freebsd-skq/sys/boot/zfs/zfsimpl.c
pjd 1b03c5bf41 Finally... Import the latest open-source ZFS version - (SPA) 28.
Few new things available from now on:

- Data deduplication.
- Triple parity RAIDZ (RAIDZ3).
- zfs diff.
- zpool split.
- Snapshot holds.
- zpool import -F. Allows to rewind corrupted pool to earlier
  transaction group.
- Possibility to import pool in read-only mode.

MFC after:	1 month
2011-02-27 19:41:40 +00:00

1709 lines
37 KiB
C

/*-
* Copyright (c) 2007 Doug Rabson
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Stand-alone ZFS file reader.
*/
#include <sys/stat.h>
#include "zfsimpl.h"
#include "zfssubr.c"
/*
* List of all vdevs, chained through v_alllink.
*/
static vdev_list_t zfs_vdevs;
/*
* List of all pools, chained through spa_link.
*/
static spa_list_t zfs_pools;
static uint64_t zfs_crc64_table[256];
static const dnode_phys_t *dnode_cache_obj = 0;
static uint64_t dnode_cache_bn;
static char *dnode_cache_buf;
static char *zap_scratch;
static char *zfs_temp_buf, *zfs_temp_end, *zfs_temp_ptr;
#define TEMP_SIZE (1024 * 1024)
static int zio_read(spa_t *spa, const blkptr_t *bp, void *buf);
static void
zfs_init(void)
{
STAILQ_INIT(&zfs_vdevs);
STAILQ_INIT(&zfs_pools);
zfs_temp_buf = malloc(TEMP_SIZE);
zfs_temp_end = zfs_temp_buf + TEMP_SIZE;
zfs_temp_ptr = zfs_temp_buf;
dnode_cache_buf = malloc(SPA_MAXBLOCKSIZE);
zap_scratch = malloc(SPA_MAXBLOCKSIZE);
zfs_init_crc();
}
static void *
zfs_alloc(size_t size)
{
char *ptr;
if (zfs_temp_ptr + size > zfs_temp_end) {
printf("ZFS: out of temporary buffer space\n");
for (;;) ;
}
ptr = zfs_temp_ptr;
zfs_temp_ptr += size;
return (ptr);
}
static void
zfs_free(void *ptr, size_t size)
{
zfs_temp_ptr -= size;
if (zfs_temp_ptr != ptr) {
printf("ZFS: zfs_alloc()/zfs_free() mismatch\n");
for (;;) ;
}
}
static int
xdr_int(const unsigned char **xdr, int *ip)
{
*ip = ((*xdr)[0] << 24)
| ((*xdr)[1] << 16)
| ((*xdr)[2] << 8)
| ((*xdr)[3] << 0);
(*xdr) += 4;
return (0);
}
static int
xdr_u_int(const unsigned char **xdr, u_int *ip)
{
*ip = ((*xdr)[0] << 24)
| ((*xdr)[1] << 16)
| ((*xdr)[2] << 8)
| ((*xdr)[3] << 0);
(*xdr) += 4;
return (0);
}
static int
xdr_uint64_t(const unsigned char **xdr, uint64_t *lp)
{
u_int hi, lo;
xdr_u_int(xdr, &hi);
xdr_u_int(xdr, &lo);
*lp = (((uint64_t) hi) << 32) | lo;
return (0);
}
static int
nvlist_find(const unsigned char *nvlist, const char *name, int type,
int* elementsp, void *valuep)
{
const unsigned char *p, *pair;
int junk;
int encoded_size, decoded_size;
p = nvlist;
xdr_int(&p, &junk);
xdr_int(&p, &junk);
pair = p;
xdr_int(&p, &encoded_size);
xdr_int(&p, &decoded_size);
while (encoded_size && decoded_size) {
int namelen, pairtype, elements;
const char *pairname;
xdr_int(&p, &namelen);
pairname = (const char*) p;
p += roundup(namelen, 4);
xdr_int(&p, &pairtype);
if (!memcmp(name, pairname, namelen) && type == pairtype) {
xdr_int(&p, &elements);
if (elementsp)
*elementsp = elements;
if (type == DATA_TYPE_UINT64) {
xdr_uint64_t(&p, (uint64_t *) valuep);
return (0);
} else if (type == DATA_TYPE_STRING) {
int len;
xdr_int(&p, &len);
(*(const char**) valuep) = (const char*) p;
return (0);
} else if (type == DATA_TYPE_NVLIST
|| type == DATA_TYPE_NVLIST_ARRAY) {
(*(const unsigned char**) valuep) =
(const unsigned char*) p;
return (0);
} else {
return (EIO);
}
} else {
/*
* Not the pair we are looking for, skip to the next one.
*/
p = pair + encoded_size;
}
pair = p;
xdr_int(&p, &encoded_size);
xdr_int(&p, &decoded_size);
}
return (EIO);
}
/*
* Return the next nvlist in an nvlist array.
