The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/boot/zfs/zfsimpl.c

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    1 /*-
    2  * Copyright (c) 2007 Doug Rabson
    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 AUTHOR 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 AUTHOR 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("$FreeBSD$");
   29 
   30 /*
   31  *      Stand-alone ZFS file reader.
   32  */
   33 
   34 #include <sys/stat.h>
   35 #include <sys/stdint.h>
   36 
   37 #include "zfsimpl.h"
   38 #include "zfssubr.c"
   39 
   40 
   41 struct zfsmount {
   42         const spa_t     *spa;
   43         objset_phys_t   objset;
   44         uint64_t        rootobj;
   45 };
   46 
   47 /*
   48  * List of all vdevs, chained through v_alllink.
   49  */
   50 static vdev_list_t zfs_vdevs;
   51 
   52  /*
   53  * List of ZFS features supported for read
   54  */
   55 static const char *features_for_read[] = {
   56         "org.illumos:lz4_compress",
   57         "com.delphix:hole_birth",
   58         "com.delphix:extensible_dataset",
   59         NULL
   60 };
   61 
   62 /*
   63  * List of all pools, chained through spa_link.
   64  */
   65 static spa_list_t zfs_pools;
   66 
   67 static uint64_t zfs_crc64_table[256];
   68 static const dnode_phys_t *dnode_cache_obj = 0;
   69 static uint64_t dnode_cache_bn;
   70 static char *dnode_cache_buf;
   71 static char *zap_scratch;
   72 static char *zfs_temp_buf, *zfs_temp_end, *zfs_temp_ptr;
   73 
   74 #define TEMP_SIZE       (1024 * 1024)
   75 
   76 static int zio_read(const spa_t *spa, const blkptr_t *bp, void *buf);
   77 static int zfs_get_root(const spa_t *spa, uint64_t *objid);
   78 static int zfs_rlookup(const spa_t *spa, uint64_t objnum, char *result);
   79 
   80 static void
   81 zfs_init(void)
   82 {
   83         STAILQ_INIT(&zfs_vdevs);
   84         STAILQ_INIT(&zfs_pools);
   85 
   86         zfs_temp_buf = malloc(TEMP_SIZE);
   87         zfs_temp_end = zfs_temp_buf + TEMP_SIZE;
   88         zfs_temp_ptr = zfs_temp_buf;
   89         dnode_cache_buf = malloc(SPA_MAXBLOCKSIZE);
   90         zap_scratch = malloc(SPA_MAXBLOCKSIZE);
   91 
   92         zfs_init_crc();
   93 }
   94 
   95 static void *
   96 zfs_alloc(size_t size)
   97 {
   98         char *ptr;
   99 
  100         if (zfs_temp_ptr + size > zfs_temp_end) {
  101                 printf("ZFS: out of temporary buffer space\n");
  102                 for (;;) ;
  103         }
  104         ptr = zfs_temp_ptr;
  105         zfs_temp_ptr += size;
  106 
  107         return (ptr);
  108 }
  109 
  110 static void
  111 zfs_free(void *ptr, size_t size)
  112 {
  113 
  114         zfs_temp_ptr -= size;
  115         if (zfs_temp_ptr != ptr) {
  116                 printf("ZFS: zfs_alloc()/zfs_free() mismatch\n");
  117                 for (;;) ;
  118         }
  119 }
  120 
  121 static int
  122 xdr_int(const unsigned char **xdr, int *ip)
  123 {
  124         *ip = ((*xdr)[0] << 24)
  125                 | ((*xdr)[1] << 16)
  126                 | ((*xdr)[2] << 8)
  127                 | ((*xdr)[3] << 0);
  128         (*xdr) += 4;
  129         return (0);
  130 }
  131 
  132 static int
  133 xdr_u_int(const unsigned char **xdr, u_int *ip)
  134 {
  135         *ip = ((*xdr)[0] << 24)
  136                 | ((*xdr)[1] << 16)
  137                 | ((*xdr)[2] << 8)
  138                 | ((*xdr)[3] << 0);
  139         (*xdr) += 4;
  140         return (0);
  141 }
  142 
  143 static int
  144 xdr_uint64_t(const unsigned char **xdr, uint64_t *lp)
  145 {
  146         u_int hi, lo;
  147 
  148         xdr_u_int(xdr, &hi);
  149         xdr_u_int(xdr, &lo);
  150         *lp = (((uint64_t) hi) << 32) | lo;
  151         return (0);
  152 }
  153 
  154 static int
  155 nvlist_find(const unsigned char *nvlist, const char *name, int type,
  156             int* elementsp, void *valuep)
  157 {
  158         const unsigned char *p, *pair;
  159         int junk;
  160         int encoded_size, decoded_size;
  161 
  162         p = nvlist;
  163         xdr_int(&p, &junk);
  164         xdr_int(&p, &junk);
  165 
  166         pair = p;
  167         xdr_int(&p, &encoded_size);
  168         xdr_int(&p, &decoded_size);
  169         while (encoded_size && decoded_size) {
  170                 int namelen, pairtype, elements;
  171                 const char *pairname;
  172 
  173                 xdr_int(&p, &namelen);
  174                 pairname = (const char*) p;
  175                 p += roundup(namelen, 4);
  176                 xdr_int(&p, &pairtype);
  177 
  178                 if (!memcmp(name, pairname, namelen) && type == pairtype) {
  179                         xdr_int(&p, &elements);
  180                         if (elementsp)
  181                                 *elementsp = elements;
  182                         if (type == DATA_TYPE_UINT64) {
  183                                 xdr_uint64_t(&p, (uint64_t *) valuep);
  184                                 return (0);
  185                         } else if (type == DATA_TYPE_STRING) {
  186                                 int len;
  187                                 xdr_int(&p, &len);
  188                                 (*(const char**) valuep) = (const char*) p;
  189                                 return (0);
  190                         } else if (type == DATA_TYPE_NVLIST
  191                                    || type == DATA_TYPE_NVLIST_ARRAY) {
  192                                 (*(const unsigned char**) valuep) =
  193                                          (const unsigned char*) p;
  194                                 return (0);
  195                         } else {
  196                                 return (EIO);
  197                         }
  198                 } else {
  199                         /*
  200                          * Not the pair we are looking for, skip to the next one.
  201                          */
  202                         p = pair + encoded_size;
  203                 }
  204 
  205                 pair = p;
  206                 xdr_int(&p, &encoded_size);
  207                 xdr_int(&p, &decoded_size);
  208         }
  209 
  210         return (EIO);
  211 }
  212 
  213 static int
  214 nvlist_check_features_for_read(const unsigned char *nvlist)
  215 {
  216         const unsigned char *p, *pair;
  217         int junk;
  218         int encoded_size, decoded_size;
  219         int rc;
  220 
  221         rc = 0;
  222 
  223         p = nvlist;
  224         xdr_int(&p, &junk);
  225         xdr_int(&p, &junk);
  226 
  227         pair = p;
  228         xdr_int(&p, &encoded_size);
  229         xdr_int(&p, &decoded_size);
  230         while (encoded_size && decoded_size) {
  231                 int namelen, pairtype;
  232                 const char *pairname;
  233                 int i, found;
  234 
  235                 found = 0;
  236 
  237                 xdr_int(&p, &namelen);
  238                 pairname = (const char*) p;
  239                 p += roundup(namelen, 4);
  240                 xdr_int(&p, &pairtype);
  241 
  242                 for (i = 0; features_for_read[i] != NULL; i++) {
  243                         if (!memcmp(pairname, features_for_read[i], namelen)) {
  244                                 found = 1;
  245                                 break;
  246                         }
  247                 }
  248 
  249                 if (!found) {
  250                         printf("ZFS: unsupported feature: %s\n", pairname);
  251                         rc = EIO;
  252                 }
  253 
  254                 p = pair + encoded_size;
  255 
  256                 pair = p;
  257                 xdr_int(&p, &encoded_size);
  258                 xdr_int(&p, &decoded_size);
  259         }
  260 
  261         return (rc);
  262 }
  263 
  264 /*
  265  * Return the next nvlist in an nvlist array.
