/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012 by Delphix. All rights reserved.
*/
/*
* Virtual Device Labels
* ---------------------
*
* The vdev label serves several distinct purposes:
*
* 1. Uniquely identify this device as part of a ZFS pool and confirm its
* identity within the pool.
*
* 2. Verify that all the devices given in a configuration are present
* within the pool.
*
* 3. Determine the uberblock for the pool.
*
* 4. In case of an import operation, determine the configuration of the
* toplevel vdev of which it is a part.
*
* 5. If an import operation cannot find all the devices in the pool,
* provide enough information to the administrator to determine which
* devices are missing.
*
* It is important to note that while the kernel is responsible for writing the
* label, it only consumes the information in the first three cases. The
* latter information is only consumed in userland when determining the
* configuration to import a pool.
*
*
* Label Organization
* ------------------
*
* Before describing the contents of the label, it's important to understand how
* the labels are written and updated with respect to the uberblock.
*
* When the pool configuration is altered, either because it was newly created
* or a device was added, we want to update all the labels such that we can deal
* with fatal failure at any point. To this end, each disk has two labels which
* are updated before and after the uberblock is synced. Assuming we have
* labels and an uberblock with the following transaction groups:
*
* L1 UB L2
* +------+ +------+ +------+
* | | | | | |
* | t10 | | t10 | | t10 |
* | | | | | |
* +------+ +------+ +------+
*
* In this stable state, the labels and the uberblock were all updated within
* the same transaction group (10). Each label is mirrored and checksummed, so
* that we can detect when we fail partway through writing the label.
*
* In order to identify which labels are valid, the labels are written in the
* following manner:
*
* 1. For each vdev, update 'L1' to the new label
* 2. Update the uberblock
* 3. For each vdev, update 'L2' to the new label
*
* Given arbitrary failure, we can determine the correct label to use based on
* the transaction group. If we fail after updating L1 but before updating the
* UB, we will notice that L1's transaction group is greater than the uberblock,
* so L2 must be valid. If we fail after writing the uberblock but before
* writing L2, we will notice that L2's transaction group is less than L1, and
* therefore L1 is valid.
*
* Another added complexity is that not every label is updated when the config
* is synced. If we add a single device, we do not want to have to re-write
* every label for every device in the pool. This means that both L1 and L2 may
* be older than the pool uberblock, because the necessary information is stored
* on another vdev.
*
*
* On-disk Format
* --------------
*
* The vdev label consists of two distinct parts, and is wrapped within the
* vdev_label_t structure. The label includes 8k of padding to permit legacy
* VTOC disk labels, but is otherwise ignored.
*
* The first half of the label is a packed nvlist which contains pool wide
* properties, per-vdev properties, and configuration information. It is
* described in more detail below.
*
* The latter half of the label consists of a redundant array of uberblocks.
* These uberblocks are updated whenever a transaction group is committed,
* or when the configuration is updated. When a pool is loaded, we scan each
* vdev for the 'best' uberblock.
*
*
* Configuration Information
* -------------------------
*
* The nvlist describing the pool and vdev contains the following elements:
*
* version ZFS on-disk version
* name Pool name
* state Pool state
* txg Transaction group in which this label was written
* pool_guid Unique identifier for this pool
* vdev_tree An nvlist describing vdev tree.
* features_for_read
* An nvlist of the features necessary for reading the MOS.
*
* Each leaf device label also contains the following:
*
* top_guid Unique ID for top-level vdev in which this is contained
* guid Unique ID for the leaf vdev
*
* The 'vs' configuration follows the format described in 'spa_config.c'.
*/
#include <sys/zfs_context.h>
#include <sys/spa.h>
#include <sys/spa_impl.h>
#include <sys/dmu.h>
#include <sys/zap.h>
#include <sys/vdev.h>
#include <sys/vdev_impl.h>
#include <sys/uberblock_impl.h>
#include <sys/metaslab.h>
#include <sys/zio.h>
#include <sys/dsl_scan.h>
#include <sys/fs/zfs.h>
/*
* Basic routines to read and write from a vdev label.
* Used throughout the rest of this file.
*/
uint64_t
vdev_label_offset(uint64_t psize, int l, uint64_t offset)
{
ASSERT(offset < sizeof (vdev_label_t));
ASSERT(P2PHASE_TYPED(psize, sizeof (vdev_label_t), uint64_t) == 0);
return (offset + l * sizeof (vdev_label_t) + (l < VDEV_LABELS / 2 ?
0 : psize - VDEV_LABELS * sizeof (vdev_label_t)));
}
/*
* Returns back the vdev label associated with the passed in offset.
