The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/geom/raid/tr_raid1.c

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    1 /*-
    2  * Copyright (c) 2010 Alexander Motin <mav@FreeBSD.org>
    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  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
   15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
   18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   24  * SUCH DAMAGE.
   25  */
   26 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD: releng/10.0/sys/geom/raid/tr_raid1.c 242328 2012-10-29 21:08:06Z mav $");
   29 
   30 #include <sys/param.h>
   31 #include <sys/bio.h>
   32 #include <sys/endian.h>
   33 #include <sys/kernel.h>
   34 #include <sys/kobj.h>
   35 #include <sys/limits.h>
   36 #include <sys/lock.h>
   37 #include <sys/malloc.h>
   38 #include <sys/mutex.h>
   39 #include <sys/sysctl.h>
   40 #include <sys/systm.h>
   41 #include <geom/geom.h>
   42 #include "geom/raid/g_raid.h"
   43 #include "g_raid_tr_if.h"
   44 
   45 SYSCTL_DECL(_kern_geom_raid_raid1);
   46 
   47 #define RAID1_REBUILD_SLAB      (1 << 20) /* One transation in a rebuild */
   48 static int g_raid1_rebuild_slab = RAID1_REBUILD_SLAB;
   49 TUNABLE_INT("kern.geom.raid.raid1.rebuild_slab_size",
   50     &g_raid1_rebuild_slab);
   51 SYSCTL_UINT(_kern_geom_raid_raid1, OID_AUTO, rebuild_slab_size, CTLFLAG_RW,
   52     &g_raid1_rebuild_slab, 0,
   53     "Amount of the disk to rebuild each read/write cycle of the rebuild.");
   54 
   55 #define RAID1_REBUILD_FAIR_IO 20 /* use 1/x of the available I/O */
   56 static int g_raid1_rebuild_fair_io = RAID1_REBUILD_FAIR_IO;
   57 TUNABLE_INT("kern.geom.raid.raid1.rebuild_fair_io",
   58     &g_raid1_rebuild_fair_io);
   59 SYSCTL_UINT(_kern_geom_raid_raid1, OID_AUTO, rebuild_fair_io, CTLFLAG_RW,
   60     &g_raid1_rebuild_fair_io, 0,
   61     "Fraction of the I/O bandwidth to use when disk busy for rebuild.");
   62 
   63 #define RAID1_REBUILD_CLUSTER_IDLE 100
   64 static int g_raid1_rebuild_cluster_idle = RAID1_REBUILD_CLUSTER_IDLE;
   65 TUNABLE_INT("kern.geom.raid.raid1.rebuild_cluster_idle",
   66     &g_raid1_rebuild_cluster_idle);
   67 SYSCTL_UINT(_kern_geom_raid_raid1, OID_AUTO, rebuild_cluster_idle, CTLFLAG_RW,
   68     &g_raid1_rebuild_cluster_idle, 0,
   69     "Number of slabs to do each time we trigger a rebuild cycle");
   70 
   71 #define RAID1_REBUILD_META_UPDATE 1024 /* update meta data every 1GB or so */
   72 static int g_raid1_rebuild_meta_update = RAID1_REBUILD_META_UPDATE;
   73 TUNABLE_INT("kern.geom.raid.raid1.rebuild_meta_update",
   74     &g_raid1_rebuild_meta_update);
   75 SYSCTL_UINT(_kern_geom_raid_raid1, OID_AUTO, rebuild_meta_update, CTLFLAG_RW,
   76     &g_raid1_rebuild_meta_update, 0,
   77     "When to update the meta data.");
   78 
   79 static MALLOC_DEFINE(M_TR_RAID1, "tr_raid1_data", "GEOM_RAID RAID1 data");
   80 
   81 #define TR_RAID1_NONE 0
   82 #define TR_RAID1_REBUILD 1
   83 #define TR_RAID1_RESYNC 2
   84 
   85 #define TR_RAID1_F_DOING_SOME   0x1
   86 #define TR_RAID1_F_LOCKED       0x2
   87 #define TR_RAID1_F_ABORT        0x4
   88 
   89 struct g_raid_tr_raid1_object {
   90         struct g_raid_tr_object  trso_base;
   91         int                      trso_starting;
   92         int                      trso_stopping;
   93         int                      trso_type;
   94         int                      trso_recover_slabs; /* slabs before rest */
   95         int                      trso_fair_io;
   96         int                      trso_meta_update;
   97         int                      trso_flags;
   98         struct g_raid_subdisk   *trso_failed_sd; /* like per volume */
   99         void                    *trso_buffer;    /* Buffer space */
  100         struct bio               trso_bio;
  101 };
  102 
  103 static g_raid_tr_taste_t g_raid_tr_taste_raid1;
  104 static g_raid_tr_event_t g_raid_tr_event_raid1;
  105 static g_raid_tr_start_t g_raid_tr_start_raid1;
  106 static g_raid_tr_stop_t g_raid_tr_stop_raid1;
  107 static g_raid_tr_iostart_t g_raid_tr_iostart_raid1;
  108 static g_raid_tr_iodone_t g_raid_tr_iodone_raid1;
  109 static g_raid_tr_kerneldump_t g_raid_tr_kerneldump_raid1;
  110 static g_raid_tr_locked_t g_raid_tr_locked_raid1;
  111 static g_raid_tr_idle_t g_raid_tr_idle_raid1;
  112 static g_raid_tr_free_t g_raid_tr_free_raid1;
  113 
  114 static kobj_method_t g_raid_tr_raid1_methods[] = {
  115         KOBJMETHOD(g_raid_tr_taste,     g_raid_tr_taste_raid1),
  116         KOBJMETHOD(g_raid_tr_event,     g_raid_tr_event_raid1),
  117         KOBJMETHOD(g_raid_tr_start,     g_raid_tr_start_raid1),
  118         KOBJMETHOD(g_raid_tr_stop,      g_raid_tr_stop_raid1),
  119         KOBJMETHOD(g_raid_tr_iostart,   g_raid_tr_iostart_raid1),
  120         KOBJMETHOD(g_raid_tr_iodone,    g_raid_tr_iodone_raid1),
  121         KOBJMETHOD(g_raid_tr_kerneldump, g_raid_tr_kerneldump_raid1),
  122         KOBJMETHOD(g_raid_tr_locked,    g_raid_tr_locked_raid1),
  123         KOBJMETHOD(g_raid_tr_idle,      g_raid_tr_idle_raid1),
  124         KOBJMETHOD(g_raid_tr_free,      g_raid_tr_free_raid1),
  125         { 0, 0 }
  126 };
  127 
  128 static struct g_raid_tr_class g_raid_tr_raid1_class = {