  266  */
  267 static const unsigned char *
  268 nvlist_next(const unsigned char *nvlist)
  269 {
  270         const unsigned char *p, *pair;
  271         int junk;
  272         int encoded_size, decoded_size;
  273 
  274         p = nvlist;
  275         xdr_int(&p, &junk);
  276         xdr_int(&p, &junk);
  277 
  278         pair = p;
  279         xdr_int(&p, &encoded_size);
  280         xdr_int(&p, &decoded_size);
  281         while (encoded_size && decoded_size) {
  282                 p = pair + encoded_size;
  283 
  284                 pair = p;
  285                 xdr_int(&p, &encoded_size);
  286                 xdr_int(&p, &decoded_size);
  287         }
  288 
  289         return p;
  290 }
  291 
  292 #ifdef TEST
  293 
  294 static const unsigned char *
  295 nvlist_print(const unsigned char *nvlist, unsigned int indent)
  296 {
  297         static const char* typenames[] = {
  298                 "DATA_TYPE_UNKNOWN",
  299                 "DATA_TYPE_BOOLEAN",
  300                 "DATA_TYPE_BYTE",
  301                 "DATA_TYPE_INT16",
  302                 "DATA_TYPE_UINT16",
  303                 "DATA_TYPE_INT32",
  304                 "DATA_TYPE_UINT32",
  305                 "DATA_TYPE_INT64",
  306                 "DATA_TYPE_UINT64",
  307                 "DATA_TYPE_STRING",
  308                 "DATA_TYPE_BYTE_ARRAY",
  309                 "DATA_TYPE_INT16_ARRAY",
  310                 "DATA_TYPE_UINT16_ARRAY",
  311                 "DATA_TYPE_INT32_ARRAY",
  312                 "DATA_TYPE_UINT32_ARRAY",
  313                 "DATA_TYPE_INT64_ARRAY",
  314                 "DATA_TYPE_UINT64_ARRAY",
  315                 "DATA_TYPE_STRING_ARRAY",
  316                 "DATA_TYPE_HRTIME",
  317                 "DATA_TYPE_NVLIST",
  318                 "DATA_TYPE_NVLIST_ARRAY",
  319                 "DATA_TYPE_BOOLEAN_VALUE",
  320                 "DATA_TYPE_INT8",
  321                 "DATA_TYPE_UINT8",
  322                 "DATA_TYPE_BOOLEAN_ARRAY",
  323                 "DATA_TYPE_INT8_ARRAY",
  324                 "DATA_TYPE_UINT8_ARRAY"
  325         };
  326 
  327         unsigned int i, j;
  328         const unsigned char *p, *pair;
  329         int junk;
  330         int encoded_size, decoded_size;
  331 
  332         p = nvlist;
  333         xdr_int(&p, &junk);
  334         xdr_int(&p, &junk);
  335 
  336         pair = p;
  337         xdr_int(&p, &encoded_size);
  338         xdr_int(&p, &decoded_size);
  339         while (encoded_size && decoded_size) {
  340                 int namelen, pairtype, elements;
  341                 const char *pairname;
  342 
  343                 xdr_int(&p, &namelen);
  344                 pairname = (const char*) p;
  345                 p += roundup(namelen, 4);
  346                 xdr_int(&p, &pairtype);
  347 
  348                 for (i = 0; i < indent; i++)
  349                         printf(" ");
  350                 printf("%s %s", typenames[pairtype], pairname);
  351 
  352                 xdr_int(&p, &elements);
  353                 switch (pairtype) {
  354                 case DATA_TYPE_UINT64: {
  355                         uint64_t val;
  356                         xdr_uint64_t(&p, &val);
  357                         printf(" = 0x%jx\n", (uintmax_t)val);
  358                         break;
  359                 }
  360 
  361                 case DATA_TYPE_STRING: {
  362                         int len;
  363                         xdr_int(&p, &len);
  364                         printf(" = \"%s\"\n", p);
  365                         break;
  366                 }
  367 
  368                 case DATA_TYPE_NVLIST:
  369                         printf("\n");
  370                         nvlist_print(p, indent + 1);
  371                         break;
  372 
  373                 case DATA_TYPE_NVLIST_ARRAY:
  374                         for (j = 0; j < elements; j++) {
  375                                 printf("[%d]\n", j);
  376                                 p = nvlist_print(p, indent + 1);
  377                                 if (j != elements - 1) {
  378                                         for (i = 0; i < indent; i++)
  379                                                 printf(" ");
  380                                         printf("%s %s", typenames[pairtype], pairname);
  381                                 }
  382                         }
  383                         break;
  384 
  385                 default:
  386                         printf("\n");
  387                 }
  388 
  389                 p = pair + encoded_size;
  390 
  391                 pair = p;
  392                 xdr_int(&p, &encoded_size);
  393                 xdr_int(&p, &decoded_size);
  394         }
  395 
  396         return p;
  397 }
  398 
  399 #endif
  400 
  401 static int
  402 vdev_read_phys(vdev_t *vdev, const blkptr_t *bp, void *buf,
  403     off_t offset, size_t size)
  404 {
  405         size_t psize;
  406         int rc;
  407 
  408         if (!vdev->v_phys_read)
  409                 return (EIO);
  410 
  411         if (bp) {
  412                 psize = BP_GET_PSIZE(bp);
  413         } else {
  414                 psize = size;
  415         }
  416 
  417         /*printf("ZFS: reading %d bytes at 0x%jx to %p\n", psize, (uintmax_t)offset, buf);*/
  418         rc = vdev->v_phys_read(vdev, vdev->v_read_priv, offset, buf, psize);
  419         if (rc)
  420                 return (rc);
  421         if (bp && zio_checksum_verify(bp, buf))
  422                 return (EIO);
  423 
  424         return (0);
  425 }
  426 
  427 static int
  428 vdev_disk_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
  429     off_t offset, size_t bytes)
  430 {
  431 
  432         return (vdev_read_phys(vdev, bp, buf,
  433                 offset + VDEV_LABEL_START_SIZE, bytes));
  434 }
  435 
  436 
  437 static int
  438 vdev_mirror_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
  439     off_t offset, size_t bytes)
  440 {
  441         vdev_t *kid;
  442         int rc;
  443 
  444         rc = EIO;
  445         STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
  446                 if (kid->v_state != VDEV_STATE_HEALTHY)
  447                         continue;
  448                 rc = kid->v_read(kid, bp, buf, offset, bytes);
  449                 if (!rc)
  450                         return (0);
  451         }
  452 
  453         return (rc);
  454 }
  455 
  456 static int
  457 vdev_replacing_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
  458     off_t offset, size_t bytes)
  459 {
  460         vdev_t *kid;
  461 
  462         /*
  463          * Here we should have two kids:
  464          * First one which is the one we are replacing and we can trust
  465          * only this one to have valid data, but it might not be present.
  466          * Second one is that one we are replacing with. It is most likely
  467          * healthy, but we can't trust it has needed data, so we won't use it.
  468          */
  469         kid = STAILQ_FIRST(&vdev->v_children);
  470         if (kid == NULL)
  471                 return (EIO);
  472         if (kid->v_state != VDEV_STATE_HEALTHY)
  473                 return (EIO);
  474         return (kid->v_read(kid, bp, buf, offset, bytes));
  475 }
  476 
  477 static vdev_t *
  478 vdev_find(uint64_t guid)
  479 {
  480         vdev_t *vdev;
  481 
  482         STAILQ_FOREACH(vdev, &zfs_vdevs, v_alllink)
  483                 if (vdev->v_guid == guid)
  484                         return (vdev);
  485 
  486         return (0);
  487 }
  488 
  489 static vdev_t *
  490 vdev_create(uint64_t guid, vdev_read_t *read)
  491 {
  492         vdev_t *vdev;
  493 
  494         vdev = malloc(sizeof(vdev_t));
  495         memset(vdev, 0, sizeof(vdev_t));
  496         STAILQ_INIT(&vdev->v_children);
  497         vdev->v_guid = guid;
  498         vdev->v_state = VDEV_STATE_OFFLINE;
  499         vdev->v_read = read;
  500         vdev->v_phys_read = 0;
  501         vdev->v_read_priv = 0;
  502         STAILQ_INSERT_TAIL(&zfs_vdevs, vdev, v_alllink);
  503 
  504         return (vdev);
  505 }
  506 
  507 static int
  508 vdev_init_from_nvlist(const unsigned char *nvlist, vdev_t *pvdev,
  509     vdev_t **vdevp, int is_newer)
  510 {
  511         int rc;
  512         uint64_t guid, id, ashift, nparity;
  513         const char *type;
  514         const char *path;
  515         vdev_t *vdev, *kid;
  516         const unsigned char *kids;
  517         int nkids, i, is_new;
  518         uint64_t is_offline, is_faulted, is_degraded, is_removed, isnt_present;
  519 
  520         if (nvlist_find(nvlist, ZPOOL_CONFIG_GUID,
  521                         DATA_TYPE_UINT64, 0, &guid)
  522             || nvlist_find(nvlist, ZPOOL_CONFIG_ID,
  523                            DATA_TYPE_UINT64, 0, &id)
  524             || nvlist_find(nvlist, ZPOOL_CONFIG_TYPE,
  525                            DATA_TYPE_STRING, 0, &type)) {
  526                 printf("ZFS: can't find vdev details\n");
  527                 return (ENOENT);
  528         }
  529 
  530         if (strcmp(type, VDEV_TYPE_MIRROR)
  531             && strcmp(type, VDEV_TYPE_DISK)
  532 #ifdef ZFS_TEST
  533             && strcmp(type, VDEV_TYPE_FILE)
  534 #endif
  535             && strcmp(type, VDEV_TYPE_RAIDZ)
  536             && strcmp(type, VDEV_TYPE_REPLACING)) {
  537                 printf("ZFS: can only boot from disk, mirror, raidz1, raidz2 and raidz3 vdevs\n");
  538                 return (EIO);
  539         }
  540 
  541         is_offline = is_removed = is_faulted = is_degraded = isnt_present = 0;
  542 
  543         nvlist_find(nvlist, ZPOOL_CONFIG_OFFLINE, DATA_TYPE_UINT64, 0,
  544                         &is_offline);
  545         nvlist_find(nvlist, ZPOOL_CONFIG_REMOVED, DATA_TYPE_UINT64, 0,
  546                         &is_removed);
  547         nvlist_find(nvlist, ZPOOL_CONFIG_FAULTED, DATA_TYPE_UINT64, 0,
  548                         &is_faulted);
  549         nvlist_find(nvlist, ZPOOL_CONFIG_DEGRADED, DATA_TYPE_UINT64, 0,
  550                         &is_degraded);
  551         nvlist_find(nvlist, ZPOOL_CONFIG_NOT_PRESENT, DATA_TYPE_UINT64, 0,
  552                         &isnt_present);
  553 
  554         vdev = vdev_find(guid);
  555         if (!vdev) {
  556                 is_new = 1;
  557 
  558                 if (!strcmp(type, VDEV_TYPE_MIRROR))
  559                         vdev = vdev_create(guid, vdev_mirror_read);
  560                 else if (!strcmp(type, VDEV_TYPE_RAIDZ))
  561                         vdev = vdev_create(guid, vdev_raidz_read);
  562                 else if (!strcmp(type, VDEV_TYPE_REPLACING))
  563                         vdev = vdev_create(guid, vdev_replacing_read);
  564                 else
  565                         vdev = vdev_create(guid, vdev_disk_read);
  566 
  567                 vdev->v_id = id;
  568                 vdev->v_top = pvdev != NULL ? pvdev : vdev;
  569                 if (nvlist_find(nvlist, ZPOOL_CONFIG_ASHIFT,
  570                         DATA_TYPE_UINT64, 0, &ashift) == 0)
  571                         vdev->v_ashift = ashift;
  572                 else
  573                         vdev->v_ashift = 0;
  574                 if (nvlist_find(nvlist, ZPOOL_CONFIG_NPARITY,
  575                         DATA_TYPE_UINT64, 0, &nparity) == 0)
  576                         vdev->v_nparity = nparity;
  577                 else
  578                         vdev->v_nparity = 0;
  579                 if (nvlist_find(nvlist, ZPOOL_CONFIG_PATH,
  580                                 DATA_TYPE_STRING, 0, &path) == 0) {
  581                         if (strncmp(path, "/dev/", 5) == 0)
  582                                 path += 5;
  583                         vdev->v_name = strdup(path);
  584                 } else {
  585                         if (!strcmp(type, "raidz")) {
  586                                 if (vdev->v_nparity == 1)
  587                                         vdev->v_name = "raidz1";
  588                                 else if (vdev->v_nparity == 2)
  589                                         vdev->v_name = "raidz2";
  590                                 else if (vdev->v_nparity == 3)
  591                                         vdev->v_name = "raidz3";
  592                                 else {
  593                                         printf("ZFS: can only boot from disk, mirror, raidz1, raidz2 and raidz3 vdevs\n");
  594                                         return (EIO);
  595                                 }
  596                         } else {
  597                                 vdev->v_name = strdup(type);
  598                         }
  599                 }
  600         } else {
  601                 is_new = 0;
  602         }
  603 
  604         if (is_new || is_newer) {
  605                 /*
  606                  * This is either new vdev or we've already seen this vdev,
  607                  * but from an older vdev label, so let's refresh its state
  608                  * from the newer label.
