zio_inject.c

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/*
 * 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.
 */

#include <sys/arc.h>
#include <sys/zio_impl.h>
#include <sys/zfs_ioctl.h>
#include <sys/vdev_impl.h>
#include <sys/dmu_objset.h>
#include <sys/fs/zfs.h>

uint32_t zio_injection_enabled;

typedef struct inject_handler {
        int                     zi_id;
        spa_t                   *zi_spa;
        zinject_record_t        zi_record;
        list_node_t             zi_link;
} inject_handler_t;

static list_t inject_handlers;
static krwlock_t inject_lock;
static int inject_next_id = 1;

static boolean_t
zio_match_handler(zbookmark_t *zb, uint64_t type,
    zinject_record_t *record, int error)
{
        /*
         * Check for a match against the MOS, which is based on type
         */
        if (zb->zb_objset == DMU_META_OBJSET &&
            record->zi_objset == DMU_META_OBJSET &&
            record->zi_object == DMU_META_DNODE_OBJECT) {
                if (record->zi_type == DMU_OT_NONE ||
                    type == record->zi_type)
                        return (record->zi_freq == 0 ||
                            spa_get_random(100) < record->zi_freq);
                else
                        return (B_FALSE);
        }

        /*
         * Check for an exact match.
         */
        if (zb->zb_objset == record->zi_objset &&
            zb->zb_object == record->zi_object &&
            zb->zb_level == record->zi_level &&
            zb->zb_blkid >= record->zi_start &&
            zb->zb_blkid <= record->zi_end &&
            error == record->zi_error)
                return (record->zi_freq == 0 ||
                    spa_get_random(100) < record->zi_freq);

        return (B_FALSE);
}

void
zio_handle_panic_injection(spa_t *spa, char *tag, uint64_t type)
{
        inject_handler_t *handler;

        rw_enter(&inject_lock, RW_READER);

        for (handler = list_head(&inject_handlers); handler != NULL;
            handler = list_next(&inject_handlers, handler)) {

                if (spa != handler->zi_spa)
                        continue;

                if (handler->zi_record.zi_type == type &&
                    strcmp(tag, handler->zi_record.zi_func) == 0)
                        panic("Panic requested in function %s\n", tag);
        }

        rw_exit(&inject_lock);
}

int
zio_handle_fault_injection(zio_t *zio, int error)
{
        int ret = 0;
        inject_handler_t *handler;

        /*
         * Ignore I/O not associated with any logical data.
         */
        if (zio->io_logical == NULL)
                return (0);

        /*
         * Currently, we only support fault injection on reads.
         */
        if (zio->io_type != ZIO_TYPE_READ)
                return (0);

        rw_enter(&inject_lock, RW_READER);

        for (handler = list_head(&inject_handlers); handler != NULL;
            handler = list_next(&inject_handlers, handler)) {

                /* Ignore errors not destined for this pool */
                if (zio->io_spa != handler->zi_spa)
                        continue;

                /* Ignore device errors and panic injection */
                if (handler->zi_record.zi_guid != 0 ||
                    handler->zi_record.zi_func[0] != '\0' ||
                    handler->zi_record.zi_duration != 0)
                        continue;

                /* If this handler matches, return EIO */
                if (zio_match_handler(&zio->io_logical->io_bookmark,
                    zio->io_bp ? BP_GET_TYPE(zio->io_bp) : DMU_OT_NONE,
                    &handler->zi_record, error)) {
                        ret = error;
                        break;
                }
        }

        rw_exit(&inject_lock);

        return (ret);
}

int
zio_handle_label_injection(zio_t *zio, int error)
{
        inject_handler_t *handler;
        vdev_t *vd = zio->io_vd;
        uint64_t offset = zio->io_offset;
        int label;
        int ret = 0;

        if (offset >= VDEV_LABEL_START_SIZE &&
            offset < vd->vdev_psize - VDEV_LABEL_END_SIZE)
                return (0);

        rw_enter(&inject_lock, RW_READER);

        for (handler = list_head(&inject_handlers); handler != NULL;
            handler = list_next(&inject_handlers, handler)) {
                uint64_t start = handler->zi_record.zi_start;
                uint64_t end = handler->zi_record.zi_end;