*/
int
vdev_label_number(uint64_t psize, uint64_t offset)
{
int l;
if (offset >= psize - VDEV_LABEL_END_SIZE) {
offset -= psize - VDEV_LABEL_END_SIZE;
offset += (VDEV_LABELS / 2) * sizeof (vdev_label_t);
}
l = offset / sizeof (vdev_label_t);
return (l < VDEV_LABELS ? l : -1);
}
static void
vdev_label_read(zio_t *zio, vdev_t *vd, int l, void *buf, uint64_t offset,
uint64_t size, zio_done_func_t *done, void *private, int flags)
{
ASSERT(spa_config_held(zio->io_spa, SCL_STATE_ALL, RW_WRITER) ==
SCL_STATE_ALL);
ASSERT(flags & ZIO_FLAG_CONFIG_WRITER);
zio_nowait(zio_read_phys(zio, vd,
vdev_label_offset(vd->vdev_psize, l, offset),
size, buf, ZIO_CHECKSUM_LABEL, done, private,
ZIO_PRIORITY_SYNC_READ, flags, B_TRUE));
}
static void
vdev_label_write(zio_t *zio, vdev_t *vd, int l, void *buf, uint64_t offset,
uint64_t size, zio_done_func_t *done, void *private, int flags)
{
ASSERT(spa_config_held(zio->io_spa, SCL_ALL, RW_WRITER) == SCL_ALL ||
(spa_config_held(zio->io_spa, SCL_CONFIG | SCL_STATE, RW_READER) ==
(SCL_CONFIG | SCL_STATE) &&
dsl_pool_sync_context(spa_get_dsl(zio->io_spa))));
ASSERT(flags & ZIO_FLAG_CONFIG_WRITER);
zio_nowait(zio_write_phys(zio, vd,
vdev_label_offset(vd->vdev_psize, l, offset),
size, buf, ZIO_CHECKSUM_LABEL, done, private,
ZIO_PRIORITY_SYNC_WRITE, flags, B_TRUE));
}
/*
* Generate the nvlist representing this vdev's config.
*/
nvlist_t *
vdev_config_generate(spa_t *spa, vdev_t *vd, boolean_t getstats,
vdev_config_flag_t flags)
{
nvlist_t *nv = NULL;
VERIFY(nvlist_alloc(&nv, NV_UNIQUE_NAME, KM_SLEEP) == 0);
VERIFY(nvlist_add_string(nv, ZPOOL_CONFIG_TYPE,
vd->vdev_ops->vdev_op_type) == 0);
if (!(flags & (VDEV_CONFIG_SPARE | VDEV_CONFIG_L2CACHE)))
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_ID, vd->vdev_id)
== 0);
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_GUID, vd->vdev_guid) == 0);
if (vd->vdev_path != NULL)
VERIFY(nvlist_add_string(nv, ZPOOL_CONFIG_PATH,
vd->vdev_path) == 0);
if (vd->vdev_devid != NULL)
VERIFY(nvlist_add_string(nv, ZPOOL_CONFIG_DEVID,
vd->vdev_devid) == 0);
if (vd->vdev_physpath != NULL)
VERIFY(nvlist_add_string(nv, ZPOOL_CONFIG_PHYS_PATH,
vd->vdev_physpath) == 0);
if (vd->vdev_fru != NULL)
VERIFY(nvlist_add_string(nv, ZPOOL_CONFIG_FRU,
vd->vdev_fru) == 0);
if (vd->vdev_nparity != 0) {
ASSERT(strcmp(vd->vdev_ops->vdev_op_type,
VDEV_TYPE_RAIDZ) == 0);
/*
* Make sure someone hasn't managed to sneak a fancy new vdev
* into a crufty old storage pool.
*/
ASSERT(vd->vdev_nparity == 1 ||
(vd->vdev_nparity <= 2 &&
spa_version(spa) >= SPA_VERSION_RAIDZ2) ||
(vd->vdev_nparity <= 3 &&
spa_version(spa) >= SPA_VERSION_RAIDZ3));
/*
* Note that we'll add the nparity tag even on storage pools
* that only support a single parity device -- older software
* will just ignore it.
*/
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_NPARITY,
vd->vdev_nparity) == 0);
}
if (vd->vdev_wholedisk != -1ULL)
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_WHOLE_DISK,
vd->vdev_wholedisk) == 0);
if (vd->vdev_not_present)
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_NOT_PRESENT, 1) == 0);
if (vd->vdev_isspare)
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_IS_SPARE, 1) == 0);
if (!(flags & (VDEV_CONFIG_SPARE | VDEV_CONFIG_L2CACHE)) &&
vd == vd->vdev_top) {
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_METASLAB_ARRAY,
vd->vdev_ms_array) == 0);
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_METASLAB_SHIFT,
vd->vdev_ms_shift) == 0);
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_ASHIFT,
vd->vdev_ashift) == 0);
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_ASIZE,
vd->vdev_asize) == 0);
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_IS_LOG,
vd->vdev_islog) == 0);
if (vd->vdev_removing)
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_REMOVING,
vd->vdev_removing) == 0);
}
if (vd->vdev_dtl_smo.smo_object != 0)
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_DTL,
vd->vdev_dtl_smo.smo_object) == 0);
if (vd->vdev_crtxg)
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_CREATE_TXG,
vd->vdev_crtxg) == 0);
if (getstats) {
vdev_stat_t vs;
pool_scan_stat_t ps;
vdev_get_stats(vd, &vs);
VERIFY(nvlist_add_uint64_array(nv, ZPOOL_CONFIG_VDEV_STATS,
(uint64_t *)&vs, sizeof (vs) / sizeof (uint64_t)) == 0);
/* provide either current or previous scan information */
if (spa_scan_get_stats(spa, &ps) == 0) {
VERIFY(nvlist_add_uint64_array(nv,
ZPOOL_CONFIG_SCAN_STATS, (uint64_t *)&ps,
sizeof (pool_scan_stat_t) / sizeof (uint64_t))
== 0);
}
}
if (!vd->vdev_ops->vdev_op_leaf) {
nvlist_t **child;
int c, idx;
ASSERT(!vd->vdev_ishole);
child = kmem_alloc(vd->vdev_children * sizeof (nvlist_t *),
KM_SLEEP);
for (c = 0, idx = 0; c < vd->vdev_children; c++) {
vdev_t *cvd = vd->vdev_child[c];
/*
* If we're generating an nvlist of removing
* vdevs then skip over any device which is
* not being removed.
