The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/geom/geom_slice.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/8.3/sys/geom/geom_slice.c 202427 2010-01-15 23:56:19Z mav $");
   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/sysctl.h>
   45 #include <sys/proc.h>
   46 #include <sys/kthread.h>
   47 #include <sys/lock.h>
   48 #include <sys/mutex.h>
   49 #include <sys/errno.h>
   50 #include <sys/sbuf.h>
   51 #include <geom/geom.h>
   52 #include <geom/geom_slice.h>
   53 #include <machine/stdarg.h>
   54 
   55 static g_access_t g_slice_access;
   56 static g_start_t g_slice_start;
   57 
   58 static struct g_slicer *
   59 g_slice_alloc(unsigned nslice, unsigned scsize)
   60 {
   61         struct g_slicer *gsp;
   62 
   63         gsp = g_malloc(sizeof *gsp, M_WAITOK | M_ZERO);
   64         if (scsize > 0)
   65                 gsp->softc = g_malloc(scsize, M_WAITOK | M_ZERO);
   66         else
   67                 gsp->softc = NULL;
   68         gsp->slices = g_malloc(nslice * sizeof(struct g_slice),
   69             M_WAITOK | M_ZERO);
   70         gsp->nslice = nslice;
   71         return (gsp);
   72 }
   73 
   74 static void
   75 g_slice_free(struct g_slicer *gsp)
   76 {
   77 
   78         if (gsp == NULL)        /* XXX: phk thinks about this */
   79                 return;
   80         g_free(gsp->slices);
   81         if (gsp->hotspot != NULL)
   82                 g_free(gsp->hotspot);
   83         if (gsp->softc != NULL)
   84                 g_free(gsp->softc);
   85         g_free(gsp);
   86 }
   87 
   88 static int
   89 g_slice_access(struct g_provider *pp, int dr, int dw, int de)
   90 {
   91         int error;
   92         u_int u;
   93         struct g_geom *gp;
   94         struct g_consumer *cp;
   95         struct g_provider *pp2;
   96         struct g_slicer *gsp;
   97         struct g_slice *gsl, *gsl2;
   98 
   99         gp = pp->geom;
  100         cp = LIST_FIRST(&gp->consumer);
  101         KASSERT (cp != NULL, ("g_slice_access but no consumer"));
  102         gsp = gp->softc;
  103         if (dr > 0 || dw > 0 || de > 0) {
  104                 gsl = &gsp->slices[pp->index];
  105                 for (u = 0; u < gsp->nslice; u++) {
  106                         gsl2 = &gsp->slices[u];
  107                         if (gsl2->length == 0)
  108                                 continue;
  109                         if (u == pp->index)
  110                                 continue;
  111                         if (gsl->offset + gsl->length <= gsl2->offset)
  112                                 continue;
  113                         if (gsl2->offset + gsl2->length <= gsl->offset)
  114                                 continue;
  115                         /* overlap */
  116                         pp2 = gsl2->provider;
  117                         if ((pp->acw + dw) > 0 && pp2->ace > 0)
  118                                 return (EPERM);
  119                         if ((pp->ace + de) > 0 && pp2->acw > 0)
  120                                 return (EPERM);
  121                 }
  122         }
  123         /* On first open, grab an extra "exclusive" bit */
  124         if (cp->acr == 0 && cp->acw == 0 && cp->ace == 0)
  125                 de++;
  126         /* ... and let go of it on last close */
  127         if ((cp->acr + dr) == 0 && (cp->acw + dw) == 0 && (cp->ace + de) == 1)
  128                 de--;
  129         error = g_access(cp, dr, dw, de);
  130         return (error);
  131 }
  132 
  133 /*
  134  * XXX: It should be possible to specify here if we should finish all of the
  135  * XXX: bio, or only the non-hot bits.  This would get messy if there were
  136  * XXX: two hot spots in the same bio, so for now we simply finish off the
  137  * XXX: entire bio.  Modifying hot data on the way to disk is frowned on
  138  * XXX: so making that considerably harder is not a bad idea anyway.