                /* Ignore device only faults or panic injection */
                if (handler->zi_record.zi_start == 0 ||
                    handler->zi_record.zi_func[0] != '\0' ||
                    handler->zi_record.zi_duration != 0)
                        continue;

                /*
                 * The injection region is the relative offsets within a
                 * vdev label. We must determine the label which is being
                 * updated and adjust our region accordingly.
                 */
                label = vdev_label_number(vd->vdev_psize, offset);
                start = vdev_label_offset(vd->vdev_psize, label, start);
                end = vdev_label_offset(vd->vdev_psize, label, end);

                if (zio->io_vd->vdev_guid == handler->zi_record.zi_guid &&
                    (offset >= start && offset <= end)) {
                        ret = error;
                        break;
                }
        }
        rw_exit(&inject_lock);
        return (ret);
}


int
zio_handle_device_injection(vdev_t *vd, zio_t *zio, int error)
{
        inject_handler_t *handler;
        int ret = 0;

        /*
         * We skip over faults in the labels unless it's during
         * device open (i.e. zio == NULL).
         */
        if (zio != NULL) {
                uint64_t offset = zio->io_offset;

                if (offset < VDEV_LABEL_START_SIZE ||
                    offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE)
                        return (0);
        }

        rw_enter(&inject_lock, RW_READER);

        for (handler = list_head(&inject_handlers); handler != NULL;
            handler = list_next(&inject_handlers, handler)) {

                /*
                 * Ignore label specific faults, panic injection
                 * or fake writes
                 */
                if (handler->zi_record.zi_start != 0 ||
                    handler->zi_record.zi_func[0] != '\0' ||
                    handler->zi_record.zi_duration != 0)
                        continue;

                if (vd->vdev_guid == handler->zi_record.zi_guid) {
                        if (handler->zi_record.zi_failfast &&
                            (zio == NULL || (zio->io_flags &
                            (ZIO_FLAG_IO_RETRY | ZIO_FLAG_TRYHARD)))) {
                                continue;
                        }

                        /* Handle type specific I/O failures */
                        if (zio != NULL &&
                            handler->zi_record.zi_iotype != ZIO_TYPES &&
                            handler->zi_record.zi_iotype != zio->io_type)
                                continue;

                        if (handler->zi_record.zi_error == error) {
                                /*
                                 * For a failed open, pretend like the device
                                 * has gone away.
                                 */
                                if (error == ENXIO)
                                        vd->vdev_stat.vs_aux =
                                            VDEV_AUX_OPEN_FAILED;

                                /*
                                 * Treat these errors as if they had been
                                 * retried so that all the appropriate stats
                                 * and FMA events are generated.
                                 */
                                if (!handler->zi_record.zi_failfast &&
                                    zio != NULL)
                                        zio->io_flags |= ZIO_FLAG_IO_RETRY;

                                ret = error;
                                break;
                        }
                        if (handler->zi_record.zi_error == ENXIO) {
                                ret = EIO;
                                break;
                        }
                }
        }

        rw_exit(&inject_lock);

        return (ret);
}

void
zio_handle_ignored_writes(zio_t *zio)
{
        inject_handler_t *handler;

        rw_enter(&inject_lock, RW_READER);

        for (handler = list_head(&inject_handlers); handler != NULL;
            handler = list_next(&inject_handlers, handler)) {

                /* Ignore errors not destined for this pool */
                if (zio->io_spa != handler->zi_spa)
                        continue;

                if (handler->zi_record.zi_duration == 0)
                        continue;

                /*
                 * Positive duration implies # of seconds, negative
                 * a number of txgs
                 */
                if (handler->zi_record.zi_timer == 0) {
                        if (handler->zi_record.zi_duration > 0)
                                handler->zi_record.zi_timer = ddi_get_lbolt64();
                        else
                                handler->zi_record.zi_timer = zio->io_txg;
                }

                /* Have a "problem" writing 60% of the time */
                if (spa_get_random(100) < 60)
                        zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES;
                break;
        }

        rw_exit(&inject_lock);
}

void
spa_handle_ignored_writes(spa_t *spa)
{
        inject_handler_t *handler;

        if (zio_injection_enabled == 0)
                return;

        rw_enter(&inject_lock, RW_READER);

        for (handler = list_head(&inject_handlers); handler != NULL;
            handler = list_next(&inject_handlers, handler)) {