*/
if ((flags & VDEV_CONFIG_REMOVING) &&
!cvd->vdev_removing)
continue;
child[idx++] = vdev_config_generate(spa, cvd,
getstats, flags);
}
if (idx) {
VERIFY(nvlist_add_nvlist_array(nv,
ZPOOL_CONFIG_CHILDREN, child, idx) == 0);
}
for (c = 0; c < idx; c++)
nvlist_free(child[c]);
kmem_free(child, vd->vdev_children * sizeof (nvlist_t *));
} else {
const char *aux = NULL;
if (vd->vdev_offline && !vd->vdev_tmpoffline)
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_OFFLINE,
B_TRUE) == 0);
if (vd->vdev_resilvering)
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_RESILVERING,
B_TRUE) == 0);
if (vd->vdev_faulted)
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_FAULTED,
B_TRUE) == 0);
if (vd->vdev_degraded)
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_DEGRADED,
B_TRUE) == 0);
if (vd->vdev_removed)
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_REMOVED,
B_TRUE) == 0);
if (vd->vdev_unspare)
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_UNSPARE,
B_TRUE) == 0);
if (vd->vdev_ishole)
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_IS_HOLE,
B_TRUE) == 0);
switch (vd->vdev_stat.vs_aux) {
case VDEV_AUX_ERR_EXCEEDED:
aux = "err_exceeded";
break;
case VDEV_AUX_EXTERNAL:
aux = "external";
break;
}
if (aux != NULL)
VERIFY(nvlist_add_string(nv, ZPOOL_CONFIG_AUX_STATE,
aux) == 0);
if (vd->vdev_splitting && vd->vdev_orig_guid != 0LL) {
VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_ORIG_GUID,
vd->vdev_orig_guid) == 0);
}
}
return (nv);
}
/*
* Generate a view of the top-level vdevs. If we currently have holes
* in the namespace, then generate an array which contains a list of holey
* vdevs. Additionally, add the number of top-level children that currently
* exist.
*/
void
vdev_top_config_generate(spa_t *spa, nvlist_t *config)
{
vdev_t *rvd = spa->spa_root_vdev;
uint64_t *array;
uint_t c, idx;
array = kmem_alloc(rvd->vdev_children * sizeof (uint64_t), KM_SLEEP);
for (c = 0, idx = 0; c < rvd->vdev_children; c++) {
vdev_t *tvd = rvd->vdev_child[c];
if (tvd->vdev_ishole)
array[idx++] = c;
}
if (idx) {
VERIFY(nvlist_add_uint64_array(config, ZPOOL_CONFIG_HOLE_ARRAY,
array, idx) == 0);
}
VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_VDEV_CHILDREN,
rvd->vdev_children) == 0);
kmem_free(array, rvd->vdev_children * sizeof (uint64_t));
}
/*
* Returns the configuration from the label of the given vdev. If 'label' is
* VDEV_BEST_LABEL, each label of the vdev will be read until a valid
* configuration is found; otherwise, only the specified label will be read.
*/
nvlist_t *
vdev_label_read_config(vdev_t *vd, int label)
{
spa_t *spa = vd->vdev_spa;
nvlist_t *config = NULL;
vdev_phys_t *vp;
zio_t *zio;
int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL |
ZIO_FLAG_SPECULATIVE;
ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
if (!vdev_readable(vd))
return (NULL);
vp = zio_buf_alloc(sizeof (vdev_phys_t));
retry:
for (int l = 0; l < VDEV_LABELS; l++) {
if (label >= 0 && label < VDEV_LABELS && label != l)
continue;
zio = zio_root(spa, NULL, NULL, flags);
vdev_label_read(zio, vd, l, vp,
offsetof(vdev_label_t, vl_vdev_phys),
sizeof (vdev_phys_t), NULL, NULL, flags);
if (zio_wait(zio) == 0 &&
nvlist_unpack(vp->vp_nvlist, sizeof (vp->vp_nvlist),
&config, 0) == 0)
break;
if (config != NULL) {
nvlist_free(config);
config = NULL;
}
}
if (config == NULL && !(flags & ZIO_FLAG_TRYHARD)) {
flags |= ZIO_FLAG_TRYHARD;
goto retry;
}
zio_buf_free(vp, sizeof (vdev_phys_t));
return (config);
}
/*
* Determine if a device is in use. The 'spare_guid' parameter will be filled
* in with the device guid if this spare is active elsewhere on the system.
