Archipelago » qemu

/*

 * Block protocol for I/O error injection

 *

 * Copyright (c) 2010 Kevin Wolf <kwolf@redhat.com>

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "qemu-common.h"

#include "block_int.h"

#include "module.h"

typedef struct BlkdebugVars {

    int state;

    /* If inject_errno != 0, an error is injected for requests */

    int inject_errno;

    /* Decides if all future requests fail (false) or only the next one and

     * after the next request inject_errno is reset to 0 (true) */

    bool inject_once;

    /* Decides if aio_readv/writev fails right away (true) or returns an error

     * return value only in the callback (false) */

    bool inject_immediately;

} BlkdebugVars;

typedef struct BDRVBlkdebugState {

    BlkdebugVars vars;

    QLIST_HEAD(list, BlkdebugRule) rules[BLKDBG_EVENT_MAX];

} BDRVBlkdebugState;

typedef struct BlkdebugAIOCB {

    BlockDriverAIOCB common;

    QEMUBH *bh;

    int ret;

} BlkdebugAIOCB;

static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb);

static AIOPool blkdebug_aio_pool = {

    .aiocb_size = sizeof(BlkdebugAIOCB),

    .cancel     = blkdebug_aio_cancel,

};

enum {

    ACTION_INJECT_ERROR,

    ACTION_SET_STATE,

};

typedef struct BlkdebugRule {

    BlkDebugEvent event;

    int action;

    int state;

    union {

        struct {

            int error;

            int immediately;

            int once;

        } inject;

        struct {

            int new_state;

        } set_state;

    } options;

    QLIST_ENTRY(BlkdebugRule) next;

} BlkdebugRule;

static QemuOptsList inject_error_opts = {

    .name = "inject-error",

    .head = QTAILQ_HEAD_INITIALIZER(inject_error_opts.head),

    .desc = {

        {

            .name = "event",

            .type = QEMU_OPT_STRING,

        },

        {

            .name = "state",

            .type = QEMU_OPT_NUMBER,

        },

        {

            .name = "errno",

            .type = QEMU_OPT_NUMBER,

        },

        {

            .name = "once",

            .type = QEMU_OPT_BOOL,

        },

        {

            .name = "immediately",

            .type = QEMU_OPT_BOOL,

        },

        { /* end of list */ }

    },

};

static QemuOptsList set_state_opts = {

    .name = "set-state",

    .head = QTAILQ_HEAD_INITIALIZER(inject_error_opts.head),

    .desc = {

        {

            .name = "event",

            .type = QEMU_OPT_STRING,

        },

        {

            .name = "state",

            .type = QEMU_OPT_NUMBER,

        },

        {

            .name = "new_state",

            .type = QEMU_OPT_NUMBER,

        },

        { /* end of list */ }

    },

};

static QemuOptsList *config_groups[] = {

    &inject_error_opts,

    &set_state_opts,

    NULL

};

static const char *event_names[BLKDBG_EVENT_MAX] = {

    [BLKDBG_L1_UPDATE]                      = "l1_update",

    [BLKDBG_L1_GROW_ALLOC_TABLE]            = "l1_grow.alloc_table",

    [BLKDBG_L1_GROW_WRITE_TABLE]            = "l1_grow.write_table",

    [BLKDBG_L1_GROW_ACTIVATE_TABLE]         = "l1_grow.activate_table",

    [BLKDBG_L2_LOAD]                        = "l2_load",

    [BLKDBG_L2_UPDATE]                      = "l2_update",

    [BLKDBG_L2_UPDATE_COMPRESSED]           = "l2_update_compressed",

    [BLKDBG_L2_ALLOC_COW_READ]              = "l2_alloc.cow_read",

    [BLKDBG_L2_ALLOC_WRITE]                 = "l2_alloc.write",

    [BLKDBG_READ]                           = "read",

    [BLKDBG_READ_AIO]                       = "read_aio",

    [BLKDBG_READ_BACKING]                   = "read_backing",

    [BLKDBG_READ_BACKING_AIO]               = "read_backing_aio",

    [BLKDBG_READ_COMPRESSED]                = "read_compressed",

    [BLKDBG_WRITE_AIO]                      = "write_aio",

    [BLKDBG_WRITE_COMPRESSED]               = "write_compressed",

    [BLKDBG_VMSTATE_LOAD]                   = "vmstate_load",

    [BLKDBG_VMSTATE_SAVE]                   = "vmstate_save",

    [BLKDBG_COW_READ]                       = "cow_read",

    [BLKDBG_COW_WRITE]                      = "cow_write",

    [BLKDBG_REFTABLE_LOAD]                  = "reftable_load",

    [BLKDBG_REFTABLE_GROW]                  = "reftable_grow",

    [BLKDBG_REFBLOCK_LOAD]                  = "refblock_load",

    [BLKDBG_REFBLOCK_UPDATE]                = "refblock_update",

    [BLKDBG_REFBLOCK_UPDATE_PART]           = "refblock_update_part",

    [BLKDBG_REFBLOCK_ALLOC]                 = "refblock_alloc",

    [BLKDBG_REFBLOCK_ALLOC_HOOKUP]          = "refblock_alloc.hookup",

    [BLKDBG_REFBLOCK_ALLOC_WRITE]           = "refblock_alloc.write",

    [BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS]    = "refblock_alloc.write_blocks",