  609                  */
  610                 if (is_offline)
  611                         vdev->v_state = VDEV_STATE_OFFLINE;
  612                 else if (is_removed)
  613                         vdev->v_state = VDEV_STATE_REMOVED;
  614                 else if (is_faulted)
  615                         vdev->v_state = VDEV_STATE_FAULTED;
  616                 else if (is_degraded)
  617                         vdev->v_state = VDEV_STATE_DEGRADED;
  618                 else if (isnt_present)
  619                         vdev->v_state = VDEV_STATE_CANT_OPEN;
  620         }
  621 
  622         rc = nvlist_find(nvlist, ZPOOL_CONFIG_CHILDREN,
  623                          DATA_TYPE_NVLIST_ARRAY, &nkids, &kids);
  624         /*
  625          * Its ok if we don't have any kids.
  626          */
  627         if (rc == 0) {
  628                 vdev->v_nchildren = nkids;
  629                 for (i = 0; i < nkids; i++) {
  630                         rc = vdev_init_from_nvlist(kids, vdev, &kid, is_newer);
  631                         if (rc)
  632                                 return (rc);
  633                         if (is_new)
  634                                 STAILQ_INSERT_TAIL(&vdev->v_children, kid,
  635                                                    v_childlink);
  636                         kids = nvlist_next(kids);
  637                 }
  638         } else {
  639                 vdev->v_nchildren = 0;
  640         }
  641 
  642         if (vdevp)
  643                 *vdevp = vdev;
  644         return (0);
  645 }
  646 
  647 static void
  648 vdev_set_state(vdev_t *vdev)
  649 {
  650         vdev_t *kid;
  651         int good_kids;
  652         int bad_kids;
  653 
  654         /*
  655          * A mirror or raidz is healthy if all its kids are healthy. A
  656          * mirror is degraded if any of its kids is healthy; a raidz
  657          * is degraded if at most nparity kids are offline.
  658          */
  659         if (STAILQ_FIRST(&vdev->v_children)) {
  660                 good_kids = 0;
  661                 bad_kids = 0;
  662                 STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
  663                         if (kid->v_state == VDEV_STATE_HEALTHY)
  664                                 good_kids++;
  665                         else
  666                                 bad_kids++;
  667                 }
  668                 if (bad_kids == 0) {
  669                         vdev->v_state = VDEV_STATE_HEALTHY;
  670                 } else {
  671                         if (vdev->v_read == vdev_mirror_read) {
  672                                 if (good_kids) {
  673                                         vdev->v_state = VDEV_STATE_DEGRADED;
  674                                 } else {
  675                                         vdev->v_state = VDEV_STATE_OFFLINE;
  676                                 }
  677                         } else if (vdev->v_read == vdev_raidz_read) {
  678                                 if (bad_kids > vdev->v_nparity) {
  679                                         vdev->v_state = VDEV_STATE_OFFLINE;
  680                                 } else {
  681                                         vdev->v_state = VDEV_STATE_DEGRADED;
  682                                 }
  683                         }
  684                 }
  685         }
  686 }
  687 
  688 static spa_t *
  689 spa_find_by_guid(uint64_t guid)
  690 {
  691         spa_t *spa;
  692 
  693         STAILQ_FOREACH(spa, &zfs_pools, spa_link)
  694                 if (spa->spa_guid == guid)
  695                         return (spa);
  696 
  697         return (0);
  698 }
  699 
  700 static spa_t *
  701 spa_find_by_name(const char *name)
  702 {
  703         spa_t *spa;
  704 
  705         STAILQ_FOREACH(spa, &zfs_pools, spa_link)
  706                 if (!strcmp(spa->spa_name, name))
  707                         return (spa);
  708 
  709         return (0);
  710 }
  711 
  712 #ifdef BOOT2
  713 static spa_t *
  714 spa_get_primary(void)
  715 {
  716 
  717         return (STAILQ_FIRST(&zfs_pools));
  718 }
  719 
  720 static vdev_t *
  721 spa_get_primary_vdev(const spa_t *spa)
  722 {
  723         vdev_t *vdev;
  724         vdev_t *kid;
  725 
  726         if (spa == NULL)
  727                 spa = spa_get_primary();
  728         if (spa == NULL)
  729                 return (NULL);
  730         vdev = STAILQ_FIRST(&spa->spa_vdevs);
  731         if (vdev == NULL)
  732                 return (NULL);
  733         for (kid = STAILQ_FIRST(&vdev->v_children); kid != NULL;
  734              kid = STAILQ_FIRST(&vdev->v_children))
  735                 vdev = kid;
  736         return (vdev);
  737 }
  738 #endif
  739 
  740 static spa_t *
  741 spa_create(uint64_t guid)
  742 {
  743         spa_t *spa;
  744 
  745         spa = malloc(sizeof(spa_t));
  746         memset(spa, 0, sizeof(spa_t));
  747         STAILQ_INIT(&spa->spa_vdevs);
  748         spa->spa_guid = guid;
  749         STAILQ_INSERT_TAIL(&zfs_pools, spa, spa_link);
  750 
  751         return (spa);
  752 }
  753 
  754 static const char *
  755 state_name(vdev_state_t state)
  756 {
  757         static const char* names[] = {
  758                 "UNKNOWN",
  759                 "CLOSED",
  760                 "OFFLINE",
  761                 "REMOVED",
  762                 "CANT_OPEN",
  763                 "FAULTED",
  764                 "DEGRADED",
  765                 "ONLINE"
  766         };
  767         return names[state];
  768 }
  769 
  770 #ifdef BOOT2
  771 
  772 #define pager_printf printf
  773 
  774 #else
  775 
  776 static void
  777 pager_printf(const char *fmt, ...)
  778 {
  779         char line[80];
  780         va_list args;
  781 
  782         va_start(args, fmt);
  783         vsprintf(line, fmt, args);
  784         va_end(args);
  785         pager_output(line);
  786 }
  787 
  788 #endif
  789 
  790 #define STATUS_FORMAT   "        %s %s\n"
  791 
  792 static void
  793 print_state(int indent, const char *name, vdev_state_t state)
  794 {
  795         int i;
  796         char buf[512];
  797 
  798         buf[0] = 0;
  799         for (i = 0; i < indent; i++)
  800                 strcat(buf, "  ");
  801         strcat(buf, name);
  802         pager_printf(STATUS_FORMAT, buf, state_name(state));
  803         
  804 }
  805 
  806 static void
  807 vdev_status(vdev_t *vdev, int indent)
  808 {
  809         vdev_t *kid;
  810         print_state(indent, vdev->v_name, vdev->v_state);
  811 
  812         STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
  813                 vdev_status(kid, indent + 1);
  814         }
  815 }
  816 
  817 static void
  818 spa_status(spa_t *spa)
  819 {
  820         static char bootfs[ZFS_MAXNAMELEN];
  821         uint64_t rootid;
  822         vdev_t *vdev;
  823         int good_kids, bad_kids, degraded_kids;
  824         vdev_state_t state;
  825 
  826         pager_printf("  pool: %s\n", spa->spa_name);
  827         if (zfs_get_root(spa, &rootid) == 0 &&
  828             zfs_rlookup(spa, rootid, bootfs) == 0) {
  829                 if (bootfs[0] == '\0')
  830                         pager_printf("bootfs: %s\n", spa->spa_name);
  831                 else
  832                         pager_printf("bootfs: %s/%s\n", spa->spa_name, bootfs);
  833         }
  834         pager_printf("config:\n\n");
  835         pager_printf(STATUS_FORMAT, "NAME", "STATE");
  836 
  837         good_kids = 0;
  838         degraded_kids = 0;
  839         bad_kids = 0;
  840         STAILQ_FOREACH(vdev, &spa->spa_vdevs, v_childlink) {
  841                 if (vdev->v_state == VDEV_STATE_HEALTHY)
  842                         good_kids++;
  843                 else if (vdev->v_state == VDEV_STATE_DEGRADED)
  844                         degraded_kids++;
  845                 else
  846                         bad_kids++;
  847         }
  848 
  849         state = VDEV_STATE_CLOSED;
  850         if (good_kids > 0 && (degraded_kids + bad_kids) == 0)
  851                 state = VDEV_STATE_HEALTHY;
  852         else if ((good_kids + degraded_kids) > 0)
  853                 state = VDEV_STATE_DEGRADED;
  854 
  855         print_state(0, spa->spa_name, state);
  856         STAILQ_FOREACH(vdev, &spa->spa_vdevs, v_childlink) {
  857                 vdev_status(vdev, 1);
  858         }
  859 }
  860 
  861 static void
  862 spa_all_status(void)
  863 {
  864         spa_t *spa;
  865         int first = 1;
  866 
  867         STAILQ_FOREACH(spa, &zfs_pools, spa_link) {
  868                 if (!first)
  869                         pager_printf("\n");
  870                 first = 0;
  871                 spa_status(spa);
  872         }
  873 }
  874 
  875 static int
  876 vdev_probe(vdev_phys_read_t *read, void *read_priv, spa_t **spap)
  877 {
  878         vdev_t vtmp;
  879         vdev_phys_t *vdev_label = (vdev_phys_t *) zap_scratch;
  880         spa_t *spa;
  881         vdev_t *vdev, *top_vdev, *pool_vdev;
  882         off_t off;
  883         blkptr_t bp;
  884         const unsigned char *nvlist;
  885         uint64_t val;
  886         uint64_t guid;
  887         uint64_t pool_txg, pool_guid;
  888         uint64_t is_log;
  889         const char *pool_name;
  890         const unsigned char *vdevs;
  891         const unsigned char *features;
  892         int i, rc, is_newer;
  893         char *upbuf;
  894         const struct uberblock *up;
  895 
  896         /*
  897          * Load the vdev label and figure out which
  898          * uberblock is most current.