*/
static boolean_t
vdev_inuse(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason,
uint64_t *spare_guid, uint64_t *l2cache_guid)
{
spa_t *spa = vd->vdev_spa;
uint64_t state, pool_guid, device_guid, txg, spare_pool;
uint64_t vdtxg = 0;
nvlist_t *label;
if (spare_guid)
*spare_guid = 0ULL;
if (l2cache_guid)
*l2cache_guid = 0ULL;
/*
* Read the label, if any, and perform some basic sanity checks.
*/
if ((label = vdev_label_read_config(vd, VDEV_BEST_LABEL)) == NULL)
return (B_FALSE);
(void) nvlist_lookup_uint64(label, ZPOOL_CONFIG_CREATE_TXG,
&vdtxg);
if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_STATE,
&state) != 0 ||
nvlist_lookup_uint64(label, ZPOOL_CONFIG_GUID,
&device_guid) != 0) {
nvlist_free(label);
return (B_FALSE);
}
if (state != POOL_STATE_SPARE && state != POOL_STATE_L2CACHE &&
(nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_GUID,
&pool_guid) != 0 ||
nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_TXG,
&txg) != 0)) {
nvlist_free(label);
return (B_FALSE);
}
nvlist_free(label);
/*
* Check to see if this device indeed belongs to the pool it claims to
* be a part of. The only way this is allowed is if the device is a hot
* spare (which we check for later on).
*/
if (state != POOL_STATE_SPARE && state != POOL_STATE_L2CACHE &&
!spa_guid_exists(pool_guid, device_guid) &&
!spa_spare_exists(device_guid, NULL, NULL) &&
!spa_l2cache_exists(device_guid, NULL))
return (B_FALSE);
/*
* If the transaction group is zero, then this an initialized (but
* unused) label. This is only an error if the create transaction
* on-disk is the same as the one we're using now, in which case the
* user has attempted to add the same vdev multiple times in the same
* transaction.
*/
if (state != POOL_STATE_SPARE && state != POOL_STATE_L2CACHE &&
txg == 0 && vdtxg == crtxg)
return (B_TRUE);
/*
* Check to see if this is a spare device. We do an explicit check for
* spa_has_spare() here because it may be on our pending list of spares
* to add. We also check if it is an l2cache device.
*/
if (spa_spare_exists(device_guid, &spare_pool, NULL) ||
spa_has_spare(spa, device_guid)) {
if (spare_guid)
*spare_guid = device_guid;
switch (reason) {
case VDEV_LABEL_CREATE:
case VDEV_LABEL_L2CACHE:
return (B_TRUE);
case VDEV_LABEL_REPLACE:
return (!spa_has_spare(spa, device_guid) ||
spare_pool != 0ULL);
case VDEV_LABEL_SPARE:
return (spa_has_spare(spa, device_guid));
}
}
/*
* Check to see if this is an l2cache device.
*/
if (spa_l2cache_exists(device_guid, NULL))
return (B_TRUE);
/*
* We can't rely on a pool's state if it's been imported
* read-only. Instead we look to see if the pools is marked
* read-only in the namespace and set the state to active.
*/
if ((spa = spa_by_guid(pool_guid, device_guid)) != NULL &&
spa_mode(spa) == FREAD)
state = POOL_STATE_ACTIVE;
/*
* If the device is marked ACTIVE, then this device is in use by another
* pool on the system.
*/
return (state == POOL_STATE_ACTIVE);
}
/*
* Initialize a vdev label. We check to make sure each leaf device is not in
* use, and writable. We put down an initial label which we will later
* overwrite with a complete label. Note that it's important to do this
* sequentially, not in parallel, so that we catch cases of multiple use of the
* same leaf vdev in the vdev we're creating -- e.g. mirroring a disk with
* itself.
*/
int
vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
{
spa_t *spa = vd->vdev_spa;
nvlist_t *label;
vdev_phys_t *vp;
char *pad2;
uberblock_t *ub;
zio_t *zio;
char *buf;
size_t buflen;
int error;
uint64_t spare_guid, l2cache_guid;
int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL;
ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
for (int c = 0; c < vd->vdev_children; c++)
if ((error = vdev_label_init(vd->vdev_child[c],
crtxg, reason)) != 0)
return (error);
/* Track the creation time for this vdev */
vd->vdev_crtxg = crtxg;
if (!vd->vdev_ops->vdev_op_leaf)
return (0);
/*
* Dead vdevs cannot be initialized.
*/
if (vdev_is_dead(vd))
return (EIO);
/*
* Determine if the vdev is in use.
*/
if (reason != VDEV_LABEL_REMOVE && reason != VDEV_LABEL_SPLIT &&
vdev_inuse(vd, crtxg, reason, &spare_guid, &l2cache_guid))
return (EBUSY);
/*
* If this is a request to add or replace a spare or l2cache device
* that is in use elsewhere on the system, then we must update the
* guid (which was initialized to a random value) to reflect the
* actual GUID (which is shared between multiple pools).
