/*
 * 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.
 * Copyright (c) 2013 Steven Hartland. All rights reserved.
 */

/*
 * This file contains the functions which analyze the status of a pool.  This
 * include both the status of an active pool, as well as the status exported
 * pools.  Returns one of the ZPOOL_STATUS_* defines describing the status of
 * the pool.  This status is independent (to a certain degree) from the state of
 * the pool.  A pool's state describes only whether or not it is capable of
 * providing the necessary fault tolerance for data.  The status describes the
 * overall status of devices.  A pool that is online can still have a device
 * that is experiencing errors.
 *
 * Only a subset of the possible faults can be detected using 'zpool status',
 * and not all possible errors correspond to a FMA message ID.  The explanation
 * is left up to the caller, depending on whether it is a live pool or an
 * import.
 */

#include <libzfs.h>
#include <libzutil.h>
#include <string.h>
#include <unistd.h>
#include "libzfs_impl.h"
#include "zfeature_common.h"

/*
 * Message ID table.  This must be kept in sync with the ZPOOL_STATUS_* defines
 * in libzfs.h.  Note that there are some status results which go past the end
 * of this table, and hence have no associated message ID.
 */
static char *zfs_msgid_table[] = {
        "ZFS-8000-14", /* ZPOOL_STATUS_CORRUPT_CACHE */
        "ZFS-8000-2Q", /* ZPOOL_STATUS_MISSING_DEV_R */
        "ZFS-8000-3C", /* ZPOOL_STATUS_MISSING_DEV_NR */
        "ZFS-8000-4J", /* ZPOOL_STATUS_CORRUPT_LABEL_R */
        "ZFS-8000-5E", /* ZPOOL_STATUS_CORRUPT_LABEL_NR */
        "ZFS-8000-6X", /* ZPOOL_STATUS_BAD_GUID_SUM */
        "ZFS-8000-72", /* ZPOOL_STATUS_CORRUPT_POOL */
        "ZFS-8000-8A", /* ZPOOL_STATUS_CORRUPT_DATA */
        "ZFS-8000-9P", /* ZPOOL_STATUS_FAILING_DEV */
        "ZFS-8000-A5", /* ZPOOL_STATUS_VERSION_NEWER */
        "ZFS-8000-EY", /* ZPOOL_STATUS_HOSTID_MISMATCH */
        "ZFS-8000-EY", /* ZPOOL_STATUS_HOSTID_ACTIVE */
        "ZFS-8000-EY", /* ZPOOL_STATUS_HOSTID_REQUIRED */
        "ZFS-8000-HC", /* ZPOOL_STATUS_IO_FAILURE_WAIT */
        "ZFS-8000-JQ", /* ZPOOL_STATUS_IO_FAILURE_CONTINUE */
        "ZFS-8000-MM", /* ZPOOL_STATUS_IO_FAILURE_MMP */
        "ZFS-8000-K4", /* ZPOOL_STATUS_BAD_LOG */
        /*
         * The following results have no message ID.
         *      ZPOOL_STATUS_UNSUP_FEAT_READ
         *      ZPOOL_STATUS_UNSUP_FEAT_WRITE
         *      ZPOOL_STATUS_FAULTED_DEV_R
         *      ZPOOL_STATUS_FAULTED_DEV_NR
         *      ZPOOL_STATUS_VERSION_OLDER
         *      ZPOOL_STATUS_FEAT_DISABLED
         *      ZPOOL_STATUS_RESILVERING
         *      ZPOOL_STATUS_OFFLINE_DEV
         *      ZPOOL_STATUS_REMOVED_DEV
         *      ZPOOL_STATUS_OK
         */
};

#define NMSGID  (sizeof (zfs_msgid_table) / sizeof (zfs_msgid_table[0]))

/* ARGSUSED */
static int
vdev_missing(uint64_t state, uint64_t aux, uint64_t errs)
{
        return (state == VDEV_STATE_CANT_OPEN &&
            aux == VDEV_AUX_OPEN_FAILED);
}

/* ARGSUSED */
static int
vdev_faulted(uint64_t state, uint64_t aux, uint64_t errs)
{
        return (state == VDEV_STATE_FAULTED);
}