*/
static const unsigned char *
nvlist_next(const unsigned char *nvlist)
{
const unsigned char *p, *pair;
int junk;
int encoded_size, decoded_size;
p = nvlist;
xdr_int(&p, &junk);
xdr_int(&p, &junk);
pair = p;
xdr_int(&p, &encoded_size);
xdr_int(&p, &decoded_size);
while (encoded_size && decoded_size) {
p = pair + encoded_size;
pair = p;
xdr_int(&p, &encoded_size);
xdr_int(&p, &decoded_size);
}
return p;
}
#ifdef TEST
static const unsigned char *
nvlist_print(const unsigned char *nvlist, unsigned int indent)
{
static const char* typenames[] = {
"DATA_TYPE_UNKNOWN",
"DATA_TYPE_BOOLEAN",
"DATA_TYPE_BYTE",
"DATA_TYPE_INT16",
"DATA_TYPE_UINT16",
"DATA_TYPE_INT32",
"DATA_TYPE_UINT32",
"DATA_TYPE_INT64",
"DATA_TYPE_UINT64",
"DATA_TYPE_STRING",
"DATA_TYPE_BYTE_ARRAY",
"DATA_TYPE_INT16_ARRAY",
"DATA_TYPE_UINT16_ARRAY",
"DATA_TYPE_INT32_ARRAY",
"DATA_TYPE_UINT32_ARRAY",
"DATA_TYPE_INT64_ARRAY",
"DATA_TYPE_UINT64_ARRAY",
"DATA_TYPE_STRING_ARRAY",
"DATA_TYPE_HRTIME",
"DATA_TYPE_NVLIST",
"DATA_TYPE_NVLIST_ARRAY",
"DATA_TYPE_BOOLEAN_VALUE",
"DATA_TYPE_INT8",
"DATA_TYPE_UINT8",
"DATA_TYPE_BOOLEAN_ARRAY",
"DATA_TYPE_INT8_ARRAY",
"DATA_TYPE_UINT8_ARRAY"
};
unsigned int i, j;
const unsigned char *p, *pair;
int junk;
int encoded_size, decoded_size;
p = nvlist;
xdr_int(&p, &junk);
xdr_int(&p, &junk);
pair = p;
xdr_int(&p, &encoded_size);
xdr_int(&p, &decoded_size);
while (encoded_size && decoded_size) {
int namelen, pairtype, elements;
const char *pairname;
xdr_int(&p, &namelen);
pairname = (const char*) p;
p += roundup(namelen, 4);
xdr_int(&p, &pairtype);
for (i = 0; i < indent; i++)
printf(" ");
printf("%s %s", typenames[pairtype], pairname);
xdr_int(&p, &elements);
switch (pairtype) {
case DATA_TYPE_UINT64: {
uint64_t val;
xdr_uint64_t(&p, &val);
printf(" = 0x%llx\n", val);
break;
}
case DATA_TYPE_STRING: {
int len;
xdr_int(&p, &len);
printf(" = \"%s\"\n", p);
break;
}
case DATA_TYPE_NVLIST:
printf("\n");
nvlist_print(p, indent + 1);
break;
case DATA_TYPE_NVLIST_ARRAY:
for (j = 0; j < elements; j++) {
printf("[%d]\n", j);
p = nvlist_print(p, indent + 1);
if (j != elements - 1) {
for (i = 0; i < indent; i++)
printf(" ");
printf("%s %s", typenames[pairtype], pairname);
}
}
break;
default:
printf("\n");
}
p = pair + encoded_size;
pair = p;
xdr_int(&p, &encoded_size);
xdr_int(&p, &decoded_size);
}
return p;
}
#endif
static int
vdev_read_phys(vdev_t *vdev, const blkptr_t *bp, void *buf,
off_t offset, size_t size)
{
size_t psize;
int rc;
if (!vdev->v_phys_read)
return (EIO);
if (bp) {
psize = BP_GET_PSIZE(bp);
} else {
psize = size;
}
/*printf("ZFS: reading %d bytes at 0x%llx to %p\n", psize, offset, buf);*/
rc = vdev->v_phys_read(vdev, vdev->v_read_priv, offset, buf, psize);
if (rc)
return (rc);
if (bp && zio_checksum_error(bp, buf, offset))
return (EIO);
return (0);
}
static int
vdev_disk_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
off_t offset, size_t bytes)
{
return (vdev_read_phys(vdev, bp, buf,
offset + VDEV_LABEL_START_SIZE, bytes));
}
static int
vdev_mirror_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
off_t offset, size_t bytes)
{
vdev_t *kid;
int rc;
rc = EIO;
STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
if (kid->v_state != VDEV_STATE_HEALTHY)
continue;
rc = kid->v_read(kid, bp, buf, offset, bytes);
if (!rc)
return (0);
}
return (rc);
}
static int
vdev_replacing_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
off_t offset, size_t bytes)
{
vdev_t *kid;
/*
* Here we should have two kids:
* First one which is the one we are replacing and we can trust
* only this one to have valid data, but it might not be present.
* Second one is that one we are replacing with. It is most likely
* healthy, but we can't trust it has needed data, so we won't use it.
*/
kid = STAILQ_FIRST(&vdev->v_children);
if (kid == NULL)
return (EIO);
if (kid->v_state != VDEV_STATE_HEALTHY)
return (EIO);
return (kid->v_read(kid, bp, buf, offset, bytes));
}
static vdev_t *
vdev_find(uint64_t guid)
{
vdev_t *vdev;
STAILQ_FOREACH(vdev, &zfs_vdevs, v_alllink)
if (vdev->v_guid == guid)
return (vdev);
return (0);
}
static vdev_t *
vdev_create(uint64_t guid, vdev_read_t *read)
{
vdev_t *vdev;
vdev = malloc(sizeof(vdev_t));
memset(vdev, 0, sizeof(vdev_t));
STAILQ_INIT(&vdev->v_children);
vdev->v_guid = guid;
vdev->v_state = VDEV_STATE_OFFLINE;
vdev->v_read = read;
vdev->v_phys_read = 0;
vdev->v_read_priv = 0;
STAILQ_INSERT_TAIL(&zfs_vdevs, vdev, v_alllink);
return (vdev);
}
static int
vdev_init_from_nvlist(const unsigned char *nvlist, vdev_t *pvdev,
vdev_t **vdevp, int is_newer)
{
int rc;
uint64_t guid, id, ashift, nparity;
const char *type;
const char *path;
vdev_t *vdev, *kid;
const unsigned char *kids;
int nkids, i, is_new;
uint64_t is_offline, is_faulted, is_degraded, is_removed, isnt_present;
if (nvlist_find(nvlist, ZPOOL_CONFIG_GUID,