*/
if (reason != VDEV_LABEL_REMOVE && reason != VDEV_LABEL_L2CACHE &&
spare_guid != 0ULL) {
uint64_t guid_delta = spare_guid - vd->vdev_guid;
vd->vdev_guid += guid_delta;
for (vdev_t *pvd = vd; pvd != NULL; pvd = pvd->vdev_parent)
pvd->vdev_guid_sum += guid_delta;
/*
* If this is a replacement, then we want to fallthrough to the
* rest of the code. If we're adding a spare, then it's already
* labeled appropriately and we can just return.
*/
if (reason == VDEV_LABEL_SPARE)
return (0);
ASSERT(reason == VDEV_LABEL_REPLACE ||
reason == VDEV_LABEL_SPLIT);
}
if (reason != VDEV_LABEL_REMOVE && reason != VDEV_LABEL_SPARE &&
l2cache_guid != 0ULL) {
uint64_t guid_delta = l2cache_guid - vd->vdev_guid;
vd->vdev_guid += guid_delta;
for (vdev_t *pvd = vd; pvd != NULL; pvd = pvd->vdev_parent)
pvd->vdev_guid_sum += guid_delta;
/*
* If this is a replacement, then we want to fallthrough to the
* rest of the code. If we're adding an l2cache, then it's
* already labeled appropriately and we can just return.
*/
if (reason == VDEV_LABEL_L2CACHE)
return (0);
ASSERT(reason == VDEV_LABEL_REPLACE);
}
/*
* Initialize its label.
*/
vp = zio_buf_alloc(sizeof (vdev_phys_t));
bzero(vp, sizeof (vdev_phys_t));
/*
* Generate a label describing the pool and our top-level vdev.
* We mark it as being from txg 0 to indicate that it's not
* really part of an active pool just yet. The labels will
* be written again with a meaningful txg by spa_sync().
*/
if (reason == VDEV_LABEL_SPARE ||
(reason == VDEV_LABEL_REMOVE && vd->vdev_isspare)) {
/*
* For inactive hot spares, we generate a special label that
* identifies as a mutually shared hot spare. We write the
* label if we are adding a hot spare, or if we are removing an
* active hot spare (in which case we want to revert the
* labels).
*/
VERIFY(nvlist_alloc(&label, NV_UNIQUE_NAME, KM_SLEEP) == 0);
VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_VERSION,
spa_version(spa)) == 0);
VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_POOL_STATE,
POOL_STATE_SPARE) == 0);
VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_GUID,
vd->vdev_guid) == 0);
} else if (reason == VDEV_LABEL_L2CACHE ||
(reason == VDEV_LABEL_REMOVE && vd->vdev_isl2cache)) {
/*
* For level 2 ARC devices, add a special label.
*/
VERIFY(nvlist_alloc(&label, NV_UNIQUE_NAME, KM_SLEEP) == 0);
VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_VERSION,
spa_version(spa)) == 0);
VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_POOL_STATE,
POOL_STATE_L2CACHE) == 0);
VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_GUID,
vd->vdev_guid) == 0);
} else {
uint64_t txg = 0ULL;
if (reason == VDEV_LABEL_SPLIT)
txg = spa->spa_uberblock.ub_txg;
label = spa_config_generate(spa, vd, txg, B_FALSE);
/*
* Add our creation time. This allows us to detect multiple
* vdev uses as described above, and automatically expires if we
* fail.
*/
VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_CREATE_TXG,
crtxg) == 0);
}
buf = vp->vp_nvlist;
buflen = sizeof (vp->vp_nvlist);
error = nvlist_pack(label, &buf, &buflen, NV_ENCODE_XDR, KM_SLEEP);
if (error != 0) {
nvlist_free(label);
zio_buf_free(vp, sizeof (vdev_phys_t));
/* EFAULT means nvlist_pack ran out of room */
return (error == EFAULT ? ENAMETOOLONG : EINVAL);
}
/*
* Initialize uberblock template.
*/
ub = zio_buf_alloc(VDEV_UBERBLOCK_RING);
bzero(ub, VDEV_UBERBLOCK_RING);
*ub = spa->spa_uberblock;
ub->ub_txg = 0;
/* Initialize the 2nd padding area. */
pad2 = zio_buf_alloc(VDEV_PAD_SIZE);
bzero(pad2, VDEV_PAD_SIZE);
/*
* Write everything in parallel.
*/
retry:
zio = zio_root(spa, NULL, NULL, flags);
for (int l = 0; l < VDEV_LABELS; l++) {
vdev_label_write(zio, vd, l, vp,
offsetof(vdev_label_t, vl_vdev_phys),
sizeof (vdev_phys_t), NULL, NULL, flags);
/*
* Skip the 1st padding area.
* Zero out the 2nd padding area where it might have
* left over data from previous filesystem format.