  139  */
  140 void
  141 g_slice_finish_hot(struct bio *bp)
  142 {
  143         struct bio *bp2;
  144         struct g_geom *gp;
  145         struct g_consumer *cp;
  146         struct g_slicer *gsp;
  147         struct g_slice *gsl;
  148         int idx;
  149 
  150         KASSERT(bp->bio_to != NULL,
  151             ("NULL bio_to in g_slice_finish_hot(%p)", bp));
  152         KASSERT(bp->bio_from != NULL,
  153             ("NULL bio_from in g_slice_finish_hot(%p)", bp));
  154         gp = bp->bio_to->geom;
  155         gsp = gp->softc;
  156         cp = LIST_FIRST(&gp->consumer);
  157         KASSERT(cp != NULL, ("NULL consumer in g_slice_finish_hot(%p)", bp));
  158         idx = bp->bio_to->index;
  159         gsl = &gsp->slices[idx];
  160 
  161         bp2 = g_clone_bio(bp);
  162         if (bp2 == NULL) {
  163                 g_io_deliver(bp, ENOMEM);
  164                 return;
  165         }
  166         if (bp2->bio_offset + bp2->bio_length > gsl->length)
  167                 bp2->bio_length = gsl->length - bp2->bio_offset;
  168         bp2->bio_done = g_std_done;
  169         bp2->bio_offset += gsl->offset;
  170         g_io_request(bp2, cp);
  171         return;
  172 }
  173 
  174 static void
  175 g_slice_done(struct bio *bp)
  176 {
  177 
  178         KASSERT(bp->bio_cmd == BIO_GETATTR &&
  179             strcmp(bp->bio_attribute, "GEOM::ident") == 0,
  180             ("bio_cmd=0x%x bio_attribute=%s", bp->bio_cmd, bp->bio_attribute));
  181 
  182         if (bp->bio_error == 0 && bp->bio_data[0] != '\0') {
  183                 char idx[8];
  184 
  185                 /* Add index to the ident received. */
  186                 snprintf(idx, sizeof(idx), "s%d",
  187                     bp->bio_parent->bio_to->index);
  188                 if (strlcat(bp->bio_data, idx, bp->bio_length) >=
  189                     bp->bio_length) {
  190                         bp->bio_error = EFAULT;
  191                 }
  192         }
  193         g_std_done(bp);
  194 }
  195 
  196 static void
  197 g_slice_start(struct bio *bp)
  198 {
  199         struct bio *bp2;
  200         struct g_provider *pp;
  201         struct g_geom *gp;
  202         struct g_consumer *cp;
  203         struct g_slicer *gsp;
  204         struct g_slice *gsl;
  205         struct g_slice_hot *ghp;
  206         int idx, error;
  207         u_int m_index;
  208         off_t t;
  209 
  210         pp = bp->bio_to;
  211         gp = pp->geom;
  212         gsp = gp->softc;
  213         cp = LIST_FIRST(&gp->consumer);
  214         idx = pp->index;
  215         gsl = &gsp->slices[idx];
  216         switch(bp->bio_cmd) {
  217         case BIO_READ:
  218         case BIO_WRITE:
  219         case BIO_DELETE:
  220                 if (bp->bio_offset > gsl->length) {
  221                         g_io_deliver(bp, EINVAL); /* XXX: EWHAT ? */
  222                         return;
  223                 }
  224                 /*
  225                  * Check if we collide with any hot spaces, and call the
  226                  * method once if so.