DATA_TYPE_UINT64, 0, &guid)
|| nvlist_find(nvlist, ZPOOL_CONFIG_ID,
DATA_TYPE_UINT64, 0, &id)
|| nvlist_find(nvlist, ZPOOL_CONFIG_TYPE,
DATA_TYPE_STRING, 0, &type)) {
printf("ZFS: can't find vdev details\n");
return (ENOENT);
}
if (strcmp(type, VDEV_TYPE_MIRROR)
&& strcmp(type, VDEV_TYPE_DISK)
&& strcmp(type, VDEV_TYPE_RAIDZ)
&& strcmp(type, VDEV_TYPE_REPLACING)) {
printf("ZFS: can only boot from disk, mirror, raidz1, raidz2 and raidz3 vdevs\n");
return (EIO);
}
is_offline = is_removed = is_faulted = is_degraded = isnt_present = 0;
nvlist_find(nvlist, ZPOOL_CONFIG_OFFLINE, DATA_TYPE_UINT64, 0,
&is_offline);
nvlist_find(nvlist, ZPOOL_CONFIG_REMOVED, DATA_TYPE_UINT64, 0,
&is_removed);
nvlist_find(nvlist, ZPOOL_CONFIG_FAULTED, DATA_TYPE_UINT64, 0,
&is_faulted);
nvlist_find(nvlist, ZPOOL_CONFIG_DEGRADED, DATA_TYPE_UINT64, 0,
&is_degraded);
nvlist_find(nvlist, ZPOOL_CONFIG_NOT_PRESENT, DATA_TYPE_UINT64, 0,
&isnt_present);
vdev = vdev_find(guid);
if (!vdev) {
is_new = 1;
if (!strcmp(type, VDEV_TYPE_MIRROR))
vdev = vdev_create(guid, vdev_mirror_read);
else if (!strcmp(type, VDEV_TYPE_RAIDZ))
vdev = vdev_create(guid, vdev_raidz_read);
else if (!strcmp(type, VDEV_TYPE_REPLACING))
vdev = vdev_create(guid, vdev_replacing_read);
else
vdev = vdev_create(guid, vdev_disk_read);
vdev->v_id = id;
vdev->v_top = pvdev != NULL ? pvdev : vdev;
if (nvlist_find(nvlist, ZPOOL_CONFIG_ASHIFT,
DATA_TYPE_UINT64, 0, &ashift) == 0)
vdev->v_ashift = ashift;
else
vdev->v_ashift = 0;
if (nvlist_find(nvlist, ZPOOL_CONFIG_NPARITY,
DATA_TYPE_UINT64, 0, &nparity) == 0)
vdev->v_nparity = nparity;
else
vdev->v_nparity = 0;
if (nvlist_find(nvlist, ZPOOL_CONFIG_PATH,
DATA_TYPE_STRING, 0, &path) == 0) {
if (strncmp(path, "/dev/", 5) == 0)
path += 5;
vdev->v_name = strdup(path);
} else {
if (!strcmp(type, "raidz")) {
if (vdev->v_nparity == 1)
vdev->v_name = "raidz1";
else if (vdev->v_nparity == 2)
vdev->v_name = "raidz2";
else if (vdev->v_nparity == 3)
vdev->v_name = "raidz3";
else {
printf("ZFS: can only boot from disk, mirror, raidz1, raidz2 and raidz3 vdevs\n");
return (EIO);
}
} else {
vdev->v_name = strdup(type);
}
}
} else {
is_new = 0;
}
if (is_new || is_newer) {
/*
* This is either new vdev or we've already seen this vdev,
* but from an older vdev label, so let's refresh its state
* from the newer label.
*/
if (is_offline)
vdev->v_state = VDEV_STATE_OFFLINE;
else if (is_removed)
vdev->v_state = VDEV_STATE_REMOVED;
else if (is_faulted)
vdev->v_state = VDEV_STATE_FAULTED;
else if (is_degraded)
vdev->v_state = VDEV_STATE_DEGRADED;
else if (isnt_present)
vdev->v_state = VDEV_STATE_CANT_OPEN;
else
vdev->v_state = VDEV_STATE_HEALTHY;
}
rc = nvlist_find(nvlist, ZPOOL_CONFIG_CHILDREN,
DATA_TYPE_NVLIST_ARRAY, &nkids, &kids);
/*
* Its ok if we don't have any kids.
*/
if (rc == 0) {
vdev->v_nchildren = nkids;
for (i = 0; i < nkids; i++) {
rc = vdev_init_from_nvlist(kids, vdev, &kid, is_newer);
if (rc)
return (rc);
if (is_new)
STAILQ_INSERT_TAIL(&vdev->v_children, kid,
v_childlink);
kids = nvlist_next(kids);
}
} else {
vdev->v_nchildren = 0;
}
if (vdevp)
*vdevp = vdev;
return (0);
}
static void
vdev_set_state(vdev_t *vdev)
{
vdev_t *kid;
int good_kids;
int bad_kids;
/*
* A mirror or raidz is healthy if all its kids are healthy. A
* mirror is degraded if any of its kids is healthy; a raidz
* is degraded if at most nparity kids are offline.
*/
if (STAILQ_FIRST(&vdev->v_children)) {
good_kids = 0;
bad_kids = 0;
STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
if (kid->v_state == VDEV_STATE_HEALTHY)
good_kids++;
else
bad_kids++;
}
if (bad_kids == 0) {
vdev->v_state = VDEV_STATE_HEALTHY;
} else {
if (vdev->v_read == vdev_mirror_read) {
if (good_kids) {
vdev->v_state = VDEV_STATE_DEGRADED;
} else {
vdev->v_state = VDEV_STATE_OFFLINE;
}
} else if (vdev->v_read == vdev_raidz_read) {
if (bad_kids > vdev->v_nparity) {
vdev->v_state = VDEV_STATE_OFFLINE;
} else {
vdev->v_state = VDEV_STATE_DEGRADED;
}
}
}
}
}
static spa_t *
spa_find_by_guid(uint64_t guid)
{
spa_t *spa;
STAILQ_FOREACH(spa, &zfs_pools, spa_link)
if (spa->spa_guid == guid)
return (spa);
return (0);
}
#ifdef BOOT2
static spa_t *
spa_find_by_name(const char *name)
{
spa_t *spa;
STAILQ_FOREACH(spa, &zfs_pools, spa_link)
if (!strcmp(spa->spa_name, name))
return (spa);
return (0);
}
#endif
static spa_t *
spa_create(uint64_t guid)
{
spa_t *spa;
spa = malloc(sizeof(spa_t));
memset(spa, 0, sizeof(spa_t));
STAILQ_INIT(&spa->spa_vdevs);
spa->spa_guid = guid;
STAILQ_INSERT_TAIL(&zfs_pools, spa, spa_link);
return (spa);
}
static const char *
state_name(vdev_state_t state)
{
static const char* names[] = {
"UNKNOWN",
"CLOSED",
"OFFLINE",
"REMOVED",
"CANT_OPEN",
"FAULTED",
"DEGRADED",
"ONLINE"
};
return names[state];
}
#ifdef BOOT2
#define pager_printf printf
#else
static void
pager_printf(const char *fmt, ...)
