blockdev.c

/*
 * QEMU host block devices
 *
 * Copyright (c) 2003-2008 Fabrice Bellard
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or
 * later.  See the COPYING file in the top-level directory.
 *
 * This file incorporates work covered by the following copyright and
 * permission notice:
 *
 * Copyright (c) 2003-2008 Fabrice Bellard
 *
 * 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/osdep.h"
#include "system/block-backend.h"
#include "system/blockdev.h"
#include "hw/block/block.h"
#include "block/blockjob.h"
#include "block/dirty-bitmap.h"
#include "block/qdict.h"
#include "monitor/monitor.h"
#include "qemu/error-report.h"
#include "qemu/option.h"
#include "qemu/qemu-print.h"
#include "qemu/config-file.h"
#include "qapi/qapi-commands-block.h"
#include "qapi/qapi-commands-transaction.h"
#include "qapi/qapi-visit-block-core.h"
#include "qobject/qdict.h"
#include "qobject/qnum.h"
#include "qobject/qstring.h"
#include "qapi/error.h"
#include "qapi/qmp/qerror.h"
#include "qobject/qlist.h"
#include "qapi/qobject-output-visitor.h"
#include "system/system.h"
#include "system/iothread.h"
#include "block/block_int.h"
#include "block/trace.h"
#include "system/runstate.h"
#include "qemu/cutils.h"
#include "qemu/help_option.h"
#include "qemu/main-loop.h"

/* Protected by BQL */
QTAILQ_HEAD(, BlockDriverState) monitor_bdrv_states = QTAILQ_HEAD_INITIALIZER(monitor_bdrv_states);

void bdrv_set_monitor_owned(BlockDriverState* bs)
{
    GLOBAL_STATE_CODE();
    QTAILQ_INSERT_TAIL(&monitor_bdrv_states, bs, monitor_list);
}

static const char* const if_name[IF_COUNT] = {
    [IF_NONE]   = "none",
    [IF_PFLASH] = "pflash",
    [IF_MTD]    = "mtd",
    [IF_SD]     = "sd",
};

static int if_max_devs[IF_COUNT] = {};

/**
 * Boards may call this to offer board-by-board overrides
 * of the default, global values.
 */
void override_max_devs(BlockInterfaceType type, int max_devs)
{
    BlockBackend* blk;
    DriveInfo*    dinfo;

    GLOBAL_STATE_CODE();

    if (max_devs <= 0) { return; }

    for (blk = blk_next(NULL); blk; blk = blk_next(blk)) {
        dinfo = blk_legacy_dinfo(blk);
        if (dinfo->type == type) {
            fprintf(stderr,
                    "Cannot override units-per-bus property of"
                    " the %s interface, because a drive of that type has"
                    " already been added.\n",
                    if_name[type]);
            assert_not_reached();
        }
    }

    if_max_devs[type] = max_devs;
}

/*
 * We automatically delete the drive when a device using it gets
 * unplugged.  Questionable feature, but we can't just drop it.
 * Device models call blockdev_mark_auto_del() to schedule the
 * automatic deletion, and generic qdev code calls blockdev_auto_del()
 * when deletion is actually safe.
 */
void blockdev_mark_auto_del(BlockBackend* blk)
{
    DriveInfo* dinfo = blk_legacy_dinfo(blk);
    BlockJob*  job;

    GLOBAL_STATE_CODE();

    if (!dinfo) { return; }

    JOB_LOCK_GUARD();

    do {
        job = block_job_next_locked(NULL);
        while (job && (job->job.cancelled || job->job.deferred_to_main_loop || !block_job_has_bdrv(job, blk_bs(blk)))) {
            job = block_job_next_locked(job);
        }
        if (job) {
            /*
             * This drops the job lock temporarily and polls, so we need to
             * restart processing the list from the start after this.
             */
            job_cancel_locked(&job->job, false);
        }
    }
    while (job);

    dinfo->auto_del = 1;
}

void blockdev_auto_del(BlockBackend* blk)
{
    DriveInfo* dinfo = blk_legacy_dinfo(blk);
    GLOBAL_STATE_CODE();

    if (dinfo && dinfo->auto_del) {
        monitor_remove_blk(blk);
        blk_unref(blk);
    }
}

static int drive_index_to_bus_id(BlockInterfaceType type, int index)
{
    int max_devs = if_max_devs[type];
    return max_devs ? index / max_devs : 0;
}

static int drive_index_to_unit_id(BlockInterfaceType type, int index)
{
    int max_devs = if_max_devs[type];
    return max_devs ? index % max_devs : index;
}

QemuOpts* drive_add(BlockInterfaceType type, int index, const char* file, const char* optstr)
{
    QemuOpts* opts;

    GLOBAL_STATE_CODE();

    opts = qemu_opts_parse_noisily(qemu_find_opts("drive"), optstr, false);
    if (!opts) { return NULL; }
    if (type != IF_DEFAULT) { qemu_opt_set(opts, "if", if_name[type], &error_abort); }
    if (index >= 0) { qemu_opt_set_number(opts, "index", index, &error_abort); }
    if (file) { qemu_opt_set(opts, "file", file, &error_abort); }
    return opts;
}

DriveInfo* drive_get(BlockInterfaceType type, int bus, int unit)
{
    BlockBackend* blk;
    DriveInfo*    dinfo;

    GLOBAL_STATE_CODE();

    for (blk = blk_next(NULL); blk; blk = blk_next(blk)) {
        dinfo = blk_legacy_dinfo(blk);
        if (dinfo && dinfo->type == type && dinfo->bus == bus && dinfo->unit == unit) { return dinfo; }
    }

    return NULL;
}

/*
 * Check board claimed all -drive that are meant to be claimed.
 * Fatal error if any remain unclaimed.
 */
void drive_check_orphaned(void)
{
    BlockBackend* blk;
    DriveInfo*    dinfo;
    Location      loc;
    bool          orphans = false;

    GLOBAL_STATE_CODE();

    for (blk = blk_next(NULL); blk; blk = blk_next(blk)) {
        dinfo = blk_legacy_dinfo(blk);
        /*
         * Ignore default drives, because we create certain default
         * drives unconditionally, then leave them unclaimed.  Not the
         * users fault.
         * Ignore IF_NONE, because leaving unclaimed IF_NONE remains
         * available for device_add is a feature.
         */
        if (dinfo->is_default || dinfo->type == IF_NONE) { continue; }
        if (!blk_get_attached_dev(blk)) {
            loc_push_none(&loc);
            qemu_opts_loc_restore(dinfo->opts);
            error_report("machine type does not support"
                         " if=%s,bus=%d,unit=%d",
                         if_name[dinfo->type], dinfo->bus, dinfo->unit);
            loc_pop(&loc);
            orphans = true;
        }
    }

    if (orphans) { exit(1); }
}

DriveInfo* drive_get_by_index(BlockInterfaceType type, int index)
{
    GLOBAL_STATE_CODE();
    return drive_get(type, drive_index_to_bus_id(type, index), drive_index_to_unit_id(type, index));
}

int drive_get_max_bus(BlockInterfaceType type)
{
    int           max_bus;
    BlockBackend* blk;
    DriveInfo*    dinfo;

    GLOBAL_STATE_CODE();

    max_bus = -1;
    for (blk = blk_next(NULL); blk; blk = blk_next(blk)) {
        dinfo = blk_legacy_dinfo(blk);
        if (dinfo && dinfo->type == type && dinfo->bus > max_bus) { max_bus = dinfo->bus; }
    }
    return max_bus;
}

static void bdrv_format_print(void* opaque, const char* name) { qemu_printf(" %s", name); }

typedef struct
{
    QEMUBH*           bh;
    BlockDriverState* bs;
} BDRVPutRefBH;

static int parse_block_error_action(const char* buf, bool is_read, Error** errp)
{
    if (!strcmp(buf, "ignore")) { return BLOCKDEV_ON_ERROR_IGNORE; }
    else if (!is_read && !strcmp(buf, "enospc")) {
        return BLOCKDEV_ON_ERROR_ENOSPC;
    }
    else if (!strcmp(buf, "stop")) {
        return BLOCKDEV_ON_ERROR_STOP;
    }
    else if (!strcmp(buf, "report")) {
        return BLOCKDEV_ON_ERROR_REPORT;
    }
    else {
        error_setg(errp, "'%s' invalid %s error action", buf, is_read ? "read" : "write");
        return -1;
    }
}

static bool parse_stats_intervals(BlockAcctStats* stats, QList* intervals, Error** errp)
{
    const QListEntry* entry;
    for (entry = qlist_first(intervals); entry; entry = qlist_next(entry)) {
        switch (qobject_type(entry->value)) {

            case QTYPE_QSTRING: {
                uint64_t    length;
                const char* str = qstring_get_str(qobject_to(QString, entry->value));
                if (parse_uint_full(str, 10, &length) == 0 && length > 0 && length <= UINT_MAX) {
                    block_acct_add_interval(stats, (unsigned)length);
                }
                else {
                    error_setg(errp, "Invalid interval length: %s", str);
                    return false;
                }
                break;
            }

            case QTYPE_QNUM: {
                int64_t length = qnum_get_int(qobject_to(QNum, entry->value));

                if (length > 0 && length <= UINT_MAX) { block_acct_add_interval(stats, (unsigned)length); }
                else {
                    error_setg(errp, "Invalid interval length: %" PRId64, length);
                    return false;
                }
                break;
            }

            default: error_setg(errp, "The specification of stats-intervals is invalid"); return false;
        }
    }
    return true;
}

typedef enum
{
    MEDIA_DISK,
    MEDIA_CDROM
} DriveMediaType;

/* All parameters but @opts are optional and may be set to NULL. */
static void extract_common_blockdev_options(QemuOpts* opts, int* bdrv_flags, BlockdevDetectZeroesOptions* detect_zeroes,
                                            Error** errp)
{
    Error*      local_error = NULL;
    const char* aio;

    if (bdrv_flags) {
        if (qemu_opt_get_bool(opts, "copy-on-read", false)) { *bdrv_flags |= BDRV_O_COPY_ON_READ; }

        if ((aio = qemu_opt_get(opts, "aio")) != NULL) {
            if (bdrv_parse_aio(aio, bdrv_flags) < 0) {
                error_setg(errp, "invalid aio option");
                return;
            }
        }
    }

    if (detect_zeroes) {
        *detect_zeroes = qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup, qemu_opt_get(opts, "detect-zeroes"),
                                         BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF, &local_error);
        if (local_error) {
            error_propagate(errp, local_error);
            return;
        }
    }
}

static OnOffAuto account_get_opt(QemuOpts* opts, const char* name)
{
    if (!qemu_opt_find(opts, name)) { return ON_OFF_AUTO_AUTO; }
    if (qemu_opt_get_bool(opts, name, true)) { return ON_OFF_AUTO_ON; }
    return ON_OFF_AUTO_OFF;
}

/* Takes the ownership of bs_opts */
static BlockBackend* blockdev_init(const char* file, QDict* bs_opts, Error** errp)
{
    const char*                 buf;
    int                         bdrv_flags = 0;
    int                         on_read_error, on_write_error;
    OnOffAuto                   account_invalid, account_failed;
    bool                        writethrough, read_only;
    BlockBackend*               blk;
    BlockDriverState*           bs;
    int                         snapshot = 0;
    Error*                      error    = NULL;
    QemuOpts*                   opts;
    QDict*                      interval_dict = NULL;
    QList*                      interval_list = NULL;
    const char*                 id;
    BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;

    /* Check common options by copying from bs_opts to opts, all other options
     * stay in bs_opts for processing by bdrv_open(). */
    id   = qdict_get_try_str(bs_opts, "id");
    opts = qemu_opts_create(&qemu_common_drive_opts, id, 1, errp);
    if (!opts) { goto err_no_opts; }

    if (!qemu_opts_absorb_qdict(opts, bs_opts, errp)) { goto early_err; }

    if (id) { qdict_del(bs_opts, "id"); }

    /* extract parameters */
    snapshot = qemu_opt_get_bool(opts, "snapshot", 0);

    account_invalid = account_get_opt(opts, "stats-account-invalid");
    account_failed  = account_get_opt(opts, "stats-account-failed");

    writethrough = !qemu_opt_get_bool(opts, BDRV_OPT_CACHE_WB, true);

    id = qemu_opts_id(opts);

    qdict_extract_subqdict(bs_opts, &interval_dict, "stats-intervals.");
    qdict_array_split(interval_dict, &interval_list);

    if (qdict_size(interval_dict) != 0) {
        error_setg(errp, "Invalid option stats-intervals.%s", qdict_first(interval_dict)->key);
        goto early_err;
    }

    extract_common_blockdev_options(opts, &bdrv_flags, &detect_zeroes, &error);
    if (error) {
        error_propagate(errp, error);
        goto early_err;
    }

    if ((buf = qemu_opt_get(opts, "format")) != NULL) {
        if (is_help_option(buf)) {
            qemu_printf("Supported formats:");
            bdrv_iterate_format(bdrv_format_print, NULL, false);
            qemu_printf("\nSupported formats (read-only):");
            bdrv_iterate_format(bdrv_format_print, NULL, true);
            qemu_printf("\n");
            goto early_err;
        }

        if (qdict_haskey(bs_opts, "driver")) {
            error_setg(errp, "Cannot specify both 'driver' and 'format'");
            goto early_err;
        }
        qdict_put_str(bs_opts, "driver", buf);
    }

    on_write_error = BLOCKDEV_ON_ERROR_ENOSPC;
    if ((buf = qemu_opt_get(opts, "werror")) != NULL) {
        on_write_error = parse_block_error_action(buf, 0, &error);
        if (error) {
            error_propagate(errp, error);
            goto early_err;
        }
    }

    on_read_error = BLOCKDEV_ON_ERROR_REPORT;
    if ((buf = qemu_opt_get(opts, "rerror")) != NULL) {
        on_read_error = parse_block_error_action(buf, 1, &error);
        if (error) {
            error_propagate(errp, error);
            goto early_err;
        }
    }

    if (snapshot) { bdrv_flags |= BDRV_O_SNAPSHOT; }

    read_only = qemu_opt_get_bool(opts, BDRV_OPT_READ_ONLY, false);