                /* Ignore errors not destined for this pool */
                if (spa != handler->zi_spa)
                        continue;

                if (handler->zi_record.zi_duration == 0)
                        continue;

                if (handler->zi_record.zi_duration > 0) {
                        VERIFY(handler->zi_record.zi_timer == 0 ||
                            handler->zi_record.zi_timer +
                            handler->zi_record.zi_duration * hz >
                            ddi_get_lbolt64());
                } else {
                        /* duration is negative so the subtraction here adds */
                        VERIFY(handler->zi_record.zi_timer == 0 ||
                            handler->zi_record.zi_timer -
                            handler->zi_record.zi_duration >=
                            spa_syncing_txg(spa));
                }
        }

        rw_exit(&inject_lock);
}

int
zio_inject_fault(char *name, int flags, int *id, zinject_record_t *record)
{
        inject_handler_t *handler;
        int error;
        spa_t *spa;

        /*
         * If this is pool-wide metadata, make sure we unload the corresponding
         * spa_t, so that the next attempt to load it will trigger the fault.
         * We call spa_reset() to unload the pool appropriately.
         */
        if (flags & ZINJECT_UNLOAD_SPA)
                if ((error = spa_reset(name)) != 0)
                        return (error);

        if (!(flags & ZINJECT_NULL)) {
                /*
                 * spa_inject_ref() will add an injection reference, which will
                 * prevent the pool from being removed from the namespace while
                 * still allowing it to be unloaded.
                 */
                if ((spa = spa_inject_addref(name)) == NULL)
                        return (ENOENT);

                handler = kmem_alloc(sizeof (inject_handler_t), KM_SLEEP);

                rw_enter(&inject_lock, RW_WRITER);

                *id = handler->zi_id = inject_next_id++;
                handler->zi_spa = spa;
                handler->zi_record = *record;
                list_insert_tail(&inject_handlers, handler);
                atomic_add_32(&zio_injection_enabled, 1);

                rw_exit(&inject_lock);
        }

        /*
         * Flush the ARC, so that any attempts to read this data will end up
         * going to the ZIO layer.  Note that this is a little overkill, but
         * we don't have the necessary ARC interfaces to do anything else, and
         * fault injection isn't a performance critical path.
         */
        if (flags & ZINJECT_FLUSH_ARC)
                arc_flush(NULL);

        return (0);
}

int
zio_inject_list_next(int *id, char *name, size_t buflen,
    zinject_record_t *record)
{
        inject_handler_t *handler;
        int ret;

        mutex_enter(&spa_namespace_lock);
        rw_enter(&inject_lock, RW_READER);

        for (handler = list_head(&inject_handlers); handler != NULL;
            handler = list_next(&inject_handlers, handler))
                if (handler->zi_id > *id)
                        break;

        if (handler) {
                *record = handler->zi_record;
                *id = handler->zi_id;
                (void) strncpy(name, spa_name(handler->zi_spa), buflen);
                ret = 0;
        } else {
                ret = ENOENT;
        }

        rw_exit(&inject_lock);
        mutex_exit(&spa_namespace_lock);

        return (ret);
}

int
zio_clear_fault(int id)
{
        inject_handler_t *handler;

        rw_enter(&inject_lock, RW_WRITER);

        for (handler = list_head(&inject_handlers); handler != NULL;
            handler = list_next(&inject_handlers, handler))
                if (handler->zi_id == id)
                        break;

        if (handler == NULL) {
                rw_exit(&inject_lock);
                return (ENOENT);
        }

        list_remove(&inject_handlers, handler);
        rw_exit(&inject_lock);

        spa_inject_delref(handler->zi_spa);
        kmem_free(handler, sizeof (inject_handler_t));
        atomic_add_32(&zio_injection_enabled, -1);

        return (0);
}

void
zio_inject_init(void)
{
        rw_init(&inject_lock, NULL, RW_DEFAULT, NULL);
        list_create(&inject_handlers, sizeof (inject_handler_t),
            offsetof(inject_handler_t, zi_link));
}

void
zio_inject_fini(void)
{
        list_destroy(&inject_handlers);
        rw_destroy(&inject_lock);
}