{
char line[80];
va_list args;
va_start(args, fmt);
vsprintf(line, fmt, args);
va_end(args);
pager_output(line);
}
#endif
#define STATUS_FORMAT " %s %s\n"
static void
print_state(int indent, const char *name, vdev_state_t state)
{
int i;
char buf[512];
buf[0] = 0;
for (i = 0; i < indent; i++)
strcat(buf, " ");
strcat(buf, name);
pager_printf(STATUS_FORMAT, buf, state_name(state));
}
static void
vdev_status(vdev_t *vdev, int indent)
{
vdev_t *kid;
print_state(indent, vdev->v_name, vdev->v_state);
STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
vdev_status(kid, indent + 1);
}
}
static void
spa_status(spa_t *spa)
{
vdev_t *vdev;
int good_kids, bad_kids, degraded_kids;
vdev_state_t state;
pager_printf(" pool: %s\n", spa->spa_name);
pager_printf("config:\n\n");
pager_printf(STATUS_FORMAT, "NAME", "STATE");
good_kids = 0;
degraded_kids = 0;
bad_kids = 0;
STAILQ_FOREACH(vdev, &spa->spa_vdevs, v_childlink) {
if (vdev->v_state == VDEV_STATE_HEALTHY)
good_kids++;
else if (vdev->v_state == VDEV_STATE_DEGRADED)
degraded_kids++;
else
bad_kids++;
}
state = VDEV_STATE_CLOSED;
if (good_kids > 0 && (degraded_kids + bad_kids) == 0)
state = VDEV_STATE_HEALTHY;
else if ((good_kids + degraded_kids) > 0)
state = VDEV_STATE_DEGRADED;
print_state(0, spa->spa_name, state);
STAILQ_FOREACH(vdev, &spa->spa_vdevs, v_childlink) {
vdev_status(vdev, 1);
}
}
static void
spa_all_status(void)
{
spa_t *spa;
int first = 1;
STAILQ_FOREACH(spa, &zfs_pools, spa_link) {
if (!first)
pager_printf("\n");
first = 0;
spa_status(spa);
}
}
static int
vdev_probe(vdev_phys_read_t *read, void *read_priv, spa_t **spap)
{
vdev_t vtmp;
vdev_phys_t *vdev_label = (vdev_phys_t *) zap_scratch;
spa_t *spa;
vdev_t *vdev, *top_vdev, *pool_vdev;
off_t off;
blkptr_t bp;
const unsigned char *nvlist;
uint64_t val;
uint64_t guid;
uint64_t pool_txg, pool_guid;
uint64_t is_log;
const char *pool_name;
const unsigned char *vdevs;
int i, rc, is_newer;
char *upbuf;
const struct uberblock *up;
/*
* Load the vdev label and figure out which
* uberblock is most current.
*/
memset(&vtmp, 0, sizeof(vtmp));
vtmp.v_phys_read = read;
vtmp.v_read_priv = read_priv;
off = offsetof(vdev_label_t, vl_vdev_phys);
BP_ZERO(&bp);
BP_SET_LSIZE(&bp, sizeof(vdev_phys_t));
BP_SET_PSIZE(&bp, sizeof(vdev_phys_t));
BP_SET_CHECKSUM(&bp, ZIO_CHECKSUM_LABEL);
BP_SET_COMPRESS(&bp, ZIO_COMPRESS_OFF);
ZIO_SET_CHECKSUM(&bp.blk_cksum, off, 0, 0, 0);
if (vdev_read_phys(&vtmp, &bp, vdev_label, off, 0))
return (EIO);
if (vdev_label->vp_nvlist[0] != NV_ENCODE_XDR) {
return (EIO);
}
nvlist = (const unsigned char *) vdev_label->vp_nvlist + 4;
if (nvlist_find(nvlist,
ZPOOL_CONFIG_VERSION,
DATA_TYPE_UINT64, 0, &val)) {
return (EIO);
}
if (val > SPA_VERSION) {
printf("ZFS: unsupported ZFS version %u (should be %u)\n",
(unsigned) val, (unsigned) SPA_VERSION);
return (EIO);
}
if (nvlist_find(nvlist,
ZPOOL_CONFIG_POOL_STATE,
DATA_TYPE_UINT64, 0, &val)) {
return (EIO);
}
if (val == POOL_STATE_DESTROYED) {
/* We don't boot only from destroyed pools. */
return (EIO);
}
if (nvlist_find(nvlist,
ZPOOL_CONFIG_POOL_TXG,
DATA_TYPE_UINT64, 0, &pool_txg)
|| nvlist_find(nvlist,
ZPOOL_CONFIG_POOL_GUID,
DATA_TYPE_UINT64, 0, &pool_guid)
|| nvlist_find(nvlist,
ZPOOL_CONFIG_POOL_NAME,
DATA_TYPE_STRING, 0, &pool_name)) {
/*
* Cache and spare devices end up here - just ignore
* them.
*/
/*printf("ZFS: can't find pool details\n");*/
return (EIO);
}
is_log = 0;
(void) nvlist_find(nvlist, ZPOOL_CONFIG_IS_LOG, DATA_TYPE_UINT64, 0,
&is_log);
if (is_log)
return (EIO);
/*
* Create the pool if this is the first time we've seen it.
*/
spa = spa_find_by_guid(pool_guid);
if (!spa) {
spa = spa_create(pool_guid);
spa->spa_name = strdup(pool_name);
}
if (pool_txg > spa->spa_txg) {
spa->spa_txg = pool_txg;
is_newer = 1;
} else
is_newer = 0;
/*
* Get the vdev tree and create our in-core copy of it.