    /* init */
    if ((!file || !*file) && !qdict_size(bs_opts)) {
        BlockBackendRootState* blk_rs;

        blk                   = blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL);
        blk_rs                = blk_get_root_state(blk);
        blk_rs->open_flags    = bdrv_flags | (read_only ? 0 : BDRV_O_RDWR);
        blk_rs->detect_zeroes = detect_zeroes;

        qobject_unref(bs_opts);
    }
    else {
        if (file && !*file) { file = NULL; }

        /* bdrv_open() defaults to the values in bdrv_flags (for compatibility
         * with other callers) rather than what we want as the real defaults.
         * Apply the defaults here instead. */
        qdict_set_default_str(bs_opts, BDRV_OPT_CACHE_DIRECT, "off");
        qdict_set_default_str(bs_opts, BDRV_OPT_CACHE_NO_FLUSH, "off");
        qdict_set_default_str(bs_opts, BDRV_OPT_READ_ONLY, read_only ? "on" : "off");
        qdict_set_default_str(bs_opts, BDRV_OPT_AUTO_READ_ONLY, "on");
        assert((bdrv_flags & BDRV_O_CACHE_MASK) == 0);

        blk = blk_new_open(file, NULL, bs_opts, bdrv_flags, errp);
        if (!blk) { goto err_no_bs_opts; }
        bs = blk_bs(blk);

        bs->detect_zeroes = detect_zeroes;

        block_acct_setup(blk_get_stats(blk), account_invalid, account_failed);

        if (!parse_stats_intervals(blk_get_stats(blk), interval_list, errp)) {
            blk_unref(blk);
            blk = NULL;
            goto err_no_bs_opts;
        }
    }

    blk_set_enable_write_cache(blk, !writethrough);
    blk_set_on_error(blk, on_read_error, on_write_error);

    if (!monitor_add_blk(blk, id, errp)) {
        blk_unref(blk);
        blk = NULL;
        goto err_no_bs_opts;
    }

err_no_bs_opts:
    qemu_opts_del(opts);
    qobject_unref(interval_dict);
    qobject_unref(interval_list);
    return blk;

early_err:
    qemu_opts_del(opts);
    qobject_unref(interval_dict);
    qobject_unref(interval_list);
err_no_opts:
    qobject_unref(bs_opts);
    return NULL;
}

/* Takes the ownership of bs_opts */
BlockDriverState* bds_tree_init(QDict* bs_opts, Error** errp)
{
    int bdrv_flags = 0;

    GLOBAL_STATE_CODE();
    /* bdrv_open() defaults to the values in bdrv_flags (for compatibility
     * with other callers) rather than what we want as the real defaults.
     * Apply the defaults here instead. */
    qdict_set_default_str(bs_opts, BDRV_OPT_CACHE_DIRECT, "off");
    qdict_set_default_str(bs_opts, BDRV_OPT_CACHE_NO_FLUSH, "off");
    qdict_set_default_str(bs_opts, BDRV_OPT_READ_ONLY, "off");

    return bdrv_open(NULL, NULL, bs_opts, bdrv_flags, errp);
}

void blockdev_close_all_bdrv_states(void)
{
    BlockDriverState *bs, *next_bs;

    GLOBAL_STATE_CODE();
    QTAILQ_FOREACH_SAFE (bs, &monitor_bdrv_states, monitor_list, next_bs) { bdrv_unref(bs); }
}

/* Iterates over the list of monitor-owned BlockDriverStates */
BlockDriverState* bdrv_next_monitor_owned(BlockDriverState* bs)
{
    GLOBAL_STATE_CODE();
    return bs ? QTAILQ_NEXT(bs, monitor_list) : QTAILQ_FIRST(&monitor_bdrv_states);
}

static bool qemu_opt_rename(QemuOpts* opts, const char* from, const char* to, Error** errp)
{
    const char* value;

    value = qemu_opt_get(opts, from);
    if (value) {
        if (qemu_opt_find(opts, to)) {
            error_setg(errp,
                       "'%s' and its alias '%s' can't be used at the "
                       "same time",
                       to, from);
            return false;
        }
    }

    /* rename all items in opts */
    while ((value = qemu_opt_get(opts, from))) {
        qemu_opt_set(opts, to, value, &error_abort);
        qemu_opt_unset(opts, from);
    }
    return true;
}

QemuOptsList qemu_legacy_drive_opts = {
    .name = "drive",
    .head = QTAILQ_HEAD_INITIALIZER(qemu_legacy_drive_opts.head),
    .desc = {{
                 .name = "bus",
                 .type = QEMU_OPT_NUMBER,
                 .help = "bus number",
             },
             {
                 .name = "unit",
                 .type = QEMU_OPT_NUMBER,
                 .help = "unit number (i.e. lun for scsi)",
             },
             {
                 .name = "index",
                 .type = QEMU_OPT_NUMBER,
                 .help = "index number",
             },
             {
                 .name = "media",
                 .type = QEMU_OPT_STRING,
                 .help = "media type (disk, cdrom)",
             },
             {
                 .name = "if",
                 .type = QEMU_OPT_STRING,
                 .help = "interface (sd, mtd, pflash)",
             },
             {
                 .name = "file",
                 .type = QEMU_OPT_STRING,
                 .help = "file name",
             },

             /* Options that are passed on, but have special semantics with -drive */
             {
                 .name = BDRV_OPT_READ_ONLY,
                 .type = QEMU_OPT_BOOL,
                 .help = "open drive file as read-only",
             },
             {
                 .name = "rerror",
                 .type = QEMU_OPT_STRING,
                 .help = "read error action",
             },
             {
                 .name = "werror",
                 .type = QEMU_OPT_STRING,
                 .help = "write error action",
             },
             {
                 .name = "copy-on-read",
                 .type = QEMU_OPT_BOOL,
                 .help = "copy read data from backing file into image file",
             },

             {/* end of list */}},
};

DriveInfo* drive_new(QemuOpts* all_opts, BlockInterfaceType block_default_type, Error** errp)
{
    const char*        value;
    BlockBackend*      blk;
    DriveInfo*         dinfo = NULL;
    QDict*             bs_opts;
    QemuOpts*          legacy_opts;
    DriveMediaType     media = MEDIA_DISK;
    BlockInterfaceType type;
    int                max_devs, bus_id, unit_id, index;
    const char *       werror, *rerror;
    bool               read_only = false;
    bool               copy_on_read;
    const char*        filename;
    int                i;

    GLOBAL_STATE_CODE();

    /* Change legacy command line options into QMP ones */
    static const struct
    {
        const char* from;
        const char* to;
    } opt_renames[] = {
        {"iops", "throttling.iops-total"},
        {"iops_rd", "throttling.iops-read"},
        {"iops_wr", "throttling.iops-write"},

        {"bps", "throttling.bps-total"},
        {"bps_rd", "throttling.bps-read"},
        {"bps_wr", "throttling.bps-write"},

        {"iops_max", "throttling.iops-total-max"},
        {"iops_rd_max", "throttling.iops-read-max"},
        {"iops_wr_max", "throttling.iops-write-max"},

        {"bps_max", "throttling.bps-total-max"},
        {"bps_rd_max", "throttling.bps-read-max"},
        {"bps_wr_max", "throttling.bps-write-max"},

        {"iops_size", "throttling.iops-size"},

        {"group", "throttling.group"},

        {"readonly", BDRV_OPT_READ_ONLY},
    };

    for (i = 0; i < ARRAY_SIZE(opt_renames); i++) {
        if (!qemu_opt_rename(all_opts, opt_renames[i].from, opt_renames[i].to, errp)) { return NULL; }
    }

    value = qemu_opt_get(all_opts, "cache");
    if (value) {
        int  flags = 0;
        bool writethrough;

        if (bdrv_parse_cache_mode(value, &flags, &writethrough) != 0) {
            error_setg(errp, "invalid cache option");
            return NULL;
        }

        /* Specific options take precedence */
        if (!qemu_opt_get(all_opts, BDRV_OPT_CACHE_WB)) {
            qemu_opt_set_bool(all_opts, BDRV_OPT_CACHE_WB, !writethrough, &error_abort);
        }
        if (!qemu_opt_get(all_opts, BDRV_OPT_CACHE_DIRECT)) {
            qemu_opt_set_bool(all_opts, BDRV_OPT_CACHE_DIRECT, !!(flags & BDRV_O_NOCACHE), &error_abort);
        }
        if (!qemu_opt_get(all_opts, BDRV_OPT_CACHE_NO_FLUSH)) {
            qemu_opt_set_bool(all_opts, BDRV_OPT_CACHE_NO_FLUSH, !!(flags & BDRV_O_NO_FLUSH), &error_abort);
        }
        qemu_opt_unset(all_opts, "cache");
    }

    /* Get a QDict for processing the options */
    bs_opts = qdict_new();
    qemu_opts_to_qdict(all_opts, bs_opts);

    legacy_opts = qemu_opts_create(&qemu_legacy_drive_opts, NULL, 0, &error_abort);
    if (!qemu_opts_absorb_qdict(legacy_opts, bs_opts, errp)) { goto fail; }

    /* Media type */
    value = qemu_opt_get(legacy_opts, "media");
    if (value) {
        if (!strcmp(value, "disk")) { media = MEDIA_DISK; }
        else if (!strcmp(value, "cdrom")) {
            media     = MEDIA_CDROM;
            read_only = true;
        }
        else {
            error_setg(errp, "'%s' invalid media", value);
            goto fail;
        }
    }

    /* copy-on-read is disabled with a warning for read-only devices */
    read_only    |= qemu_opt_get_bool(legacy_opts, BDRV_OPT_READ_ONLY, false);
    copy_on_read  = qemu_opt_get_bool(legacy_opts, "copy-on-read", false);

    if (read_only && copy_on_read) {
        warn_report("disabling copy-on-read on read-only drive");
        copy_on_read = false;
    }

    qdict_put_str(bs_opts, BDRV_OPT_READ_ONLY, read_only ? "on" : "off");
    qdict_put_str(bs_opts, "copy-on-read", copy_on_read ? "on" : "off");

    /* Controller type */
    value = qemu_opt_get(legacy_opts, "if");
    if (value) {
        for (type = 0; type < IF_COUNT && strcmp(value, if_name[type]); type++) { }
        if (type == IF_COUNT) {
            error_setg(errp, "unsupported bus type '%s'", value);
            goto fail;
        }
    }
    else {
        type = block_default_type;
    }

    /* Device address specified by bus/unit or index.
     * If none was specified, try to find the first free one. */
    bus_id  = qemu_opt_get_number(legacy_opts, "bus", 0);
    unit_id = qemu_opt_get_number(legacy_opts, "unit", -1);
    index   = qemu_opt_get_number(legacy_opts, "index", -1);

    max_devs = if_max_devs[type];

    if (index != -1) {
        if (bus_id != 0 || unit_id != -1) {
            error_setg(errp, "index cannot be used with bus and unit");
            goto fail;
        }
        bus_id  = drive_index_to_bus_id(type, index);
        unit_id = drive_index_to_unit_id(type, index);
    }

    if (unit_id == -1) {
        unit_id = 0;
        while (drive_get(type, bus_id, unit_id) != NULL) {
            unit_id++;
            if (max_devs && unit_id >= max_devs) {
                unit_id -= max_devs;
                bus_id++;
            }
        }
    }

    if (max_devs && unit_id >= max_devs) {
        error_setg(errp, "unit %d too big (max is %d)", unit_id, max_devs - 1);
        goto fail;
    }

    if (drive_get(type, bus_id, unit_id) != NULL) {
        error_setg(errp, "drive with bus=%d, unit=%d (index=%d) exists", bus_id, unit_id, index);
        goto fail;
    }

    /* no id supplied -> create one */
    if (qemu_opts_id(all_opts) == NULL) {
        char* new_id;
        if (max_devs) { new_id = g_strdup_printf("%s%i%i", if_name[type], bus_id, unit_id); }
        else {
            new_id = g_strdup_printf("%s%i", if_name[type], unit_id);
        }
        qdict_put_str(bs_opts, "id", new_id);
        g_free(new_id);
    }

    filename = qemu_opt_get(legacy_opts, "file");

