flush: only detect lack of flush support in one place

[zfs.git] / cmd / zed / agents / zfs_retire.c

/*
 * 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 https://opensource.org/licenses/CDDL-1.0.
 * 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) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
 *
 * Copyright (c) 2016, Intel Corporation.
 * Copyright (c) 2018, loli10K <ezomori.nozomu@gmail.com>
 */

/*
 * The ZFS retire agent is responsible for managing hot spares across all pools.
 * When we see a device fault or a device removal, we try to open the associated
 * pool and look for any hot spares.  We iterate over any available hot spares
 * and attempt a 'zpool replace' for each one.
 *
 * For vdevs diagnosed as faulty, the agent is also responsible for proactively
 * marking the vdev FAULTY (for I/O errors) or DEGRADED (for checksum errors).
 */

#include <sys/fs/zfs.h>
#include <sys/fm/protocol.h>
#include <sys/fm/fs/zfs.h>
#include <libzutil.h>
#include <libzfs.h>
#include <string.h>
#include <libgen.h>

#include "zfs_agents.h"
#include "fmd_api.h"


typedef struct zfs_retire_repaired {
        struct zfs_retire_repaired      *zrr_next;
        uint64_t                        zrr_pool;
        uint64_t                        zrr_vdev;
} zfs_retire_repaired_t;

typedef struct zfs_retire_data {
        libzfs_handle_t                 *zrd_hdl;
        zfs_retire_repaired_t           *zrd_repaired;
} zfs_retire_data_t;

static void
zfs_retire_clear_data(fmd_hdl_t *hdl, zfs_retire_data_t *zdp)
{
        zfs_retire_repaired_t *zrp;

        while ((zrp = zdp->zrd_repaired) != NULL) {
                zdp->zrd_repaired = zrp->zrr_next;
                fmd_hdl_free(hdl, zrp, sizeof (zfs_retire_repaired_t));
        }
}

/*
 * Find a pool with a matching GUID.
 */
typedef struct find_cbdata {
        uint64_t        cb_guid;
        zpool_handle_t  *cb_zhp;
        nvlist_t        *cb_vdev;
        uint64_t        cb_vdev_guid;
        uint64_t        cb_num_spares;
} find_cbdata_t;

static int
find_pool(zpool_handle_t *zhp, void *data)
{
        find_cbdata_t *cbp = data;

        if (cbp->cb_guid ==
            zpool_get_prop_int(zhp, ZPOOL_PROP_GUID, NULL)) {
                cbp->cb_zhp = zhp;
                return (1);
        }

        zpool_close(zhp);
        return (0);
}

/*
 * Find a vdev within a tree with a matching GUID.
 */
static nvlist_t *
find_vdev(libzfs_handle_t *zhdl, nvlist_t *nv, uint64_t search_guid)
{
        uint64_t guid;
        nvlist_t **child;
        uint_t c, children;
        nvlist_t *ret;

        if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) == 0 &&
            guid == search_guid) {
                fmd_hdl_debug(fmd_module_hdl("zfs-retire"),
                    "matched vdev %llu", guid);
                return (nv);
        }

        if (nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_CHILDREN,
            &child, &children) != 0)
                return (NULL);

        for (c = 0; c < children; c++) {
                if ((ret = find_vdev(zhdl, child[c], search_guid)) != NULL)
                        return (ret);
        }

        if (nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_L2CACHE,
            &child, &children) != 0)
                return (NULL);

        for (c = 0; c < children; c++) {
                if ((ret = find_vdev(zhdl, child[c], search_guid)) != NULL)
                        return (ret);
        }

        if (nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_SPARES,
            &child, &children) != 0)
                return (NULL);

        for (c = 0; c < children; c++) {
                if ((ret = find_vdev(zhdl, child[c], search_guid)) != NULL)
                        return (ret);
        }

        return (NULL);
}

static int
remove_spares(zpool_handle_t *zhp, void *data)
{
        nvlist_t *config, *nvroot;
        nvlist_t **spares;
        uint_t nspares;
        char *devname;
        find_cbdata_t *cbp = data;
        uint64_t spareguid = 0;
        vdev_stat_t *vs;
        unsigned int c;

        config = zpool_get_config(zhp, NULL);
        if (nvlist_lookup_nvlist(config,
            ZPOOL_CONFIG_VDEV_TREE, &nvroot) != 0) {
                zpool_close(zhp);
                return (0);
        }

        if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES,
            &spares, &nspares) != 0) {
                zpool_close(zhp);
                return (0);
        }