  899          */
  900         memset(&vtmp, 0, sizeof(vtmp));
  901         vtmp.v_phys_read = read;
  902         vtmp.v_read_priv = read_priv;
  903         off = offsetof(vdev_label_t, vl_vdev_phys);
  904         BP_ZERO(&bp);
  905         BP_SET_LSIZE(&bp, sizeof(vdev_phys_t));
  906         BP_SET_PSIZE(&bp, sizeof(vdev_phys_t));
  907         BP_SET_CHECKSUM(&bp, ZIO_CHECKSUM_LABEL);
  908         BP_SET_COMPRESS(&bp, ZIO_COMPRESS_OFF);
  909         DVA_SET_OFFSET(BP_IDENTITY(&bp), off);
  910         ZIO_SET_CHECKSUM(&bp.blk_cksum, off, 0, 0, 0);
  911         if (vdev_read_phys(&vtmp, &bp, vdev_label, off, 0))
  912                 return (EIO);
  913 
  914         if (vdev_label->vp_nvlist[0] != NV_ENCODE_XDR) {
  915                 return (EIO);
  916         }
  917 
  918         nvlist = (const unsigned char *) vdev_label->vp_nvlist + 4;
  919 
  920         if (nvlist_find(nvlist,
  921                         ZPOOL_CONFIG_VERSION,
  922                         DATA_TYPE_UINT64, 0, &val)) {
  923                 return (EIO);
  924         }
  925 
  926         if (!SPA_VERSION_IS_SUPPORTED(val)) {
  927                 printf("ZFS: unsupported ZFS version %u (should be %u)\n",
  928                     (unsigned) val, (unsigned) SPA_VERSION);
  929                 return (EIO);
  930         }
  931 
  932         /* Check ZFS features for read */
  933         if (nvlist_find(nvlist,
  934                         ZPOOL_CONFIG_FEATURES_FOR_READ,
  935                         DATA_TYPE_NVLIST, 0, &features) == 0
  936             && nvlist_check_features_for_read(features) != 0)
  937                 return (EIO);
  938 
  939         if (nvlist_find(nvlist,
  940                         ZPOOL_CONFIG_POOL_STATE,
  941                         DATA_TYPE_UINT64, 0, &val)) {
  942                 return (EIO);
  943         }
  944 
  945         if (val == POOL_STATE_DESTROYED) {
  946                 /* We don't boot only from destroyed pools. */
  947                 return (EIO);
  948         }
  949 
  950         if (nvlist_find(nvlist,
  951                         ZPOOL_CONFIG_POOL_TXG,
  952                         DATA_TYPE_UINT64, 0, &pool_txg)
  953             || nvlist_find(nvlist,
  954                            ZPOOL_CONFIG_POOL_GUID,
  955                            DATA_TYPE_UINT64, 0, &pool_guid)
  956             || nvlist_find(nvlist,
  957                            ZPOOL_CONFIG_POOL_NAME,
  958                            DATA_TYPE_STRING, 0, &pool_name)) {
  959                 /*
  960                  * Cache and spare devices end up here - just ignore
  961                  * them.
  962                  */
  963                 /*printf("ZFS: can't find pool details\n");*/
  964                 return (EIO);
  965         }
  966 
  967         is_log = 0;
  968         (void) nvlist_find(nvlist, ZPOOL_CONFIG_IS_LOG, DATA_TYPE_UINT64, 0,
  969             &is_log);
  970         if (is_log)
  971                 return (EIO);
  972 
  973         /*
  974          * Create the pool if this is the first time we've seen it.
  975          */
  976         spa = spa_find_by_guid(pool_guid);
  977         if (!spa) {
  978                 spa = spa_create(pool_guid);
  979                 spa->spa_name = strdup(pool_name);
  980         }
  981         if (pool_txg > spa->spa_txg) {
  982                 spa->spa_txg = pool_txg;
  983                 is_newer = 1;
  984         } else
  985                 is_newer = 0;
  986 
  987         /*
  988          * Get the vdev tree and create our in-core copy of it.
  989          * If we already have a vdev with this guid, this must
  990          * be some kind of alias (overlapping slices, dangerously dedicated
  991          * disks etc).
  992          */
  993         if (nvlist_find(nvlist,
  994                         ZPOOL_CONFIG_GUID,
  995                         DATA_TYPE_UINT64, 0, &guid)) {
  996                 return (EIO);
  997         }
  998         vdev = vdev_find(guid);
  999         if (vdev && vdev->v_phys_read)  /* Has this vdev already been inited? */
 1000                 return (EIO);
 1001 
 1002         if (nvlist_find(nvlist,
 1003                         ZPOOL_CONFIG_VDEV_TREE,
 1004                         DATA_TYPE_NVLIST, 0, &vdevs)) {
 1005                 return (EIO);
 1006         }
 1007 
 1008         rc = vdev_init_from_nvlist(vdevs, NULL, &top_vdev, is_newer);
 1009         if (rc)
 1010                 return (rc);
 1011 
 1012         /*
 1013          * Add the toplevel vdev to the pool if its not already there.
 1014          */
 1015         STAILQ_FOREACH(pool_vdev, &spa->spa_vdevs, v_childlink)
 1016                 if (top_vdev == pool_vdev)
 1017                         break;
 1018         if (!pool_vdev && top_vdev)
 1019                 STAILQ_INSERT_TAIL(&spa->spa_vdevs, top_vdev, v_childlink);
 1020 
 1021         /*
 1022          * We should already have created an incomplete vdev for this
 1023          * vdev. Find it and initialise it with our read proc.
 1024          */
 1025         vdev = vdev_find(guid);
 1026         if (vdev) {
 1027                 vdev->v_phys_read = read;
 1028                 vdev->v_read_priv = read_priv;
 1029                 vdev->v_state = VDEV_STATE_HEALTHY;
 1030         } else {
 1031                 printf("ZFS: inconsistent nvlist contents\n");
 1032                 return (EIO);
 1033         }
 1034 
 1035         /*
 1036          * Re-evaluate top-level vdev state.
 1037          */
 1038         vdev_set_state(top_vdev);
 1039 
 1040         /*
 1041          * Ok, we are happy with the pool so far. Lets find
 1042          * the best uberblock and then we can actually access
 1043          * the contents of the pool.