/* ARGSUSED */
static int
vdev_errors(uint64_t state, uint64_t aux, uint64_t errs)
{
        return (state == VDEV_STATE_DEGRADED || errs != 0);
}

/* ARGSUSED */
static int
vdev_broken(uint64_t state, uint64_t aux, uint64_t errs)
{
        return (state == VDEV_STATE_CANT_OPEN);
}

/* ARGSUSED */
static int
vdev_offlined(uint64_t state, uint64_t aux, uint64_t errs)
{
        return (state == VDEV_STATE_OFFLINE);
}

/* ARGSUSED */
static int
vdev_removed(uint64_t state, uint64_t aux, uint64_t errs)
{
        return (state == VDEV_STATE_REMOVED);
}

/*
 * Detect if any leaf devices that have seen errors or could not be opened.
 */
static boolean_t
find_vdev_problem(nvlist_t *vdev, int (*func)(uint64_t, uint64_t, uint64_t))
{
        nvlist_t **child;
        vdev_stat_t *vs;
        uint_t c, children;
        char *type;

        /*
         * Ignore problems within a 'replacing' vdev, since we're presumably in
         * the process of repairing any such errors, and don't want to call them
         * out again.  We'll pick up the fact that a resilver is happening
         * later.
         */
        verify(nvlist_lookup_string(vdev, ZPOOL_CONFIG_TYPE, &type) == 0);
        if (strcmp(type, VDEV_TYPE_REPLACING) == 0)
                return (B_FALSE);

        if (nvlist_lookup_nvlist_array(vdev, ZPOOL_CONFIG_CHILDREN, &child,
            &children) == 0) {
                for (c = 0; c < children; c++)
                        if (find_vdev_problem(child[c], func))
                                return (B_TRUE);
        } else {
                verify(nvlist_lookup_uint64_array(vdev, ZPOOL_CONFIG_VDEV_STATS,
                    (uint64_t **)&vs, &c) == 0);

                if (func(vs->vs_state, vs->vs_aux,
                    vs->vs_read_errors +
                    vs->vs_write_errors +
                    vs->vs_checksum_errors))
                        return (B_TRUE);
        }

        /*
         * Check any L2 cache devs
         */
        if (nvlist_lookup_nvlist_array(vdev, ZPOOL_CONFIG_L2CACHE, &child,
            &children) == 0) {
                for (c = 0; c < children; c++)
                        if (find_vdev_problem(child[c], func))
                                return (B_TRUE);
        }

        return (B_FALSE);
}

/*
 * Active pool health status.
 *
 * To determine the status for a pool, we make several passes over the config,
 * picking the most egregious error we find.  In order of importance, we do the
 * following:
 *
 *      - Check for a complete and valid configuration
 *      - Look for any faulted or missing devices in a non-replicated config
 *      - Check for any data errors
 *      - Check for any faulted or missing devices in a replicated config
 *      - Look for any devices showing errors
 *      - Check for any resilvering devices
 *
 * There can obviously be multiple errors within a single pool, so this routine
 * only picks the most damaging of all the current errors to report.
 */
static zpool_status_t
check_status(nvlist_t *config, boolean_t isimport, zpool_errata_t *erratap)
{
        nvlist_t *nvroot;
        vdev_stat_t *vs;
        pool_scan_stat_t *ps = NULL;
        uint_t vsc, psc;
        uint64_t nerr;
        uint64_t version;
        uint64_t stateval;
        uint64_t suspended;
        uint64_t hostid = 0;
        uint64_t errata = 0;
        unsigned long system_hostid = get_system_hostid();

        verify(nvlist_lookup_uint64(config, ZPOOL_CONFIG_VERSION,
            &version) == 0);
        verify(nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE,
            &nvroot) == 0);
        verify(nvlist_lookup_uint64_array(nvroot, ZPOOL_CONFIG_VDEV_STATS,
            (uint64_t **)&vs, &vsc) == 0);
        verify(nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_STATE,
            &stateval) == 0);