    /* Check werror/rerror compatibility with if=... */
    werror = qemu_opt_get(legacy_opts, "werror");
    if (werror != NULL) {
        if (type != IF_NONE) {
            error_setg(errp, "werror is not supported by this bus type");
            goto fail;
        }
        qdict_put_str(bs_opts, "werror", werror);
    }

    rerror = qemu_opt_get(legacy_opts, "rerror");
    if (rerror != NULL) {
        if (type != IF_NONE) {
            error_setg(errp, "rerror is not supported by this bus type");
            goto fail;
        }
        qdict_put_str(bs_opts, "rerror", rerror);
    }

    /* Actual block device init: Functionality shared with blockdev-add */
    blk     = blockdev_init(filename, bs_opts, errp);
    bs_opts = NULL;
    if (!blk) { goto fail; }

    /* Create legacy DriveInfo */
    dinfo       = g_malloc0(sizeof(*dinfo));
    dinfo->opts = all_opts;

    dinfo->type = type;
    dinfo->bus  = bus_id;
    dinfo->unit = unit_id;

    blk_set_legacy_dinfo(blk, dinfo);

    switch (type) {
        case IF_NONE: dinfo->media_cd = media == MEDIA_CDROM; break;
        default     : break;
    }

fail:
    qemu_opts_del(legacy_opts);
    qobject_unref(bs_opts);
    return dinfo;
}

static BlockDriverState* qmp_get_root_bs(const char* name, Error** errp)
{
    BlockDriverState* bs;

    GRAPH_RDLOCK_GUARD_MAINLOOP();

    bs = bdrv_lookup_bs(name, name, errp);
    if (bs == NULL) { return NULL; }

    if (!bdrv_is_root_node(bs)) {
        error_setg(errp, "Need a root block node");
        return NULL;
    }

    if (!bdrv_is_inserted(bs)) {
        error_setg(errp, "Device has no medium");
        bs = NULL;
    }

    return bs;
}

static void blockdev_do_action(TransactionAction* action, Error** errp)
{
    TransactionActionList list;

    list.value = action;
    list.next  = NULL;
    qmp_transaction(&list, NULL, errp);
}

void qmp_blockdev_snapshot_sync(const char* device, const char* node_name, const char* snapshot_file,
                                const char* snapshot_node_name, const char* format, bool has_mode, NewImageMode mode,
                                Error** errp)
{
    BlockdevSnapshotSync snapshot = {
        .device             = (char*)device,
        .node_name          = (char*)node_name,
        .snapshot_file      = (char*)snapshot_file,
        .snapshot_node_name = (char*)snapshot_node_name,
        .format             = (char*)format,
        .has_mode           = has_mode,
        .mode               = mode,
    };
    TransactionAction action = {
        .type                          = TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC,
        .u.blockdev_snapshot_sync.data = &snapshot,
    };
    blockdev_do_action(&action, errp);
}

void qmp_blockdev_snapshot(const char* node, const char* overlay, Error** errp)
{
    BlockdevSnapshot  snapshot_data = {.node = (char*)node, .overlay = (char*)overlay};
    TransactionAction action        = {
        .type                     = TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT,
        .u.blockdev_snapshot.data = &snapshot_data,
    };
    blockdev_do_action(&action, errp);
}

void qmp_blockdev_snapshot_internal_sync(const char* device, const char* name, Error** errp)
{
    BlockdevSnapshotInternal snapshot = {.device = (char*)device, .name = (char*)name};
    TransactionAction        action   = {
        .type                                   = TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_INTERNAL_SYNC,
        .u.blockdev_snapshot_internal_sync.data = &snapshot,
    };
    blockdev_do_action(&action, errp);
}

SnapshotInfo* qmp_blockdev_snapshot_delete_internal_sync(const char* device, const char* id, const char* name,
                                                         Error** errp)
{
    BlockDriverState* bs;
    QEMUSnapshotInfo  sn;
    Error*            local_err = NULL;
    SnapshotInfo*     info      = NULL;
    int               ret;

    GLOBAL_STATE_CODE();

    bdrv_drain_all_begin();
    bdrv_graph_rdlock_main_loop();

    bs = qmp_get_root_bs(device, errp);
    if (!bs) { goto error; }

    if (!id && !name) {
        error_setg(errp, "Name or id must be provided");
        goto error;
    }

    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE, errp)) { goto error; }

    ret = bdrv_snapshot_find_by_id_and_name(bs, id, name, &sn, &local_err);
    if (local_err) {
        error_propagate(errp, local_err);
        goto error;
    }
    if (!ret) {
        error_setg(errp,
                   "Snapshot with id '%s' and name '%s' does not exist on "
                   "device '%s'",
                   STR_OR_NULL(id), STR_OR_NULL(name), device);
        goto error;
    }

    bdrv_snapshot_delete(bs, id, name, &local_err);
    if (local_err) {
        error_propagate(errp, local_err);
        goto error;
    }

    info                = g_new0(SnapshotInfo, 1);
    info->id            = g_strdup(sn.id_str);
    info->name          = g_strdup(sn.name);
    info->date_nsec     = sn.date_nsec;
    info->date_sec      = sn.date_sec;
    info->vm_state_size = sn.vm_state_size;
    info->vm_clock_nsec = sn.vm_clock_nsec % 1000000000;
    info->vm_clock_sec  = sn.vm_clock_nsec / 1000000000;

error:
    bdrv_graph_rdunlock_main_loop();
    bdrv_drain_all_end();
    return info;
}

/* internal snapshot private data */
typedef struct InternalSnapshotState
{
    BlockDriverState* bs;
    QEMUSnapshotInfo  sn;
    bool              created;
} InternalSnapshotState;

static void          internal_snapshot_abort(void* opaque);
static void          internal_snapshot_clean(void* opaque);
TransactionActionDrv internal_snapshot_drv = {
    .abort = internal_snapshot_abort,
    .clean = internal_snapshot_clean,
};

static void internal_snapshot_action(BlockdevSnapshotInternal* internal, Transaction* tran, Error** errp)
{
    Error*                 local_err = NULL;
    const char*            device;
    const char*            name;
    BlockDriverState *     bs, *check_bs;
    QEMUSnapshotInfo       old_sn, *sn;
    bool                   ret;
    int64_t                rt;
    InternalSnapshotState* state = g_new0(InternalSnapshotState, 1);
    int                    ret1;

    GLOBAL_STATE_CODE();
    bdrv_graph_rdlock_main_loop();

    tran_add(tran, &internal_snapshot_drv, state);

    device = internal->device;
    name   = internal->name;

    bs = qmp_get_root_bs(device, errp);
    if (!bs) {
        bdrv_graph_rdunlock_main_loop();
        return;
    }

    state->bs = bs;

    /* Need to drain while unlocked. */
    bdrv_graph_rdunlock_main_loop();
    /* Paired with .clean() */
    bdrv_drained_begin(bs);

    GRAPH_RDLOCK_GUARD_MAINLOOP();

    /* Make sure the root bs did not change with the drain. */
    check_bs = qmp_get_root_bs(device, errp);
    if (bs != check_bs) {
        if (check_bs) {
            error_setg(errp, "Block node of device '%s' unexpectedly changed", device);
        } /* else errp is already set */
        return;
    }

    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT, errp)) { return; }

    if (bdrv_is_read_only(bs)) {
        error_setg(errp, "Device '%s' is read only", device);
        return;
    }

    if (!bdrv_can_snapshot(bs)) {
        error_setg(errp,
                   "Block format '%s' used by device '%s' "
                   "does not support internal snapshots",
                   bs->drv->format_name, device);
        return;
    }

    if (!strlen(name)) {
        error_setg(errp, "Name is empty");
        return;
    }

    /* check whether a snapshot with name exist */
    ret = bdrv_snapshot_find_by_id_and_name(bs, NULL, name, &old_sn, &local_err);
    if (local_err) {
        error_propagate(errp, local_err);
        return;
    }
    else if (ret) {
        error_setg(errp, "Snapshot with name '%s' already exists on device '%s'", name, device);
        return;
    }

    /* 3. take the snapshot */
    sn = &state->sn;
    pstrcpy(sn->name, sizeof(sn->name), name);
    rt                = g_get_real_time();
    sn->date_sec      = rt / G_USEC_PER_SEC;
    sn->date_nsec     = (rt % G_USEC_PER_SEC) * 1000;
    sn->vm_clock_nsec = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);

    ret1 = bdrv_snapshot_create(bs, sn);
    if (ret1 < 0) {
        error_setg_errno(errp, -ret1, "Failed to create snapshot '%s' on device '%s'", name, device);
        return;
    }

    /* 4. succeed, mark a snapshot is created */
    state->created = true;
}

static void internal_snapshot_abort(void* opaque)
{
    InternalSnapshotState* state       = opaque;
    BlockDriverState*      bs          = state->bs;
    QEMUSnapshotInfo*      sn          = &state->sn;
    Error*                 local_error = NULL;

    GLOBAL_STATE_CODE();

    if (!state->created) { return; }

    bdrv_drain_all_begin();
    bdrv_graph_rdlock_main_loop();

    if (bdrv_snapshot_delete(bs, sn->id_str, sn->name, &local_error) < 0) {
        error_reportf_err(local_error,
                          "Failed to delete snapshot with id '%s' and "
                          "name '%s' on device '%s' in abort: ",
                          sn->id_str, sn->name, bdrv_get_device_name(bs));
    }
    bdrv_graph_rdunlock_main_loop();
    bdrv_drain_all_end();
}

static void internal_snapshot_clean(void* opaque)
{
    g_autofree InternalSnapshotState* state = opaque;

    if (!state->bs) { return; }

    bdrv_drained_end(state->bs);
}

/* external snapshot private data */
typedef struct ExternalSnapshotState
{
    BlockDriverState* old_bs;
    BlockDriverState* new_bs;
    bool              overlay_appended;
} ExternalSnapshotState;

static void          external_snapshot_commit(void* opaque);
static void          external_snapshot_abort(void* opaque);
static void          external_snapshot_clean(void* opaque);
TransactionActionDrv external_snapshot_drv = {
    .commit = external_snapshot_commit,
    .abort  = external_snapshot_abort,
    .clean  = external_snapshot_clean,
};

static void external_snapshot_action(TransactionAction* action, Transaction* tran, Error** errp)
{
    int    ret;
    int    flags     = 0;
    QDict* options   = NULL;
    Error* local_err = NULL;
    /* Device and node name of the image to generate the snapshot from */
    const char* device;
    const char* node_name;
    /* Reference to the new image (for 'blockdev-snapshot') */
    const char* snapshot_ref;
    /* File name of the new image (for 'blockdev-snapshot-sync') */
    const char*            new_image_file;
    ExternalSnapshotState* state = g_new0(ExternalSnapshotState, 1);
    uint64_t               perm, shared;
    BlockDriverState*      check_bs;

    /* TODO We'll eventually have to take a writer lock in this function */
    bdrv_graph_rdlock_main_loop();

    tran_add(tran, &external_snapshot_drv, state);

    /* 'blockdev-snapshot' and 'blockdev-snapshot-sync' have similar
     * purpose but a different set of parameters */
    switch (action->type) {
        case TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT: {
            BlockdevSnapshot* s = action->u.blockdev_snapshot.data;
            device              = s->node;
            node_name           = s->node;
            new_image_file      = NULL;
            snapshot_ref        = s->overlay;
        } break;
        case TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC: {
            BlockdevSnapshotSync* s = action->u.blockdev_snapshot_sync.data;
            device                  = s->device;
            node_name               = s->node_name;
            new_image_file          = s->snapshot_file;
            snapshot_ref            = NULL;
        } break;
        default: assert_not_reached();
    }

    /* start processing */

    state->old_bs = bdrv_lookup_bs(device, node_name, errp);
    if (!state->old_bs) {
        bdrv_graph_rdunlock_main_loop();
        return;
    }

    /* Need to drain while unlocked. */
    bdrv_graph_rdunlock_main_loop();
    /* Paired with .clean() */
    bdrv_drained_begin(state->old_bs);
    bdrv_graph_rdlock_main_loop();

    /* Make sure the associated bs did not change with the drain. */
    check_bs = bdrv_lookup_bs(device, node_name, errp);
    if (state->old_bs != check_bs) {
        if (check_bs) {
            error_setg(errp, "Block node of device '%s' unexpectedly changed", device);
        } /* else errp is already set */
        goto unlock;
    }

    if (!bdrv_is_inserted(state->old_bs)) {
        error_setg(errp, "Device '%s' has no medium", bdrv_get_device_or_node_name(state->old_bs));
        goto unlock;
    }

    if (bdrv_op_is_blocked(state->old_bs, BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT, errp)) { goto unlock; }

    if (!bdrv_is_read_only(state->old_bs)) {
        ret = bdrv_flush(state->old_bs);
        if (ret < 0) {
            error_setg_errno(errp, -ret, "Write to node '%s' failed", bdrv_get_device_or_node_name(state->old_bs));
            goto unlock;
        }
    }

    if (action->type == TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC) {
        BlockdevSnapshotSync* s      = action->u.blockdev_snapshot_sync.data;
        const char*           format = s->format ?: "qcow2";
        enum NewImageMode     mode;
        const char*           snapshot_node_name = s->snapshot_node_name;

        if (node_name && !snapshot_node_name) {
            error_setg(errp, "New overlay node-name missing");
            goto unlock;
        }

        if (snapshot_node_name && bdrv_lookup_bs(snapshot_node_name, snapshot_node_name, NULL)) {
            error_setg(errp, "New overlay node-name already in use");
            goto unlock;
        }

        flags  = state->old_bs->open_flags;
        flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_COPY_ON_READ);
        flags |= BDRV_O_NO_BACKING;

