   {
           struct g_consumer *cp;
   
           if (dev == NULL)
                   return (NULL);
           if (devsw(dev) != &g_dev_cdevsw)
                   return (NULL);
           cp = dev->si_drv2;
           return (cp->provider);
   }
   
   
   static struct g_geom *
   g_dev_taste(struct g_class *mp, struct g_provider *pp, int insist __unused)
   {
           struct g_geom *gp;
           struct g_consumer *cp;
           static int unit = GEOM_MINOR_PROVIDERS;
           int error;
           dev_t dev;
   
           g_trace(G_T_TOPOLOGY, "dev_taste(%s,%s)", mp->name, pp->name);
           g_topology_assert();
           LIST_FOREACH(cp, &pp->consumers, consumers)
                   if (cp->geom->class == mp)
                           return (NULL);
           gp = g_new_geomf(mp, pp->name);
           gp->orphan = g_dev_orphan;
           cp = g_new_consumer(gp);
           error = g_attach(cp, pp);
           KASSERT(error == 0,
               ("g_dev_taste(%s) failed to g_attach, err=%d", pp->name, error));
           /*
            * XXX: I'm not 100% sure we can call make_dev(9) without Giant
            * yet.  Once we can, we don't need to drop topology here either.
            */
           g_topology_unlock();
           mtx_lock(&Giant);
           dev = make_dev(&g_dev_cdevsw, unit2minor(unit++),
               UID_ROOT, GID_OPERATOR, 0640, gp->name);
           if (pp->flags & G_PF_CANDELETE)
                   dev->si_flags |= SI_CANDELETE;
           mtx_unlock(&Giant);
           g_topology_lock();
           dev->si_iosize_max = MAXPHYS;
           dev->si_stripesize = pp->stripesize;
           dev->si_stripeoffset = pp->stripeoffset;
           gp->softc = dev;
           dev->si_drv1 = gp;
           dev->si_drv2 = cp;
           return (gp);
   }
   
   static int
   g_dev_open(dev_t dev, int flags, int fmt, struct thread *td)
   {
           struct g_geom *gp;
           struct g_consumer *cp;
           int error, r, w, e;
   
           gp = dev->si_drv1;
           cp = dev->si_drv2;
           if (gp == NULL || cp == NULL || gp->softc != dev)
                   return(ENXIO);          /* g_dev_taste() not done yet */
   
           g_trace(G_T_ACCESS, "g_dev_open(%s, %d, %d, %p)",
               gp->name, flags, fmt, td);
           r = flags & FREAD ? 1 : 0;
           w = flags & FWRITE ? 1 : 0;
   #ifdef notyet
           e = flags & O_EXCL ? 1 : 0;
   #else
           e = 0;
   #endif
           g_topology_lock();
           if (dev->si_devsw == NULL)
                   error = ENXIO;          /* We were orphaned */
           else
                   error = g_access_rel(cp, r, w, e);
           g_topology_unlock();
           g_waitidle();
           if (!error)
                   dev->si_bsize_phys = cp->provider->sectorsize;
           return(error);
   }
   
   static int
   g_dev_close(dev_t dev, int flags, int fmt, struct thread *td)
   {
           struct g_geom *gp;
           struct g_consumer *cp;
           int error, r, w, e, i;
   
           gp = dev->si_drv1;
           cp = dev->si_drv2;
           if (gp == NULL || cp == NULL)
                   return(ENXIO);
           g_trace(G_T_ACCESS, "g_dev_close(%s, %d, %d, %p)",
               gp->name, flags, fmt, td);
           r = flags & FREAD ? -1 : 0;
           w = flags & FWRITE ? -1 : 0;
   #ifdef notyet
           e = flags & O_EXCL ? -1 : 0;
   #else
           e = 0;
   #endif
           g_topology_lock();
           if (dev->si_devsw == NULL)
                   error = ENXIO;          /* We were orphaned */
           else
                   error = g_access_rel(cp, r, w, e);
           for (i = 0; i < 10 * hz;) {
                   if (cp->acr != 0 || cp->acw != 0)
                           break;
                   if (cp->nstart == cp->nend)
                           break;
                   tsleep(&i, PRIBIO, "gdevwclose", hz / 10);
                   i += hz / 10;
           }
           if (cp->acr == 0 && cp->acw == 0 && cp->nstart != cp->nend) {
                   printf("WARNING: Final close of geom_dev(%s) %s %s",
                       gp->name,
                       "still has outstanding I/O after 10 seconds.",
                       "Completing close anyway, panic may happen later.");
           }
           g_topology_unlock();
           g_waitidle();
           return (error);
   }
   
   /*
    * XXX: Until we have unmessed the ioctl situation, there is a race against
    * XXX: a concurrent orphanization.  We cannot close it by holding topology
    * XXX: since that would prevent us from doing our job, and stalling events
    * XXX: will break (actually: stall) the BSD disklabel hacks.
    */
   static int
   g_dev_ioctl(dev_t dev, u_long cmd, caddr_t data, int fflag, struct thread *td)
   {
           struct g_geom *gp;
           struct g_consumer *cp;
           struct g_kerneldump kd;
           int i, error;
           u_int u;
   
           gp = dev->si_drv1;
           cp = dev->si_drv2;
   
           error = 0;
           KASSERT(cp->acr || cp->acw,
               ("Consumer with zero access count in g_dev_ioctl"));
   