*/
vdev_label_write(zio, vd, l, pad2,
offsetof(vdev_label_t, vl_pad2),
VDEV_PAD_SIZE, NULL, NULL, flags);
vdev_label_write(zio, vd, l, ub,
offsetof(vdev_label_t, vl_uberblock),
VDEV_UBERBLOCK_RING, NULL, NULL, flags);
}
error = zio_wait(zio);
if (error != 0 && !(flags & ZIO_FLAG_TRYHARD)) {
flags |= ZIO_FLAG_TRYHARD;
goto retry;
}
nvlist_free(label);
zio_buf_free(pad2, VDEV_PAD_SIZE);
zio_buf_free(ub, VDEV_UBERBLOCK_RING);
zio_buf_free(vp, sizeof (vdev_phys_t));
/*
* If this vdev hasn't been previously identified as a spare, then we
* mark it as such only if a) we are labeling it as a spare, or b) it
* exists as a spare elsewhere in the system. Do the same for
* level 2 ARC devices.
*/
if (error == 0 && !vd->vdev_isspare &&
(reason == VDEV_LABEL_SPARE ||
spa_spare_exists(vd->vdev_guid, NULL, NULL)))
spa_spare_add(vd);
if (error == 0 && !vd->vdev_isl2cache &&
(reason == VDEV_LABEL_L2CACHE ||
spa_l2cache_exists(vd->vdev_guid, NULL)))
spa_l2cache_add(vd);
return (error);
}
/*
* ==========================================================================
* uberblock load/sync
* ==========================================================================
*/
/*
* Consider the following situation: txg is safely synced to disk. We've
* written the first uberblock for txg + 1, and then we lose power. When we
* come back up, we fail to see the uberblock for txg + 1 because, say,
* it was on a mirrored device and the replica to which we wrote txg + 1
* is now offline. If we then make some changes and sync txg + 1, and then
* the missing replica comes back, then for a few seconds we'll have two
* conflicting uberblocks on disk with the same txg. The solution is simple:
* among uberblocks with equal txg, choose the one with the latest timestamp.
*/
static int
vdev_uberblock_compare(uberblock_t *ub1, uberblock_t *ub2)
{
if (ub1->ub_txg < ub2->ub_txg)
return (-1);
if (ub1->ub_txg > ub2->ub_txg)
return (1);
if (ub1->ub_timestamp < ub2->ub_timestamp)
return (-1);
if (ub1->ub_timestamp > ub2->ub_timestamp)
return (1);
return (0);
}
struct ubl_cbdata {
uberblock_t *ubl_ubbest; /* Best uberblock */
vdev_t *ubl_vd; /* vdev associated with the above */
int ubl_label; /* Label associated with the above */
};
static void
vdev_uberblock_load_done(zio_t *zio)
{
vdev_t *vd = zio->io_vd;
spa_t *spa = zio->io_spa;
zio_t *rio = zio->io_private;
uberblock_t *ub = zio->io_data;
struct ubl_cbdata *cbp = rio->io_private;
ASSERT3U(zio->io_size, ==, VDEV_UBERBLOCK_SIZE(vd));
if (zio->io_error == 0 && uberblock_verify(ub) == 0) {
mutex_enter(&rio->io_lock);
if (ub->ub_txg <= spa->spa_load_max_txg &&
vdev_uberblock_compare(ub, cbp->ubl_ubbest) > 0) {
/*
* Keep track of the vdev and label in which this
* uberblock was found. We will use this information
* later to obtain the config nvlist associated with
* this uberblock.
*/
*cbp->ubl_ubbest = *ub;
cbp->ubl_vd = vd;
cbp->ubl_label = vdev_label_number(vd->vdev_psize,
zio->io_offset);
}
mutex_exit(&rio->io_lock);
}
zio_buf_free(zio->io_data, zio->io_size);
}
static void
vdev_uberblock_load_impl(zio_t *zio, vdev_t *vd, int flags,
struct ubl_cbdata *cbp)
{
for (int c = 0; c < vd->vdev_children; c++)
vdev_uberblock_load_impl(zio, vd->vdev_child[c], flags, cbp);
if (vd->vdev_ops->vdev_op_leaf && vdev_readable(vd)) {
for (int l = 0; l < VDEV_LABELS; l++) {
for (int n = 0; n < VDEV_UBERBLOCK_COUNT(vd); n++) {
vdev_label_read(zio, vd, l,
zio_buf_alloc(VDEV_UBERBLOCK_SIZE(vd)),
VDEV_UBERBLOCK_OFFSET(vd, n),
VDEV_UBERBLOCK_SIZE(vd),
vdev_uberblock_load_done, zio, flags);
}
}
}
}
/*
* Reads the 'best' uberblock from disk along with its associated
* configuration. First, we read the uberblock array of each label of each
* vdev, keeping track of the uberblock with the highest txg in each array.
* Then, we read the configuration from the same label as the best uberblock.