 1044          */
 1045         upbuf = zfs_alloc(VDEV_UBERBLOCK_SIZE(vdev));
 1046         up = (const struct uberblock *)upbuf;
 1047         for (i = 0;
 1048              i < VDEV_UBERBLOCK_COUNT(vdev);
 1049              i++) {
 1050                 off = VDEV_UBERBLOCK_OFFSET(vdev, i);
 1051                 BP_ZERO(&bp);
 1052                 DVA_SET_OFFSET(&bp.blk_dva[0], off);
 1053                 BP_SET_LSIZE(&bp, VDEV_UBERBLOCK_SIZE(vdev));
 1054                 BP_SET_PSIZE(&bp, VDEV_UBERBLOCK_SIZE(vdev));
 1055                 BP_SET_CHECKSUM(&bp, ZIO_CHECKSUM_LABEL);
 1056                 BP_SET_COMPRESS(&bp, ZIO_COMPRESS_OFF);
 1057                 ZIO_SET_CHECKSUM(&bp.blk_cksum, off, 0, 0, 0);
 1058 
 1059                 if (vdev_read_phys(vdev, &bp, upbuf, off, 0))
 1060                         continue;
 1061 
 1062                 if (up->ub_magic != UBERBLOCK_MAGIC)
 1063                         continue;
 1064                 if (up->ub_txg < spa->spa_txg)
 1065                         continue;
 1066                 if (up->ub_txg > spa->spa_uberblock.ub_txg) {
 1067                         spa->spa_uberblock = *up;
 1068                 } else if (up->ub_txg == spa->spa_uberblock.ub_txg) {
 1069                         if (up->ub_timestamp > spa->spa_uberblock.ub_timestamp)
 1070                                 spa->spa_uberblock = *up;
 1071                 }
 1072         }
 1073         zfs_free(upbuf, VDEV_UBERBLOCK_SIZE(vdev));
 1074 
 1075         if (spap)
 1076                 *spap = spa;
 1077         return (0);
 1078 }
 1079 
 1080 static int
 1081 ilog2(int n)
 1082 {
 1083         int v;
 1084 
 1085         for (v = 0; v < 32; v++)
 1086                 if (n == (1 << v))
 1087                         return v;
 1088         return -1;
 1089 }
 1090 
 1091 static int
 1092 zio_read_gang(const spa_t *spa, const blkptr_t *bp, void *buf)
 1093 {
 1094         blkptr_t gbh_bp;
 1095         zio_gbh_phys_t zio_gb;
 1096         char *pbuf;
 1097         int i;
 1098 
 1099         /* Artificial BP for gang block header. */
 1100         gbh_bp = *bp;
 1101         BP_SET_PSIZE(&gbh_bp, SPA_GANGBLOCKSIZE);
 1102         BP_SET_LSIZE(&gbh_bp, SPA_GANGBLOCKSIZE);
 1103         BP_SET_CHECKSUM(&gbh_bp, ZIO_CHECKSUM_GANG_HEADER);
 1104         BP_SET_COMPRESS(&gbh_bp, ZIO_COMPRESS_OFF);
 1105         for (i = 0; i < SPA_DVAS_PER_BP; i++)
 1106                 DVA_SET_GANG(&gbh_bp.blk_dva[i], 0);
 1107 
 1108         /* Read gang header block using the artificial BP. */
 1109         if (zio_read(spa, &gbh_bp, &zio_gb))
 1110                 return (EIO);
 1111 
 1112         pbuf = buf;
 1113         for (i = 0; i < SPA_GBH_NBLKPTRS; i++) {
 1114                 blkptr_t *gbp = &zio_gb.zg_blkptr[i];
 1115 
 1116                 if (BP_IS_HOLE(gbp))
 1117                         continue;
 1118                 if (zio_read(spa, gbp, pbuf))
 1119                         return (EIO);
 1120                 pbuf += BP_GET_PSIZE(gbp);
 1121         }
 1122 
 1123         if (zio_checksum_verify(bp, buf))
 1124                 return (EIO);
 1125         return (0);
 1126 }
 1127 
 1128 static int
 1129 zio_read(const spa_t *spa, const blkptr_t *bp, void *buf)
 1130 {
 1131         int cpfunc = BP_GET_COMPRESS(bp);
 1132         uint64_t align, size;
 1133         void *pbuf;
 1134         int i, error;
 1135 
 1136         error = EIO;
 1137 
 1138         for (i = 0; i < SPA_DVAS_PER_BP; i++) {
 1139                 const dva_t *dva = &bp->blk_dva[i];
 1140                 vdev_t *vdev;
 1141                 int vdevid;
 1142                 off_t offset;
 1143 
 1144                 if (!dva->dva_word[0] && !dva->dva_word[1])
 1145                         continue;
 1146 
 1147                 vdevid = DVA_GET_VDEV(dva);
 1148                 offset = DVA_GET_OFFSET(dva);
 1149                 STAILQ_FOREACH(vdev, &spa->spa_vdevs, v_childlink) {
 1150                         if (vdev->v_id == vdevid)
 1151                                 break;
 1152                 }
 1153                 if (!vdev || !vdev->v_read)
 1154                         continue;
 1155 
 1156                 size = BP_GET_PSIZE(bp);
 1157                 if (vdev->v_read == vdev_raidz_read) {
 1158                         align = 1ULL << vdev->v_top->v_ashift;
 1159                         if (P2PHASE(size, align) != 0)
 1160                                 size = P2ROUNDUP(size, align);
 1161                 }
 1162                 if (size != BP_GET_PSIZE(bp) || cpfunc != ZIO_COMPRESS_OFF)
 1163                         pbuf = zfs_alloc(size);
 1164                 else
 1165                         pbuf = buf;
 1166 
 1167                 if (DVA_GET_GANG(dva))
 1168                         error = zio_read_gang(spa, bp, pbuf);
 1169                 else
 1170                         error = vdev->v_read(vdev, bp, pbuf, offset, size);
 1171                 if (error == 0) {
 1172                         if (cpfunc != ZIO_COMPRESS_OFF)
 1173                                 error = zio_decompress_data(cpfunc, pbuf,
 1174                                     BP_GET_PSIZE(bp), buf, BP_GET_LSIZE(bp));
 1175                         else if (size != BP_GET_PSIZE(bp))
 1176                                 bcopy(pbuf, buf, BP_GET_PSIZE(bp));
 1177                 }
 1178                 if (buf != pbuf)
 1179                         zfs_free(pbuf, size);
 1180                 if (error == 0)
 1181                         break;
 1182         }
 1183         if (error != 0)
 1184                 printf("ZFS: i/o error - all block copies unavailable\n");
 1185         return (error);
 1186 }
 1187 
 1188 static int
 1189 dnode_read(const spa_t *spa, const dnode_phys_t *dnode, off_t offset, void *buf, size_t buflen)
 1190 {
 1191         int ibshift = dnode->dn_indblkshift - SPA_BLKPTRSHIFT;
 1192         int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
 1193         int nlevels = dnode->dn_nlevels;
 1194         int i, rc;
 1195 
 1196         /*
 1197          * Note: bsize may not be a power of two here so we need to do an
 1198          * actual divide rather than a bitshift.
 1199          */
 1200         while (buflen > 0) {
 1201                 uint64_t bn = offset / bsize;
 1202                 int boff = offset % bsize;
 1203                 int ibn;
 1204                 const blkptr_t *indbp;
 1205                 blkptr_t bp;
 1206 
 1207                 if (bn > dnode->dn_maxblkid)
 1208                         return (EIO);
 1209 
 1210                 if (dnode == dnode_cache_obj && bn == dnode_cache_bn)
 1211                         goto cached;
 1212 
 1213                 indbp = dnode->dn_blkptr;
 1214                 for (i = 0; i < nlevels; i++) {
 1215                         /*
 1216                          * Copy the bp from the indirect array so that
 1217                          * we can re-use the scratch buffer for multi-level
 1218                          * objects.
 1219                          */
 1220                         ibn = bn >> ((nlevels - i - 1) * ibshift);
 1221                         ibn &= ((1 << ibshift) - 1);
 1222                         bp = indbp[ibn];
 1223                         rc = zio_read(spa, &bp, dnode_cache_buf);
 1224                         if (rc)
 1225                                 return (rc);
 1226                         indbp = (const blkptr_t *) dnode_cache_buf;
 1227                 }
 1228                 dnode_cache_obj = dnode;
 1229                 dnode_cache_bn = bn;
 1230         cached:
 1231 
 1232                 /*
 1233                  * The buffer contains our data block. Copy what we
 1234                  * need from it and loop.
 1235                  */ 
 1236                 i = bsize - boff;
 1237                 if (i > buflen) i = buflen;
 1238                 memcpy(buf, &dnode_cache_buf[boff], i);
 1239                 buf = ((char*) buf) + i;
 1240                 offset += i;
 1241                 buflen -= i;
 1242         }
 1243 
 1244         return (0);
 1245 }
 1246 
 1247 /*
 1248  * Lookup a value in a microzap directory. Assumes that the zap
 1249  * scratch buffer contains the directory contents.
 1250  */
 1251 static int
 1252 mzap_lookup(const dnode_phys_t *dnode, const char *name, uint64_t *value)
 1253 {
 1254         const mzap_phys_t *mz;
 1255         const mzap_ent_phys_t *mze;
 1256         size_t size;
 1257         int chunks, i;
 1258 
 1259         /*
 1260          * Microzap objects use exactly one block. Read the whole
 1261          * thing.
 1262          */
 1263         size = dnode->dn_datablkszsec * 512;
 1264 
 1265         mz = (const mzap_phys_t *) zap_scratch;
 1266         chunks = size / MZAP_ENT_LEN - 1;
 1267 
 1268         for (i = 0; i < chunks; i++) {
 1269                 mze = &mz->mz_chunk[i];
 1270                 if (!strcmp(mze->mze_name, name)) {
 1271                         *value = mze->mze_value;
 1272                         return (0);
 1273                 }
 1274         }
 1275 
 1276         return (ENOENT);
 1277 }
 1278 
 1279 /*
 1280  * Compare a name with a zap leaf entry. Return non-zero if the name
 1281  * matches.
 1282  */
 1283 static int
 1284 fzap_name_equal(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc, const char *name)
 1285 {
 1286         size_t namelen;
 1287         const zap_leaf_chunk_t *nc;
 1288         const char *p;
 1289 
 1290         namelen = zc->l_entry.le_name_numints;
 1291                         
 1292         nc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_name_chunk);
 1293         p = name;
 1294         while (namelen > 0) {
 1295                 size_t len;
 1296                 len = namelen;
 1297                 if (len > ZAP_LEAF_ARRAY_BYTES)
 1298                         len = ZAP_LEAF_ARRAY_BYTES;
 1299                 if (memcmp(p, nc->l_array.la_array, len))
 1300                         return (0);
 1301                 p += len;
 1302                 namelen -= len;
 1303                 nc = &ZAP_LEAF_CHUNK(zl, nc->l_array.la_next);
 1304         }
 1305 
 1306         return 1;
 1307 }
 1308 
 1309 /*
 1310  * Extract a uint64_t value from a zap leaf entry.
 1311  */
 1312 static uint64_t
 1313 fzap_leaf_value(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc)
 1314 {
 1315         const zap_leaf_chunk_t *vc;
 1316         int i;
 1317         uint64_t value;
 1318         const uint8_t *p;
 1319 
 1320         vc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_value_chunk);
 1321         for (i = 0, value = 0, p = vc->l_array.la_array; i < 8; i++) {
 1322                 value = (value << 8) | p[i];
 1323         }
 1324 
 1325         return value;
 1326 }
 1327 
 1328 /*
 1329  * Lookup a value in a fatzap directory. Assumes that the zap scratch
 1330  * buffer contains the directory header.
 1331  */
 1332 static int
 1333 fzap_lookup(const spa_t *spa, const dnode_phys_t *dnode, const char *name, uint64_t *value)
 1334 {
 1335         int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
 1336         zap_phys_t zh = *(zap_phys_t *) zap_scratch;
 1337         fat_zap_t z;
 1338         uint64_t *ptrtbl;
 1339         uint64_t hash;
 1340         int rc;
 1341 
 1342         if (zh.zap_magic != ZAP_MAGIC)
 1343                 return (EIO);
 1344 
 1345         z.zap_block_shift = ilog2(bsize);
 1346         z.zap_phys = (zap_phys_t *) zap_scratch;
 1347 
 1348         /*
 1349          * Figure out where the pointer table is and read it in if necessary.