  129         "RAID1",
  130         g_raid_tr_raid1_methods,
  131         sizeof(struct g_raid_tr_raid1_object),
  132         .trc_enable = 1,
  133         .trc_priority = 100
  134 };
  135 
  136 static void g_raid_tr_raid1_rebuild_abort(struct g_raid_tr_object *tr);
  137 static void g_raid_tr_raid1_maybe_rebuild(struct g_raid_tr_object *tr,
  138     struct g_raid_subdisk *sd);
  139 
  140 static int
  141 g_raid_tr_taste_raid1(struct g_raid_tr_object *tr, struct g_raid_volume *vol)
  142 {
  143         struct g_raid_tr_raid1_object *trs;
  144 
  145         trs = (struct g_raid_tr_raid1_object *)tr;
  146         if (tr->tro_volume->v_raid_level != G_RAID_VOLUME_RL_RAID1 ||
  147             (tr->tro_volume->v_raid_level_qualifier != G_RAID_VOLUME_RLQ_R1SM &&
  148              tr->tro_volume->v_raid_level_qualifier != G_RAID_VOLUME_RLQ_R1MM))
  149                 return (G_RAID_TR_TASTE_FAIL);
  150         trs->trso_starting = 1;
  151         return (G_RAID_TR_TASTE_SUCCEED);
  152 }
  153 
  154 static int
  155 g_raid_tr_update_state_raid1(struct g_raid_volume *vol,
  156     struct g_raid_subdisk *sd)
  157 {
  158         struct g_raid_tr_raid1_object *trs;
  159         struct g_raid_softc *sc;
  160         struct g_raid_subdisk *tsd, *bestsd;
  161         u_int s;
  162         int i, na, ns;
  163 
  164         sc = vol->v_softc;
  165         trs = (struct g_raid_tr_raid1_object *)vol->v_tr;
  166         if (trs->trso_stopping &&
  167             (trs->trso_flags & TR_RAID1_F_DOING_SOME) == 0)
  168                 s = G_RAID_VOLUME_S_STOPPED;
  169         else if (trs->trso_starting)
  170                 s = G_RAID_VOLUME_S_STARTING;
  171         else {
  172                 /* Make sure we have at least one ACTIVE disk. */
  173                 na = g_raid_nsubdisks(vol, G_RAID_SUBDISK_S_ACTIVE);
  174                 if (na == 0) {
  175                         /*
  176                          * Critical situation! We have no any active disk!
  177                          * Choose the best disk we have to make it active.
  178                          */
  179                         bestsd = &vol->v_subdisks[0];
  180                         for (i = 1; i < vol->v_disks_count; i++) {
  181                                 tsd = &vol->v_subdisks[i];
  182                                 if (tsd->sd_state > bestsd->sd_state)
  183                                         bestsd = tsd;
  184                                 else if (tsd->sd_state == bestsd->sd_state &&
  185                                     (tsd->sd_state == G_RAID_SUBDISK_S_REBUILD ||
  186                                      tsd->sd_state == G_RAID_SUBDISK_S_RESYNC) &&
  187                                     tsd->sd_rebuild_pos > bestsd->sd_rebuild_pos)
  188                                         bestsd = tsd;
  189                         }
  190                         if (bestsd->sd_state >= G_RAID_SUBDISK_S_UNINITIALIZED) {
  191                                 /* We found reasonable candidate. */
  192                                 G_RAID_DEBUG1(1, sc,
  193                                     "Promote subdisk %s:%d from %s to ACTIVE.",
  194                                     vol->v_name, bestsd->sd_pos,
  195                                     g_raid_subdisk_state2str(bestsd->sd_state));
  196                                 g_raid_change_subdisk_state(bestsd,
  197                                     G_RAID_SUBDISK_S_ACTIVE);
  198                                 g_raid_write_metadata(sc,
  199                                     vol, bestsd, bestsd->sd_disk);
  200                         }
  201                 }
  202                 na = g_raid_nsubdisks(vol, G_RAID_SUBDISK_S_ACTIVE);
  203                 ns = g_raid_nsubdisks(vol, G_RAID_SUBDISK_S_STALE) +
  204                      g_raid_nsubdisks(vol, G_RAID_SUBDISK_S_RESYNC);
  205                 if (na == vol->v_disks_count)
  206                         s = G_RAID_VOLUME_S_OPTIMAL;
  207                 else if (na + ns == vol->v_disks_count)
  208                         s = G_RAID_VOLUME_S_SUBOPTIMAL;
  209                 else if (na > 0)
  210                         s = G_RAID_VOLUME_S_DEGRADED;
  211                 else
  212                         s = G_RAID_VOLUME_S_BROKEN;
  213                 g_raid_tr_raid1_maybe_rebuild(vol->v_tr, sd);
  214         }
  215         if (s != vol->v_state) {
  216                 g_raid_event_send(vol, G_RAID_VOLUME_S_ALIVE(s) ?
  217                     G_RAID_VOLUME_E_UP : G_RAID_VOLUME_E_DOWN,
  218                     G_RAID_EVENT_VOLUME);
  219                 g_raid_change_volume_state(vol, s);
  220                 if (!trs->trso_starting && !trs->trso_stopping)
  221                         g_raid_write_metadata(sc, vol, NULL, NULL);
  222         }
  223         return (0);
  224 }
  225 
  226 static void
  227 g_raid_tr_raid1_fail_disk(struct g_raid_softc *sc, struct g_raid_subdisk *sd,
  228     struct g_raid_disk *disk)
  229 {
  230         /*
  231          * We don't fail the last disk in the pack, since it still has decent
  232          * data on it and that's better than failing the disk if it is the root
  233          * file system.