        for (int i = 0; i < nspares; i++) {
                if (nvlist_lookup_uint64(spares[i], ZPOOL_CONFIG_GUID,
                    &spareguid) == 0 && spareguid == cbp->cb_vdev_guid) {
                        devname = zpool_vdev_name(NULL, zhp, spares[i],
                            B_FALSE);
                        nvlist_lookup_uint64_array(spares[i],
                            ZPOOL_CONFIG_VDEV_STATS, (uint64_t **)&vs, &c);
                        if (vs->vs_state != VDEV_STATE_REMOVED &&
                            zpool_vdev_remove_wanted(zhp, devname) == 0)
                                cbp->cb_num_spares++;
                        break;
                }
        }

        zpool_close(zhp);
        return (0);
}

/*
 * Given a vdev guid, find and remove all spares associated with it.
 */
static int
find_and_remove_spares(libzfs_handle_t *zhdl, uint64_t vdev_guid)
{
        find_cbdata_t cb;

        cb.cb_num_spares = 0;
        cb.cb_vdev_guid = vdev_guid;
        zpool_iter(zhdl, remove_spares, &cb);

        return (cb.cb_num_spares);
}

/*
 * Given a (pool, vdev) GUID pair, find the matching pool and vdev.
 */
static zpool_handle_t *
find_by_guid(libzfs_handle_t *zhdl, uint64_t pool_guid, uint64_t vdev_guid,
    nvlist_t **vdevp)
{
        find_cbdata_t cb;
        zpool_handle_t *zhp;
        nvlist_t *config, *nvroot;

        /*
         * Find the corresponding pool and make sure the vdev still exists.
         */
        cb.cb_guid = pool_guid;
        if (zpool_iter(zhdl, find_pool, &cb) != 1)
                return (NULL);

        zhp = cb.cb_zhp;
        config = zpool_get_config(zhp, NULL);
        if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE,
            &nvroot) != 0) {
                zpool_close(zhp);
                return (NULL);
        }

        if (vdev_guid != 0) {
                if ((*vdevp = find_vdev(zhdl, nvroot, vdev_guid)) == NULL) {
                        zpool_close(zhp);
                        return (NULL);
                }
        }

        return (zhp);
}

/*
 * Given a vdev, attempt to replace it with every known spare until one
 * succeeds or we run out of devices to try.
 * Return whether we were successful or not in replacing the device.
 */
static boolean_t
replace_with_spare(fmd_hdl_t *hdl, zpool_handle_t *zhp, nvlist_t *vdev)
{
        nvlist_t *config, *nvroot, *replacement;
        nvlist_t **spares;
        uint_t s, nspares;
        char *dev_name;
        zprop_source_t source;
        int ashift;

        config = zpool_get_config(zhp, NULL);
        if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE,
            &nvroot) != 0)
                return (B_FALSE);

        /*
         * Find out if there are any hot spares available in the pool.
         */
        if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES,
            &spares, &nspares) != 0)
                return (B_FALSE);

        /*
         * lookup "ashift" pool property, we may need it for the replacement
         */
        ashift = zpool_get_prop_int(zhp, ZPOOL_PROP_ASHIFT, &source);

        replacement = fmd_nvl_alloc(hdl, FMD_SLEEP);

        (void) nvlist_add_string(replacement, ZPOOL_CONFIG_TYPE,
            VDEV_TYPE_ROOT);

        dev_name = zpool_vdev_name(NULL, zhp, vdev, B_FALSE);

        /*
         * Try to replace each spare, ending when we successfully
         * replace it.
         */
        for (s = 0; s < nspares; s++) {
                boolean_t rebuild = B_FALSE;
                const char *spare_name, *type;

                if (nvlist_lookup_string(spares[s], ZPOOL_CONFIG_PATH,
                    &spare_name) != 0)
                        continue;

                /* prefer sequential resilvering for distributed spares */
                if ((nvlist_lookup_string(spares[s], ZPOOL_CONFIG_TYPE,
                    &type) == 0) && strcmp(type, VDEV_TYPE_DRAID_SPARE) == 0)
                        rebuild = B_TRUE;

                /* if set, add the "ashift" pool property to the spare nvlist */
                if (source != ZPROP_SRC_DEFAULT)
                        (void) nvlist_add_uint64(spares[s],
                            ZPOOL_CONFIG_ASHIFT, ashift);