 1350          */
 1351         if (zh.zap_ptrtbl.zt_blk) {
 1352                 rc = dnode_read(spa, dnode, zh.zap_ptrtbl.zt_blk * bsize,
 1353                                zap_scratch, bsize);
 1354                 if (rc)
 1355                         return (rc);
 1356                 ptrtbl = (uint64_t *) zap_scratch;
 1357         } else {
 1358                 ptrtbl = &ZAP_EMBEDDED_PTRTBL_ENT(&z, 0);
 1359         }
 1360 
 1361         hash = zap_hash(zh.zap_salt, name);
 1362 
 1363         zap_leaf_t zl;
 1364         zl.l_bs = z.zap_block_shift;
 1365 
 1366         off_t off = ptrtbl[hash >> (64 - zh.zap_ptrtbl.zt_shift)] << zl.l_bs;
 1367         zap_leaf_chunk_t *zc;
 1368 
 1369         rc = dnode_read(spa, dnode, off, zap_scratch, bsize);
 1370         if (rc)
 1371                 return (rc);
 1372 
 1373         zl.l_phys = (zap_leaf_phys_t *) zap_scratch;
 1374 
 1375         /*
 1376          * Make sure this chunk matches our hash.
 1377          */
 1378         if (zl.l_phys->l_hdr.lh_prefix_len > 0
 1379             && zl.l_phys->l_hdr.lh_prefix
 1380             != hash >> (64 - zl.l_phys->l_hdr.lh_prefix_len))
 1381                 return (ENOENT);
 1382 
 1383         /*
 1384          * Hash within the chunk to find our entry.
 1385          */
 1386         int shift = (64 - ZAP_LEAF_HASH_SHIFT(&zl) - zl.l_phys->l_hdr.lh_prefix_len);
 1387         int h = (hash >> shift) & ((1 << ZAP_LEAF_HASH_SHIFT(&zl)) - 1);
 1388         h = zl.l_phys->l_hash[h];
 1389         if (h == 0xffff)
 1390                 return (ENOENT);
 1391         zc = &ZAP_LEAF_CHUNK(&zl, h);
 1392         while (zc->l_entry.le_hash != hash) {
 1393                 if (zc->l_entry.le_next == 0xffff) {
 1394                         zc = 0;
 1395                         break;
 1396                 }
 1397                 zc = &ZAP_LEAF_CHUNK(&zl, zc->l_entry.le_next);
 1398         }
 1399         if (fzap_name_equal(&zl, zc, name)) {
 1400                 if (zc->l_entry.le_value_intlen * zc->l_entry.le_value_numints > 8)
 1401                         return (E2BIG);
 1402                 *value = fzap_leaf_value(&zl, zc);
 1403                 return (0);
 1404         }
 1405 
 1406         return (ENOENT);
 1407 }
 1408 
 1409 /*
 1410  * Lookup a name in a zap object and return its value as a uint64_t.
 1411  */
 1412 static int
 1413 zap_lookup(const spa_t *spa, const dnode_phys_t *dnode, const char *name, uint64_t *value)
 1414 {
 1415         int rc;
 1416         uint64_t zap_type;
 1417         size_t size = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
 1418 
 1419         rc = dnode_read(spa, dnode, 0, zap_scratch, size);
 1420         if (rc)
 1421                 return (rc);
 1422 
 1423         zap_type = *(uint64_t *) zap_scratch;
 1424         if (zap_type == ZBT_MICRO)
 1425                 return mzap_lookup(dnode, name, value);
 1426         else if (zap_type == ZBT_HEADER)
 1427                 return fzap_lookup(spa, dnode, name, value);
 1428         printf("ZFS: invalid zap_type=%d\n", (int)zap_type);
 1429         return (EIO);
 1430 }
 1431 
 1432 /*
 1433  * List a microzap directory. Assumes that the zap scratch buffer contains
 1434  * the directory contents.
 1435  */
 1436 static int
 1437 mzap_list(const dnode_phys_t *dnode)
 1438 {
 1439         const mzap_phys_t *mz;
 1440         const mzap_ent_phys_t *mze;
 1441         size_t size;
 1442         int chunks, i;
 1443 
 1444         /*
 1445          * Microzap objects use exactly one block. Read the whole
 1446          * thing.
 1447          */
 1448         size = dnode->dn_datablkszsec * 512;
 1449         mz = (const mzap_phys_t *) zap_scratch;
 1450         chunks = size / MZAP_ENT_LEN - 1;
 1451 
 1452         for (i = 0; i < chunks; i++) {
 1453                 mze = &mz->mz_chunk[i];
 1454                 if (mze->mze_name[0])
 1455                         //printf("%-32s 0x%jx\n", mze->mze_name, (uintmax_t)mze->mze_value);
 1456                         printf("%s\n", mze->mze_name);
 1457         }
 1458 
 1459         return (0);
 1460 }
 1461 
 1462 /*
 1463  * List a fatzap directory. Assumes that the zap scratch buffer contains
 1464  * the directory header.
 1465  */
 1466 static int
 1467 fzap_list(const spa_t *spa, const dnode_phys_t *dnode)
 1468 {
 1469         int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
 1470         zap_phys_t zh = *(zap_phys_t *) zap_scratch;
 1471         fat_zap_t z;
 1472         int i, j;
 1473 
 1474         if (zh.zap_magic != ZAP_MAGIC)
 1475                 return (EIO);
 1476 
 1477         z.zap_block_shift = ilog2(bsize);
 1478         z.zap_phys = (zap_phys_t *) zap_scratch;
 1479 
 1480         /*
 1481          * This assumes that the leaf blocks start at block 1. The
 1482          * documentation isn't exactly clear on this.
 1483          */
 1484         zap_leaf_t zl;
 1485         zl.l_bs = z.zap_block_shift;
 1486         for (i = 0; i < zh.zap_num_leafs; i++) {
 1487                 off_t off = (i + 1) << zl.l_bs;
 1488                 char name[256], *p;
 1489                 uint64_t value;
 1490 
 1491                 if (dnode_read(spa, dnode, off, zap_scratch, bsize))
 1492                         return (EIO);
 1493 
 1494                 zl.l_phys = (zap_leaf_phys_t *) zap_scratch;
 1495 
 1496                 for (j = 0; j < ZAP_LEAF_NUMCHUNKS(&zl); j++) {
 1497                         zap_leaf_chunk_t *zc, *nc;
 1498                         int namelen;
 1499 
 1500                         zc = &ZAP_LEAF_CHUNK(&zl, j);
 1501                         if (zc->l_entry.le_type != ZAP_CHUNK_ENTRY)
 1502                                 continue;
 1503                         namelen = zc->l_entry.le_name_numints;
 1504                         if (namelen > sizeof(name))
 1505                                 namelen = sizeof(name);
 1506 
 1507                         /*
 1508                          * Paste the name back together.
 1509                          */
 1510                         nc = &ZAP_LEAF_CHUNK(&zl, zc->l_entry.le_name_chunk);
 1511                         p = name;
 1512                         while (namelen > 0) {
 1513                                 int len;
 1514                                 len = namelen;
 1515                                 if (len > ZAP_LEAF_ARRAY_BYTES)
 1516                                         len = ZAP_LEAF_ARRAY_BYTES;
 1517                                 memcpy(p, nc->l_array.la_array, len);
 1518                                 p += len;
 1519                                 namelen -= len;
 1520                                 nc = &ZAP_LEAF_CHUNK(&zl, nc->l_array.la_next);
 1521                         }
 1522 
 1523                         /*
 1524                          * Assume the first eight bytes of the value are
 1525                          * a uint64_t.
 1526                          */
 1527                         value = fzap_leaf_value(&zl, zc);
 1528 
 1529                         //printf("%s 0x%jx\n", name, (uintmax_t)value);
 1530                         printf("%s\n", name);
 1531                 }
 1532         }
 1533 
 1534         return (0);
 1535 }
 1536 
 1537 /*
 1538  * List a zap directory.
 1539  */
 1540 static int
 1541 zap_list(const spa_t *spa, const dnode_phys_t *dnode)
 1542 {
 1543         uint64_t zap_type;
 1544         size_t size = dnode->dn_datablkszsec * 512;
 1545 
 1546         if (dnode_read(spa, dnode, 0, zap_scratch, size))
 1547                 return (EIO);
 1548 
 1549         zap_type = *(uint64_t *) zap_scratch;
 1550         if (zap_type == ZBT_MICRO)
 1551                 return mzap_list(dnode);
 1552         else
 1553                 return fzap_list(spa, dnode);
 1554 }
 1555 
 1556 static int
 1557 objset_get_dnode(const spa_t *spa, const objset_phys_t *os, uint64_t objnum, dnode_phys_t *dnode)
 1558 {
 1559         off_t offset;
 1560 
 1561         offset = objnum * sizeof(dnode_phys_t);
 1562         return dnode_read(spa, &os->os_meta_dnode, offset,
 1563                 dnode, sizeof(dnode_phys_t));
 1564 }
 1565 
 1566 static int
 1567 mzap_rlookup(const spa_t *spa, const dnode_phys_t *dnode, char *name, uint64_t value)
 1568 {
 1569         const mzap_phys_t *mz;
 1570         const mzap_ent_phys_t *mze;
 1571         size_t size;
 1572         int chunks, i;
 1573 
 1574         /*
 1575          * Microzap objects use exactly one block. Read the whole
 1576          * thing.