* If we already have a vdev with this guid, this must
* be some kind of alias (overlapping slices, dangerously dedicated
* disks etc).
*/
if (nvlist_find(nvlist,
ZPOOL_CONFIG_GUID,
DATA_TYPE_UINT64, 0, &guid)) {
return (EIO);
}
vdev = vdev_find(guid);
if (vdev && vdev->v_phys_read) /* Has this vdev already been inited? */
return (EIO);
if (nvlist_find(nvlist,
ZPOOL_CONFIG_VDEV_TREE,
DATA_TYPE_NVLIST, 0, &vdevs)) {
return (EIO);
}
rc = vdev_init_from_nvlist(vdevs, NULL, &top_vdev, is_newer);
if (rc)
return (rc);
/*
* Add the toplevel vdev to the pool if its not already there.
*/
STAILQ_FOREACH(pool_vdev, &spa->spa_vdevs, v_childlink)
if (top_vdev == pool_vdev)
break;
if (!pool_vdev && top_vdev)
STAILQ_INSERT_TAIL(&spa->spa_vdevs, top_vdev, v_childlink);
/*
* We should already have created an incomplete vdev for this
* vdev. Find it and initialise it with our read proc.
*/
vdev = vdev_find(guid);
if (vdev) {
vdev->v_phys_read = read;
vdev->v_read_priv = read_priv;
} else {
printf("ZFS: inconsistent nvlist contents\n");
return (EIO);
}
/*
* Re-evaluate top-level vdev state.
*/
vdev_set_state(top_vdev);
/*
* Ok, we are happy with the pool so far. Lets find
* the best uberblock and then we can actually access
* the contents of the pool.
*/
upbuf = zfs_alloc(VDEV_UBERBLOCK_SIZE(vdev));
up = (const struct uberblock *)upbuf;
for (i = 0;
i < VDEV_UBERBLOCK_COUNT(vdev);
i++) {
off = VDEV_UBERBLOCK_OFFSET(vdev, i);
BP_ZERO(&bp);
DVA_SET_OFFSET(&bp.blk_dva[0], off);
BP_SET_LSIZE(&bp, VDEV_UBERBLOCK_SIZE(vdev));
BP_SET_PSIZE(&bp, VDEV_UBERBLOCK_SIZE(vdev));
BP_SET_CHECKSUM(&bp, ZIO_CHECKSUM_LABEL);
BP_SET_COMPRESS(&bp, ZIO_COMPRESS_OFF);
ZIO_SET_CHECKSUM(&bp.blk_cksum, off, 0, 0, 0);
if (vdev_read_phys(vdev, NULL, upbuf, off, VDEV_UBERBLOCK_SIZE(vdev)))
continue;
if (up->ub_magic != UBERBLOCK_MAGIC)
continue;
if (up->ub_txg < spa->spa_txg)
continue;
if (up->ub_txg > spa->spa_uberblock.ub_txg) {
spa->spa_uberblock = *up;
} else if (up->ub_txg == spa->spa_uberblock.ub_txg) {
if (up->ub_timestamp > spa->spa_uberblock.ub_timestamp)
spa->spa_uberblock = *up;
}
}
zfs_free(upbuf, VDEV_UBERBLOCK_SIZE(vdev));
if (spap)
*spap = spa;
return (0);
}
static int
ilog2(int n)
{
int v;
for (v = 0; v < 32; v++)
if (n == (1 << v))
return v;
return -1;
}
static int
zio_read_gang(spa_t *spa, const blkptr_t *bp, const dva_t *dva, void *buf)
{
zio_gbh_phys_t zio_gb;
vdev_t *vdev;
int vdevid;
off_t offset;
int i;
vdevid = DVA_GET_VDEV(dva);
offset = DVA_GET_OFFSET(dva);
STAILQ_FOREACH(vdev, &spa->spa_vdevs, v_childlink)
if (vdev->v_id == vdevid)
break;
if (!vdev || !vdev->v_read)
return (EIO);
if (vdev->v_read(vdev, NULL, &zio_gb, offset, SPA_GANGBLOCKSIZE))
return (EIO);
for (i = 0; i < SPA_GBH_NBLKPTRS; i++) {
blkptr_t *gbp = &zio_gb.zg_blkptr[i];
if (BP_IS_HOLE(gbp))
continue;
if (zio_read(spa, gbp, buf))
return (EIO);
buf = (char*)buf + BP_GET_PSIZE(gbp);
}
return (0);
}
static int
zio_read(spa_t *spa, const blkptr_t *bp, void *buf)
{
int cpfunc = BP_GET_COMPRESS(bp);
uint64_t align, size;
void *pbuf;
int i, error;
error = EIO;
for (i = 0; i < SPA_DVAS_PER_BP; i++) {
const dva_t *dva = &bp->blk_dva[i];
vdev_t *vdev;
int vdevid;
off_t offset;
if (!dva->dva_word[0] && !dva->dva_word[1])
continue;
if (DVA_GET_GANG(dva)) {
error = zio_read_gang(spa, bp, dva, buf);
if (error != 0)
continue;
} else {
vdevid = DVA_GET_VDEV(dva);
offset = DVA_GET_OFFSET(dva);
STAILQ_FOREACH(vdev, &spa->spa_vdevs, v_childlink) {
if (vdev->v_id == vdevid)
break;
}
if (!vdev || !vdev->v_read)
continue;
size = BP_GET_PSIZE(bp);
align = 1ULL << vdev->v_top->v_ashift;
if (P2PHASE(size, align) != 0)
size = P2ROUNDUP(size, align);
if (size != BP_GET_PSIZE(bp) || cpfunc != ZIO_COMPRESS_OFF)
pbuf = zfs_alloc(size);
else
pbuf = buf;
error = vdev->v_read(vdev, bp, pbuf, offset, size);
if (error == 0) {
if (cpfunc != ZIO_COMPRESS_OFF) {
error = zio_decompress_data(cpfunc,
pbuf, BP_GET_PSIZE(bp), buf,
BP_GET_LSIZE(bp));
} else if (size != BP_GET_PSIZE(bp)) {
bcopy(pbuf, buf, BP_GET_PSIZE(bp));
}
}
if (buf != pbuf)
zfs_free(pbuf, size);
if (error != 0)
continue;
}
error = 0;
break;
}
if (error != 0)
printf("ZFS: i/o error - all block copies unavailable\n");
return (error);
}
static int
dnode_read(spa_t *spa, const dnode_phys_t *dnode, off_t offset, void *buf, size_t buflen)
{
int ibshift = dnode->dn_indblkshift - SPA_BLKPTRSHIFT;
int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
int nlevels = dnode->dn_nlevels;
int i, rc;
/*
* Note: bsize may not be a power of two here so we need to do an
* actual divide rather than a bitshift.