                (void) nvlist_add_nvlist_array(replacement,
                    ZPOOL_CONFIG_CHILDREN, (const nvlist_t **)&spares[s], 1);

                fmd_hdl_debug(hdl, "zpool_vdev_replace '%s' with spare '%s'",
                    dev_name, zfs_basename(spare_name));

                if (zpool_vdev_attach(zhp, dev_name, spare_name,
                    replacement, B_TRUE, rebuild) == 0) {
                        free(dev_name);
                        nvlist_free(replacement);
                        return (B_TRUE);
                }
        }

        free(dev_name);
        nvlist_free(replacement);

        return (B_FALSE);
}

/*
 * Repair this vdev if we had diagnosed a 'fault.fs.zfs.device' and
 * ASRU is now usable.  ZFS has found the device to be present and
 * functioning.
 */
static void
zfs_vdev_repair(fmd_hdl_t *hdl, nvlist_t *nvl)
{
        zfs_retire_data_t *zdp = fmd_hdl_getspecific(hdl);
        zfs_retire_repaired_t *zrp;
        uint64_t pool_guid, vdev_guid;
        if (nvlist_lookup_uint64(nvl, FM_EREPORT_PAYLOAD_ZFS_POOL_GUID,
            &pool_guid) != 0 || nvlist_lookup_uint64(nvl,
            FM_EREPORT_PAYLOAD_ZFS_VDEV_GUID, &vdev_guid) != 0)
                return;

        /*
         * Before checking the state of the ASRU, go through and see if we've
         * already made an attempt to repair this ASRU.  This list is cleared
         * whenever we receive any kind of list event, and is designed to
         * prevent us from generating a feedback loop when we attempt repairs
         * against a faulted pool.  The problem is that checking the unusable
         * state of the ASRU can involve opening the pool, which can post
         * statechange events but otherwise leave the pool in the faulted
         * state.  This list allows us to detect when a statechange event is
         * due to our own request.
         */
        for (zrp = zdp->zrd_repaired; zrp != NULL; zrp = zrp->zrr_next) {
                if (zrp->zrr_pool == pool_guid &&
                    zrp->zrr_vdev == vdev_guid)
                        return;
        }

        zrp = fmd_hdl_alloc(hdl, sizeof (zfs_retire_repaired_t), FMD_SLEEP);
        zrp->zrr_next = zdp->zrd_repaired;
        zrp->zrr_pool = pool_guid;
        zrp->zrr_vdev = vdev_guid;
        zdp->zrd_repaired = zrp;

        fmd_hdl_debug(hdl, "marking repaired vdev %llu on pool %llu",
            vdev_guid, pool_guid);
}

static void
zfs_retire_recv(fmd_hdl_t *hdl, fmd_event_t *ep, nvlist_t *nvl,
    const char *class)
{
        (void) ep;
        uint64_t pool_guid, vdev_guid;
        zpool_handle_t *zhp;
        nvlist_t *resource, *fault;
        nvlist_t **faults;
        uint_t f, nfaults;
        zfs_retire_data_t *zdp = fmd_hdl_getspecific(hdl);
        libzfs_handle_t *zhdl = zdp->zrd_hdl;
        boolean_t fault_device, degrade_device;
        boolean_t is_repair;
        boolean_t l2arc = B_FALSE;
        boolean_t spare = B_FALSE;
        const char *scheme;
        nvlist_t *vdev = NULL;
        const char *uuid;
        int repair_done = 0;
        boolean_t retire;
        boolean_t is_disk;
        vdev_aux_t aux;
        uint64_t state = 0;
        vdev_stat_t *vs;
        unsigned int c;

        fmd_hdl_debug(hdl, "zfs_retire_recv: '%s'", class);

        (void) nvlist_lookup_uint64(nvl, FM_EREPORT_PAYLOAD_ZFS_VDEV_STATE,
            &state);

        /*
         * If this is a resource notifying us of device removal then simply
         * check for an available spare and continue unless the device is a
         * l2arc vdev, in which case we just offline it.
         */
        if (strcmp(class, "resource.fs.zfs.removed") == 0 ||
            (strcmp(class, "resource.fs.zfs.statechange") == 0 &&
            (state == VDEV_STATE_REMOVED || state == VDEV_STATE_FAULTED))) {
                const char *devtype;
                char *devname;

                if (nvlist_lookup_string(nvl, FM_EREPORT_PAYLOAD_ZFS_VDEV_TYPE,
                    &devtype) == 0) {
                        if (strcmp(devtype, VDEV_TYPE_SPARE) == 0)
                                spare = B_TRUE;
                        else if (strcmp(devtype, VDEV_TYPE_L2CACHE) == 0)
                                l2arc = B_TRUE;
                }