  234          *
  235          * XXX should this be controlled via a tunable?  It makes sense for
  236          * the volume that has / on it.  I can't think of a case where we'd
  237          * want the volume to go away on this kind of event.
  238          */
  239         if (g_raid_nsubdisks(sd->sd_volume, G_RAID_SUBDISK_S_ACTIVE) == 1 &&
  240             g_raid_get_subdisk(sd->sd_volume, G_RAID_SUBDISK_S_ACTIVE) == sd)
  241                 return;
  242         g_raid_fail_disk(sc, sd, disk);
  243 }
  244 
  245 static void
  246 g_raid_tr_raid1_rebuild_some(struct g_raid_tr_object *tr)
  247 {
  248         struct g_raid_tr_raid1_object *trs;
  249         struct g_raid_subdisk *sd, *good_sd;
  250         struct bio *bp;
  251 
  252         trs = (struct g_raid_tr_raid1_object *)tr;
  253         if (trs->trso_flags & TR_RAID1_F_DOING_SOME)
  254                 return;
  255         sd = trs->trso_failed_sd;
  256         good_sd = g_raid_get_subdisk(sd->sd_volume, G_RAID_SUBDISK_S_ACTIVE);
  257         if (good_sd == NULL) {
  258                 g_raid_tr_raid1_rebuild_abort(tr);
  259                 return;
  260         }
  261         bp = &trs->trso_bio;
  262         memset(bp, 0, sizeof(*bp));
  263         bp->bio_offset = sd->sd_rebuild_pos;
  264         bp->bio_length = MIN(g_raid1_rebuild_slab,
  265             sd->sd_size - sd->sd_rebuild_pos);
  266         bp->bio_data = trs->trso_buffer;
  267         bp->bio_cmd = BIO_READ;
  268         bp->bio_cflags = G_RAID_BIO_FLAG_SYNC;
  269         bp->bio_caller1 = good_sd;
  270         trs->trso_flags |= TR_RAID1_F_DOING_SOME;
  271         trs->trso_flags |= TR_RAID1_F_LOCKED;
  272         g_raid_lock_range(sd->sd_volume,        /* Lock callback starts I/O */
  273            bp->bio_offset, bp->bio_length, NULL, bp);
  274 }
  275 
  276 static void
  277 g_raid_tr_raid1_rebuild_done(struct g_raid_tr_raid1_object *trs)
  278 {
  279         struct g_raid_volume *vol;
  280         struct g_raid_subdisk *sd;
  281 
  282         vol = trs->trso_base.tro_volume;
  283         sd = trs->trso_failed_sd;
  284         g_raid_write_metadata(vol->v_softc, vol, sd, sd->sd_disk);
  285         free(trs->trso_buffer, M_TR_RAID1);
  286         trs->trso_buffer = NULL;
  287         trs->trso_flags &= ~TR_RAID1_F_DOING_SOME;
  288         trs->trso_type = TR_RAID1_NONE;
  289         trs->trso_recover_slabs = 0;
  290         trs->trso_failed_sd = NULL;
  291         g_raid_tr_update_state_raid1(vol, NULL);
  292 }
  293 
  294 static void
  295 g_raid_tr_raid1_rebuild_finish(struct g_raid_tr_object *tr)
  296 {
  297         struct g_raid_tr_raid1_object *trs;
  298         struct g_raid_subdisk *sd;
  299 
  300         trs = (struct g_raid_tr_raid1_object *)tr;
  301         sd = trs->trso_failed_sd;
  302         G_RAID_DEBUG1(0, tr->tro_volume->v_softc,
  303             "Subdisk %s:%d-%s rebuild completed.",
  304             sd->sd_volume->v_name, sd->sd_pos,
  305             sd->sd_disk ? g_raid_get_diskname(sd->sd_disk) : "[none]");
  306         g_raid_change_subdisk_state(sd, G_RAID_SUBDISK_S_ACTIVE);
  307         sd->sd_rebuild_pos = 0;
  308         g_raid_tr_raid1_rebuild_done(trs);
  309 }
  310 
  311 static void
  312 g_raid_tr_raid1_rebuild_abort(struct g_raid_tr_object *tr)
  313 {
  314         struct g_raid_tr_raid1_object *trs;
  315         struct g_raid_subdisk *sd;
  316         struct g_raid_volume *vol;
  317         off_t len;
  318 
  319         vol = tr->tro_volume;
  320         trs = (struct g_raid_tr_raid1_object *)tr;
  321         sd = trs->trso_failed_sd;
  322         if (trs->trso_flags & TR_RAID1_F_DOING_SOME) {
  323                 G_RAID_DEBUG1(1, vol->v_softc,
  324                     "Subdisk %s:%d-%s rebuild is aborting.",
  325                     sd->sd_volume->v_name, sd->sd_pos,
  326                     sd->sd_disk ? g_raid_get_diskname(sd->sd_disk) : "[none]");
  327                 trs->trso_flags |= TR_RAID1_F_ABORT;
  328         } else {
  329                 G_RAID_DEBUG1(0, vol->v_softc,
  330                     "Subdisk %s:%d-%s rebuild aborted.",
  331                     sd->sd_volume->v_name, sd->sd_pos,
  332                     sd->sd_disk ? g_raid_get_diskname(sd->sd_disk) : "[none]");
  333                 trs->trso_flags &= ~TR_RAID1_F_ABORT;
  334                 if (trs->trso_flags & TR_RAID1_F_LOCKED) {
  335                         trs->trso_flags &= ~TR_RAID1_F_LOCKED;
  336                         len = MIN(g_raid1_rebuild_slab,
  337                             sd->sd_size - sd->sd_rebuild_pos);
  338                         g_raid_unlock_range(tr->tro_volume,
  339                             sd->sd_rebuild_pos, len);
  340                 }
  341                 g_raid_tr_raid1_rebuild_done(trs);
  342         }
  343 }
  344 
  345 static void
  346 g_raid_tr_raid1_rebuild_start(struct g_raid_tr_object *tr)
  347 {
  348         struct g_raid_volume *vol;
  349         struct g_raid_tr_raid1_object *trs;
  350         struct g_raid_subdisk *sd, *fsd;
  351 
  352         vol = tr->tro_volume;
  353         trs = (struct g_raid_tr_raid1_object *)tr;
  354         if (trs->trso_failed_sd) {
  355                 G_RAID_DEBUG1(1, vol->v_softc,
  356                     "Already rebuild in start rebuild. pos %jd\n",
  357                     (intmax_t)trs->trso_failed_sd->sd_rebuild_pos);
  358                 return;
  359         }
  360         sd = g_raid_get_subdisk(vol, G_RAID_SUBDISK_S_ACTIVE);
  361         if (sd == NULL) {
