Commit c88a1de5 authored by Benoît Canet's avatar Benoît Canet Committed by Kevin Wolf
Browse files

quorum: Add quorum_open() and quorum_close(). 



Example of command line:

-drive if=virtio,driver=quorum,\
children.0.file.filename=1.raw,\
children.0.node-name=1.raw,\
children.0.driver=raw,\
children.1.file.filename=2.raw,\
children.1.node-name=2.raw,\
children.1.driver=raw,\
children.2.file.filename=3.raw,\
children.2.node-name=3.raw,\
children.2.driver=raw,\
vote-threshold=2

blkverify=on with vote-threshold=2 and two files can be passed to
emulate blkverify.

Signed-off-by: default avatarBenoit Canet <benoit@irqsave.net>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 98a7a38f

block/quorum.c

+161 −0
Original line number Diff line number Diff line
@@ -20,6 +20,9 @@ 


#define HASH_LENGTH 32



#define QUORUM_OPT_VOTE_THRESHOLD "vote-threshold"

#define QUORUM_OPT_BLKVERIFY      "blkverify"



/* This union holds a vote hash value */

typedef union QuorumVoteValue {

    char h[HASH_LENGTH];       /* SHA-256 hash */
@@ -672,12 +675,170 @@ static bool quorum_recurse_is_first_non_filter(BlockDriverState *bs, 
    return false;

}



static int quorum_valid_threshold(int threshold, int num_children, Error **errp)

{



    if (threshold < 1) {

        error_set(errp, QERR_INVALID_PARAMETER_VALUE,

                  "vote-threshold", "value >= 1");

        return -ERANGE;

    }



    if (threshold > num_children) {

        error_setg(errp, "threshold may not exceed children count");

        return -ERANGE;

    }



    return 0;

}



static QemuOptsList quorum_runtime_opts = {

    .name = "quorum",

    .head = QTAILQ_HEAD_INITIALIZER(quorum_runtime_opts.head),

    .desc = {

        {

            .name = QUORUM_OPT_VOTE_THRESHOLD,

            .type = QEMU_OPT_NUMBER,

            .help = "The number of vote needed for reaching quorum",

        },

        {

            .name = QUORUM_OPT_BLKVERIFY,

            .type = QEMU_OPT_BOOL,

            .help = "Trigger block verify mode if set",

        },

        { /* end of list */ }

    },

};



static int quorum_open(BlockDriverState *bs, QDict *options, int flags,

                       Error **errp)

{

    BDRVQuorumState *s = bs->opaque;

    Error *local_err = NULL;

    QemuOpts *opts;

    bool *opened;

    QDict *sub = NULL;

    QList *list = NULL;

    const QListEntry *lentry;

    const QDictEntry *dentry;

    int i;

    int ret = 0;



    qdict_flatten(options);

    qdict_extract_subqdict(options, &sub, "children.");

    qdict_array_split(sub, &list);



    /* count how many different children are present and validate

     * qdict_size(sub) address the open by reference case

     */

    s->num_children = !qlist_size(list) ? qdict_size(sub) : qlist_size(list);

    if (s->num_children < 2) {

        error_setg(&local_err,

                   "Number of provided children must be greater than 1");

        ret = -EINVAL;

        goto exit;

    }



    opts = qemu_opts_create(&quorum_runtime_opts, NULL, 0, &error_abort);

    qemu_opts_absorb_qdict(opts, options, &local_err);

    if (error_is_set(&local_err)) {

        ret = -EINVAL;

        goto exit;

    }



    s->threshold = qemu_opt_get_number(opts, QUORUM_OPT_VOTE_THRESHOLD, 0);



    /* and validate it against s->num_children */

    ret = quorum_valid_threshold(s->threshold, s->num_children, &local_err);

    if (ret < 0) {

        goto exit;

    }



    /* is the driver in blkverify mode */

    if (qemu_opt_get_bool(opts, QUORUM_OPT_BLKVERIFY, false) &&

        s->num_children == 2 && s->threshold == 2) {

        s->is_blkverify = true;

    } else if (qemu_opt_get_bool(opts, QUORUM_OPT_BLKVERIFY, false)) {

        fprintf(stderr, "blkverify mode is set by setting blkverify=on "