                if (nvlist_lookup_uint64(nvl,
                    FM_EREPORT_PAYLOAD_ZFS_VDEV_GUID, &vdev_guid) != 0)
                        return;

                if (vdev_guid == 0) {
                        fmd_hdl_debug(hdl, "Got a zero GUID");
                        return;
                }

                if (spare) {
                        int nspares = find_and_remove_spares(zhdl, vdev_guid);
                        fmd_hdl_debug(hdl, "%d spares removed", nspares);
                        return;
                }

                if (nvlist_lookup_uint64(nvl, FM_EREPORT_PAYLOAD_ZFS_POOL_GUID,
                    &pool_guid) != 0)
                        return;

                if ((zhp = find_by_guid(zhdl, pool_guid, vdev_guid,
                    &vdev)) == NULL)
                        return;

                devname = zpool_vdev_name(NULL, zhp, vdev, B_FALSE);

                nvlist_lookup_uint64_array(vdev, ZPOOL_CONFIG_VDEV_STATS,
                    (uint64_t **)&vs, &c);

                /*
                 * If state removed is requested for already removed vdev,
                 * its a loopback event from spa_async_remove(). Just
                 * ignore it.
                 */
                if ((vs->vs_state == VDEV_STATE_REMOVED && state ==
                    VDEV_STATE_REMOVED) || vs->vs_state == VDEV_STATE_OFFLINE)
                        return;

                /* Remove the vdev since device is unplugged */
                int remove_status = 0;
                if (l2arc || (strcmp(class, "resource.fs.zfs.removed") == 0)) {
                        remove_status = zpool_vdev_remove_wanted(zhp, devname);
                        fmd_hdl_debug(hdl, "zpool_vdev_remove_wanted '%s'"
                            ", err:%d", devname, libzfs_errno(zhdl));
                }

                /* Replace the vdev with a spare if its not a l2arc */
                if (!l2arc && !remove_status &&
                    (!fmd_prop_get_int32(hdl, "spare_on_remove") ||
                    replace_with_spare(hdl, zhp, vdev) == B_FALSE)) {
                        /* Could not handle with spare */
                        fmd_hdl_debug(hdl, "no spare for '%s'", devname);
                }

                free(devname);
                zpool_close(zhp);
                return;
        }

        if (strcmp(class, FM_LIST_RESOLVED_CLASS) == 0)
                return;

        /*
         * Note: on Linux statechange events are more than just
         * healthy ones so we need to confirm the actual state value.
         */
        if (strcmp(class, "resource.fs.zfs.statechange") == 0 &&
            state == VDEV_STATE_HEALTHY) {
                zfs_vdev_repair(hdl, nvl);
                return;
        }
        if (strcmp(class, "sysevent.fs.zfs.vdev_remove") == 0) {
                zfs_vdev_repair(hdl, nvl);
                return;
        }

        zfs_retire_clear_data(hdl, zdp);

        if (strcmp(class, FM_LIST_REPAIRED_CLASS) == 0)
                is_repair = B_TRUE;
        else
                is_repair = B_FALSE;

        /*
         * We subscribe to zfs faults as well as all repair events.
         */
        if (nvlist_lookup_nvlist_array(nvl, FM_SUSPECT_FAULT_LIST,
            &faults, &nfaults) != 0)
                return;

        for (f = 0; f < nfaults; f++) {
                fault = faults[f];

                fault_device = B_FALSE;
                degrade_device = B_FALSE;
                is_disk = B_FALSE;

                if (nvlist_lookup_boolean_value(fault, FM_SUSPECT_RETIRE,
                    &retire) == 0 && retire == 0)
                        continue;

                /*
                 * While we subscribe to fault.fs.zfs.*, we only take action
                 * for faults targeting a specific vdev (open failure or SERD
                 * failure).  We also subscribe to fault.io.* events, so that
                 * faulty disks will be faulted in the ZFS configuration.
                 */
                if (fmd_nvl_class_match(hdl, fault, "fault.fs.zfs.vdev.io")) {
                        fault_device = B_TRUE;
                } else if (fmd_nvl_class_match(hdl, fault,
                    "fault.fs.zfs.vdev.checksum")) {
                        degrade_device = B_TRUE;
                } else if (fmd_nvl_class_match(hdl, fault,
                    "fault.fs.zfs.vdev.slow_io")) {
                        degrade_device = B_TRUE;
                } else if (fmd_nvl_class_match(hdl, fault,
                    "fault.fs.zfs.device")) {
                        fault_device = B_FALSE;
                } else if (fmd_nvl_class_match(hdl, fault, "fault.io.*")) {
                        is_disk = B_TRUE;
                        fault_device = B_TRUE;
                } else {
                        continue;
                }

                if (is_disk) {
                        continue;
                } else {
                        /*
                         * This is a ZFS fault.  Lookup the resource, and
                         * attempt to find the matching vdev.
                         */
                        if (nvlist_lookup_nvlist(fault, FM_FAULT_RESOURCE,
                            &resource) != 0 ||
                            nvlist_lookup_string(resource, FM_FMRI_SCHEME,
                            &scheme) != 0)
                                continue;