  362                 G_RAID_DEBUG1(1, vol->v_softc,
  363                     "No active disk to rebuild.  night night.");
  364                 return;
  365         }
  366         fsd = g_raid_get_subdisk(vol, G_RAID_SUBDISK_S_RESYNC);
  367         if (fsd == NULL)
  368                 fsd = g_raid_get_subdisk(vol, G_RAID_SUBDISK_S_REBUILD);
  369         if (fsd == NULL) {
  370                 fsd = g_raid_get_subdisk(vol, G_RAID_SUBDISK_S_STALE);
  371                 if (fsd != NULL) {
  372                         fsd->sd_rebuild_pos = 0;
  373                         g_raid_change_subdisk_state(fsd,
  374                             G_RAID_SUBDISK_S_RESYNC);
  375                         g_raid_write_metadata(vol->v_softc, vol, fsd, NULL);
  376                 } else {
  377                         fsd = g_raid_get_subdisk(vol,
  378                             G_RAID_SUBDISK_S_UNINITIALIZED);
  379                         if (fsd == NULL)
  380                                 fsd = g_raid_get_subdisk(vol,
  381                                     G_RAID_SUBDISK_S_NEW);
  382                         if (fsd != NULL) {
  383                                 fsd->sd_rebuild_pos = 0;
  384                                 g_raid_change_subdisk_state(fsd,
  385                                     G_RAID_SUBDISK_S_REBUILD);
  386                                 g_raid_write_metadata(vol->v_softc,
  387                                     vol, fsd, NULL);
  388                         }
  389                 }
  390         }
  391         if (fsd == NULL) {
  392                 G_RAID_DEBUG1(1, vol->v_softc,
  393                     "No failed disk to rebuild.  night night.");
  394                 return;
  395         }
  396         trs->trso_failed_sd = fsd;
  397         G_RAID_DEBUG1(0, vol->v_softc,
  398             "Subdisk %s:%d-%s rebuild start at %jd.",
  399             fsd->sd_volume->v_name, fsd->sd_pos,
  400             fsd->sd_disk ? g_raid_get_diskname(fsd->sd_disk) : "[none]",
  401             trs->trso_failed_sd->sd_rebuild_pos);
  402         trs->trso_type = TR_RAID1_REBUILD;
  403         trs->trso_buffer = malloc(g_raid1_rebuild_slab, M_TR_RAID1, M_WAITOK);
  404         trs->trso_meta_update = g_raid1_rebuild_meta_update;
  405         g_raid_tr_raid1_rebuild_some(tr);
  406 }
  407 
  408 
  409 static void
  410 g_raid_tr_raid1_maybe_rebuild(struct g_raid_tr_object *tr,
  411     struct g_raid_subdisk *sd)
  412 {
  413         struct g_raid_volume *vol;
  414         struct g_raid_tr_raid1_object *trs;
  415         int na, nr;
  416         
  417         /*
  418          * If we're stopping, don't do anything.  If we don't have at least one
  419          * good disk and one bad disk, we don't do anything.  And if there's a
  420          * 'good disk' stored in the trs, then we're in progress and we punt.
  421          * If we make it past all these checks, we need to rebuild.
  422          */
  423         vol = tr->tro_volume;
  424         trs = (struct g_raid_tr_raid1_object *)tr;
  425         if (trs->trso_stopping)
  426                 return;
  427         na = g_raid_nsubdisks(vol, G_RAID_SUBDISK_S_ACTIVE);
  428         nr = g_raid_nsubdisks(vol, G_RAID_SUBDISK_S_REBUILD) +
  429             g_raid_nsubdisks(vol, G_RAID_SUBDISK_S_RESYNC);
  430         switch(trs->trso_type) {
  431         case TR_RAID1_NONE:
  432                 if (na == 0)
  433                         return;
  434                 if (nr == 0) {
  435                         nr = g_raid_nsubdisks(vol, G_RAID_SUBDISK_S_NEW) +
  436                             g_raid_nsubdisks(vol, G_RAID_SUBDISK_S_STALE) +
  437                             g_raid_nsubdisks(vol, G_RAID_SUBDISK_S_UNINITIALIZED);
  438                         if (nr == 0)
  439                                 return;
  440                 }
  441                 g_raid_tr_raid1_rebuild_start(tr);
  442                 break;
  443         case TR_RAID1_REBUILD:
  444                 if (na == 0 || nr == 0 || trs->trso_failed_sd == sd)
  445                         g_raid_tr_raid1_rebuild_abort(tr);
  446                 break;
  447         case TR_RAID1_RESYNC:
  448                 break;
  449         }
  450 }
  451 
  452 static int
  453 g_raid_tr_event_raid1(struct g_raid_tr_object *tr,
  454     struct g_raid_subdisk *sd, u_int event)
  455 {
  456 
  457         g_raid_tr_update_state_raid1(tr->tro_volume, sd);
  458         return (0);
  459 }
  460 
  461 static int
  462 g_raid_tr_start_raid1(struct g_raid_tr_object *tr)
  463 {
  464         struct g_raid_tr_raid1_object *trs;
  465         struct g_raid_volume *vol;
  466 
  467         trs = (struct g_raid_tr_raid1_object *)tr;
  468         vol = tr->tro_volume;
  469         trs->trso_starting = 0;
  470         g_raid_tr_update_state_raid1(vol, NULL);
  471         return (0);
  472 }
  473 
  474 static int
  475 g_raid_tr_stop_raid1(struct g_raid_tr_object *tr)
  476 {
  477         struct g_raid_tr_raid1_object *trs;
  478         struct g_raid_volume *vol;
  479 
  480         trs = (struct g_raid_tr_raid1_object *)tr;
  481         vol = tr->tro_volume;
  482         trs->trso_starting = 0;
  483         trs->trso_stopping = 1;
  484         g_raid_tr_update_state_raid1(vol, NULL);
  485         return (0);
  486 }
  487 
  488 /*
  489  * Select the disk to read from.  Take into account: subdisk state, running
  490  * error recovery, average disk load, head position and possible cache hits.