        /* create new image w/backing file */
        mode = s->has_mode ? s->mode : NEW_IMAGE_MODE_ABSOLUTE_PATHS;
        if (mode != NEW_IMAGE_MODE_EXISTING) {
            int64_t size = bdrv_getlength(state->old_bs);
            if (size < 0) {
                error_setg_errno(errp, -size, "bdrv_getlength failed");
                goto unlock;
            }
            bdrv_refresh_filename(state->old_bs);

            bdrv_img_create(new_image_file, format, state->old_bs->filename, state->old_bs->drv->format_name, NULL,
                            size, flags, false, &local_err);

            if (local_err) {
                error_propagate(errp, local_err);
                goto unlock;
            }
        }

        options = qdict_new();
        if (snapshot_node_name) { qdict_put_str(options, "node-name", snapshot_node_name); }
        qdict_put_str(options, "driver", format);
    }

    state->new_bs = bdrv_open(new_image_file, snapshot_ref, options, flags, errp);

    /* We will manually add the backing_hd field to the bs later */
    if (!state->new_bs) { goto unlock; }

    /*
     * Allow attaching a backing file to an overlay that's already in use only
     * if the parents don't assume that they are already seeing a valid image.
     * (Specifically, allow it as a mirror target, which is write-only access.)
     */
    bdrv_get_cumulative_perm(state->new_bs, &perm, &shared);
    if (perm & BLK_PERM_CONSISTENT_READ) {
        error_setg(errp, "The overlay is already in use");
        goto unlock;
    }

    if (state->new_bs->drv->is_filter) {
        error_setg(errp, "Filters cannot be used as overlays");
        goto unlock;
    }

    if (bdrv_cow_child(state->new_bs)) {
        error_setg(errp, "The overlay already has a backing image");
        goto unlock;
    }

    if (!state->new_bs->drv->supports_backing) {
        error_setg(errp, "The overlay does not support backing images");
        goto unlock;
    }

    if (bdrv_is_inactive(state->old_bs) && !bdrv_is_inactive(state->new_bs)) {
        bdrv_graph_rdunlock_main_loop();
        bdrv_drain_all_begin();
        bdrv_graph_rdlock_main_loop();
        ret = bdrv_inactivate(state->new_bs, errp);
        bdrv_drain_all_end();
        if (ret < 0) { goto unlock; }
    }

    ret = bdrv_append(state->new_bs, state->old_bs, errp);
    if (ret < 0) { goto unlock; }
    state->overlay_appended = true;
unlock:
    bdrv_graph_rdunlock_main_loop();
}

static void external_snapshot_commit(void* opaque)
{
    ExternalSnapshotState* state = opaque;

    /* We don't need (or want) to use the transactional
     * bdrv_reopen_multiple() across all the entries at once, because we
     * don't want to abort all of them if one of them fails the reopen */
    if (!qatomic_read(&state->old_bs->copy_on_read)) { bdrv_reopen_set_read_only(state->old_bs, true, NULL); }
}

static void external_snapshot_abort(void* opaque)
{
    ExternalSnapshotState* state = opaque;
    if (state->new_bs) {
        if (state->overlay_appended) {
            AioContext* aio_context;
            AioContext* tmp_context;
            int         ret;

            bdrv_graph_wrlock_drained();

            aio_context = bdrv_get_aio_context(state->old_bs);

            /*
             * Note that state->old_bs would not disappear during the
             * write-locked section, because the unref from
             * bdrv_set_backing_hd() only happens at the end of the write-locked
             * section. However, just be explicit about keeping a reference and
             * don't rely on that implicit detail.
             */
            bdrv_ref(state->old_bs);
            bdrv_set_backing_hd(state->new_bs, NULL, &error_abort);

            /*
             * The call to bdrv_set_backing_hd() above returns state->old_bs to
             * the main AioContext. As we're still going to be using it, return
             * it to the AioContext it was before.
             */
            tmp_context = bdrv_get_aio_context(state->old_bs);
            if (aio_context != tmp_context) {
                ret = bdrv_try_change_aio_context_locked(state->old_bs, aio_context, NULL, NULL);
                assert(ret == 0);
            }

            bdrv_replace_node(state->new_bs, state->old_bs, &error_abort);
            bdrv_graph_wrunlock();

            bdrv_unref(state->old_bs); /* bdrv_replace_node() ref'ed old_bs */
        }
    }
}

static void external_snapshot_clean(void* opaque)
{
    g_autofree ExternalSnapshotState* state = opaque;

    if (!state->old_bs) { return; }

    bdrv_drained_end(state->old_bs);
    bdrv_unref(state->new_bs);
}

typedef struct DriveBackupState
{
    BlockDriverState* bs;
    BlockJob*         job;
} DriveBackupState;

static BlockJob* do_backup_common(BackupCommon* backup, BlockDriverState* bs, BlockDriverState* target_bs,
                                  AioContext* aio_context, JobTxn* txn, Error** errp);

static void          drive_backup_commit(void* opaque);
static void          drive_backup_abort(void* opaque);
static void          drive_backup_clean(void* opaque);
TransactionActionDrv drive_backup_drv = {
    .commit = drive_backup_commit,
    .abort  = drive_backup_abort,
    .clean  = drive_backup_clean,
};

static void drive_backup_action(DriveBackup* backup, JobTxn* block_job_txn, Transaction* tran, Error** errp)
{
    DriveBackupState* state = g_new0(DriveBackupState, 1);
    BlockDriverState* bs;
    BlockDriverState* target_bs;
    BlockDriverState* source = NULL;
    AioContext*       aio_context;
    const char*       format;
    QDict*            options;
    Error*            local_err = NULL;
    int               flags;
    int64_t           size;
    bool              set_backing_hd = false;
    int               ret;

    GLOBAL_STATE_CODE();

    tran_add(tran, &drive_backup_drv, state);

    if (!backup->has_mode) { backup->mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS; }

    bs = bdrv_lookup_bs(backup->device, backup->device, errp);
    if (!bs) { return; }

    if (!bs->drv) {
        error_setg(errp, "Device has no medium");
        return;
    }

    aio_context = bdrv_get_aio_context(bs);

    state->bs = bs;
    /* Paired with .clean() */
    bdrv_drained_begin(bs);

    format = backup->format;
    if (!format && backup->mode != NEW_IMAGE_MODE_EXISTING) { format = bs->drv->format_name; }

    /* Early check to avoid creating target */
    bdrv_graph_rdlock_main_loop();
    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
        bdrv_graph_rdunlock_main_loop();
        return;
    }

    flags = bs->open_flags | BDRV_O_RDWR;

    /*
     * See if we have a backing HD we can use to create our new image
     * on top of.
     */
    if (backup->sync == MIRROR_SYNC_MODE_TOP) {
        /*
         * Backup will not replace the source by the target, so none
         * of the filters skipped here will be removed (in contrast to
         * mirror).  Therefore, we can skip all of them when looking
         * for the first COW relationship.
         */
        source = bdrv_cow_bs(bdrv_skip_filters(bs));
        if (!source) { backup->sync = MIRROR_SYNC_MODE_FULL; }
    }
    if (backup->sync == MIRROR_SYNC_MODE_NONE) {
        source          = bs;
        flags          |= BDRV_O_NO_BACKING;
        set_backing_hd  = true;
    }
    bdrv_graph_rdunlock_main_loop();

    size = bdrv_getlength(bs);
    if (size < 0) {
        error_setg_errno(errp, -size, "bdrv_getlength failed");
        return;
    }

    if (backup->mode != NEW_IMAGE_MODE_EXISTING) {
        assert(format);
        if (source) {
            /* Implicit filters should not appear in the filename */
            BlockDriverState* explicit_backing;

            bdrv_graph_rdlock_main_loop();
            explicit_backing = bdrv_skip_implicit_filters(source);
            bdrv_refresh_filename(explicit_backing);
            bdrv_graph_rdunlock_main_loop();

            bdrv_img_create(backup->target, format, explicit_backing->filename, explicit_backing->drv->format_name,
                            NULL, size, flags, false, &local_err);
        }
        else {
            bdrv_img_create(backup->target, format, NULL, NULL, NULL, size, flags, false, &local_err);
        }
    }

    if (local_err) {
        error_propagate(errp, local_err);
        return;
    }

    options = qdict_new();
    qdict_put_str(options, "discard", "unmap");
    qdict_put_str(options, "detect-zeroes", "unmap");
    if (format) { qdict_put_str(options, "driver", format); }

    target_bs = bdrv_open(backup->target, NULL, options, flags, errp);
    if (!target_bs) { return; }

    ret = bdrv_try_change_aio_context(target_bs, aio_context, NULL, errp);
    if (ret < 0) {
        bdrv_unref(target_bs);
        return;
    }

    if (set_backing_hd) {
        bdrv_graph_wrlock_drained();
        ret = bdrv_set_backing_hd(target_bs, source, errp);
        bdrv_graph_wrunlock();
        if (ret < 0) { goto unref; }
    }

    state->job = do_backup_common(qapi_DriveBackup_base(backup), bs, target_bs, aio_context, block_job_txn, errp);

unref:
    bdrv_unref(target_bs);
}

static void drive_backup_commit(void* opaque)
{
    DriveBackupState* state = opaque;

    assert(state->job);
    job_start(&state->job->job);
}

static void drive_backup_abort(void* opaque)
{
    DriveBackupState* state = opaque;

    if (state->job) { job_cancel_sync(&state->job->job, true); }
}

static void drive_backup_clean(void* opaque)
{
    g_autofree DriveBackupState* state = opaque;

    if (!state->bs) { return; }

    bdrv_drained_end(state->bs);
}

typedef struct BlockdevBackupState
{
    BlockDriverState* bs;
    BlockJob*         job;
} BlockdevBackupState;

static void          blockdev_backup_commit(void* opaque);
static void          blockdev_backup_abort(void* opaque);
static void          blockdev_backup_clean(void* opaque);
TransactionActionDrv blockdev_backup_drv = {
    .commit = blockdev_backup_commit,
    .abort  = blockdev_backup_abort,
    .clean  = blockdev_backup_clean,
};

static void blockdev_backup_action(BlockdevBackup* backup, JobTxn* block_job_txn, Transaction* tran, Error** errp)
{
    BlockdevBackupState* state = g_new0(BlockdevBackupState, 1);
    BlockDriverState*    bs;
    BlockDriverState*    target_bs;
    AioContext*          aio_context;
    int                  ret;

    tran_add(tran, &blockdev_backup_drv, state);

    bs = bdrv_lookup_bs(backup->device, backup->device, errp);
    if (!bs) { return; }

    target_bs = bdrv_lookup_bs(backup->target, backup->target, errp);
    if (!target_bs) { return; }

    /* Honor bdrv_try_change_aio_context() context acquisition requirements. */
    aio_context = bdrv_get_aio_context(bs);

    ret = bdrv_try_change_aio_context(target_bs, aio_context, NULL, errp);
    if (ret < 0) { return; }

    state->bs = bs;

    /* Paired with .clean() */
    bdrv_drained_begin(state->bs);

    state->job = do_backup_common(qapi_BlockdevBackup_base(backup), bs, target_bs, aio_context, block_job_txn, errp);
}

static void blockdev_backup_commit(void* opaque)
{
    BlockdevBackupState* state = opaque;

    assert(state->job);
    job_start(&state->job->job);
}

static void blockdev_backup_abort(void* opaque)
{
    BlockdevBackupState* state = opaque;

    if (state->job) { job_cancel_sync(&state->job->job, true); }
}

static void blockdev_backup_clean(void* opaque)
{
    g_autofree BlockdevBackupState* state = opaque;

    if (!state->bs) { return; }

    bdrv_drained_end(state->bs);
}

typedef struct BlockDirtyBitmapState
{
    BdrvDirtyBitmap*  bitmap;
    BlockDriverState* bs;
    HBitmap*          backup;
    bool              was_enabled;
} BlockDirtyBitmapState;

static void          block_dirty_bitmap_add_abort(void* opaque);
TransactionActionDrv block_dirty_bitmap_add_drv = {
    .abort = block_dirty_bitmap_add_abort,
    .clean = g_free,
};

static void block_dirty_bitmap_add_action(BlockDirtyBitmapAdd* action, Transaction* tran, Error** errp)
{
    Error*                 local_err = NULL;
    BlockDirtyBitmapState* state     = g_new0(BlockDirtyBitmapState, 1);

    tran_add(tran, &block_dirty_bitmap_add_drv, state);