  227                  */
  228                 t = bp->bio_offset + gsl->offset;
  229                 for (m_index = 0; m_index < gsp->nhotspot; m_index++) {
  230                         ghp = &gsp->hotspot[m_index];
  231                         if (t >= ghp->offset + ghp->length)
  232                                 continue;
  233                         if (t + bp->bio_length <= ghp->offset)
  234                                 continue;
  235                         switch(bp->bio_cmd) {
  236                         case BIO_READ:          idx = ghp->ract; break;
  237                         case BIO_WRITE:         idx = ghp->wact; break;
  238                         case BIO_DELETE:        idx = ghp->dact; break;
  239                         }
  240                         switch(idx) {
  241                         case G_SLICE_HOT_ALLOW:
  242                                 /* Fall out and continue normal processing */
  243                                 continue;
  244                         case G_SLICE_HOT_DENY:
  245                                 g_io_deliver(bp, EROFS);
  246                                 return;
  247                         case G_SLICE_HOT_START:
  248                                 error = gsp->start(bp);
  249                                 if (error && error != EJUSTRETURN)
  250                                         g_io_deliver(bp, error);
  251                                 return;
  252                         case G_SLICE_HOT_CALL:
  253                                 error = g_post_event(gsp->hot, bp, M_NOWAIT,
  254                                     gp, NULL);
  255                                 if (error)
  256                                         g_io_deliver(bp, error);
  257                                 return;
  258                         }
  259                         break;
  260                 }
  261                 bp2 = g_clone_bio(bp);
  262                 if (bp2 == NULL) {
  263                         g_io_deliver(bp, ENOMEM);
  264                         return;
  265                 }
  266                 if (bp2->bio_offset + bp2->bio_length > gsl->length)
  267                         bp2->bio_length = gsl->length - bp2->bio_offset;
  268                 bp2->bio_done = g_std_done;
  269                 bp2->bio_offset += gsl->offset;
  270                 g_io_request(bp2, cp);
  271                 return;
  272         case BIO_GETATTR:
  273                 /* Give the real method a chance to override */
  274                 if (gsp->start != NULL && gsp->start(bp))
  275                         return;
  276                 if (!strcmp("GEOM::ident", bp->bio_attribute)) {
  277                         bp2 = g_clone_bio(bp);
  278                         if (bp2 == NULL) {
  279                                 g_io_deliver(bp, ENOMEM);
  280                                 return;
  281                         }
  282                         bp2->bio_done = g_slice_done;
  283                         g_io_request(bp2, cp);
  284                         return;
  285                 }
  286                 if (!strcmp("GEOM::kerneldump", bp->bio_attribute)) {
  287                         struct g_kerneldump *gkd;
  288 
  289                         gkd = (struct g_kerneldump *)bp->bio_data;
  290                         gkd->offset += gsp->slices[idx].offset;
  291                         if (gkd->length > gsp->slices[idx].length)
  292                                 gkd->length = gsp->slices[idx].length;
  293                         /* now, pass it on downwards... */
  294                 }
  295                 /* FALLTHROUGH */
  296         case BIO_FLUSH:
  297                 bp2 = g_clone_bio(bp);
  298                 if (bp2 == NULL) {
  299                         g_io_deliver(bp, ENOMEM);
  300                         return;
  301                 }
  302                 bp2->bio_done = g_std_done;
  303                 g_io_request(bp2, cp);
  304                 break;
  305         default:
  306                 g_io_deliver(bp, EOPNOTSUPP);
  307                 return;
  308         }
  309 }
  310 
  311 void
  312 g_slice_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp)
  313 {
  314         struct g_slicer *gsp;
  315 
  316         gsp = gp->softc;
  317         if (indent == NULL) {
  318                 sbuf_printf(sb, " i %u", pp->index);
  319                 sbuf_printf(sb, " o %ju", 
  320                     (uintmax_t)gsp->slices[pp->index].offset);
  321                 return;
  322         }
  323         if (pp != NULL) {
  324                 sbuf_printf(sb, "%s<index>%u</index>\n", indent, pp->index);
  325                 sbuf_printf(sb, "%s<length>%ju</length>\n",
  326                     indent, (uintmax_t)gsp->slices[pp->index].length);
  327                 sbuf_printf(sb, "%s<seclength>%ju</seclength>\n", indent,
  328                     (uintmax_t)gsp->slices[pp->index].length / 512);
  329                 sbuf_printf(sb, "%s<offset>%ju</offset>\n", indent,
  330                     (uintmax_t)gsp->slices[pp->index].offset);
  331                 sbuf_printf(sb, "%s<secoffset>%ju</secoffset>\n", indent,
  332                     (uintmax_t)gsp->slices[pp->index].offset / 512);
  333         }
  334 }
  335 
  336 int
  337 g_slice_config(struct g_geom *gp, u_int idx, int how, off_t offset, off_t length, u_int sectorsize, const char *fmt, ...)