  491  */
  492 #define ABS(x)          (((x) >= 0) ? (x) : (-(x)))
  493 static struct g_raid_subdisk *
  494 g_raid_tr_raid1_select_read_disk(struct g_raid_volume *vol, struct bio *bp,
  495     u_int mask)
  496 {
  497         struct g_raid_subdisk *sd, *best;
  498         int i, prio, bestprio;
  499 
  500         best = NULL;
  501         bestprio = INT_MAX;
  502         for (i = 0; i < vol->v_disks_count; i++) {
  503                 sd = &vol->v_subdisks[i];
  504                 if (sd->sd_state != G_RAID_SUBDISK_S_ACTIVE &&
  505                     ((sd->sd_state != G_RAID_SUBDISK_S_REBUILD &&
  506                       sd->sd_state != G_RAID_SUBDISK_S_RESYNC) ||
  507                      bp->bio_offset + bp->bio_length > sd->sd_rebuild_pos))
  508                         continue;
  509                 if ((mask & (1 << i)) != 0)
  510                         continue;
  511                 prio = G_RAID_SUBDISK_LOAD(sd);
  512                 prio += min(sd->sd_recovery, 255) << 22;
  513                 prio += (G_RAID_SUBDISK_S_ACTIVE - sd->sd_state) << 16;
  514                 /* If disk head is precisely in position - highly prefer it. */
  515                 if (G_RAID_SUBDISK_POS(sd) == bp->bio_offset)
  516                         prio -= 2 * G_RAID_SUBDISK_LOAD_SCALE;
  517                 else
  518                 /* If disk head is close to position - prefer it. */
  519                 if (ABS(G_RAID_SUBDISK_POS(sd) - bp->bio_offset) <
  520                     G_RAID_SUBDISK_TRACK_SIZE)
  521                         prio -= 1 * G_RAID_SUBDISK_LOAD_SCALE;
  522                 if (prio < bestprio) {
  523                         best = sd;
  524                         bestprio = prio;
  525                 }
  526         }
  527         return (best);
  528 }
  529 
  530 static void
  531 g_raid_tr_iostart_raid1_read(struct g_raid_tr_object *tr, struct bio *bp)
  532 {
  533         struct g_raid_subdisk *sd;
  534         struct bio *cbp;
  535 
  536         sd = g_raid_tr_raid1_select_read_disk(tr->tro_volume, bp, 0);
  537         KASSERT(sd != NULL, ("No active disks in volume %s.",
  538                 tr->tro_volume->v_name));
  539 
  540         cbp = g_clone_bio(bp);
  541         if (cbp == NULL) {
  542                 g_raid_iodone(bp, ENOMEM);
  543                 return;
  544         }
  545 
  546         g_raid_subdisk_iostart(sd, cbp);
  547 }
  548 
  549 static void
  550 g_raid_tr_iostart_raid1_write(struct g_raid_tr_object *tr, struct bio *bp)
  551 {
  552         struct g_raid_volume *vol;
  553         struct g_raid_subdisk *sd;
  554         struct bio_queue_head queue;
  555         struct bio *cbp;
  556         int i;
  557 
  558         vol = tr->tro_volume;
  559 
  560         /*
  561          * Allocate all bios before sending any request, so we can return
  562          * ENOMEM in nice and clean way.
  563          */
  564         bioq_init(&queue);
  565         for (i = 0; i < vol->v_disks_count; i++) {
  566                 sd = &vol->v_subdisks[i];
  567                 switch (sd->sd_state) {
  568                 case G_RAID_SUBDISK_S_ACTIVE:
  569                         break;
  570                 case G_RAID_SUBDISK_S_REBUILD:
  571                         /*
  572                          * When rebuilding, only part of this subdisk is
  573                          * writable, the rest will be written as part of the
  574                          * that process.
  575                          */
  576                         if (bp->bio_offset >= sd->sd_rebuild_pos)
  577                                 continue;
  578                         break;
  579                 case G_RAID_SUBDISK_S_STALE:
  580                 case G_RAID_SUBDISK_S_RESYNC:
  581                         /*
  582                          * Resyncing still writes on the theory that the
  583                          * resync'd disk is very close and writing it will
  584                          * keep it that way better if we keep up while
  585                          * resyncing.