 1577          */
 1578         size = dnode->dn_datablkszsec * 512;
 1579 
 1580         mz = (const mzap_phys_t *) zap_scratch;
 1581         chunks = size / MZAP_ENT_LEN - 1;
 1582 
 1583         for (i = 0; i < chunks; i++) {
 1584                 mze = &mz->mz_chunk[i];
 1585                 if (value == mze->mze_value) {
 1586                         strcpy(name, mze->mze_name);
 1587                         return (0);
 1588                 }
 1589         }
 1590 
 1591         return (ENOENT);
 1592 }
 1593 
 1594 static void
 1595 fzap_name_copy(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc, char *name)
 1596 {
 1597         size_t namelen;
 1598         const zap_leaf_chunk_t *nc;
 1599         char *p;
 1600 
 1601         namelen = zc->l_entry.le_name_numints;
 1602 
 1603         nc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_name_chunk);
 1604         p = name;
 1605         while (namelen > 0) {
 1606                 size_t len;
 1607                 len = namelen;
 1608                 if (len > ZAP_LEAF_ARRAY_BYTES)
 1609                         len = ZAP_LEAF_ARRAY_BYTES;
 1610                 memcpy(p, nc->l_array.la_array, len);
 1611                 p += len;
 1612                 namelen -= len;
 1613                 nc = &ZAP_LEAF_CHUNK(zl, nc->l_array.la_next);
 1614         }
 1615 
 1616         *p = '\0';
 1617 }
 1618 
 1619 static int
 1620 fzap_rlookup(const spa_t *spa, const dnode_phys_t *dnode, char *name, uint64_t value)
 1621 {
 1622         int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
 1623         zap_phys_t zh = *(zap_phys_t *) zap_scratch;
 1624         fat_zap_t z;
 1625         int i, j;
 1626 
 1627         if (zh.zap_magic != ZAP_MAGIC)
 1628                 return (EIO);
 1629 
 1630         z.zap_block_shift = ilog2(bsize);
 1631         z.zap_phys = (zap_phys_t *) zap_scratch;
 1632 
 1633         /*
 1634          * This assumes that the leaf blocks start at block 1. The
 1635          * documentation isn't exactly clear on this.
 1636          */
 1637         zap_leaf_t zl;
 1638         zl.l_bs = z.zap_block_shift;
 1639         for (i = 0; i < zh.zap_num_leafs; i++) {
 1640                 off_t off = (i + 1) << zl.l_bs;
 1641 
 1642                 if (dnode_read(spa, dnode, off, zap_scratch, bsize))
 1643                         return (EIO);
 1644 
 1645                 zl.l_phys = (zap_leaf_phys_t *) zap_scratch;
 1646 
 1647                 for (j = 0; j < ZAP_LEAF_NUMCHUNKS(&zl); j++) {
 1648                         zap_leaf_chunk_t *zc;
 1649 
 1650                         zc = &ZAP_LEAF_CHUNK(&zl, j);
 1651                         if (zc->l_entry.le_type != ZAP_CHUNK_ENTRY)
 1652                                 continue;
 1653                         if (zc->l_entry.le_value_intlen != 8 ||
 1654                             zc->l_entry.le_value_numints != 1)
 1655                                 continue;
 1656 
 1657                         if (fzap_leaf_value(&zl, zc) == value) {
 1658                                 fzap_name_copy(&zl, zc, name);
 1659                                 return (0);
 1660                         }
 1661                 }
 1662         }
 1663 
 1664         return (ENOENT);
 1665 }
 1666 
 1667 static int
 1668 zap_rlookup(const spa_t *spa, const dnode_phys_t *dnode, char *name, uint64_t value)
 1669 {
 1670         int rc;
 1671         uint64_t zap_type;
 1672         size_t size = dnode->dn_datablkszsec * 512;
 1673 
 1674         rc = dnode_read(spa, dnode, 0, zap_scratch, size);
 1675         if (rc)
 1676                 return (rc);
 1677 
 1678         zap_type = *(uint64_t *) zap_scratch;
 1679         if (zap_type == ZBT_MICRO)
 1680                 return mzap_rlookup(spa, dnode, name, value);
 1681         else
 1682                 return fzap_rlookup(spa, dnode, name, value);
 1683 }
 1684 
 1685 static int
 1686 zfs_rlookup(const spa_t *spa, uint64_t objnum, char *result)
 1687 {
 1688         char name[256];
 1689         char component[256];
 1690         uint64_t dir_obj, parent_obj, child_dir_zapobj;
 1691         dnode_phys_t child_dir_zap, dataset, dir, parent;
 1692         dsl_dir_phys_t *dd;
 1693         dsl_dataset_phys_t *ds;
 1694         char *p;
 1695         int len;
 1696 
 1697         p = &name[sizeof(name) - 1];
 1698         *p = '\0';
 1699 
 1700         if (objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset)) {
 1701                 printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
 1702                 return (EIO);
 1703         }
 1704         ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
 1705         dir_obj = ds->ds_dir_obj;
 1706 
 1707         for (;;) {
 1708                 if (objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir) != 0)
 1709                         return (EIO);
 1710                 dd = (dsl_dir_phys_t *)&dir.dn_bonus;
 1711 
 1712                 /* Actual loop condition. */
 1713                 parent_obj  = dd->dd_parent_obj;
 1714                 if (parent_obj == 0)
 1715                         break;
 1716 
 1717                 if (objset_get_dnode(spa, &spa->spa_mos, parent_obj, &parent) != 0)
 1718                         return (EIO);
 1719                 dd = (dsl_dir_phys_t *)&parent.dn_bonus;
 1720                 child_dir_zapobj = dd->dd_child_dir_zapobj;
 1721                 if (objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj, &child_dir_zap) != 0)
 1722                         return (EIO);
 1723                 if (zap_rlookup(spa, &child_dir_zap, component, dir_obj) != 0)
 1724                         return (EIO);
 1725 
 1726                 len = strlen(component);
 1727                 p -= len;
 1728                 memcpy(p, component, len);
 1729                 --p;
 1730                 *p = '/';
 1731 
 1732                 /* Actual loop iteration. */
 1733                 dir_obj = parent_obj;
 1734         }
 1735 
 1736         if (*p != '\0')
 1737                 ++p;
 1738         strcpy(result, p);
 1739 
 1740         return (0);
 1741 }
 1742 
 1743 static int
 1744 zfs_lookup_dataset(const spa_t *spa, const char *name, uint64_t *objnum)
 1745 {
 1746         char element[256];
 1747         uint64_t dir_obj, child_dir_zapobj;
 1748         dnode_phys_t child_dir_zap, dir;
 1749         dsl_dir_phys_t *dd;
 1750         const char *p, *q;
 1751 
 1752         if (objset_get_dnode(spa, &spa->spa_mos, DMU_POOL_DIRECTORY_OBJECT, &dir))
 1753                 return (EIO);
 1754         if (zap_lookup(spa, &dir, DMU_POOL_ROOT_DATASET, &dir_obj))
 1755                 return (EIO);
 1756 
 1757         p = name;
 1758         for (;;) {
 1759                 if (objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir))
 1760                         return (EIO);
 1761                 dd = (dsl_dir_phys_t *)&dir.dn_bonus;
 1762 
 1763                 while (*p == '/')
 1764                         p++;
 1765                 /* Actual loop condition #1. */
 1766                 if (*p == '\0')
 1767                         break;
 1768 
 1769                 q = strchr(p, '/');
 1770                 if (q) {
 1771                         memcpy(element, p, q - p);
 1772                         element[q - p] = '\0';
 1773                         p = q + 1;
 1774                 } else {
 1775                         strcpy(element, p);
 1776                         p += strlen(p);
 1777                 }
 1778 
 1779                 child_dir_zapobj = dd->dd_child_dir_zapobj;
 1780                 if (objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj, &child_dir_zap) != 0)
 1781                         return (EIO);
 1782 
 1783                 /* Actual loop condition #2. */
 1784                 if (zap_lookup(spa, &child_dir_zap, element, &dir_obj) != 0)
 1785                         return (ENOENT);
 1786         }
 1787 
 1788         *objnum = dd->dd_head_dataset_obj;
 1789         return (0);
 1790 }
 1791 
 1792 #ifndef BOOT2
 1793 static int
 1794 zfs_list_dataset(const spa_t *spa, uint64_t objnum/*, int pos, char *entry*/)
 1795 {
 1796         uint64_t dir_obj, child_dir_zapobj;
 1797         dnode_phys_t child_dir_zap, dir, dataset;
 1798         dsl_dataset_phys_t *ds;
 1799         dsl_dir_phys_t *dd;
 1800 
 1801         if (objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset)) {
 1802                 printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
 1803                 return (EIO);
 1804         }
 1805         ds = (dsl_dataset_phys_t *) &dataset.dn_bonus;
 1806         dir_obj = ds->ds_dir_obj;
 1807 
 1808         if (objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir)) {
 1809                 printf("ZFS: can't find dirobj %ju\n", (uintmax_t)dir_obj);
 1810                 return (EIO);
 1811         }
 1812         dd = (dsl_dir_phys_t *)&dir.dn_bonus;
 1813 
 1814         child_dir_zapobj = dd->dd_child_dir_zapobj;
 1815         if (objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj, &child_dir_zap) != 0) {
 1816                 printf("ZFS: can't find child zap %ju\n", (uintmax_t)dir_obj);
 1817                 return (EIO);
 1818         }
 1819 
 1820         return (zap_list(spa, &child_dir_zap) != 0);
 1821 }
 1822 #endif
 1823 
 1824 /*
 1825  * Find the object set given the object number of its dataset object
 1826  * and return its details in *objset
 1827  */
 1828 static int
 1829 zfs_mount_dataset(const spa_t *spa, uint64_t objnum, objset_phys_t *objset)
 1830 {
 1831         dnode_phys_t dataset;
 1832         dsl_dataset_phys_t *ds;
 1833 
 1834         if (objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset)) {
 1835                 printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
 1836                 return (EIO);
 1837         }
 1838 
 1839         ds = (dsl_dataset_phys_t *) &dataset.dn_bonus;
 1840         if (zio_read(spa, &ds->ds_bp, objset)) {
 1841                 printf("ZFS: can't read object set for dataset %ju\n",
 1842                     (uintmax_t)objnum);
 1843                 return (EIO);
 1844         }
 1845 
 1846         return (0);
 1847 }
 1848 
 1849 /*
 1850  * Find the object set pointed to by the BOOTFS property or the root
 1851  * dataset if there is none and return its details in *objset
 1852  */
 1853 static int
 1854 zfs_get_root(const spa_t *spa, uint64_t *objid)
 1855 {
 1856         dnode_phys_t dir, propdir;
 1857         uint64_t props, bootfs, root;
 1858 
 1859         *objid = 0;
 1860 
 1861         /*
 1862          * Start with the MOS directory object.