        /*
         * Currently resilvering a vdev
         */
        (void) nvlist_lookup_uint64_array(nvroot, ZPOOL_CONFIG_SCAN_STATS,
            (uint64_t **)&ps, &psc);
        if (ps != NULL && ps->pss_func == POOL_SCAN_RESILVER &&
            ps->pss_state == DSS_SCANNING)
                return (ZPOOL_STATUS_RESILVERING);

        /*
         * The multihost property is set and the pool may be active.
         */
        if (vs->vs_state == VDEV_STATE_CANT_OPEN &&
            vs->vs_aux == VDEV_AUX_ACTIVE) {
                mmp_state_t mmp_state;
                nvlist_t *nvinfo;

                nvinfo = fnvlist_lookup_nvlist(config, ZPOOL_CONFIG_LOAD_INFO);
                mmp_state = fnvlist_lookup_uint64(nvinfo,
                    ZPOOL_CONFIG_MMP_STATE);

                if (mmp_state == MMP_STATE_ACTIVE)
                        return (ZPOOL_STATUS_HOSTID_ACTIVE);
                else if (mmp_state == MMP_STATE_NO_HOSTID)
                        return (ZPOOL_STATUS_HOSTID_REQUIRED);
                else
                        return (ZPOOL_STATUS_HOSTID_MISMATCH);
        }

        /*
         * Pool last accessed by another system.
         */
        (void) nvlist_lookup_uint64(config, ZPOOL_CONFIG_HOSTID, &hostid);
        if (hostid != 0 && (unsigned long)hostid != system_hostid &&
            stateval == POOL_STATE_ACTIVE)
                return (ZPOOL_STATUS_HOSTID_MISMATCH);

        /*
         * Newer on-disk version.
         */
        if (vs->vs_state == VDEV_STATE_CANT_OPEN &&
            vs->vs_aux == VDEV_AUX_VERSION_NEWER)
                return (ZPOOL_STATUS_VERSION_NEWER);

        /*
         * Unsupported feature(s).
         */
        if (vs->vs_state == VDEV_STATE_CANT_OPEN &&
            vs->vs_aux == VDEV_AUX_UNSUP_FEAT) {
                nvlist_t *nvinfo;

                verify(nvlist_lookup_nvlist(config, ZPOOL_CONFIG_LOAD_INFO,
                    &nvinfo) == 0);
                if (nvlist_exists(nvinfo, ZPOOL_CONFIG_CAN_RDONLY))
                        return (ZPOOL_STATUS_UNSUP_FEAT_WRITE);
                return (ZPOOL_STATUS_UNSUP_FEAT_READ);
        }

        /*
         * Check that the config is complete.
         */
        if (vs->vs_state == VDEV_STATE_CANT_OPEN &&
            vs->vs_aux == VDEV_AUX_BAD_GUID_SUM)
                return (ZPOOL_STATUS_BAD_GUID_SUM);

        /*
         * Check whether the pool has suspended.
         */
        if (nvlist_lookup_uint64(config, ZPOOL_CONFIG_SUSPENDED,
            &suspended) == 0) {
                uint64_t reason;

                if (nvlist_lookup_uint64(config, ZPOOL_CONFIG_SUSPENDED_REASON,
                    &reason) == 0 && reason == ZIO_SUSPEND_MMP)
                        return (ZPOOL_STATUS_IO_FAILURE_MMP);

                if (suspended == ZIO_FAILURE_MODE_CONTINUE)
                        return (ZPOOL_STATUS_IO_FAILURE_CONTINUE);
                return (ZPOOL_STATUS_IO_FAILURE_WAIT);
        }

        /*
         * Could not read a log.
         */
        if (vs->vs_state == VDEV_STATE_CANT_OPEN &&
            vs->vs_aux == VDEV_AUX_BAD_LOG) {
                return (ZPOOL_STATUS_BAD_LOG);
        }