    /* AIO context taken and released within qmp_block_dirty_bitmap_add */
    qmp_block_dirty_bitmap_add(action->node, action->name, action->has_granularity, action->granularity,
                               action->has_persistent, action->persistent, action->has_disabled, action->disabled,
                               &local_err);

    if (!local_err) { state->bitmap = block_dirty_bitmap_lookup(action->node, action->name, NULL, &error_abort); }
    else {
        error_propagate(errp, local_err);
    }
}

static void block_dirty_bitmap_add_abort(void* opaque)
{
    BlockDirtyBitmapState* state = opaque;

    if (state->bitmap) { bdrv_release_dirty_bitmap(state->bitmap); }
}

static void          block_dirty_bitmap_restore(void* opaque);
static void          block_dirty_bitmap_free_backup(void* opaque);
TransactionActionDrv block_dirty_bitmap_clear_drv = {
    .abort  = block_dirty_bitmap_restore,
    .commit = block_dirty_bitmap_free_backup,
    .clean  = g_free,
};

static void block_dirty_bitmap_clear_action(BlockDirtyBitmap* action, Transaction* tran, Error** errp)
{
    BlockDirtyBitmapState* state = g_new0(BlockDirtyBitmapState, 1);

    tran_add(tran, &block_dirty_bitmap_clear_drv, state);

    state->bitmap = block_dirty_bitmap_lookup(action->node, action->name, &state->bs, errp);
    if (!state->bitmap) { return; }

    if (bdrv_dirty_bitmap_check(state->bitmap, BDRV_BITMAP_DEFAULT, errp)) { return; }

    bdrv_clear_dirty_bitmap(state->bitmap, &state->backup);
}

static void block_dirty_bitmap_restore(void* opaque)
{
    BlockDirtyBitmapState* state = opaque;

    if (state->backup) { bdrv_restore_dirty_bitmap(state->bitmap, state->backup); }
}

static void block_dirty_bitmap_free_backup(void* opaque)
{
    BlockDirtyBitmapState* state = opaque;

    hbitmap_free(state->backup);
}

static void          block_dirty_bitmap_enable_abort(void* opaque);
TransactionActionDrv block_dirty_bitmap_enable_drv = {
    .abort = block_dirty_bitmap_enable_abort,
    .clean = g_free,
};

static void block_dirty_bitmap_enable_action(BlockDirtyBitmap* action, Transaction* tran, Error** errp)
{
    BlockDirtyBitmapState* state = g_new0(BlockDirtyBitmapState, 1);

    tran_add(tran, &block_dirty_bitmap_enable_drv, state);

    state->bitmap = block_dirty_bitmap_lookup(action->node, action->name, NULL, errp);
    if (!state->bitmap) { return; }

    if (bdrv_dirty_bitmap_check(state->bitmap, BDRV_BITMAP_ALLOW_RO, errp)) { return; }

    state->was_enabled = bdrv_dirty_bitmap_enabled(state->bitmap);
    bdrv_enable_dirty_bitmap(state->bitmap);
}

static void block_dirty_bitmap_enable_abort(void* opaque)
{
    BlockDirtyBitmapState* state = opaque;

    if (!state->was_enabled) { bdrv_disable_dirty_bitmap(state->bitmap); }
}

static void          block_dirty_bitmap_disable_abort(void* opaque);
TransactionActionDrv block_dirty_bitmap_disable_drv = {
    .abort = block_dirty_bitmap_disable_abort,
    .clean = g_free,
};

static void block_dirty_bitmap_disable_action(BlockDirtyBitmap* action, Transaction* tran, Error** errp)
{
    BlockDirtyBitmapState* state = g_new0(BlockDirtyBitmapState, 1);

    tran_add(tran, &block_dirty_bitmap_disable_drv, state);

    state->bitmap = block_dirty_bitmap_lookup(action->node, action->name, NULL, errp);
    if (!state->bitmap) { return; }

    if (bdrv_dirty_bitmap_check(state->bitmap, BDRV_BITMAP_ALLOW_RO, errp)) { return; }

    state->was_enabled = bdrv_dirty_bitmap_enabled(state->bitmap);
    bdrv_disable_dirty_bitmap(state->bitmap);
}

static void block_dirty_bitmap_disable_abort(void* opaque)
{
    BlockDirtyBitmapState* state = opaque;

    if (state->was_enabled) { bdrv_enable_dirty_bitmap(state->bitmap); }
}

TransactionActionDrv block_dirty_bitmap_merge_drv = {
    .commit = block_dirty_bitmap_free_backup,
    .abort  = block_dirty_bitmap_restore,
    .clean  = g_free,
};

static void block_dirty_bitmap_merge_action(BlockDirtyBitmapMerge* action, Transaction* tran, Error** errp)
{
    BlockDirtyBitmapState* state = g_new0(BlockDirtyBitmapState, 1);

    tran_add(tran, &block_dirty_bitmap_merge_drv, state);

    state->bitmap = block_dirty_bitmap_merge(action->node, action->target, action->bitmaps, &state->backup, errp);
}

static void          block_dirty_bitmap_remove_commit(void* opaque);
static void          block_dirty_bitmap_remove_abort(void* opaque);
TransactionActionDrv block_dirty_bitmap_remove_drv = {
    .commit = block_dirty_bitmap_remove_commit,
    .abort  = block_dirty_bitmap_remove_abort,
    .clean  = g_free,
};

static void block_dirty_bitmap_remove_action(BlockDirtyBitmap* action, Transaction* tran, Error** errp)
{
    BlockDirtyBitmapState* state = g_new0(BlockDirtyBitmapState, 1);

    tran_add(tran, &block_dirty_bitmap_remove_drv, state);

    state->bitmap = block_dirty_bitmap_remove(action->node, action->name, false, &state->bs, errp);
    if (state->bitmap) {
        bdrv_dirty_bitmap_skip_store(state->bitmap, true);
        bdrv_dirty_bitmap_set_busy(state->bitmap, true);
    }
}

static void block_dirty_bitmap_remove_abort(void* opaque)
{
    BlockDirtyBitmapState* state = opaque;

    if (state->bitmap) {
        bdrv_dirty_bitmap_skip_store(state->bitmap, false);
        bdrv_dirty_bitmap_set_busy(state->bitmap, false);
    }
}

static void block_dirty_bitmap_remove_commit(void* opaque)
{
    BlockDirtyBitmapState* state = opaque;

    bdrv_dirty_bitmap_set_busy(state->bitmap, false);
    bdrv_release_dirty_bitmap(state->bitmap);
}

static void          abort_commit(void* opaque);
TransactionActionDrv abort_drv = {
    .commit = abort_commit,
};

static void abort_action(Transaction* tran, Error** errp)
{
    tran_add(tran, &abort_drv, NULL);
    error_setg(errp, "Transaction aborted using Abort action");
}

static void abort_commit(void* opaque) { assert_not_reached(); /* this action never succeeds */ }

static void transaction_action(TransactionAction* act, JobTxn* block_job_txn, Transaction* tran, Error** errp)
{
    switch (act->type) {
        case TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT     :
        case TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC: external_snapshot_action(act, tran, errp); return;
        case TRANSACTION_ACTION_KIND_DRIVE_BACKUP:
            drive_backup_action(act->u.drive_backup.data, block_job_txn, tran, errp);
            return;
        case TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP:
            blockdev_backup_action(act->u.blockdev_backup.data, block_job_txn, tran, errp);
            return;
        case TRANSACTION_ACTION_KIND_ABORT: abort_action(tran, errp); return;
        case TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_INTERNAL_SYNC:
            internal_snapshot_action(act->u.blockdev_snapshot_internal_sync.data, tran, errp);
            return;
        case TRANSACTION_ACTION_KIND_BLOCK_DIRTY_BITMAP_ADD:
            block_dirty_bitmap_add_action(act->u.block_dirty_bitmap_add.data, tran, errp);
            return;
        case TRANSACTION_ACTION_KIND_BLOCK_DIRTY_BITMAP_CLEAR:
            block_dirty_bitmap_clear_action(act->u.block_dirty_bitmap_clear.data, tran, errp);
            return;
        case TRANSACTION_ACTION_KIND_BLOCK_DIRTY_BITMAP_ENABLE:
            block_dirty_bitmap_enable_action(act->u.block_dirty_bitmap_enable.data, tran, errp);
            return;
        case TRANSACTION_ACTION_KIND_BLOCK_DIRTY_BITMAP_DISABLE:
            block_dirty_bitmap_disable_action(act->u.block_dirty_bitmap_disable.data, tran, errp);
            return;
        case TRANSACTION_ACTION_KIND_BLOCK_DIRTY_BITMAP_MERGE:
            block_dirty_bitmap_merge_action(act->u.block_dirty_bitmap_merge.data, tran, errp);
            return;
        case TRANSACTION_ACTION_KIND_BLOCK_DIRTY_BITMAP_REMOVE:
            block_dirty_bitmap_remove_action(act->u.block_dirty_bitmap_remove.data, tran, errp);
            return;
        /*
         * Where are transactions for MIRROR, COMMIT and STREAM?
         * Although these blockjobs use transaction callbacks like the backup job,
         * these jobs do not necessarily adhere to transaction semantics.
         * These jobs may not fully undo all of their actions on abort, nor do they
         * necessarily work in transactions with more than one job in them.
         */
        case TRANSACTION_ACTION_KIND__MAX:
        default                          : assert_not_reached();
    };
}

/*
 * 'Atomic' group operations.  The operations are performed as a set, and if
 * any fail then we roll back all operations in the group.
 *
 * Always run under BQL.
 */
void qmp_transaction(TransactionActionList* actions, struct TransactionProperties* properties, Error** errp)
{
    TransactionActionList* act;
    JobTxn*                block_job_txn = NULL;
    Error*                 local_err     = NULL;
    Transaction*           tran;
    ActionCompletionMode   comp_mode = properties ? properties->completion_mode : ACTION_COMPLETION_MODE_INDIVIDUAL;

    GLOBAL_STATE_CODE();

    /* Does this transaction get canceled as a group on failure?
     * If not, we don't really need to make a JobTxn.
     */
    if (comp_mode != ACTION_COMPLETION_MODE_INDIVIDUAL) {
        for (act = actions; act; act = act->next) {
            TransactionActionKind type = act->value->type;

            if (type != TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP && type != TRANSACTION_ACTION_KIND_DRIVE_BACKUP) {
                error_setg(errp,
                           "Action '%s' does not support transaction property "
                           "completion-mode = %s",
                           TransactionActionKind_str(type), ActionCompletionMode_str(comp_mode));
                return;
            }
        }

        block_job_txn = job_txn_new();
    }

    /* drain all i/o before any operations */
    bdrv_drain_all();

    tran = tran_new();

    /* We don't do anything in this loop that commits us to the operations */
    for (act = actions; act; act = act->next) {
        transaction_action(act->value, block_job_txn, tran, &local_err);
        if (local_err) {
            error_propagate(errp, local_err);
            goto delete_and_fail;
        }
    }

    tran_commit(tran);

    /* success */
    goto exit;

delete_and_fail:
    /* failure, and it is all-or-none; roll back all operations */
    tran_abort(tran);
exit:
    job_txn_unref(block_job_txn);
}

BlockDirtyBitmapSha256* qmp_x_debug_block_dirty_bitmap_sha256(const char* node, const char* name, Error** errp)
{
    BdrvDirtyBitmap*        bitmap;
    BlockDriverState*       bs;
    BlockDirtyBitmapSha256* ret = NULL;
    char*                   sha256;

    bitmap = block_dirty_bitmap_lookup(node, name, &bs, errp);
    if (!bitmap || !bs) { return NULL; }

    sha256 = bdrv_dirty_bitmap_sha256(bitmap, errp);
    if (sha256 == NULL) { return NULL; }

    ret         = g_new(BlockDirtyBitmapSha256, 1);
    ret->sha256 = sha256;

    return ret;
}

void coroutine_fn qmp_block_resize(const char* device, const char* node_name, int64_t size, Error** errp)
{
    Error*            local_err = NULL;
    BlockBackend*     blk;
    BlockDriverState* bs;
    AioContext*       old_ctx;

    bs = bdrv_lookup_bs(device, node_name, &local_err);
    if (local_err) {
        error_propagate(errp, local_err);
        return;
    }

    if (size < 0) {
        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "size", "a >0 size");
        return;
    }

    bdrv_graph_co_rdlock();
    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_RESIZE, errp)) {
        bdrv_graph_co_rdunlock();
        return;
    }
    bdrv_graph_co_rdunlock();

    blk = blk_co_new_with_bs(bs, BLK_PERM_RESIZE, BLK_PERM_ALL, errp);
    if (!blk) { return; }

    bdrv_drained_begin(bs);

    old_ctx = bdrv_co_enter(bs);
    blk_co_truncate(blk, size, false, PREALLOC_MODE_OFF, 0, errp);
    bdrv_co_leave(bs, old_ctx);

    bdrv_drained_end(bs);
    blk_co_unref(blk);
}

void qmp_block_stream(const char* job_id, const char* device, const char* base, const char* base_node,
                      const char* backing_file, bool has_backing_mask_protocol, bool backing_mask_protocol,
                      const char* bottom, bool has_on_error, BlockdevOnError on_error, const char* filter_node_name,
                      bool has_auto_finalize, bool auto_finalize, bool has_auto_dismiss, bool auto_dismiss,
                      Error** errp)
{
    BlockDriverState *bs, *iter, *iter_end;
    BlockDriverState* base_bs   = NULL;
    BlockDriverState* bottom_bs = NULL;
    AioContext*       aio_context;
    Error*            local_err = NULL;
    int               job_flags = JOB_DEFAULT;