  586                          */
  587                         break;
  588                 default:
  589                         continue;
  590                 }
  591                 cbp = g_clone_bio(bp);
  592                 if (cbp == NULL)
  593                         goto failure;
  594                 cbp->bio_caller1 = sd;
  595                 bioq_insert_tail(&queue, cbp);
  596         }
  597         for (cbp = bioq_first(&queue); cbp != NULL;
  598             cbp = bioq_first(&queue)) {
  599                 bioq_remove(&queue, cbp);
  600                 sd = cbp->bio_caller1;
  601                 cbp->bio_caller1 = NULL;
  602                 g_raid_subdisk_iostart(sd, cbp);
  603         }
  604         return;
  605 failure:
  606         for (cbp = bioq_first(&queue); cbp != NULL;
  607             cbp = bioq_first(&queue)) {
  608                 bioq_remove(&queue, cbp);
  609                 g_destroy_bio(cbp);
  610         }
  611         if (bp->bio_error == 0)
  612                 bp->bio_error = ENOMEM;
  613         g_raid_iodone(bp, bp->bio_error);
  614 }
  615 
  616 static void
  617 g_raid_tr_iostart_raid1(struct g_raid_tr_object *tr, struct bio *bp)
  618 {
  619         struct g_raid_volume *vol;
  620         struct g_raid_tr_raid1_object *trs;
  621 
  622         vol = tr->tro_volume;
  623         trs = (struct g_raid_tr_raid1_object *)tr;
  624         if (vol->v_state != G_RAID_VOLUME_S_OPTIMAL &&
  625             vol->v_state != G_RAID_VOLUME_S_SUBOPTIMAL &&
  626             vol->v_state != G_RAID_VOLUME_S_DEGRADED) {
  627                 g_raid_iodone(bp, EIO);
  628                 return;
  629         }
  630         /*
  631          * If we're rebuilding, squeeze in rebuild activity every so often,
  632          * even when the disk is busy.  Be sure to only count real I/O
  633          * to the disk.  All 'SPECIAL' I/O is traffic generated to the disk
  634          * by this module.
  635          */
  636         if (trs->trso_failed_sd != NULL &&
  637             !(bp->bio_cflags & G_RAID_BIO_FLAG_SPECIAL)) {
  638                 /* Make this new or running now round short. */
  639                 trs->trso_recover_slabs = 0;
  640                 if (--trs->trso_fair_io <= 0) {
  641                         trs->trso_fair_io = g_raid1_rebuild_fair_io;
  642                         g_raid_tr_raid1_rebuild_some(tr);
  643                 }
  644         }
  645         switch (bp->bio_cmd) {
  646         case BIO_READ:
  647                 g_raid_tr_iostart_raid1_read(tr, bp);
  648                 break;
  649         case BIO_WRITE:
  650         case BIO_DELETE:
  651                 g_raid_tr_iostart_raid1_write(tr, bp);
  652                 break;
  653         case BIO_FLUSH:
  654                 g_raid_tr_flush_common(tr, bp);
  655                 break;
  656         default:
  657                 KASSERT(1 == 0, ("Invalid command here: %u (volume=%s)",
  658                     bp->bio_cmd, vol->v_name));
  659                 break;
  660         }
  661 }
  662 
  663 static void
  664 g_raid_tr_iodone_raid1(struct g_raid_tr_object *tr,
  665     struct g_raid_subdisk *sd, struct bio *bp)
  666 {
  667         struct bio *cbp;
  668         struct g_raid_subdisk *nsd;
  669         struct g_raid_volume *vol;
  670         struct bio *pbp;
  671         struct g_raid_tr_raid1_object *trs;
  672         uintptr_t *mask;
  673         int error, do_write;
  674 
  675         trs = (struct g_raid_tr_raid1_object *)tr;
  676         vol = tr->tro_volume;
  677         if (bp->bio_cflags & G_RAID_BIO_FLAG_SYNC) {
  678                 /*
  679                  * This operation is part of a rebuild or resync operation.
  680                  * See what work just got done, then schedule the next bit of
  681                  * work, if any.  Rebuild/resync is done a little bit at a
  682                  * time.  Either when a timeout happens, or after we get a
  683                  * bunch of I/Os to the disk (to make sure an active system
  684                  * will complete in a sane amount of time).
  685                  *
  686                  * We are setup to do differing amounts of work for each of
  687                  * these cases.  so long as the slabs is smallish (less than
  688                  * 50 or so, I'd guess, but that's just a WAG), we shouldn't
  689                  * have any bio starvation issues.  For active disks, we do
  690                  * 5MB of data, for inactive ones, we do 50MB.
  691                  */
  692                 if (trs->trso_type == TR_RAID1_REBUILD) {
  693                         if (bp->bio_cmd == BIO_READ) {
  694 
  695                                 /* Immediately abort rebuild, if requested. */
  696                                 if (trs->trso_flags & TR_RAID1_F_ABORT) {
  697                                         trs->trso_flags &= ~TR_RAID1_F_DOING_SOME;
  698                                         g_raid_tr_raid1_rebuild_abort(tr);
  699                                         return;
  700                                 }
  701 
  702                                 /* On read error, skip and cross fingers. */
  703                                 if (bp->bio_error != 0) {
  704                                         G_RAID_LOGREQ(0, bp,
  705                                             "Read error during rebuild (%d), "
  706                                             "possible data loss!",
  707                                             bp->bio_error);
  708                                         goto rebuild_round_done;
  709                                 }
  710 
  711                                 /*
  712                                  * The read operation finished, queue the
  713                                  * write and get out.
  714                                  */
  715                                 G_RAID_LOGREQ(4, bp, "rebuild read done. %d",
  716                                     bp->bio_error);
  717                                 bp->bio_cmd = BIO_WRITE;
  718                                 bp->bio_cflags = G_RAID_BIO_FLAG_SYNC;
  719                                 G_RAID_LOGREQ(4, bp, "Queueing rebuild write.");
  720                                 g_raid_subdisk_iostart(trs->trso_failed_sd, bp);
  721                         } else {
  722                                 /*
  723                                  * The write operation just finished.  Do
  724                                  * another.  We keep cloning the master bio
  725                                  * since it has the right buffers allocated to
  726                                  * it.