*/
void
vdev_uberblock_load(vdev_t *rvd, uberblock_t *ub, nvlist_t **config)
{
int i;
zio_t *zio;
spa_t *spa = rvd->vdev_spa;
struct ubl_cbdata cb;
int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL |
ZIO_FLAG_SPECULATIVE | ZIO_FLAG_TRYHARD;
ASSERT(ub);
ASSERT(config);
bzero(ub, sizeof (uberblock_t));
*config = NULL;
cb.ubl_ubbest = ub;
cb.ubl_vd = NULL;
spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
zio = zio_root(spa, NULL, &cb, flags);
vdev_uberblock_load_impl(zio, rvd, flags, &cb);
(void) zio_wait(zio);
if (cb.ubl_vd != NULL) {
for (i = cb.ubl_label % 2; i < VDEV_LABELS; i += 2) {
*config = vdev_label_read_config(cb.ubl_vd, i);
if (*config != NULL)
break;
}
}
spa_config_exit(spa, SCL_ALL, FTAG);
}
/*
* On success, increment root zio's count of good writes.
* We only get credit for writes to known-visible vdevs; see spa_vdev_add().
*/
static void
vdev_uberblock_sync_done(zio_t *zio)
{
uint64_t *good_writes = zio->io_private;
if (zio->io_error == 0 && zio->io_vd->vdev_top->vdev_ms_array != 0)
atomic_add_64(good_writes, 1);
}
/*
* Write the uberblock to all labels of all leaves of the specified vdev.
*/
static void
vdev_uberblock_sync(zio_t *zio, uberblock_t *ub, vdev_t *vd, int flags)
{
uberblock_t *ubbuf;
int n;
for (int c = 0; c < vd->vdev_children; c++)
vdev_uberblock_sync(zio, ub, vd->vdev_child[c], flags);
if (!vd->vdev_ops->vdev_op_leaf)
return;
if (!vdev_writeable(vd))
return;
n = ub->ub_txg & (VDEV_UBERBLOCK_COUNT(vd) - 1);
ubbuf = zio_buf_alloc(VDEV_UBERBLOCK_SIZE(vd));
bzero(ubbuf, VDEV_UBERBLOCK_SIZE(vd));
*ubbuf = *ub;
for (int l = 0; l < VDEV_LABELS; l++)
vdev_label_write(zio, vd, l, ubbuf,
VDEV_UBERBLOCK_OFFSET(vd, n), VDEV_UBERBLOCK_SIZE(vd),
vdev_uberblock_sync_done, zio->io_private,
flags | ZIO_FLAG_DONT_PROPAGATE);
zio_buf_free(ubbuf, VDEV_UBERBLOCK_SIZE(vd));
}
int
vdev_uberblock_sync_list(vdev_t **svd, int svdcount, uberblock_t *ub, int flags)
{
spa_t *spa = svd[0]->vdev_spa;
zio_t *zio;
uint64_t good_writes = 0;
zio = zio_root(spa, NULL, &good_writes, flags);
for (int v = 0; v < svdcount; v++)
vdev_uberblock_sync(zio, ub, svd[v], flags);
(void) zio_wait(zio);
/*
* Flush the uberblocks to disk. This ensures that the odd labels
* are no longer needed (because the new uberblocks and the even
* labels are safely on disk), so it is safe to overwrite them.
*/
zio = zio_root(spa, NULL, NULL, flags);
for (int v = 0; v < svdcount; v++)
zio_flush(zio, svd[v]);
(void) zio_wait(zio);
return (good_writes >= 1 ? 0 : EIO);
}
/*
* On success, increment the count of good writes for our top-level vdev.
*/
static void
vdev_label_sync_done(zio_t *zio)
{
uint64_t *good_writes = zio->io_private;
if (zio->io_error == 0)
atomic_add_64(good_writes, 1);
}
/*
* If there weren't enough good writes, indicate failure to the parent.
*/
static void
vdev_label_sync_top_done(zio_t *zio)
{
uint64_t *good_writes = zio->io_private;
if (*good_writes == 0)
zio->io_error = EIO;
kmem_free(good_writes, sizeof (uint64_t));
}
/*
* We ignore errors for log and cache devices, simply free the private data.
*/
static void
vdev_label_sync_ignore_done(zio_t *zio)
{
kmem_free(zio->io_private, sizeof (uint64_t));
}
/*
* Write all even or odd labels to all leaves of the specified vdev.
*/
static void
vdev_label_sync(zio_t *zio, vdev_t *vd, int l, uint64_t txg, int flags)
{
nvlist_t *label;
vdev_phys_t *vp;
char *buf;
size_t buflen;
for (int c = 0; c < vd->vdev_children; c++)
vdev_label_sync(zio, vd->vdev_child[c], l, txg, flags);
if (!vd->vdev_ops->vdev_op_leaf)
return;
if (!vdev_writeable(vd))
return;
/*
* Generate a label describing the top-level config to which we belong.
*/
label = spa_config_generate(vd->vdev_spa, vd, txg, B_FALSE);
vp = zio_buf_alloc(sizeof (vdev_phys_t));
bzero(vp, sizeof (vdev_phys_t));
buf = vp->vp_nvlist;
buflen = sizeof (vp->vp_nvlist);
if (nvlist_pack(label, &buf, &buflen, NV_ENCODE_XDR, KM_SLEEP) == 0) {
for (; l < VDEV_LABELS; l += 2) {
vdev_label_write(zio, vd, l, vp,
offsetof(vdev_label_t, vl_vdev_phys),
sizeof (vdev_phys_t),
vdev_label_sync_done, zio->io_private,
flags | ZIO_FLAG_DONT_PROPAGATE);
}
}
zio_buf_free(vp, sizeof (vdev_phys_t));
nvlist_free(label);
}
int
vdev_label_sync_list(spa_t *spa, int l, uint64_t txg, int flags)
{
list_t *dl = &spa->spa_config_dirty_list;
vdev_t *vd;
zio_t *zio;
int error;
/*
* Write the new labels to disk.