    GLOBAL_STATE_CODE();

    if (base && base_node) {
        error_setg(errp, "'base' and 'base-node' cannot be specified "
                         "at the same time");
        return;
    }

    if (base && bottom) {
        error_setg(errp, "'base' and 'bottom' cannot be specified "
                         "at the same time");
        return;
    }

    if (bottom && base_node) {
        error_setg(errp, "'bottom' and 'base-node' cannot be specified "
                         "at the same time");
        return;
    }

    if (!has_backing_mask_protocol) { backing_mask_protocol = false; }

    if (!has_on_error) { on_error = BLOCKDEV_ON_ERROR_REPORT; }

    bs = bdrv_lookup_bs(device, device, errp);
    if (!bs) { return; }

    aio_context = bdrv_get_aio_context(bs);

    bdrv_graph_rdlock_main_loop();
    if (base) {
        base_bs = bdrv_find_backing_image(bs, base);
        if (base_bs == NULL) {
            error_setg(errp, "Can't find '%s' in the backing chain", base);
            goto out_rdlock;
        }
        assert(bdrv_get_aio_context(base_bs) == aio_context);
    }

    if (base_node) {
        base_bs = bdrv_lookup_bs(NULL, base_node, errp);
        if (!base_bs) { goto out_rdlock; }
        if (bs == base_bs || !bdrv_chain_contains(bs, base_bs)) {
            error_setg(errp, "Node '%s' is not a backing image of '%s'", base_node, device);
            goto out_rdlock;
        }
        assert(bdrv_get_aio_context(base_bs) == aio_context);

        bdrv_refresh_filename(base_bs);
    }

    if (bottom) {
        bottom_bs = bdrv_lookup_bs(NULL, bottom, errp);
        if (!bottom_bs) { goto out_rdlock; }
        if (!bottom_bs->drv) {
            error_setg(errp, "Node '%s' is not open", bottom);
            goto out_rdlock;
        }
        if (bottom_bs->drv->is_filter) {
            error_setg(errp,
                       "Node '%s' is a filter, use a non-filter node "
                       "as 'bottom'",
                       bottom);
            goto out_rdlock;
        }
        if (!bdrv_chain_contains(bs, bottom_bs)) {
            error_setg(errp, "Node '%s' is not in a chain starting from '%s'", bottom, device);
            goto out_rdlock;
        }
        assert(bdrv_get_aio_context(bottom_bs) == aio_context);
    }

    /*
     * Check for op blockers in the whole chain between bs and base (or bottom)
     */
    iter_end = bottom ? bdrv_filter_or_cow_bs(bottom_bs) : base_bs;
    for (iter = bs; iter && iter != iter_end; iter = bdrv_filter_or_cow_bs(iter)) {
        if (bdrv_op_is_blocked(iter, BLOCK_OP_TYPE_STREAM, errp)) { goto out_rdlock; }
    }
    bdrv_graph_rdunlock_main_loop();

    /* if we are streaming the entire chain, the result will have no backing
     * file, and specifying one is therefore an error */
    if (!base_bs && backing_file) {
        error_setg(errp, "backing file specified, but streaming the "
                         "entire chain");
        return;
    }

    if (has_auto_finalize && !auto_finalize) { job_flags |= JOB_MANUAL_FINALIZE; }
    if (has_auto_dismiss && !auto_dismiss) { job_flags |= JOB_MANUAL_DISMISS; }

    stream_start(job_id, bs, base_bs, backing_file, backing_mask_protocol, bottom_bs, job_flags, on_error,
                 filter_node_name, &local_err);
    if (local_err) {
        error_propagate(errp, local_err);
        return;
    }

    trace_qmp_block_stream(bs);
    return;

out_rdlock:
    bdrv_graph_rdunlock_main_loop();
}

void qmp_block_commit(const char* job_id, const char* device, const char* base_node, const char* base,
                      const char* top_node, const char* top, const char* backing_file, bool has_backing_mask_protocol,
                      bool backing_mask_protocol, bool has_on_error, BlockdevOnError on_error,
                      const char* filter_node_name, bool has_auto_finalize, bool auto_finalize, bool has_auto_dismiss,
                      bool auto_dismiss, Error** errp)
{
    BlockDriverState* bs;
    BlockDriverState* iter;
    BlockDriverState *base_bs, *top_bs;
    AioContext*       aio_context;
    Error*            local_err = NULL;
    int               job_flags = JOB_DEFAULT;
    uint64_t          top_perm, top_shared;

    /* TODO We'll eventually have to take a writer lock in this function */
    GRAPH_RDLOCK_GUARD_MAINLOOP();

    if (!has_on_error) { on_error = BLOCKDEV_ON_ERROR_REPORT; }
    if (has_auto_finalize && !auto_finalize) { job_flags |= JOB_MANUAL_FINALIZE; }
    if (has_auto_dismiss && !auto_dismiss) { job_flags |= JOB_MANUAL_DISMISS; }
    if (!has_backing_mask_protocol) { backing_mask_protocol = false; }

    /* Important Note:
     *  libvirt relies on the DeviceNotFound error class in order to probe for
     *  live commit feature versions; for this to work, we must make sure to
     *  perform the device lookup before any generic errors that may occur in a
     *  scenario in which all optional arguments are omitted. */
    bs = qmp_get_root_bs(device, &local_err);
    if (!bs) {
        bs = bdrv_lookup_bs(device, device, NULL);
        if (!bs) {
            error_free(local_err);
            error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND, "Device '%s' not found", device);
        }
        else {
            error_propagate(errp, local_err);
        }
        return;
    }

    aio_context = bdrv_get_aio_context(bs);

    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, errp)) { return; }

    /* default top_bs is the active layer */
    top_bs = bs;

    if (top_node && top) {
        error_setg(errp, "'top-node' and 'top' are mutually exclusive");
        return;
    }
    else if (top_node) {
        top_bs = bdrv_lookup_bs(NULL, top_node, errp);
        if (top_bs == NULL) { return; }
        if (!bdrv_chain_contains(bs, top_bs)) {
            error_setg(errp, "'%s' is not in this backing file chain", top_node);
            return;
        }
    }
    else if (top) {
        /* This strcmp() is just a shortcut, there is no need to
         * refresh @bs's filename.  If it mismatches,
         * bdrv_find_backing_image() will do the refresh and may still
         * return @bs. */
        if (strcmp(bs->filename, top) != 0) { top_bs = bdrv_find_backing_image(bs, top); }
    }

    if (top_bs == NULL) {
        error_setg(errp, "Top image file %s not found", top ? top : "NULL");
        return;
    }

    assert(bdrv_get_aio_context(top_bs) == aio_context);

    if (base_node && base) {
        error_setg(errp, "'base-node' and 'base' are mutually exclusive");
        return;
    }
    else if (base_node) {
        base_bs = bdrv_lookup_bs(NULL, base_node, errp);
        if (base_bs == NULL) { return; }
        if (!bdrv_chain_contains(top_bs, base_bs)) {
            error_setg(errp, "'%s' is not in this backing file chain", base_node);
            return;
        }
    }
    else if (base) {
        base_bs = bdrv_find_backing_image(top_bs, base);
        if (base_bs == NULL) {
            error_setg(errp, "Can't find '%s' in the backing chain", base);
            return;
        }
    }
    else {
        base_bs = bdrv_find_base(top_bs);
        if (base_bs == NULL) {
            error_setg(errp, "There is no backimg image");
            return;
        }
    }

    assert(bdrv_get_aio_context(base_bs) == aio_context);

    for (iter = top_bs; iter != bdrv_filter_or_cow_bs(base_bs); iter = bdrv_filter_or_cow_bs(iter)) {
        if (bdrv_op_is_blocked(iter, BLOCK_OP_TYPE_COMMIT_TARGET, errp)) { return; }
    }

    /* Do not allow attempts to commit an image into itself */
    if (top_bs == base_bs) {
        error_setg(errp, "cannot commit an image into itself");
        return;
    }

    /*
     * Active commit is required if and only if someone has taken a
     * WRITE permission on the top node.  Historically, we have always
     * used active commit for top nodes, so continue that practice
     * lest we possibly break clients that rely on this behavior, e.g.
     * to later attach this node to a writing parent.
     * (Active commit is never really wrong.)
     */
    bdrv_get_cumulative_perm(top_bs, &top_perm, &top_shared);
    if (top_perm & BLK_PERM_WRITE || bdrv_skip_filters(top_bs) == bdrv_skip_filters(bs)) {
        if (backing_file) {
            if (bdrv_skip_filters(top_bs) == bdrv_skip_filters(bs)) {
                error_setg(errp, "'backing-file' specified,"
                                 " but 'top' is the active layer");
            }
            else {
                error_setg(errp, "'backing-file' specified, but 'top' has a "
                                 "writer on it");
            }
            return;
        }
        if (!job_id) {
            /*
             * Emulate here what block_job_create() does, because it
             * is possible that @bs != @top_bs (the block job should
             * be named after @bs, even if @top_bs is the actual
             * source)
             */
            job_id = bdrv_get_device_name(bs);
        }
        commit_active_start(job_id, top_bs, base_bs, job_flags, on_error, filter_node_name, NULL, NULL, false,
                            &local_err);
    }
    else {
        BlockDriverState* overlay_bs = bdrv_find_overlay(bs, top_bs);
        if (bdrv_op_is_blocked(overlay_bs, BLOCK_OP_TYPE_COMMIT_TARGET, errp)) { return; }
        commit_start(job_id, bs, base_bs, top_bs, job_flags, on_error, backing_file, backing_mask_protocol,
                     filter_node_name, &local_err);
    }
    if (local_err != NULL) {
        error_propagate(errp, local_err);
        return;
    }
}

/* Common QMP interface for drive-backup and blockdev-backup */
static BlockJob* do_backup_common(BackupCommon* backup, BlockDriverState* bs, BlockDriverState* target_bs,
                                  AioContext* aio_context, JobTxn* txn, Error** errp)
{
    BlockJob*        job          = NULL;
    BdrvDirtyBitmap* bmap         = NULL;
    BackupPerf       perf         = {.max_workers = 64};
    int              job_flags    = JOB_DEFAULT;
    OnCbwError       on_cbw_error = ON_CBW_ERROR_BREAK_GUEST_WRITE;

    if (!backup->has_on_source_error) { backup->on_source_error = BLOCKDEV_ON_ERROR_REPORT; }
    if (!backup->has_on_target_error) { backup->on_target_error = BLOCKDEV_ON_ERROR_REPORT; }
    if (!backup->has_auto_finalize) { backup->auto_finalize = true; }
    if (!backup->has_auto_dismiss) { backup->auto_dismiss = true; }
    if (!backup->has_compress) { backup->compress = false; }

    if (backup->x_perf) {
        if (backup->x_perf->has_use_copy_range) { perf.use_copy_range = backup->x_perf->use_copy_range; }
        if (backup->x_perf->has_max_workers) { perf.max_workers = backup->x_perf->max_workers; }
        if (backup->x_perf->has_max_chunk) { perf.max_chunk = backup->x_perf->max_chunk; }
        if (backup->x_perf->has_min_cluster_size) { perf.min_cluster_size = backup->x_perf->min_cluster_size; }
    }

    if ((backup->sync == MIRROR_SYNC_MODE_BITMAP) || (backup->sync == MIRROR_SYNC_MODE_INCREMENTAL)) {
        /* done before desugaring 'incremental' to print the right message */
        if (!backup->bitmap) {
            error_setg(errp,
                       "must provide a valid bitmap name for "
                       "'%s' sync mode",
                       MirrorSyncMode_str(backup->sync));
            return NULL;
        }
    }

    if (backup->sync == MIRROR_SYNC_MODE_INCREMENTAL) {
        if (backup->has_bitmap_mode && backup->bitmap_mode != BITMAP_SYNC_MODE_ON_SUCCESS) {
            error_setg(errp,
                       "Bitmap sync mode must be '%s' "
                       "when using sync mode '%s'",
                       BitmapSyncMode_str(BITMAP_SYNC_MODE_ON_SUCCESS), MirrorSyncMode_str(backup->sync));
            return NULL;
        }
        backup->has_bitmap_mode = true;
        backup->sync            = MIRROR_SYNC_MODE_BITMAP;
        backup->bitmap_mode     = BITMAP_SYNC_MODE_ON_SUCCESS;
    }

    if (backup->bitmap) {
        bmap = bdrv_find_dirty_bitmap(bs, backup->bitmap);
        if (!bmap) {
            error_setg(errp, "Bitmap '%s' could not be found", backup->bitmap);
            return NULL;
        }
        if (!backup->has_bitmap_mode) {
            error_setg(errp, "Bitmap sync mode must be given "
                             "when providing a bitmap");
            return NULL;
        }
        if (bdrv_dirty_bitmap_check(bmap, BDRV_BITMAP_ALLOW_RO, errp)) { return NULL; }