  727                                  */
  728                                 G_RAID_LOGREQ(4, bp,
  729                                     "rebuild write done. Error %d",
  730                                     bp->bio_error);
  731                                 nsd = trs->trso_failed_sd;
  732                                 if (bp->bio_error != 0 ||
  733                                     trs->trso_flags & TR_RAID1_F_ABORT) {
  734                                         if ((trs->trso_flags &
  735                                             TR_RAID1_F_ABORT) == 0) {
  736                                                 g_raid_tr_raid1_fail_disk(sd->sd_softc,
  737                                                     nsd, nsd->sd_disk);
  738                                         }
  739                                         trs->trso_flags &= ~TR_RAID1_F_DOING_SOME;
  740                                         g_raid_tr_raid1_rebuild_abort(tr);
  741                                         return;
  742                                 }
  743 rebuild_round_done:
  744                                 nsd = trs->trso_failed_sd;
  745                                 trs->trso_flags &= ~TR_RAID1_F_LOCKED;
  746                                 g_raid_unlock_range(sd->sd_volume,
  747                                     bp->bio_offset, bp->bio_length);
  748                                 nsd->sd_rebuild_pos += bp->bio_length;
  749                                 if (nsd->sd_rebuild_pos >= nsd->sd_size) {
  750                                         g_raid_tr_raid1_rebuild_finish(tr);
  751                                         return;
  752                                 }
  753 
  754                                 /* Abort rebuild if we are stopping */
  755                                 if (trs->trso_stopping) {
  756                                         trs->trso_flags &= ~TR_RAID1_F_DOING_SOME;
  757                                         g_raid_tr_raid1_rebuild_abort(tr);
  758                                         return;
  759                                 }
  760 
  761                                 if (--trs->trso_meta_update <= 0) {
  762                                         g_raid_write_metadata(vol->v_softc,
  763                                             vol, nsd, nsd->sd_disk);
  764                                         trs->trso_meta_update =
  765                                             g_raid1_rebuild_meta_update;
  766                                 }
  767                                 trs->trso_flags &= ~TR_RAID1_F_DOING_SOME;
  768                                 if (--trs->trso_recover_slabs <= 0)
  769                                         return;
  770                                 g_raid_tr_raid1_rebuild_some(tr);
  771                         }
  772                 } else if (trs->trso_type == TR_RAID1_RESYNC) {
  773                         /*
  774                          * read good sd, read bad sd in parallel.  when both
  775                          * done, compare the buffers.  write good to the bad
  776                          * if different.  do the next bit of work.
  777                          */
  778                         panic("Somehow, we think we're doing a resync");
  779                 }
  780                 return;
  781         }
  782         pbp = bp->bio_parent;
  783         pbp->bio_inbed++;
  784         if (bp->bio_cmd == BIO_READ && bp->bio_error != 0) {
  785                 /*
  786                  * Read failed on first drive.  Retry the read error on
  787                  * another disk drive, if available, before erroring out the
  788                  * read.
  789                  */
  790                 sd->sd_disk->d_read_errs++;
  791                 G_RAID_LOGREQ(0, bp,
  792                     "Read error (%d), %d read errors total",
  793                     bp->bio_error, sd->sd_disk->d_read_errs);
  794 
  795                 /*
  796                  * If there are too many read errors, we move to degraded.
  797                  * XXX Do we want to FAIL the drive (eg, make the user redo
  798                  * everything to get it back in sync), or just degrade the
  799                  * drive, which kicks off a resync?
  800                  */
  801                 do_write = 1;
  802                 if (sd->sd_disk->d_read_errs > g_raid_read_err_thresh) {
  803                         g_raid_tr_raid1_fail_disk(sd->sd_softc, sd, sd->sd_disk);
  804                         if (pbp->bio_children == 1)
  805                                 do_write = 0;
  806                 }
  807 
  808                 /*
  809                  * Find the other disk, and try to do the I/O to it.
  810                  */
  811                 mask = (uintptr_t *)(&pbp->bio_driver2);
  812                 if (pbp->bio_children == 1) {
  813                         /* Save original subdisk. */
  814                         pbp->bio_driver1 = do_write ? sd : NULL;
  815                         *mask = 0;
  816                 }
  817                 *mask |= 1 << sd->sd_pos;
  818                 nsd = g_raid_tr_raid1_select_read_disk(vol, pbp, *mask);
  819                 if (nsd != NULL && (cbp = g_clone_bio(pbp)) != NULL) {
  820                         g_destroy_bio(bp);
  821                         G_RAID_LOGREQ(2, cbp, "Retrying read from %d",
  822                             nsd->sd_pos);
  823                         if (pbp->bio_children == 2 && do_write) {
  824                                 sd->sd_recovery++;
  825                                 cbp->bio_caller1 = nsd;
  826                                 pbp->bio_pflags = G_RAID_BIO_FLAG_LOCKED;
  827                                 /* Lock callback starts I/O */
  828                                 g_raid_lock_range(sd->sd_volume,
  829                                     cbp->bio_offset, cbp->bio_length, pbp, cbp);
  830                         } else {
  831                                 g_raid_subdisk_iostart(nsd, cbp);
  832                         }
  833                         return;
  834                 }
  835                 /*
  836                  * We can't retry.  Return the original error by falling
  837                  * through.  This will happen when there's only one good disk.
  838                  * We don't need to fail the raid, since its actual state is
  839                  * based on the state of the subdisks.
  840                  */
  841                 G_RAID_LOGREQ(2, bp, "Couldn't retry read, failing it");
  842         }
  843         if (bp->bio_cmd == BIO_READ &&
  844             bp->bio_error == 0 &&
  845             pbp->bio_children > 1 &&
  846             pbp->bio_driver1 != NULL) {
  847                 /*
  848                  * If it was a read, and bio_children is >1, then we just
  849                  * recovered the data from the second drive.  We should try to
  850                  * write that data to the first drive if sector remapping is
  851                  * enabled.  A write should put the data in a new place on the
  852                  * disk, remapping the bad sector.  Do we need to do that by
  853                  * queueing a request to the main worker thread?  It doesn't
  854                  * affect the return code of this current read, and can be
  855                  * done at our liesure.  However, to make the code simpler, it
  856                  * is done syncrhonously.
