aboutsummaryrefslogtreecommitdiffstats
path: root/uts/common/fs/zfs/vdev_label.c
diff options
context:
space:
mode:
Diffstat (limited to 'uts/common/fs/zfs/vdev_label.c')
-rw-r--r--uts/common/fs/zfs/vdev_label.c1216
1 files changed, 1216 insertions, 0 deletions
diff --git a/uts/common/fs/zfs/vdev_label.c b/uts/common/fs/zfs/vdev_label.c
new file mode 100644
index 000000000000..c08ed8ba0467
--- /dev/null
+++ b/uts/common/fs/zfs/vdev_label.c
@@ -0,0 +1,1216 @@
+/*
+ * 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.
+ */
+
+/*
+ * 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.
+ *
+ * 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));
+}
+
+nvlist_t *
+vdev_label_read_config(vdev_t *vd)
+{
+ 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++) {
+
+ 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)) == 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 new 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);
+}
+
+static void
+vdev_uberblock_load_done(zio_t *zio)
+{
+ spa_t *spa = zio->io_spa;
+ zio_t *rio = zio->io_private;
+ uberblock_t *ub = zio->io_data;
+ uberblock_t *ubbest = rio->io_private;
+
+ ASSERT3U(zio->io_size, ==, VDEV_UBERBLOCK_SIZE(zio->io_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, ubbest) > 0)
+ *ubbest = *ub;
+ mutex_exit(&rio->io_lock);
+ }
+
+ zio_buf_free(zio->io_data, zio->io_size);
+}
+
+void
+vdev_uberblock_load(zio_t *zio, vdev_t *vd, uberblock_t *ubbest)
+{
+ spa_t *spa = vd->vdev_spa;
+ vdev_t *rvd = spa->spa_root_vdev;
+ int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL |
+ ZIO_FLAG_SPECULATIVE | ZIO_FLAG_TRYHARD;
+
+ if (vd == rvd) {
+ ASSERT(zio == NULL);
+ spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+ zio = zio_root(spa, NULL, ubbest, flags);
+ bzero(ubbest, sizeof (uberblock_t));
+ }
+
+ ASSERT(zio != NULL);
+
+ for (int c = 0; c < vd->vdev_children; c++)
+ vdev_uberblock_load(zio, vd->vdev_child[c], ubbest);
+
+ 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);
+ }
+ }
+ }
+
+ if (vd == rvd) {
+ (void) zio_wait(zio);
+ 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));
+}