        /* This does not produce a useful bitmap artifact: */
        if (backup->sync == MIRROR_SYNC_MODE_NONE) {
            error_setg(errp,
                       "sync mode '%s' does not produce meaningful bitmap"
                       " outputs",
                       MirrorSyncMode_str(backup->sync));
            return NULL;
        }

        /* If the bitmap isn't used for input or output, this is useless: */
        if (backup->bitmap_mode == BITMAP_SYNC_MODE_NEVER && backup->sync != MIRROR_SYNC_MODE_BITMAP) {
            error_setg(errp,
                       "Bitmap sync mode '%s' has no meaningful effect"
                       " when combined with sync mode '%s'",
                       BitmapSyncMode_str(backup->bitmap_mode), MirrorSyncMode_str(backup->sync));
            return NULL;
        }
    }

    if (!backup->bitmap && backup->has_bitmap_mode) {
        error_setg(errp, "Cannot specify bitmap sync mode without a bitmap");
        return NULL;
    }

    if (!backup->auto_finalize) { job_flags |= JOB_MANUAL_FINALIZE; }
    if (!backup->auto_dismiss) { job_flags |= JOB_MANUAL_DISMISS; }

    if (backup->has_on_cbw_error) { on_cbw_error = backup->on_cbw_error; }

    job = backup_job_create(backup->job_id, bs, target_bs, backup->sync, bmap, backup->bitmap_mode, backup->compress,
                            backup->discard_source, backup->filter_node_name, &perf, backup->on_source_error,
                            backup->on_target_error, on_cbw_error, job_flags, NULL, NULL, txn, errp);
    return job;
}

void qmp_drive_backup(DriveBackup* backup, Error** errp)
{
    TransactionAction action = {
        .type                = TRANSACTION_ACTION_KIND_DRIVE_BACKUP,
        .u.drive_backup.data = backup,
    };
    blockdev_do_action(&action, errp);
}

BlockDeviceInfoList* qmp_query_named_block_nodes(bool has_flat, bool flat, Error** errp)
{
    bool return_flat = has_flat && flat;

    return bdrv_named_nodes_list(return_flat, errp);
}

XDbgBlockGraph* qmp_x_debug_query_block_graph(Error** errp)
{
    GRAPH_RDLOCK_GUARD_MAINLOOP();

    return bdrv_get_xdbg_block_graph(errp);
}

void qmp_blockdev_backup(BlockdevBackup* backup, Error** errp)
{
    TransactionAction action = {
        .type                   = TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP,
        .u.blockdev_backup.data = backup,
    };
    blockdev_do_action(&action, errp);
}

/* Parameter check and block job starting for drive mirroring.
 * Caller should hold @device and @target's aio context (must be the same).
 **/
static void blockdev_mirror_common(const char* job_id, BlockDriverState* bs, BlockDriverState* target,
                                   const char* replaces, enum MirrorSyncMode sync, BlockMirrorBackingMode backing_mode,
                                   bool target_is_zero, bool has_granularity, uint32_t granularity, bool has_buf_size,
                                   int64_t buf_size, bool has_on_source_error, BlockdevOnError on_source_error,
                                   bool has_on_target_error, BlockdevOnError on_target_error, bool has_unmap,
                                   bool unmap, const char* filter_node_name, bool has_copy_mode,
                                   MirrorCopyMode copy_mode, bool has_auto_finalize, bool auto_finalize,
                                   bool has_auto_dismiss, bool auto_dismiss, Error** errp)
{
    BlockDriverState* unfiltered_bs;
    int               job_flags = JOB_DEFAULT;

    GLOBAL_STATE_CODE();
    GRAPH_RDLOCK_GUARD_MAINLOOP();

    if (!has_on_source_error) { on_source_error = BLOCKDEV_ON_ERROR_REPORT; }
    if (!has_on_target_error) { on_target_error = BLOCKDEV_ON_ERROR_REPORT; }
    if (!has_granularity) { granularity = 0; }
    if (!has_buf_size) { buf_size = 0; }
    if (!has_unmap) { unmap = true; }
    if (!has_copy_mode) { copy_mode = MIRROR_COPY_MODE_BACKGROUND; }
    if (has_auto_finalize && !auto_finalize) { job_flags |= JOB_MANUAL_FINALIZE; }
    if (has_auto_dismiss && !auto_dismiss) { job_flags |= JOB_MANUAL_DISMISS; }

    if (granularity != 0 && (granularity < 512 || granularity > 1048576 * 64)) {
        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "granularity", "a value in range [512B, 64MB]");
        return;
    }
    if (granularity & (granularity - 1)) {
        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "granularity", "a power of 2");
        return;
    }

    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_MIRROR_SOURCE, errp)) { return; }
    if (bdrv_op_is_blocked(target, BLOCK_OP_TYPE_MIRROR_TARGET, errp)) { return; }

    if (!replaces) {
        /* We want to mirror from @bs, but keep implicit filters on top */
        unfiltered_bs = bdrv_skip_implicit_filters(bs);
        if (unfiltered_bs != bs) { replaces = unfiltered_bs->node_name; }
    }

    if (replaces) {
        BlockDriverState* to_replace_bs;
        int64_t           bs_size, replace_size;

        bs_size = bdrv_getlength(bs);
        if (bs_size < 0) {
            error_setg_errno(errp, -bs_size, "Failed to query device's size");
            return;
        }

        to_replace_bs = check_to_replace_node(bs, replaces, errp);
        if (!to_replace_bs) { return; }

        replace_size = bdrv_getlength(to_replace_bs);

        if (replace_size < 0) {
            error_setg_errno(errp, -replace_size, "Failed to query the replacement node's size");
            return;
        }
        if (bs_size != replace_size) {
            error_setg(errp, "cannot replace image with a mirror image of "
                             "different size");
            return;
        }
    }

    /* pass the node name to replace to mirror start since it's loose coupling
     * and will allow to check whether the node still exist at mirror completion
     */
    mirror_start(job_id, bs, target, replaces, job_flags, granularity, buf_size, sync, backing_mode, target_is_zero,
                 on_source_error, on_target_error, unmap, filter_node_name, copy_mode, errp);
}

void qmp_drive_mirror(DriveMirror* arg, Error** errp)
{
    BlockDriverState*      bs;
    BlockDriverState *     target_backing_bs, *target_bs;
    AioContext*            aio_context;
    BlockMirrorBackingMode backing_mode;
    Error*                 local_err = NULL;
    QDict*                 options   = NULL;
    int                    flags;
    int64_t                size;
    const char*            format = arg->format;
    bool                   target_is_zero;
    int                    ret;

    bs = qmp_get_root_bs(arg->device, errp);
    if (!bs) { return; }

    /* Early check to avoid creating target */
    bdrv_graph_rdlock_main_loop();
    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_MIRROR_SOURCE, errp)) {
        bdrv_graph_rdunlock_main_loop();
        return;
    }

    aio_context = bdrv_get_aio_context(bs);

    if (!arg->has_mode) { arg->mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS; }

    if (!arg->format) { format = (arg->mode == NEW_IMAGE_MODE_EXISTING ? NULL : bs->drv->format_name); }

    flags             = bs->open_flags | BDRV_O_RDWR;
    target_backing_bs = bdrv_cow_bs(bdrv_skip_filters(bs));
    if (!target_backing_bs && arg->sync == MIRROR_SYNC_MODE_TOP) { arg->sync = MIRROR_SYNC_MODE_FULL; }
    if (arg->sync == MIRROR_SYNC_MODE_NONE) { target_backing_bs = bs; }
    bdrv_graph_rdunlock_main_loop();

    size = bdrv_getlength(bs);
    if (size < 0) {
        error_setg_errno(errp, -size, "bdrv_getlength failed");
        return;
    }

    if (arg->replaces) {
        if (!arg->node_name) {
            error_setg(errp, "a node-name must be provided when replacing a"
                             " named node of the graph");
            return;
        }
    }

    if (arg->mode == NEW_IMAGE_MODE_ABSOLUTE_PATHS) { backing_mode = MIRROR_SOURCE_BACKING_CHAIN; }
    else {
        backing_mode = MIRROR_OPEN_BACKING_CHAIN;
    }

    /* Don't open backing image in create() */
    flags |= BDRV_O_NO_BACKING;

    if ((arg->sync == MIRROR_SYNC_MODE_FULL || !target_backing_bs) && arg->mode != NEW_IMAGE_MODE_EXISTING) {
        /* create new image w/o backing file */
        assert(format);
        bdrv_img_create(arg->target, format, NULL, NULL, NULL, size, flags, false, &local_err);
    }
    else {
        BlockDriverState* explicit_backing;

        switch (arg->mode) {
            case NEW_IMAGE_MODE_EXISTING: break;
            case NEW_IMAGE_MODE_ABSOLUTE_PATHS:
                /*
                 * Create new image with backing file.
                 * Implicit filters should not appear in the filename.
                 */
                bdrv_graph_rdlock_main_loop();
                explicit_backing = bdrv_skip_implicit_filters(target_backing_bs);
                bdrv_refresh_filename(explicit_backing);
                bdrv_graph_rdunlock_main_loop();

                bdrv_img_create(arg->target, format, explicit_backing->filename, explicit_backing->drv->format_name,
                                NULL, size, flags, false, &local_err);
                break;
            default: assert_not_reached();
        }
    }

    if (local_err) {
        error_propagate(errp, local_err);
        return;
    }

    options = qdict_new();
    if (arg->node_name) { qdict_put_str(options, "node-name", arg->node_name); }
    if (format) { qdict_put_str(options, "driver", format); }

    /* Mirroring takes care of copy-on-write using the source's backing
     * file.
     */
    target_bs = bdrv_open(arg->target, NULL, options, flags, errp);
    if (!target_bs) { return; }

    bdrv_graph_rdlock_main_loop();
    target_is_zero = (arg->mode != NEW_IMAGE_MODE_EXISTING && bdrv_has_zero_init(target_bs));
    bdrv_graph_rdunlock_main_loop();

    ret = bdrv_try_change_aio_context(target_bs, aio_context, NULL, errp);
    if (ret < 0) {
        bdrv_unref(target_bs);
        return;
    }

    blockdev_mirror_common(arg->job_id, bs, target_bs, arg->replaces, arg->sync, backing_mode, target_is_zero,
                           arg->has_granularity, arg->granularity, arg->has_buf_size, arg->buf_size,
                           arg->has_on_source_error, arg->on_source_error, arg->has_on_target_error,
                           arg->on_target_error, arg->has_unmap, arg->unmap, NULL, arg->has_copy_mode, arg->copy_mode,
                           arg->has_auto_finalize, arg->auto_finalize, arg->has_auto_dismiss, arg->auto_dismiss, errp);
    bdrv_unref(target_bs);
}

void qmp_blockdev_mirror(const char* job_id, const char* device, const char* target, const char* replaces,
                         MirrorSyncMode sync, bool has_granularity, uint32_t granularity, bool has_buf_size,
                         int64_t buf_size, bool has_on_source_error, BlockdevOnError on_source_error,
                         bool has_on_target_error, BlockdevOnError on_target_error, const char* filter_node_name,
                         bool has_copy_mode, MirrorCopyMode copy_mode, bool has_auto_finalize, bool auto_finalize,
                         bool has_auto_dismiss, bool auto_dismiss, bool has_target_is_zero, bool target_is_zero,
                         Error** errp)
{
    BlockDriverState*      bs;
    BlockDriverState*      target_bs;
    AioContext*            aio_context;
    BlockMirrorBackingMode backing_mode = MIRROR_LEAVE_BACKING_CHAIN;
    int                    ret;

    bs = qmp_get_root_bs(device, errp);
    if (!bs) { return; }

    target_bs = bdrv_lookup_bs(target, target, errp);
    if (!target_bs) { return; }

    aio_context = bdrv_get_aio_context(bs);

    ret = bdrv_try_change_aio_context(target_bs, aio_context, NULL, errp);
    if (ret < 0) { return; }

    blockdev_mirror_common(job_id, bs, target_bs, replaces, sync, backing_mode, has_target_is_zero && target_is_zero,
                           has_granularity, granularity, has_buf_size, buf_size, has_on_source_error, on_source_error,
                           has_on_target_error, on_target_error, true, true, filter_node_name, has_copy_mode, copy_mode,
                           has_auto_finalize, auto_finalize, has_auto_dismiss, auto_dismiss, errp);
}

/*
 * Get a block job using its ID. Called with job_mutex held.
 */
static BlockJob* find_block_job_locked(const char* id, Error** errp)
{
    BlockJob* job;

    assert(id != NULL);

    job = block_job_get_locked(id);

    if (!job) {
        error_set(errp, ERROR_CLASS_DEVICE_NOT_ACTIVE, "Block job '%s' not found", id);
        return NULL;
    }

    return job;
}

void qmp_block_job_cancel(const char* device, bool has_force, bool force, Error** errp)
{
    BlockJob* job;

    JOB_LOCK_GUARD();
    job = find_block_job_locked(device, errp);

    if (!job) { return; }

    if (!has_force) { force = false; }

    if (job_user_paused_locked(&job->job) && !force) {
        error_setg(errp, "The block job for device '%s' is currently paused", device);
        return;
    }

    trace_qmp_block_job_cancel(job);
    job_user_cancel_locked(&job->job, force, errp);
}

void qmp_block_job_pause(const char* device, Error** errp)
{
    BlockJob* job;