*/
while (buflen > 0) {
uint64_t bn = offset / bsize;
int boff = offset % bsize;
int ibn;
const blkptr_t *indbp;
blkptr_t bp;
if (bn > dnode->dn_maxblkid)
return (EIO);
if (dnode == dnode_cache_obj && bn == dnode_cache_bn)
goto cached;
indbp = dnode->dn_blkptr;
for (i = 0; i < nlevels; i++) {
/*
* Copy the bp from the indirect array so that
* we can re-use the scratch buffer for multi-level
* objects.
*/
ibn = bn >> ((nlevels - i - 1) * ibshift);
ibn &= ((1 << ibshift) - 1);
bp = indbp[ibn];
rc = zio_read(spa, &bp, dnode_cache_buf);
if (rc)
return (rc);
indbp = (const blkptr_t *) dnode_cache_buf;
}
dnode_cache_obj = dnode;
dnode_cache_bn = bn;
cached:
/*
* The buffer contains our data block. Copy what we
* need from it and loop.
*/
i = bsize - boff;
if (i > buflen) i = buflen;
memcpy(buf, &dnode_cache_buf[boff], i);
buf = ((char*) buf) + i;
offset += i;
buflen -= i;
}
return (0);
}
/*
* Lookup a value in a microzap directory. Assumes that the zap
* scratch buffer contains the directory contents.
*/
static int
mzap_lookup(spa_t *spa, const dnode_phys_t *dnode, const char *name, uint64_t *value)
{
const mzap_phys_t *mz;
const mzap_ent_phys_t *mze;
size_t size;
int chunks, i;
/*
* Microzap objects use exactly one block. Read the whole
* thing.
*/
size = dnode->dn_datablkszsec * 512;
mz = (const mzap_phys_t *) zap_scratch;
chunks = size / MZAP_ENT_LEN - 1;
for (i = 0; i < chunks; i++) {
mze = &mz->mz_chunk[i];
if (!strcmp(mze->mze_name, name)) {
*value = mze->mze_value;
return (0);
}
}
return (ENOENT);
}
/*
* Compare a name with a zap leaf entry. Return non-zero if the name
* matches.
*/
static int
fzap_name_equal(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc, const char *name)
{
size_t namelen;
const zap_leaf_chunk_t *nc;
const char *p;
namelen = zc->l_entry.le_name_length;
nc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_name_chunk);
p = name;
while (namelen > 0) {
size_t len;
len = namelen;
if (len > ZAP_LEAF_ARRAY_BYTES)
len = ZAP_LEAF_ARRAY_BYTES;
if (memcmp(p, nc->l_array.la_array, len))
return (0);
p += len;
namelen -= len;
nc = &ZAP_LEAF_CHUNK(zl, nc->l_array.la_next);
}
return 1;
}
/*
* Extract a uint64_t value from a zap leaf entry.
*/
static uint64_t
fzap_leaf_value(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc)
{
const zap_leaf_chunk_t *vc;
int i;
uint64_t value;
const uint8_t *p;
vc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_value_chunk);
for (i = 0, value = 0, p = vc->l_array.la_array; i < 8; i++) {
value = (value << 8) | p[i];
}
return value;
}
/*
* Lookup a value in a fatzap directory. Assumes that the zap scratch
* buffer contains the directory header.
*/
static int
fzap_lookup(spa_t *spa, const dnode_phys_t *dnode, const char *name, uint64_t *value)
{
int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
zap_phys_t zh = *(zap_phys_t *) zap_scratch;
fat_zap_t z;
uint64_t *ptrtbl;
uint64_t hash;
int rc;
if (zh.zap_magic != ZAP_MAGIC)
return (EIO);
z.zap_block_shift = ilog2(bsize);
z.zap_phys = (zap_phys_t *) zap_scratch;
/*
* Figure out where the pointer table is and read it in if necessary.
*/
if (zh.zap_ptrtbl.zt_blk) {
rc = dnode_read(spa, dnode, zh.zap_ptrtbl.zt_blk * bsize,
zap_scratch, bsize);
if (rc)
return (rc);
ptrtbl = (uint64_t *) zap_scratch;
} else {
ptrtbl = &ZAP_EMBEDDED_PTRTBL_ENT(&z, 0);
}
hash = zap_hash(zh.zap_salt, name);
zap_leaf_t zl;
zl.l_bs = z.zap_block_shift;
off_t off = ptrtbl[hash >> (64 - zh.zap_ptrtbl.zt_shift)] << zl.l_bs;
zap_leaf_chunk_t *zc;
rc = dnode_read(spa, dnode, off, zap_scratch, bsize);
if (rc)
return (rc);
zl.l_phys = (zap_leaf_phys_t *) zap_scratch;
/*
* Make sure this chunk matches our hash.
*/
if (zl.l_phys->l_hdr.lh_prefix_len > 0
&& zl.l_phys->l_hdr.lh_prefix
!= hash >> (64 - zl.l_phys->l_hdr.lh_prefix_len))
return (ENOENT);
/*
* Hash within the chunk to find our entry.