           i = IOCPARM_LEN(cmd);
           switch (cmd) {
           case DIOCGSECTORSIZE:
                   *(u_int *)data = cp->provider->sectorsize;
                   if (*(u_int *)data == 0)
                           error = ENOENT;
                   break;
           case DIOCGMEDIASIZE:
                   *(off_t *)data = cp->provider->mediasize;
                   if (*(off_t *)data == 0)
                           error = ENOENT;
                   break;
           case DIOCGFWSECTORS:
                   error = g_io_getattr("GEOM::fwsectors", cp, &i, data);
                   if (error == 0 && *(u_int *)data == 0)
                           error = ENOENT;
                   break;
           case DIOCGFWHEADS:
                   error = g_io_getattr("GEOM::fwheads", cp, &i, data);
                   if (error == 0 && *(u_int *)data == 0)
                           error = ENOENT;
                   break;
           case DIOCGFRONTSTUFF:
                   error = g_io_getattr("GEOM::frontstuff", cp, &i, data);
                   break;
           case DIOCSKERNELDUMP:
                   u = *((u_int *)data);
                   if (!u) {
                           set_dumper(NULL);
                           error = 0;
                           break;
                   }
                   kd.offset = 0;
                   kd.length = OFF_MAX;
                   i = sizeof kd;
                   error = g_io_getattr("GEOM::kerneldump", cp, &i, &kd);
                   if (!error)
                           dev->si_flags |= SI_DUMPDEV;
                   break;
   
           default:
                   if (cp->provider->geom->ioctl != NULL) {
                           error = cp->provider->geom->ioctl(cp->provider, cmd, data, td);
                   } else {
                           error = ENOIOCTL;
                   }
           }
   
           g_waitidle();
           return (error);
   }
   
   static void
   g_dev_done(struct bio *bp2)
   {
           struct bio *bp;
   
           bp = bp2->bio_parent;
           bp->bio_error = bp2->bio_error;
           if (bp->bio_error != 0) {
                   g_trace(G_T_BIO, "g_dev_done(%p) had error %d",
                       bp2, bp->bio_error);
                   bp->bio_flags |= BIO_ERROR;
           } else {
                   g_trace(G_T_BIO, "g_dev_done(%p/%p) resid %ld completed %jd",
                       bp2, bp, bp->bio_resid, (intmax_t)bp2->bio_completed);
           }
           bp->bio_resid = bp->bio_bcount - bp2->bio_completed;
           g_destroy_bio(bp2);
           biodone(bp);
   }
   
   static void
   g_dev_strategy(struct bio *bp)
   {
           struct g_consumer *cp;
           struct bio *bp2;
           dev_t dev;
   
           KASSERT(bp->bio_cmd == BIO_READ ||
                   bp->bio_cmd == BIO_WRITE ||
                   bp->bio_cmd == BIO_DELETE,
                   ("Wrong bio_cmd bio=%p cmd=%d", bp, bp->bio_cmd));
           dev = bp->bio_dev;
           cp = dev->si_drv2;
           KASSERT(cp->acr || cp->acw,
               ("Consumer with zero access count in g_dev_strategy"));
   
           for (;;) {
                   /*
                    * XXX: This is not an ideal solution, but I belive it to
                    * XXX: deadlock safe, all things considered.
                    */
                   bp2 = g_clone_bio(bp);
                   if (bp2 != NULL)
                           break;
                   tsleep(&bp, PRIBIO, "gdstrat", hz / 10);
           }
           KASSERT(bp2 != NULL, ("XXX: ENOMEM in a bad place"));
           bp2->bio_length = (off_t)bp->bio_bcount;
           bp2->bio_done = g_dev_done;
           g_trace(G_T_BIO,
               "g_dev_strategy(%p/%p) offset %jd length %jd data %p cmd %d",
               bp, bp2, (intmax_t)bp->bio_offset, (intmax_t)bp2->bio_length,
               bp2->bio_data, bp2->bio_cmd);
           g_io_request(bp2, cp);
           KASSERT(cp->acr || cp->acw,
               ("g_dev_strategy raced with g_dev_close and lost"));
   
   }
   
   /*
    * g_dev_orphan()
    *
    * Called from below when the provider orphaned us.
    * - Clear any dump settings.
    * - Destroy the dev_t to prevent any more request from coming in.  The
    *   provider is already marked with an error, so anything which comes in
    *   in the interrim will be returned immediately.
    * - Wait for any outstanding I/O to finish.
    * - Set our access counts to zero, whatever they were.
    * - Detach and self-destruct.
    */
   
   static void
   g_dev_orphan(struct g_consumer *cp)
   {
           struct g_geom *gp;
           dev_t dev;
   
           g_topology_assert();
           gp = cp->geom;
           dev = gp->softc;
           g_trace(G_T_TOPOLOGY, "g_dev_orphan(%p(%s))", cp, gp->name);
   
           /* Reset any dump-area set on this device */
           if (dev->si_flags & SI_DUMPDEV)
                   set_dumper(NULL);
   
           /* Destroy the dev_t so we get no more requests */
           destroy_dev(dev);
   
           /* Wait for the cows to come home */
           while (cp->nstart != cp->nend)
                   msleep(&dev, NULL, PRIBIO, "gdevorphan", hz / 10);
   
           if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
                   g_access_rel(cp, -cp->acr, -cp->acw, -cp->ace);
   
           g_detach(cp);
           g_destroy_consumer(cp);
           g_destroy_geom(gp);
   }
   
   DECLARE_GEOM_CLASS(g_dev_class, g_dev);

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