                "and using two files with vote_threshold=2\n");

    }



    /* allocate the children BlockDriverState array */

    s->bs = g_new0(BlockDriverState *, s->num_children);

    opened = g_new0(bool, s->num_children);



    /* Open by file name or options dict (command line or QMP) */

    if (s->num_children == qlist_size(list)) {

        for (i = 0, lentry = qlist_first(list); lentry;

            lentry = qlist_next(lentry), i++) {

            QDict *d = qobject_to_qdict(lentry->value);

            QINCREF(d);

            ret = bdrv_open(&s->bs[i], NULL, NULL, d, flags, NULL, &local_err);

            if (ret < 0) {

                goto close_exit;

            }

            opened[i] = true;

        }

    /* Open by QMP references */

    } else {

        for (i = 0, dentry = qdict_first(sub); dentry;

             dentry = qdict_next(sub, dentry), i++) {

            QString *string = qobject_to_qstring(dentry->value);

            ret = bdrv_open(&s->bs[i], NULL, qstring_get_str(string), NULL,

                            flags, NULL, &local_err);

            if (ret < 0) {

                goto close_exit;

            }

            opened[i] = true;

        }

    }



    g_free(opened);

    goto exit;



close_exit:

    /* cleanup on error */

    for (i = 0; i < s->num_children; i++) {

        if (!opened[i]) {

            continue;

        }

        bdrv_unref(s->bs[i]);

    }

    g_free(s->bs);

    g_free(opened);

exit:

    /* propagate error */

    if (error_is_set(&local_err)) {

        error_propagate(errp, local_err);

    }

    QDECREF(list);

    QDECREF(sub);

    return ret;

}



static void quorum_close(BlockDriverState *bs)

{

    BDRVQuorumState *s = bs->opaque;

    int i;



    for (i = 0; i < s->num_children; i++) {

        bdrv_unref(s->bs[i]);

    }



    g_free(s->bs);

}



static BlockDriver bdrv_quorum = {

    .format_name        = "quorum",

    .protocol_name      = "quorum",



    .instance_size      = sizeof(BDRVQuorumState),



    .bdrv_file_open     = quorum_open,

    .bdrv_close         = quorum_close,



    .authorizations     = { true, true },



    .bdrv_co_flush_to_disk = quorum_co_flush,



    .bdrv_getlength     = quorum_getlength,

monitor.c

+3 −0
Original line number Diff line number Diff line
@@ -640,6 +640,9 @@ static void monitor_protocol_event_init(void) 
    monitor_protocol_event_throttle(QEVENT_RTC_CHANGE, 1000);

    monitor_protocol_event_throttle(QEVENT_BALLOON_CHANGE, 1000);

    monitor_protocol_event_throttle(QEVENT_WATCHDOG, 1000);

    /* limit the rate of quorum events to avoid hammering the management */

    monitor_protocol_event_throttle(QEVENT_QUORUM_REPORT_BAD, 1000);

    monitor_protocol_event_throttle(QEVENT_QUORUM_FAILURE, 1000);

}



/**

qapi-schema.json

+20 −1
Original line number Diff line number Diff line
@@ -4431,6 +4431,24 @@ 
  'data': { 'test': 'BlockdevRef',

            'raw': 'BlockdevRef' } }



##

# @BlockdevOptionsQuorum

#

# Driver specific block device options for Quorum

#

# @blkverify:      #optional true if the driver must print content mismatch

#

# @children:       the children block device to use

#

# @vote_threshold: the vote limit under which a read will fail

#

# Since: 2.0

##

{ 'type': 'BlockdevOptionsQuorum',

  'data': { '*blkverify': 'bool',

            'children': [ 'BlockdevRef' ],

            'vote-threshold': 'int' } }



##

# @BlockdevOptions

#
@@ -4470,7 +4488,8 @@ 
      'vdi':        'BlockdevOptionsGenericFormat',

      'vhdx':       'BlockdevOptionsGenericFormat',

      'vmdk':       'BlockdevOptionsGenericCOWFormat',

      'vpc':        'BlockdevOptionsGenericFormat'

      'vpc':        'BlockdevOptionsGenericFormat',

      'quorum':     'BlockdevOptionsQuorum'

  } }



##