    JOB_LOCK_GUARD();
    job = find_block_job_locked(device, errp);

    if (!job) { return; }

    trace_qmp_block_job_pause(job);
    job_user_pause_locked(&job->job, errp);
}

void qmp_block_job_resume(const char* device, Error** errp)
{
    BlockJob* job;

    JOB_LOCK_GUARD();
    job = find_block_job_locked(device, errp);

    if (!job) { return; }

    trace_qmp_block_job_resume(job);
    job_user_resume_locked(&job->job, errp);
}

void qmp_block_job_complete(const char* device, Error** errp)
{
    BlockJob* job;

    JOB_LOCK_GUARD();
    job = find_block_job_locked(device, errp);

    if (!job) { return; }

    trace_qmp_block_job_complete(job);
    job_complete_locked(&job->job, errp);
}

void qmp_block_job_finalize(const char* id, Error** errp)
{
    BlockJob* job;

    JOB_LOCK_GUARD();
    job = find_block_job_locked(id, errp);

    if (!job) { return; }

    trace_qmp_block_job_finalize(job);
    job_ref_locked(&job->job);
    job_finalize_locked(&job->job, errp);

    job_unref_locked(&job->job);
}

void qmp_block_job_dismiss(const char* id, Error** errp)
{
    BlockJob* bjob;
    Job*      job;

    JOB_LOCK_GUARD();
    bjob = find_block_job_locked(id, errp);

    if (!bjob) { return; }

    trace_qmp_block_job_dismiss(bjob);
    job = &bjob->job;
    job_dismiss_locked(&job, errp);
}

void qmp_block_job_change(BlockJobChangeOptions* opts, Error** errp)
{
    BlockJob* job;

    JOB_LOCK_GUARD();
    job = find_block_job_locked(opts->id, errp);

    if (!job) { return; }

    block_job_change_locked(job, opts, errp);
}

void qmp_change_backing_file(const char* device, const char* image_node_name, const char* backing_file, Error** errp)
{
    BlockDriverState* bs        = NULL;
    BlockDriverState* image_bs  = NULL;
    Error*            local_err = NULL;
    bool              ro;
    int               ret;

    bs = qmp_get_root_bs(device, errp);
    if (!bs) { return; }

    bdrv_graph_rdlock_main_loop();

    image_bs = bdrv_lookup_bs(NULL, image_node_name, &local_err);
    if (local_err) {
        error_propagate(errp, local_err);
        goto out_rdlock;
    }

    if (!image_bs) {
        error_setg(errp, "image file not found");
        goto out_rdlock;
    }

    if (bdrv_find_base(image_bs) == image_bs) {
        error_setg(errp, "not allowing backing file change on an image "
                         "without a backing file");
        goto out_rdlock;
    }

    /* even though we are not necessarily operating on bs, we need it to
     * determine if block ops are currently prohibited on the chain */
    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_CHANGE, errp)) { goto out_rdlock; }

    /* final sanity check */
    if (!bdrv_chain_contains(bs, image_bs)) {
        error_setg(errp, "'%s' and image file are not in the same chain", device);
        goto out_rdlock;
    }
    bdrv_graph_rdunlock_main_loop();

    /* if not r/w, reopen to make r/w */
    ro = bdrv_is_read_only(image_bs);

    if (ro) {
        if (bdrv_reopen_set_read_only(image_bs, false, errp) != 0) { return; }
    }

    ret = bdrv_change_backing_file(image_bs, backing_file, image_bs->drv ? image_bs->drv->format_name : "", false);

    if (ret < 0) {
        error_setg_errno(errp, -ret, "Could not change backing file to '%s'", backing_file);
        /* don't exit here, so we can try to restore open flags if
         * appropriate */
    }

    if (ro) { bdrv_reopen_set_read_only(image_bs, true, errp); }
    return;

out_rdlock:
    bdrv_graph_rdunlock_main_loop();
}

void qmp_blockdev_add(BlockdevOptions* options, Error** errp)
{
    BlockDriverState* bs;
    QObject*          obj;
    Visitor*          v = qobject_output_visitor_new(&obj);
    QDict*            qdict;

    visit_type_BlockdevOptions(v, NULL, &options, &error_abort);
    visit_complete(v, &obj);
    qdict = qobject_to(QDict, obj);

    qdict_flatten(qdict);

    if (!qdict_get_try_str(qdict, "node-name")) {
        error_setg(errp, "'node-name' must be specified for the root node");
        goto fail;
    }

    bs = bds_tree_init(qdict, errp);
    if (!bs) { goto fail; }

    bdrv_set_monitor_owned(bs);

fail:
    visit_free(v);
}

void qmp_blockdev_reopen(BlockdevOptionsList* reopen_list, Error** errp)
{
    BlockReopenQueue* queue = NULL;

    /* Add each one of the BDS that we want to reopen to the queue */
    for (; reopen_list != NULL; reopen_list = reopen_list->next) {
        BlockdevOptions*  options = reopen_list->value;
        BlockDriverState* bs;
        QObject*          obj;
        Visitor*          v;
        QDict*            qdict;

        /* Check for the selected node name */
        if (!options->node_name) {
            error_setg(errp, "node-name not specified");
            goto fail;
        }

        bs = bdrv_find_node(options->node_name);
        if (!bs) {
            error_setg(errp, "Failed to find node with node-name='%s'", options->node_name);
            goto fail;
        }

        /* Put all options in a QDict and flatten it */
        v = qobject_output_visitor_new(&obj);
        visit_type_BlockdevOptions(v, NULL, &options, &error_abort);
        visit_complete(v, &obj);
        visit_free(v);

        qdict = qobject_to(QDict, obj);

        qdict_flatten(qdict);

        queue = bdrv_reopen_queue(queue, bs, qdict, false);
    }

    /* Perform the reopen operation */
    bdrv_reopen_multiple(queue, errp);
    queue = NULL;

fail:
    bdrv_reopen_queue_free(queue);
}

void qmp_blockdev_del(const char* node_name, Error** errp)
{
    BlockDriverState* bs;

    GLOBAL_STATE_CODE();
    GRAPH_RDLOCK_GUARD_MAINLOOP();

    bs = bdrv_find_node(node_name);
    if (!bs) {
        error_setg(errp, "Failed to find node with node-name='%s'", node_name);
        return;
    }
    if (bdrv_has_blk(bs)) {
        error_setg(errp, "Node %s is in use", node_name);
        return;
    }

    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_DRIVE_DEL, errp)) { return; }

    if (!QTAILQ_IN_USE(bs, monitor_list)) {
        error_setg(errp, "Node %s is not owned by the monitor", bs->node_name);
        return;
    }

    if (bs->refcnt > 1) {
        error_setg(errp, "Block device %s is in use", bdrv_get_device_or_node_name(bs));
        return;
    }

    QTAILQ_REMOVE(&monitor_bdrv_states, bs, monitor_list);
    bdrv_unref(bs);
}

void qmp_blockdev_set_active(const char* node_name, bool active, Error** errp)
{
    BlockDriverState* bs;
    int               ret;

    GLOBAL_STATE_CODE();

    if (!node_name) {
        if (active) { bdrv_activate_all(errp); }
        else {
            ret = bdrv_inactivate_all();
            if (ret < 0) { error_setg_errno(errp, -ret, "Failed to inactivate all nodes"); }
        }
        return;
    }

    if (!active) { bdrv_drain_all_begin(); }
    bdrv_graph_rdlock_main_loop();

    bs = bdrv_find_node(node_name);
    if (!bs) {
        error_setg(errp, "Failed to find node with node-name='%s'", node_name);
        goto unlock;
    }
    if (active) { bdrv_activate(bs, errp); }
    else {
        bdrv_inactivate(bs, errp);
    }

unlock:
    bdrv_graph_rdunlock_main_loop();
    if (!active) { bdrv_drain_all_end(); }
}

static BdrvChild* GRAPH_RDLOCK bdrv_find_child(BlockDriverState* parent_bs, const char* child_name)
{
    BdrvChild* child;

    QLIST_FOREACH (child, &parent_bs->children, next) {
        if (strcmp(child->name, child_name) == 0) { return child; }
    }

    return NULL;
}

void qmp_x_blockdev_change(const char* parent, const char* child, const char* node, Error** errp)
{
    BlockDriverState *parent_bs, *new_bs = NULL;
    BdrvChild*        p_child;

    bdrv_graph_wrlock_drained();

    parent_bs = bdrv_lookup_bs(parent, parent, errp);
    if (!parent_bs) { goto out; }

    if (!child == !node) {
        if (child) { error_setg(errp, "The parameters child and node are in conflict"); }
        else {
            error_setg(errp, "Either child or node must be specified");
        }
        goto out;
    }

    if (child) {
        p_child = bdrv_find_child(parent_bs, child);
        if (!p_child) {
            error_setg(errp, "Node '%s' does not have child '%s'", parent, child);
            goto out;
        }
        bdrv_del_child(parent_bs, p_child, errp);
    }

    if (node) {
        new_bs = bdrv_find_node(node);
        if (!new_bs) {
            error_setg(errp, "Node '%s' not found", node);
            goto out;
        }
        bdrv_add_child(parent_bs, new_bs, errp);
    }

out:
    bdrv_graph_wrunlock();
}

BlockJobInfoList* qmp_query_block_jobs(Error** errp)
{
    BlockJobInfoList *head = NULL, **tail = &head;
    BlockJob*         job;

    JOB_LOCK_GUARD();

    for (job = block_job_next_locked(NULL); job; job = block_job_next_locked(job)) {
        BlockJobInfo* value;

        if (block_job_is_internal(job)) { continue; }
        value = block_job_query_locked(job, errp);
        if (!value) {
            qapi_free_BlockJobInfoList(head);
            return NULL;
        }
        QAPI_LIST_APPEND(tail, value);
    }

    return head;
}

void qmp_x_blockdev_set_iothread(const char* node_name, StrOrNull* iothread, bool has_force, bool force, Error** errp)
{
    AioContext*       new_context;
    BlockDriverState* bs;

    bdrv_drain_all_begin();
    bdrv_graph_rdlock_main_loop();

    bs = bdrv_find_node(node_name);
    if (!bs) {
        error_setg(errp, "Failed to find node with node-name='%s'", node_name);
        goto out;
    }

    /* Protects against accidents. */
    if (!(has_force && force) && bdrv_has_blk(bs)) {
        error_setg(errp,
                   "Node %s is associated with a BlockBackend and could "
                   "be in use (use force=true to override this check)",
                   node_name);
        goto out;
    }

    if (iothread->type == QTYPE_QSTRING) {
        IOThread* obj = iothread_by_id(iothread->u.s);
        if (!obj) {
            error_setg(errp, "Cannot find iothread %s", iothread->u.s);
            goto out;
        }

        new_context = iothread_get_aio_context(obj);
    }
    else {
        new_context = qemu_get_aio_context();
    }

    bdrv_try_change_aio_context_locked(bs, new_context, NULL, errp);

out:
    bdrv_graph_rdunlock_main_loop();
    bdrv_drain_all_end();
}

QemuOptsList qemu_common_drive_opts = {
    .name = "drive",
    .head = QTAILQ_HEAD_INITIALIZER(qemu_common_drive_opts.head),
    .desc = {{
                 .name = "snapshot",
                 .type = QEMU_OPT_BOOL,
                 .help = "enable/disable snapshot mode",
             },
             {
                 .name = "aio",
                 .type = QEMU_OPT_STRING,
                 .help = "host AIO implementation (threads, native, io_uring)",
             },
             {
                 .name = BDRV_OPT_CACHE_WB,
                 .type = QEMU_OPT_BOOL,
                 .help = "Enable writeback mode",
             },
             {
                 .name = "format",
                 .type = QEMU_OPT_STRING,
                 .help = "disk format (raw, qcow2, ...)",
             },
             {
                 .name = "rerror",
                 .type = QEMU_OPT_STRING,
                 .help = "read error action",
             },
             {
                 .name = "werror",
                 .type = QEMU_OPT_STRING,
                 .help = "write error action",
             },
             {
                 .name = BDRV_OPT_READ_ONLY,
                 .type = QEMU_OPT_BOOL,
                 .help = "open drive file as read-only",
             },
             {
                 .name = "copy-on-read",
                 .type = QEMU_OPT_BOOL,
                 .help = "copy read data from backing file into image file",
             },
             {
                 .name = "detect-zeroes",
                 .type = QEMU_OPT_STRING,
                 .help = "try to optimize zero writes (off, on, unmap)",
             },
             {
                 .name = "stats-account-invalid",
                 .type = QEMU_OPT_BOOL,
                 .help = "whether to account for invalid I/O operations "
                         "in the statistics",
             },
             {
                 .name = "stats-account-failed",
                 .type = QEMU_OPT_BOOL,
                 .help = "whether to account for failed I/O operations "
                         "in the statistics",
             },
             {/* end of list */}},
};

QemuOptsList qemu_drive_opts = {
    .name = "drive",
    .head = QTAILQ_HEAD_INITIALIZER(qemu_drive_opts.head),
    .desc =
        {/*
          * no elements => accept any params
          * validation will happen later
          */
         {/* end of list */}},
};