  338 {
  339         struct g_provider *pp, *pp2;
  340         struct g_slicer *gsp;
  341         struct g_slice *gsl;
  342         va_list ap;
  343         struct sbuf *sb;
  344         int acc;
  345 
  346         g_trace(G_T_TOPOLOGY, "g_slice_config(%s, %d, %d)",
  347              gp->name, idx, how);
  348         g_topology_assert();
  349         gsp = gp->softc;
  350         if (idx >= gsp->nslice)
  351                 return(EINVAL);
  352         gsl = &gsp->slices[idx];
  353         pp = gsl->provider;
  354         if (pp != NULL)
  355                 acc = pp->acr + pp->acw + pp->ace;
  356         else
  357                 acc = 0;
  358         if (acc != 0 && how != G_SLICE_CONFIG_FORCE) {
  359                 if (length < gsl->length)
  360                         return(EBUSY);
  361                 if (offset != gsl->offset)
  362                         return(EBUSY);
  363         }
  364         /* XXX: check offset + length <= MEDIASIZE */
  365         if (how == G_SLICE_CONFIG_CHECK)
  366                 return (0);
  367         gsl->length = length;
  368         gsl->offset = offset;
  369         gsl->sectorsize = sectorsize;
  370         if (length == 0) {
  371                 if (pp == NULL)
  372                         return (0);
  373                 if (bootverbose)
  374                         printf("GEOM: Deconfigure %s\n", pp->name);
  375                 g_wither_provider(pp, ENXIO);
  376                 gsl->provider = NULL;
  377                 gsp->nprovider--;
  378                 return (0);
  379         }
  380         if (pp != NULL) {
  381                 if (bootverbose)
  382                         printf("GEOM: Reconfigure %s, start %jd length %jd end %jd\n",
  383                             pp->name, (intmax_t)offset, (intmax_t)length,
  384                             (intmax_t)(offset + length - 1));
  385                 pp->mediasize = gsl->length;
  386                 return (0);
  387         }
  388         sb = sbuf_new_auto();
  389         va_start(ap, fmt);
  390         sbuf_vprintf(sb, fmt, ap);
  391         va_end(ap);
  392         sbuf_finish(sb);
  393         pp = g_new_providerf(gp, sbuf_data(sb));
  394         pp2 = LIST_FIRST(&gp->consumer)->provider;
  395         pp->flags = pp2->flags & G_PF_CANDELETE;
  396         pp->stripesize = pp2->stripesize;
  397         pp->stripeoffset = pp2->stripeoffset + offset;
  398         if (pp->stripesize > 0)
  399                 pp->stripeoffset %= pp->stripesize;
  400         if (0 && bootverbose)
  401                 printf("GEOM: Configure %s, start %jd length %jd end %jd\n",
  402                     pp->name, (intmax_t)offset, (intmax_t)length,
  403                     (intmax_t)(offset + length - 1));
  404         pp->index = idx;
  405         pp->mediasize = gsl->length;
  406         pp->sectorsize = gsl->sectorsize;
  407         gsl->provider = pp;
  408         gsp->nprovider++;
  409         g_error_provider(pp, 0);
  410         sbuf_delete(sb);
  411         return(0);
  412 }
  413 
  414 /*
  415  * Configure "hotspots".  A hotspot is a piece of the parent device which
  416  * this particular slicer cares about for some reason.  Typically because
  417  * it contains meta-data used to configure the slicer.
  418  * A hotspot is identified by its index number. The offset and length are
  419  * relative to the parent device, and the three "?act" fields specify
  420  * what action to take on BIO_READ, BIO_DELETE and BIO_WRITE.
  421  *
  422  * XXX: There may be a race relative to g_slice_start() here, if an existing
  423  * XXX: hotspot is changed wile I/O is happening.  Should this become a problem
  424  * XXX: we can protect the hotspot stuff with a mutex.