*/
zio = zio_root(spa, NULL, NULL, flags);
for (vd = list_head(dl); vd != NULL; vd = list_next(dl, vd)) {
uint64_t *good_writes = kmem_zalloc(sizeof (uint64_t),
KM_SLEEP);
ASSERT(!vd->vdev_ishole);
zio_t *vio = zio_null(zio, spa, NULL,
(vd->vdev_islog || vd->vdev_aux != NULL) ?
vdev_label_sync_ignore_done : vdev_label_sync_top_done,
good_writes, flags);
vdev_label_sync(vio, vd, l, txg, flags);
zio_nowait(vio);
}
error = zio_wait(zio);
/*
* Flush the new labels to disk.
*/
zio = zio_root(spa, NULL, NULL, flags);
for (vd = list_head(dl); vd != NULL; vd = list_next(dl, vd))
zio_flush(zio, vd);
(void) zio_wait(zio);
return (error);
}
/*
* Sync the uberblock and any changes to the vdev configuration.
*
* The order of operations is carefully crafted to ensure that
* if the system panics or loses power at any time, the state on disk
* is still transactionally consistent. The in-line comments below
* describe the failure semantics at each stage.
*
* Moreover, vdev_config_sync() is designed to be idempotent: if it fails
* at any time, you can just call it again, and it will resume its work.
*/
int
vdev_config_sync(vdev_t **svd, int svdcount, uint64_t txg, boolean_t tryhard)
{
spa_t *spa = svd[0]->vdev_spa;
uberblock_t *ub = &spa->spa_uberblock;
vdev_t *vd;
zio_t *zio;
int error;
int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL;
/*
* Normally, we don't want to try too hard to write every label and
* uberblock. If there is a flaky disk, we don't want the rest of the
* sync process to block while we retry. But if we can't write a
* single label out, we should retry with ZIO_FLAG_TRYHARD before
* bailing out and declaring the pool faulted.
*/
if (tryhard)
flags |= ZIO_FLAG_TRYHARD;
ASSERT(ub->ub_txg <= txg);
/*
* If this isn't a resync due to I/O errors,
* and nothing changed in this transaction group,
* and the vdev configuration hasn't changed,
* then there's nothing to do.
*/
if (ub->ub_txg < txg &&
uberblock_update(ub, spa->spa_root_vdev, txg) == B_FALSE &&
list_is_empty(&spa->spa_config_dirty_list))
return (0);
if (txg > spa_freeze_txg(spa))
return (0);
ASSERT(txg <= spa->spa_final_txg);
/*
* Flush the write cache of every disk that's been written to
* in this transaction group. This ensures that all blocks
* written in this txg will be committed to stable storage
* before any uberblock that references them.
*/
zio = zio_root(spa, NULL, NULL, flags);
for (vd = txg_list_head(&spa->spa_vdev_txg_list, TXG_CLEAN(txg)); vd;
vd = txg_list_next(&spa->spa_vdev_txg_list, vd, TXG_CLEAN(txg)))
zio_flush(zio, vd);
(void) zio_wait(zio);
/*
* Sync out the even labels (L0, L2) for every dirty vdev. If the
* system dies in the middle of this process, that's OK: all of the
* even labels that made it to disk will be newer than any uberblock,
* and will therefore be considered invalid. The odd labels (L1, L3),
* which have not yet been touched, will still be valid. We flush
* the new labels to disk to ensure that all even-label updates
* are committed to stable storage before the uberblock update.
*/
if ((error = vdev_label_sync_list(spa, 0, txg, flags)) != 0)
return (error);
/*
* Sync the uberblocks to all vdevs in svd[].
* If the system dies in the middle of this step, there are two cases
* to consider, and the on-disk state is consistent either way:
*
* (1) If none of the new uberblocks made it to disk, then the
* previous uberblock will be the newest, and the odd labels
* (which had not yet been touched) will be valid with respect
* to that uberblock.
*
* (2) If one or more new uberblocks made it to disk, then they
* will be the newest, and the even labels (which had all
* been successfully committed) will be valid with respect
* to the new uberblocks.
*/
if ((error = vdev_uberblock_sync_list(svd, svdcount, ub, flags)) != 0)
return (error);
/*
* Sync out odd labels for every dirty vdev. If the system dies
* in the middle of this process, the even labels and the new
* uberblocks will suffice to open the pool. The next time
* the pool is opened, the first thing we'll do -- before any
* user data is modified -- is mark every vdev dirty so that
* all labels will be brought up to date. We flush the new labels
* to disk to ensure that all odd-label updates are committed to
* stable storage before the next transaction group begins.
*/
return (vdev_label_sync_list(spa, 1, txg, flags));
}