 1863          */
 1864         if (objset_get_dnode(spa, &spa->spa_mos, DMU_POOL_DIRECTORY_OBJECT, &dir)) {
 1865                 printf("ZFS: can't read MOS object directory\n");
 1866                 return (EIO);
 1867         }
 1868 
 1869         /*
 1870          * Lookup the pool_props and see if we can find a bootfs.
 1871          */
 1872         if (zap_lookup(spa, &dir, DMU_POOL_PROPS, &props) == 0
 1873              && objset_get_dnode(spa, &spa->spa_mos, props, &propdir) == 0
 1874              && zap_lookup(spa, &propdir, "bootfs", &bootfs) == 0
 1875              && bootfs != 0)
 1876         {
 1877                 *objid = bootfs;
 1878                 return (0);
 1879         }
 1880         /*
 1881          * Lookup the root dataset directory
 1882          */
 1883         if (zap_lookup(spa, &dir, DMU_POOL_ROOT_DATASET, &root)
 1884             || objset_get_dnode(spa, &spa->spa_mos, root, &dir)) {
 1885                 printf("ZFS: can't find root dsl_dir\n");
 1886                 return (EIO);
 1887         }
 1888 
 1889         /*
 1890          * Use the information from the dataset directory's bonus buffer
 1891          * to find the dataset object and from that the object set itself.
 1892          */
 1893         dsl_dir_phys_t *dd = (dsl_dir_phys_t *) &dir.dn_bonus;
 1894         *objid = dd->dd_head_dataset_obj;
 1895         return (0);
 1896 }
 1897 
 1898 static int
 1899 zfs_mount(const spa_t *spa, uint64_t rootobj, struct zfsmount *mount)
 1900 {
 1901 
 1902         mount->spa = spa;
 1903 
 1904         /*
 1905          * Find the root object set if not explicitly provided
 1906          */
 1907         if (rootobj == 0 && zfs_get_root(spa, &rootobj)) {
 1908                 printf("ZFS: can't find root filesystem\n");
 1909                 return (EIO);
 1910         }
 1911 
 1912         if (zfs_mount_dataset(spa, rootobj, &mount->objset)) {
 1913                 printf("ZFS: can't open root filesystem\n");
 1914                 return (EIO);
 1915         }
 1916 
 1917         mount->rootobj = rootobj;
 1918 
 1919         return (0);
 1920 }
 1921 
 1922 static int
 1923 zfs_spa_init(spa_t *spa)
 1924 {
 1925 
 1926         if (zio_read(spa, &spa->spa_uberblock.ub_rootbp, &spa->spa_mos)) {
 1927                 printf("ZFS: can't read MOS of pool %s\n", spa->spa_name);
 1928                 return (EIO);
 1929         }
 1930         if (spa->spa_mos.os_type != DMU_OST_META) {
 1931                 printf("ZFS: corrupted MOS of pool %s\n", spa->spa_name);
 1932                 return (EIO);
 1933         }
 1934         return (0);
 1935 }
 1936 
 1937 static int
 1938 zfs_dnode_stat(const spa_t *spa, dnode_phys_t *dn, struct stat *sb)
 1939 {
 1940 
 1941         if (dn->dn_bonustype != DMU_OT_SA) {
 1942                 znode_phys_t *zp = (znode_phys_t *)dn->dn_bonus;
 1943 
 1944                 sb->st_mode = zp->zp_mode;
 1945                 sb->st_uid = zp->zp_uid;
 1946                 sb->st_gid = zp->zp_gid;
 1947                 sb->st_size = zp->zp_size;
 1948         } else {
 1949                 sa_hdr_phys_t *sahdrp;
 1950                 int hdrsize;
 1951                 size_t size = 0;
 1952                 void *buf = NULL;
 1953 
 1954                 if (dn->dn_bonuslen != 0)
 1955                         sahdrp = (sa_hdr_phys_t *)DN_BONUS(dn);
 1956                 else {
 1957                         if ((dn->dn_flags & DNODE_FLAG_SPILL_BLKPTR) != 0) {
 1958                                 blkptr_t *bp = &dn->dn_spill;
 1959                                 int error;
 1960 
 1961                                 size = BP_GET_LSIZE(bp);
 1962                                 buf = zfs_alloc(size);
 1963                                 error = zio_read(spa, bp, buf);
 1964                                 if (error != 0) {
 1965                                         zfs_free(buf, size);
 1966                                         return (error);
 1967                                 }
 1968                                 sahdrp = buf;
 1969                         } else {
 1970                                 return (EIO);
 1971                         }
 1972                 }
 1973                 hdrsize = SA_HDR_SIZE(sahdrp);
 1974                 sb->st_mode = *(uint64_t *)((char *)sahdrp + hdrsize +
 1975                     SA_MODE_OFFSET);
 1976                 sb->st_uid = *(uint64_t *)((char *)sahdrp + hdrsize +
 1977                     SA_UID_OFFSET);
 1978                 sb->st_gid = *(uint64_t *)((char *)sahdrp + hdrsize +
 1979                     SA_GID_OFFSET);
 1980                 sb->st_size = *(uint64_t *)((char *)sahdrp + hdrsize +
 1981                     SA_SIZE_OFFSET);
 1982                 if (buf != NULL)
 1983                         zfs_free(buf, size);
 1984         }
 1985 
 1986         return (0);
 1987 }
 1988 
 1989 /*
 1990  * Lookup a file and return its dnode.
 1991  */
 1992 static int
 1993 zfs_lookup(const struct zfsmount *mount, const char *upath, dnode_phys_t *dnode)
 1994 {
 1995         int rc;
 1996         uint64_t objnum, rootnum, parentnum;
 1997         const spa_t *spa;
 1998         dnode_phys_t dn;
 1999         const char *p, *q;
 2000         char element[256];
 2001         char path[1024];
 2002         int symlinks_followed = 0;
 2003         struct stat sb;
 2004 
 2005         spa = mount->spa;
 2006         if (mount->objset.os_type != DMU_OST_ZFS) {
 2007                 printf("ZFS: unexpected object set type %ju\n",
 2008                     (uintmax_t)mount->objset.os_type);
 2009                 return (EIO);
 2010         }
 2011 
 2012         /*
 2013          * Get the root directory dnode.
 2014          */
 2015         rc = objset_get_dnode(spa, &mount->objset, MASTER_NODE_OBJ, &dn);
 2016         if (rc)
 2017                 return (rc);
 2018 
 2019         rc = zap_lookup(spa, &dn, ZFS_ROOT_OBJ, &rootnum);
 2020         if (rc)
 2021                 return (rc);
 2022 
 2023         rc = objset_get_dnode(spa, &mount->objset, rootnum, &dn);
 2024         if (rc)
 2025                 return (rc);
 2026 
 2027         objnum = rootnum;
 2028         p = upath;
 2029         while (p && *p) {
 2030                 while (*p == '/')
 2031                         p++;
 2032                 if (!*p)
 2033                         break;
 2034                 q = strchr(p, '/');
 2035                 if (q) {
 2036                         memcpy(element, p, q - p);
 2037                         element[q - p] = 0;
 2038                         p = q;
 2039                 } else {
 2040                         strcpy(element, p);
 2041                         p = 0;
 2042                 }
 2043 
 2044                 rc = zfs_dnode_stat(spa, &dn, &sb);
 2045                 if (rc)
 2046                         return (rc);
 2047                 if (!S_ISDIR(sb.st_mode))
 2048                         return (ENOTDIR);
 2049 
 2050                 parentnum = objnum;
 2051                 rc = zap_lookup(spa, &dn, element, &objnum);
 2052                 if (rc)
 2053                         return (rc);
 2054                 objnum = ZFS_DIRENT_OBJ(objnum);
 2055 
 2056                 rc = objset_get_dnode(spa, &mount->objset, objnum, &dn);
 2057                 if (rc)
 2058                         return (rc);
 2059 
 2060                 /*
 2061                  * Check for symlink.
 2062                  */
 2063                 rc = zfs_dnode_stat(spa, &dn, &sb);
 2064                 if (rc)
 2065                         return (rc);
 2066                 if (S_ISLNK(sb.st_mode)) {
 2067                         if (symlinks_followed > 10)
 2068                                 return (EMLINK);
 2069                         symlinks_followed++;
 2070 
 2071                         /*
 2072                          * Read the link value and copy the tail of our
 2073                          * current path onto the end.
 2074                          */
 2075                         if (p)
 2076                                 strcpy(&path[sb.st_size], p);
 2077                         else
 2078                                 path[sb.st_size] = 0;
 2079                         if (sb.st_size + sizeof(znode_phys_t) <= dn.dn_bonuslen) {
 2080                                 memcpy(path, &dn.dn_bonus[sizeof(znode_phys_t)],
 2081                                         sb.st_size);
 2082                         } else {
 2083                                 rc = dnode_read(spa, &dn, 0, path, sb.st_size);
 2084                                 if (rc)
 2085                                         return (rc);
 2086                         }
 2087 
 2088                         /*
 2089                          * Restart with the new path, starting either at
 2090                          * the root or at the parent depending whether or
 2091                          * not the link is relative.
 2092                          */
 2093                         p = path;
 2094                         if (*p == '/')
 2095                                 objnum = rootnum;
 2096                         else
 2097                                 objnum = parentnum;
 2098                         objset_get_dnode(spa, &mount->objset, objnum, &dn);
 2099                 }
 2100         }
 2101 
 2102         *dnode = dn;
 2103         return (0);
 2104 }

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