    [BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE]     = "refblock_alloc.write_table",

    [BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE]    = "refblock_alloc.switch_table",

    [BLKDBG_CLUSTER_ALLOC]                  = "cluster_alloc",

    [BLKDBG_CLUSTER_ALLOC_BYTES]            = "cluster_alloc_bytes",

    [BLKDBG_CLUSTER_FREE]                   = "cluster_free",

};

static int get_event_by_name(const char *name, BlkDebugEvent *event)

{

    int i;

    for (i = 0; i < BLKDBG_EVENT_MAX; i++) {

        if (!strcmp(event_names[i], name)) {

            *event = i;

            return 0;

        }

    }

    return -1;

}

struct add_rule_data {

    BDRVBlkdebugState *s;

    int action;

};

static int add_rule(QemuOpts *opts, void *opaque)

{

    struct add_rule_data *d = opaque;

    BDRVBlkdebugState *s = d->s;

    const char* event_name;

    BlkDebugEvent event;

    struct BlkdebugRule *rule;

    /* Find the right event for the rule */

    event_name = qemu_opt_get(opts, "event");

    if (!event_name || get_event_by_name(event_name, &event) < 0) {

        return -1;

    }

    /* Set attributes common for all actions */

    rule = qemu_mallocz(sizeof(*rule));

    *rule = (struct BlkdebugRule) {

        .event  = event,

        .action = d->action,

        .state  = qemu_opt_get_number(opts, "state", 0),

    };

    /* Parse action-specific options */

    switch (d->action) {

    case ACTION_INJECT_ERROR:

        rule->options.inject.error = qemu_opt_get_number(opts, "errno", EIO);

        rule->options.inject.once  = qemu_opt_get_bool(opts, "once", 0);

        rule->options.inject.immediately =

            qemu_opt_get_bool(opts, "immediately", 0);

        break;

    case ACTION_SET_STATE:

        rule->options.set_state.new_state =

            qemu_opt_get_number(opts, "new_state", 0);

        break;

    };

    /* Add the rule */

    QLIST_INSERT_HEAD(&s->rules[event], rule, next);

    return 0;

}

static int read_config(BDRVBlkdebugState *s, const char *filename)

{

    FILE *f;

    int ret;

    struct add_rule_data d;

    f = fopen(filename, "r");

    if (f == NULL) {

        return -errno;

    }

    ret = qemu_config_parse(f, config_groups, filename);

    if (ret < 0) {

        goto fail;

    }

    d.s = s;

    d.action = ACTION_INJECT_ERROR;

    qemu_opts_foreach(&inject_error_opts, add_rule, &d, 0);

    d.action = ACTION_SET_STATE;

    qemu_opts_foreach(&set_state_opts, add_rule, &d, 0);

    ret = 0;

fail:

    fclose(f);

    return ret;

}

/* Valid blkdebug filenames look like blkdebug:path/to/config:path/to/image */

static int blkdebug_open(BlockDriverState *bs, const char *filename, int flags)

{

    BDRVBlkdebugState *s = bs->opaque;

    int ret;

    char *config, *c;

    /* Parse the blkdebug: prefix */

    if (strncmp(filename, "blkdebug:", strlen("blkdebug:"))) {

        return -EINVAL;

    }

    filename += strlen("blkdebug:");

    /* Read rules from config file */

    c = strchr(filename, ':');

    if (c == NULL) {

        return -EINVAL;

    }

    config = strdup(filename);

    config[c - filename] = '\0';

    ret = read_config(s, config);

    free(config);

    if (ret < 0) {

        return ret;

    }

    filename = c + 1;

    /* Open the backing file */

    ret = bdrv_file_open(&bs->file, filename, flags);

    if (ret < 0) {

        return ret;

    }

    return 0;

}

static void error_callback_bh(void *opaque)

{

    struct BlkdebugAIOCB *acb = opaque;

    qemu_bh_delete(acb->bh);

    acb->common.cb(acb->common.opaque, acb->ret);

    qemu_aio_release(acb);