        /*
         * Bad devices in non-replicated config.
         */
        if (vs->vs_state == VDEV_STATE_CANT_OPEN &&
            find_vdev_problem(nvroot, vdev_faulted))
                return (ZPOOL_STATUS_FAULTED_DEV_NR);

        if (vs->vs_state == VDEV_STATE_CANT_OPEN &&
            find_vdev_problem(nvroot, vdev_missing))
                return (ZPOOL_STATUS_MISSING_DEV_NR);

        if (vs->vs_state == VDEV_STATE_CANT_OPEN &&
            find_vdev_problem(nvroot, vdev_broken))
                return (ZPOOL_STATUS_CORRUPT_LABEL_NR);

        /*
         * Corrupted pool metadata
         */
        if (vs->vs_state == VDEV_STATE_CANT_OPEN &&
            vs->vs_aux == VDEV_AUX_CORRUPT_DATA)
                return (ZPOOL_STATUS_CORRUPT_POOL);

        /*
         * Persistent data errors.
         */
        if (!isimport) {
                if (nvlist_lookup_uint64(config, ZPOOL_CONFIG_ERRCOUNT,
                    &nerr) == 0 && nerr != 0)
                        return (ZPOOL_STATUS_CORRUPT_DATA);
        }

        /*
         * Missing devices in a replicated config.
         */
        if (find_vdev_problem(nvroot, vdev_faulted))
                return (ZPOOL_STATUS_FAULTED_DEV_R);
        if (find_vdev_problem(nvroot, vdev_missing))
                return (ZPOOL_STATUS_MISSING_DEV_R);
        if (find_vdev_problem(nvroot, vdev_broken))
                return (ZPOOL_STATUS_CORRUPT_LABEL_R);

        /*
         * Devices with errors
         */
        if (!isimport && find_vdev_problem(nvroot, vdev_errors))
                return (ZPOOL_STATUS_FAILING_DEV);

        /*
         * Offlined devices
         */
        if (find_vdev_problem(nvroot, vdev_offlined))
                return (ZPOOL_STATUS_OFFLINE_DEV);

        /*
         * Removed device
         */
        if (find_vdev_problem(nvroot, vdev_removed))
                return (ZPOOL_STATUS_REMOVED_DEV);

        /*
         * Informational errata available.
         */
        (void) nvlist_lookup_uint64(config, ZPOOL_CONFIG_ERRATA, &errata);
        if (errata) {
                *erratap = errata;
                return (ZPOOL_STATUS_ERRATA);
        }

        /*
         * Outdated, but usable, version
         */
        if (SPA_VERSION_IS_SUPPORTED(version) && version != SPA_VERSION)
                return (ZPOOL_STATUS_VERSION_OLDER);

        /*
         * Usable pool with disabled features
         */
        if (version >= SPA_VERSION_FEATURES) {
                int i;
                nvlist_t *feat;

                if (isimport) {
                        feat = fnvlist_lookup_nvlist(config,
                            ZPOOL_CONFIG_LOAD_INFO);
                        if (nvlist_exists(feat, ZPOOL_CONFIG_ENABLED_FEAT))
                                feat = fnvlist_lookup_nvlist(feat,
                                    ZPOOL_CONFIG_ENABLED_FEAT);
                } else {
                        feat = fnvlist_lookup_nvlist(config,
                            ZPOOL_CONFIG_FEATURE_STATS);
                }

                for (i = 0; i < SPA_FEATURES; i++) {
                        zfeature_info_t *fi = &spa_feature_table[i];
                        if (!nvlist_exists(feat, fi->fi_guid))
                                return (ZPOOL_STATUS_FEAT_DISABLED);
                }
        }

        return (ZPOOL_STATUS_OK);
}

zpool_status_t
zpool_get_status(zpool_handle_t *zhp, char **msgid, zpool_errata_t *errata)
{
        zpool_status_t ret = check_status(zhp->zpool_config, B_FALSE, errata);

        if (ret >= NMSGID)
                *msgid = NULL;
        else
                *msgid = zfs_msgid_table[ret];

        return (ret);
}

zpool_status_t
zpool_import_status(nvlist_t *config, char **msgid, zpool_errata_t *errata)
{
        zpool_status_t ret = check_status(config, B_TRUE, errata);

        if (ret >= NMSGID)
                *msgid = NULL;
        else
                *msgid = zfs_msgid_table[ret];

        return (ret);
}