*/
int shift = (64 - ZAP_LEAF_HASH_SHIFT(&zl) - zl.l_phys->l_hdr.lh_prefix_len);
int h = (hash >> shift) & ((1 << ZAP_LEAF_HASH_SHIFT(&zl)) - 1);
h = zl.l_phys->l_hash[h];
if (h == 0xffff)
return (ENOENT);
zc = &ZAP_LEAF_CHUNK(&zl, h);
while (zc->l_entry.le_hash != hash) {
if (zc->l_entry.le_next == 0xffff) {
zc = 0;
break;
}
zc = &ZAP_LEAF_CHUNK(&zl, zc->l_entry.le_next);
}
if (fzap_name_equal(&zl, zc, name)) {
*value = fzap_leaf_value(&zl, zc);
return (0);
}
return (ENOENT);
}
/*
* Lookup a name in a zap object and return its value as a uint64_t.
*/
static int
zap_lookup(spa_t *spa, const dnode_phys_t *dnode, const char *name, uint64_t *value)
{
int rc;
uint64_t zap_type;
size_t size = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
rc = dnode_read(spa, dnode, 0, zap_scratch, size);
if (rc)
return (rc);
zap_type = *(uint64_t *) zap_scratch;
if (zap_type == ZBT_MICRO)
return mzap_lookup(spa, dnode, name, value);
else if (zap_type == ZBT_HEADER)
return fzap_lookup(spa, dnode, name, value);
printf("ZFS: invalid zap_type=%d\n", (int)zap_type);
return (EIO);
}
#ifdef BOOT2
/*
* List a microzap directory. Assumes that the zap scratch buffer contains
* the directory contents.
*/
static int
mzap_list(spa_t *spa, const dnode_phys_t *dnode)
{
const mzap_phys_t *mz;
const mzap_ent_phys_t *mze;
size_t size;
int chunks, i;
/*
* Microzap objects use exactly one block. Read the whole
* thing.
*/
size = dnode->dn_datablkszsec * 512;
mz = (const mzap_phys_t *) zap_scratch;
chunks = size / MZAP_ENT_LEN - 1;
for (i = 0; i < chunks; i++) {
mze = &mz->mz_chunk[i];
if (mze->mze_name[0])
//printf("%-32s 0x%llx\n", mze->mze_name, mze->mze_value);
printf("%s\n", mze->mze_name);
}
return (0);
}
/*
* List a fatzap directory. Assumes that the zap scratch buffer contains
* the directory header.
*/
static int
fzap_list(spa_t *spa, const dnode_phys_t *dnode)
{
int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
zap_phys_t zh = *(zap_phys_t *) zap_scratch;
fat_zap_t z;
int i, j;
if (zh.zap_magic != ZAP_MAGIC)
return (EIO);
z.zap_block_shift = ilog2(bsize);
z.zap_phys = (zap_phys_t *) zap_scratch;
/*
* This assumes that the leaf blocks start at block 1. The
* documentation isn't exactly clear on this.
*/
zap_leaf_t zl;
zl.l_bs = z.zap_block_shift;
for (i = 0; i < zh.zap_num_leafs; i++) {
off_t off = (i + 1) << zl.l_bs;
char name[256], *p;
uint64_t value;
if (dnode_read(spa, dnode, off, zap_scratch, bsize))
return (EIO);
zl.l_phys = (zap_leaf_phys_t *) zap_scratch;
for (j = 0; j < ZAP_LEAF_NUMCHUNKS(&zl); j++) {
zap_leaf_chunk_t *zc, *nc;
int namelen;
zc = &ZAP_LEAF_CHUNK(&zl, j);
if (zc->l_entry.le_type != ZAP_CHUNK_ENTRY)
continue;
namelen = zc->l_entry.le_name_length;
if (namelen > sizeof(name))
namelen = sizeof(name);
/*
* Paste the name back together.
*/
nc = &ZAP_LEAF_CHUNK(&zl, zc->l_entry.le_name_chunk);
p = name;
while (namelen > 0) {
int len;
len = namelen;
if (len > ZAP_LEAF_ARRAY_BYTES)
len = ZAP_LEAF_ARRAY_BYTES;
memcpy(p, nc->l_array.la_array, len);
p += len;
namelen -= len;
nc = &ZAP_LEAF_CHUNK(&zl, nc->l_array.la_next);
}
/*
* Assume the first eight bytes of the value are
* a uint64_t.
*/
value = fzap_leaf_value(&zl, zc);
printf("%s 0x%llx\n", name, value);
}
}
return (0);
}
/*
* List a zap directory.
*/
static int
zap_list(spa_t *spa, const dnode_phys_t *dnode)
{
uint64_t zap_type;
size_t size = dnode->dn_datablkszsec * 512;
if (dnode_read(spa, dnode, 0, zap_scratch, size))
return (EIO);
zap_type = *(uint64_t *) zap_scratch;
if (zap_type == ZBT_MICRO)
return mzap_list(spa, dnode);
else
return fzap_list(spa, dnode);
}
#endif
static int
objset_get_dnode(spa_t *spa, const objset_phys_t *os, uint64_t objnum, dnode_phys_t *dnode)
{
off_t offset;
offset = objnum * sizeof(dnode_phys_t);
return dnode_read(spa, &os->os_meta_dnode, offset,
dnode, sizeof(dnode_phys_t));
}
/*
* Find the object set given the object number of its dataset object
* and return its details in *objset
*/
static int
zfs_mount_dataset(spa_t *spa, uint64_t objnum, objset_phys_t *objset)
{
dnode_phys_t dataset;
dsl_dataset_phys_t *ds;
if (objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset)) {
printf("ZFS: can't find dataset %llu\n", objnum);
return (EIO);
}
ds = (dsl_dataset_phys_t *) &dataset.dn_bonus;
if (zio_read(spa, &ds->ds_bp, objset)) {
printf("ZFS: can't read object set for dataset %llu\n", objnum);
return (EIO);
}
return (0);
}
/*
* Find the object set pointed to by the BOOTFS property or the root
* dataset if there is none and return its details in *objset
*/
static int
zfs_mount_root(spa_t *spa, objset_phys_t *objset)
{
dnode_phys_t dir, propdir;
uint64_t props, bootfs, root;
/*
* Start with the MOS directory object.
*/
if (objset_get_dnode(spa, &spa->spa_mos, DMU_POOL_DIRECTORY_OBJECT, &dir)) {
printf("ZFS: can't read MOS object directory\n");
return (EIO);
}
/*
* Lookup the pool_props and see if we can find a bootfs.