  857                  */
  858                 G_RAID_LOGREQ(3, bp, "Recovered data from other drive");
  859                 cbp = g_clone_bio(pbp);
  860                 if (cbp != NULL) {
  861                         g_destroy_bio(bp);
  862                         cbp->bio_cmd = BIO_WRITE;
  863                         cbp->bio_cflags = G_RAID_BIO_FLAG_REMAP;
  864                         G_RAID_LOGREQ(2, cbp,
  865                             "Attempting bad sector remap on failing drive.");
  866                         g_raid_subdisk_iostart(pbp->bio_driver1, cbp);
  867                         return;
  868                 }
  869         }
  870         if (pbp->bio_pflags & G_RAID_BIO_FLAG_LOCKED) {
  871                 /*
  872                  * We're done with a recovery, mark the range as unlocked.
  873                  * For any write errors, we agressively fail the disk since
  874                  * there was both a READ and a WRITE error at this location.
  875                  * Both types of errors generally indicates the drive is on
  876                  * the verge of total failure anyway.  Better to stop trusting
  877                  * it now.  However, we need to reset error to 0 in that case
  878                  * because we're not failing the original I/O which succeeded.
  879                  */
  880                 if (bp->bio_cmd == BIO_WRITE && bp->bio_error) {
  881                         G_RAID_LOGREQ(0, bp, "Remap write failed: "
  882                             "failing subdisk.");
  883                         g_raid_tr_raid1_fail_disk(sd->sd_softc, sd, sd->sd_disk);
  884                         bp->bio_error = 0;
  885                 }
  886                 if (pbp->bio_driver1 != NULL) {
  887                         ((struct g_raid_subdisk *)pbp->bio_driver1)
  888                             ->sd_recovery--;
  889                 }
  890                 G_RAID_LOGREQ(2, bp, "REMAP done %d.", bp->bio_error);
  891                 g_raid_unlock_range(sd->sd_volume, bp->bio_offset,
  892                     bp->bio_length);
  893         }
  894         if (pbp->bio_cmd != BIO_READ) {
  895                 if (pbp->bio_inbed == 1 || pbp->bio_error != 0)
  896                         pbp->bio_error = bp->bio_error;
  897                 if (pbp->bio_cmd == BIO_WRITE && bp->bio_error != 0) {
  898                         G_RAID_LOGREQ(0, bp, "Write failed: failing subdisk.");
  899                         g_raid_tr_raid1_fail_disk(sd->sd_softc, sd, sd->sd_disk);
  900                 }
  901                 error = pbp->bio_error;
  902         } else
  903                 error = bp->bio_error;
  904         g_destroy_bio(bp);
  905         if (pbp->bio_children == pbp->bio_inbed) {
  906                 pbp->bio_completed = pbp->bio_length;
  907                 g_raid_iodone(pbp, error);
  908         }
  909 }
  910 
  911 static int
  912 g_raid_tr_kerneldump_raid1(struct g_raid_tr_object *tr,
  913     void *virtual, vm_offset_t physical, off_t offset, size_t length)
  914 {
  915         struct g_raid_volume *vol;
  916         struct g_raid_subdisk *sd;
  917         int error, i, ok;
  918 
  919         vol = tr->tro_volume;
  920         error = 0;
  921         ok = 0;
  922         for (i = 0; i < vol->v_disks_count; i++) {
  923                 sd = &vol->v_subdisks[i];
  924                 switch (sd->sd_state) {
  925                 case G_RAID_SUBDISK_S_ACTIVE:
  926                         break;
  927                 case G_RAID_SUBDISK_S_REBUILD:
  928                         /*
  929                          * When rebuilding, only part of this subdisk is
  930                          * writable, the rest will be written as part of the
  931                          * that process.
  932                          */
  933                         if (offset >= sd->sd_rebuild_pos)
  934                                 continue;
  935                         break;
  936                 case G_RAID_SUBDISK_S_STALE:
  937                 case G_RAID_SUBDISK_S_RESYNC:
  938                         /*
  939                          * Resyncing still writes on the theory that the
  940                          * resync'd disk is very close and writing it will
  941                          * keep it that way better if we keep up while
  942                          * resyncing.
  943                          */
  944                         break;
  945                 default:
  946                         continue;
  947                 }
  948                 error = g_raid_subdisk_kerneldump(sd,
  949                     virtual, physical, offset, length);
  950                 if (error == 0)
  951                         ok++;
  952         }
  953         return (ok > 0 ? 0 : error);
  954 }
  955 
  956 static int
  957 g_raid_tr_locked_raid1(struct g_raid_tr_object *tr, void *argp)
  958 {
  959         struct bio *bp;
  960         struct g_raid_subdisk *sd;
  961 
  962         bp = (struct bio *)argp;
  963         sd = (struct g_raid_subdisk *)bp->bio_caller1;
  964         g_raid_subdisk_iostart(sd, bp);
  965 
  966         return (0);
  967 }
  968 
  969 static int
  970 g_raid_tr_idle_raid1(struct g_raid_tr_object *tr)
  971 {
  972         struct g_raid_tr_raid1_object *trs;
  973 
  974         trs = (struct g_raid_tr_raid1_object *)tr;
  975         trs->trso_fair_io = g_raid1_rebuild_fair_io;
  976         trs->trso_recover_slabs = g_raid1_rebuild_cluster_idle;
  977         if (trs->trso_type == TR_RAID1_REBUILD)
  978                 g_raid_tr_raid1_rebuild_some(tr);
  979         return (0);
  980 }
  981 
  982 static int
  983 g_raid_tr_free_raid1(struct g_raid_tr_object *tr)
  984 {
  985         struct g_raid_tr_raid1_object *trs;
  986 
  987         trs = (struct g_raid_tr_raid1_object *)tr;
  988 
  989         if (trs->trso_buffer != NULL) {
  990                 free(trs->trso_buffer, M_TR_RAID1);
  991                 trs->trso_buffer = NULL;
  992         }
  993         return (0);
  994 }
  995 
  996 G_RAID_TR_DECLARE(raid1, "RAID1");

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