                        if (strcmp(scheme, FM_FMRI_SCHEME_ZFS) != 0)
                                continue;

                        if (nvlist_lookup_uint64(resource, FM_FMRI_ZFS_POOL,
                            &pool_guid) != 0)
                                continue;

                        if (nvlist_lookup_uint64(resource, FM_FMRI_ZFS_VDEV,
                            &vdev_guid) != 0) {
                                if (is_repair)
                                        vdev_guid = 0;
                                else
                                        continue;
                        }

                        if ((zhp = find_by_guid(zhdl, pool_guid, vdev_guid,
                            &vdev)) == NULL)
                                continue;

                        aux = VDEV_AUX_ERR_EXCEEDED;
                }

                if (vdev_guid == 0) {
                        /*
                         * For pool-level repair events, clear the entire pool.
                         */
                        fmd_hdl_debug(hdl, "zpool_clear of pool '%s'",
                            zpool_get_name(zhp));
                        (void) zpool_clear(zhp, NULL, NULL);
                        zpool_close(zhp);
                        continue;
                }

                /*
                 * If this is a repair event, then mark the vdev as repaired and
                 * continue.
                 */
                if (is_repair) {
                        repair_done = 1;
                        fmd_hdl_debug(hdl, "zpool_clear of pool '%s' vdev %llu",
                            zpool_get_name(zhp), vdev_guid);
                        (void) zpool_vdev_clear(zhp, vdev_guid);
                        zpool_close(zhp);
                        continue;
                }

                /*
                 * Actively fault the device if needed.
                 */
                if (fault_device)
                        (void) zpool_vdev_fault(zhp, vdev_guid, aux);
                if (degrade_device)
                        (void) zpool_vdev_degrade(zhp, vdev_guid, aux);

                if (fault_device || degrade_device)
                        fmd_hdl_debug(hdl, "zpool_vdev_%s: vdev %llu on '%s'",
                            fault_device ? "fault" : "degrade", vdev_guid,
                            zpool_get_name(zhp));

                /*
                 * Attempt to substitute a hot spare.
                 */
                (void) replace_with_spare(hdl, zhp, vdev);

                zpool_close(zhp);
        }

        if (strcmp(class, FM_LIST_REPAIRED_CLASS) == 0 && repair_done &&
            nvlist_lookup_string(nvl, FM_SUSPECT_UUID, &uuid) == 0)
                fmd_case_uuresolved(hdl, uuid);
}

static const fmd_hdl_ops_t fmd_ops = {
        zfs_retire_recv,        /* fmdo_recv */
        NULL,                   /* fmdo_timeout */
        NULL,                   /* fmdo_close */
        NULL,                   /* fmdo_stats */
        NULL,                   /* fmdo_gc */
};

static const fmd_prop_t fmd_props[] = {
        { "spare_on_remove", FMD_TYPE_BOOL, "true" },
        { NULL, 0, NULL }
};

static const fmd_hdl_info_t fmd_info = {
        "ZFS Retire Agent", "1.0", &fmd_ops, fmd_props
};

void
_zfs_retire_init(fmd_hdl_t *hdl)
{
        zfs_retire_data_t *zdp;
        libzfs_handle_t *zhdl;

        if ((zhdl = libzfs_init()) == NULL)
                return;

        if (fmd_hdl_register(hdl, FMD_API_VERSION, &fmd_info) != 0) {
                libzfs_fini(zhdl);
                return;
        }

        zdp = fmd_hdl_zalloc(hdl, sizeof (zfs_retire_data_t), FMD_SLEEP);
        zdp->zrd_hdl = zhdl;

        fmd_hdl_setspecific(hdl, zdp);
}

void
_zfs_retire_fini(fmd_hdl_t *hdl)
{
        zfs_retire_data_t *zdp = fmd_hdl_getspecific(hdl);

        if (zdp != NULL) {
                zfs_retire_clear_data(hdl, zdp);
                libzfs_fini(zdp->zrd_hdl);
                fmd_hdl_free(hdl, zdp, sizeof (zfs_retire_data_t));
        }
}