*/
if (zap_lookup(spa, &dir, DMU_POOL_PROPS, &props) == 0
&& objset_get_dnode(spa, &spa->spa_mos, props, &propdir) == 0
&& zap_lookup(spa, &propdir, "bootfs", &bootfs) == 0
&& bootfs != 0)
return zfs_mount_dataset(spa, bootfs, objset);
/*
* Lookup the root dataset directory
*/
if (zap_lookup(spa, &dir, DMU_POOL_ROOT_DATASET, &root)
|| objset_get_dnode(spa, &spa->spa_mos, root, &dir)) {
printf("ZFS: can't find root dsl_dir\n");
return (EIO);
}
/*
* Use the information from the dataset directory's bonus buffer
* to find the dataset object and from that the object set itself.
*/
dsl_dir_phys_t *dd = (dsl_dir_phys_t *) &dir.dn_bonus;
return zfs_mount_dataset(spa, dd->dd_head_dataset_obj, objset);
}
static int
zfs_mount_pool(spa_t *spa)
{
/*
* Find the MOS and work our way in from there.
*/
if (zio_read(spa, &spa->spa_uberblock.ub_rootbp, &spa->spa_mos)) {
printf("ZFS: can't read MOS\n");
return (EIO);
}
/*
* Find the root object set
*/
if (zfs_mount_root(spa, &spa->spa_root_objset)) {
printf("Can't find root filesystem - giving up\n");
return (EIO);
}
return (0);
}
static int
zfs_dnode_stat(spa_t *spa, dnode_phys_t *dn, struct stat *sb)
{
if (dn->dn_bonustype != DMU_OT_SA) {
znode_phys_t *zp = (znode_phys_t *)dn->dn_bonus;
sb->st_mode = zp->zp_mode;
sb->st_uid = zp->zp_uid;
sb->st_gid = zp->zp_gid;
sb->st_size = zp->zp_size;
} else {
sa_hdr_phys_t *sahdrp;
int hdrsize;
size_t size = 0;
void *buf = NULL;
if (dn->dn_bonuslen != 0)
sahdrp = (sa_hdr_phys_t *)DN_BONUS(dn);
else {
if ((dn->dn_flags & DNODE_FLAG_SPILL_BLKPTR) != 0) {
blkptr_t *bp = &dn->dn_spill;
int error;
size = BP_GET_LSIZE(bp);
buf = zfs_alloc(size);
error = zio_read(spa, bp, buf);
if (error != 0) {
zfs_free(buf, size);
return (error);
}
sahdrp = buf;
} else {
return (EIO);
}
}
hdrsize = SA_HDR_SIZE(sahdrp);
sb->st_mode = *(uint64_t *)((char *)sahdrp + hdrsize +
SA_MODE_OFFSET);
sb->st_uid = *(uint64_t *)((char *)sahdrp + hdrsize +
SA_UID_OFFSET);
sb->st_gid = *(uint64_t *)((char *)sahdrp + hdrsize +
SA_GID_OFFSET);
sb->st_size = *(uint64_t *)((char *)sahdrp + hdrsize +
SA_SIZE_OFFSET);
if (buf != NULL)
zfs_free(buf, size);
}
return (0);
}
/*
* Lookup a file and return its dnode.
*/
static int
zfs_lookup(spa_t *spa, const char *upath, dnode_phys_t *dnode)
{
int rc;
uint64_t objnum, rootnum, parentnum;
dnode_phys_t dn;
const char *p, *q;
char element[256];
char path[1024];
int symlinks_followed = 0;
struct stat sb;
if (spa->spa_root_objset.os_type != DMU_OST_ZFS) {
printf("ZFS: unexpected object set type %llu\n",
spa->spa_root_objset.os_type);
return (EIO);
}
/*
* Get the root directory dnode.
*/
rc = objset_get_dnode(spa, &spa->spa_root_objset, MASTER_NODE_OBJ, &dn);
if (rc)
return (rc);
rc = zap_lookup(spa, &dn, ZFS_ROOT_OBJ, &rootnum);
if (rc)
return (rc);
rc = objset_get_dnode(spa, &spa->spa_root_objset, rootnum, &dn);
if (rc)
return (rc);
objnum = rootnum;
p = upath;
while (p && *p) {
while (*p == '/')
p++;
if (!*p)
break;
q = strchr(p, '/');
if (q) {
memcpy(element, p, q - p);
element[q - p] = 0;
p = q;
} else {
strcpy(element, p);
p = 0;
}
rc = zfs_dnode_stat(spa, &dn, &sb);
if (rc)
return (rc);
if (!S_ISDIR(sb.st_mode))
return (ENOTDIR);
parentnum = objnum;
rc = zap_lookup(spa, &dn, element, &objnum);
if (rc)
return (rc);
objnum = ZFS_DIRENT_OBJ(objnum);
rc = objset_get_dnode(spa, &spa->spa_root_objset, objnum, &dn);
if (rc)
return (rc);
/*
* Check for symlink.
*/
rc = zfs_dnode_stat(spa, &dn, &sb);
if (rc)
return (rc);
if (S_ISLNK(sb.st_mode)) {
if (symlinks_followed > 10)
return (EMLINK);
symlinks_followed++;
/*
* Read the link value and copy the tail of our
* current path onto the end.
*/
if (p)
strcpy(&path[sb.st_size], p);
else
path[sb.st_size] = 0;
if (sb.st_size + sizeof(znode_phys_t) <= dn.dn_bonuslen) {
memcpy(path, &dn.dn_bonus[sizeof(znode_phys_t)],
sb.st_size);
} else {
rc = dnode_read(spa, &dn, 0, path, sb.st_size);
if (rc)
return (rc);
}
/*
* Restart with the new path, starting either at
* the root or at the parent depending whether or
* not the link is relative.
*/
p = path;
if (*p == '/')
objnum = rootnum;
else
objnum = parentnum;
objset_get_dnode(spa, &spa->spa_root_objset, objnum, &dn);
}
}
*dnode = dn;
return (0);
}