  425  */
  426 
  427 int
  428 g_slice_conf_hot(struct g_geom *gp, u_int idx, off_t offset, off_t length, int ract, int dact, int wact)
  429 {
  430         struct g_slicer *gsp;
  431         struct g_slice_hot *gsl, *gsl2;
  432 
  433         g_trace(G_T_TOPOLOGY, "g_slice_conf_hot(%s, idx: %d, off: %jd, len: %jd)",
  434             gp->name, idx, (intmax_t)offset, (intmax_t)length);
  435         g_topology_assert();
  436         gsp = gp->softc;
  437         gsl = gsp->hotspot;
  438         if(idx >= gsp->nhotspot) {
  439                 gsl2 = g_malloc((idx + 1) * sizeof *gsl2, M_WAITOK | M_ZERO);
  440                 if (gsp->hotspot != NULL)
  441                         bcopy(gsp->hotspot, gsl2, gsp->nhotspot * sizeof *gsl2);
  442                 gsp->hotspot = gsl2;
  443                 if (gsp->hotspot != NULL)
  444                         g_free(gsl);
  445                 gsl = gsl2;
  446                 gsp->nhotspot = idx + 1;
  447         }
  448         gsl[idx].offset = offset;
  449         gsl[idx].length = length;
  450         KASSERT(!((ract | dact | wact) & G_SLICE_HOT_START)
  451             || gsp->start != NULL, ("G_SLICE_HOT_START but no slice->start"));
  452         /* XXX: check that we _have_ a start function if HOT_START specified */
  453         gsl[idx].ract = ract;
  454         gsl[idx].dact = dact;
  455         gsl[idx].wact = wact;
  456         return (0);
  457 }
  458 
  459 void
  460 g_slice_spoiled(struct g_consumer *cp)
  461 {
  462         struct g_geom *gp;
  463         struct g_slicer *gsp;
  464 
  465         g_topology_assert();
  466         gp = cp->geom;
  467         g_trace(G_T_TOPOLOGY, "g_slice_spoiled(%p/%s)", cp, gp->name);
  468         gsp = gp->softc;
  469         gp->softc = NULL;
  470         g_slice_free(gsp);
  471         g_wither_geom(gp, ENXIO);
  472 }
  473 
  474 int
  475 g_slice_destroy_geom(struct gctl_req *req, struct g_class *mp, struct g_geom *gp)
  476 {
  477 
  478         g_slice_spoiled(LIST_FIRST(&gp->consumer));
  479         return (0);
  480 }
  481 
  482 struct g_geom *
  483 g_slice_new(struct g_class *mp, u_int slices, struct g_provider *pp, struct g_consumer **cpp, void *extrap, int extra, g_slice_start_t *start)
  484 {
  485         struct g_geom *gp;
  486         struct g_slicer *gsp;
  487         struct g_consumer *cp;
  488         void **vp;
  489         int error;
  490 
  491         g_topology_assert();
  492         vp = (void **)extrap;
  493         gp = g_new_geomf(mp, "%s", pp->name);
  494         gsp = g_slice_alloc(slices, extra);
  495         gsp->start = start;
  496         gp->access = g_slice_access;
  497         gp->orphan = g_slice_orphan;
  498         gp->softc = gsp;
  499         gp->start = g_slice_start;
  500         gp->spoiled = g_slice_spoiled;
  501         if (gp->dumpconf == NULL)
  502                 gp->dumpconf = g_slice_dumpconf;
  503         if (gp->class->destroy_geom == NULL)
  504                 gp->class->destroy_geom = g_slice_destroy_geom;
  505         cp = g_new_consumer(gp);
  506         error = g_attach(cp, pp);
  507         if (error == 0)
  508                 error = g_access(cp, 1, 0, 0);
  509         if (error) {
  510                 g_wither_geom(gp, ENXIO);
  511                 return (NULL);
  512         }
  513         if (extrap != NULL)
  514                 *vp = gsp->softc;
  515         *cpp = cp;
  516         return (gp);
  517 }
  518 
  519 void
  520 g_slice_orphan(struct g_consumer *cp)
  521 {
  522 
  523         g_trace(G_T_TOPOLOGY, "g_slice_orphan(%p/%s)", cp, cp->provider->name);
  524         g_topology_assert();
  525         KASSERT(cp->provider->error != 0,
  526             ("g_slice_orphan with error == 0"));
  527 
  528         /* XXX: Not good enough we leak the softc and its suballocations */
  529         g_slice_free(cp->geom->softc);
  530         g_wither_geom(cp->geom, cp->provider->error);
  531 }

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