}

static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb)

{

    BlkdebugAIOCB *acb = container_of(blockacb, BlkdebugAIOCB, common);

    qemu_aio_release(acb);

}

static BlockDriverAIOCB *inject_error(BlockDriverState *bs,

    BlockDriverCompletionFunc *cb, void *opaque)

{

    BDRVBlkdebugState *s = bs->opaque;

    int error = s->vars.inject_errno;

    struct BlkdebugAIOCB *acb;

    QEMUBH *bh;

    if (s->vars.inject_once) {

        s->vars.inject_errno = 0;

    }

    if (s->vars.inject_immediately) {

        return NULL;

    }

    acb = qemu_aio_get(&blkdebug_aio_pool, bs, cb, opaque);

    acb->ret = -error;

    bh = qemu_bh_new(error_callback_bh, acb);

    acb->bh = bh;

    qemu_bh_schedule(bh);

    return &acb->common;

}

static BlockDriverAIOCB *blkdebug_aio_readv(BlockDriverState *bs,

    int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,

    BlockDriverCompletionFunc *cb, void *opaque)

{

    BDRVBlkdebugState *s = bs->opaque;

    if (s->vars.inject_errno) {

        return inject_error(bs, cb, opaque);

    }

    BlockDriverAIOCB *acb =

        bdrv_aio_readv(bs->file, sector_num, qiov, nb_sectors, cb, opaque);

    return acb;

}

static BlockDriverAIOCB *blkdebug_aio_writev(BlockDriverState *bs,

    int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,

    BlockDriverCompletionFunc *cb, void *opaque)

{

    BDRVBlkdebugState *s = bs->opaque;

    if (s->vars.inject_errno) {

        return inject_error(bs, cb, opaque);

    }

    BlockDriverAIOCB *acb =

        bdrv_aio_writev(bs->file, sector_num, qiov, nb_sectors, cb, opaque);

    return acb;

}

static void blkdebug_close(BlockDriverState *bs)

{

    BDRVBlkdebugState *s = bs->opaque;

    BlkdebugRule *rule, *next;

    int i;

    for (i = 0; i < BLKDBG_EVENT_MAX; i++) {

        QLIST_FOREACH_SAFE(rule, &s->rules[i], next, next) {

            QLIST_REMOVE(rule, next);

            qemu_free(rule);

        }

    }

}

static void blkdebug_flush(BlockDriverState *bs)

{

    bdrv_flush(bs->file);

}

static BlockDriverAIOCB *blkdebug_aio_flush(BlockDriverState *bs,

    BlockDriverCompletionFunc *cb, void *opaque)

{

    return bdrv_aio_flush(bs->file, cb, opaque);

}

static void process_rule(BlockDriverState *bs, struct BlkdebugRule *rule,

    BlkdebugVars *old_vars)

{

    BDRVBlkdebugState *s = bs->opaque;

    BlkdebugVars *vars = &s->vars;

    /* Only process rules for the current state */

    if (rule->state && rule->state != old_vars->state) {

        return;

    }

    /* Take the action */

    switch (rule->action) {

    case ACTION_INJECT_ERROR:

        vars->inject_errno       = rule->options.inject.error;

        vars->inject_once        = rule->options.inject.once;

        vars->inject_immediately = rule->options.inject.immediately;

        break;

    case ACTION_SET_STATE:

        vars->state              = rule->options.set_state.new_state;

        break;

    }

}

static void blkdebug_debug_event(BlockDriverState *bs, BlkDebugEvent event)

{

    BDRVBlkdebugState *s = bs->opaque;

    struct BlkdebugRule *rule;

    BlkdebugVars old_vars = s->vars;

    if (event < 0 || event >= BLKDBG_EVENT_MAX) {

        return;

    }

    QLIST_FOREACH(rule, &s->rules[event], next) {

        process_rule(bs, rule, &old_vars);

    }

}

static BlockDriver bdrv_blkdebug = {

    .format_name        = "blkdebug",

    .protocol_name      = "blkdebug",

    .instance_size      = sizeof(BDRVBlkdebugState),

    .bdrv_file_open     = blkdebug_open,

    .bdrv_close         = blkdebug_close,

    .bdrv_flush         = blkdebug_flush,

    .bdrv_aio_readv     = blkdebug_aio_readv,

    .bdrv_aio_writev    = blkdebug_aio_writev,

    .bdrv_aio_flush     = blkdebug_aio_flush,

    .bdrv_debug_event   = blkdebug_debug_event,

};

static void bdrv_blkdebug_init(void)

{

    bdrv_register(&bdrv_blkdebug);

}

block_init(bdrv_blkdebug_init);