Commit 98292c61 authored by Wen Congyang's avatar Wen Congyang Committed by Max Reitz
Browse files

quorum: implement bdrv_add_child() and bdrv_del_child() 



Signed-off-by: default avatarWen Congyang <wency@cn.fujitsu.com>
Signed-off-by: default avatarzhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: default avatarGonglei <arei.gonglei@huawei.com>
Signed-off-by: default avatarChanglong Xie <xiecl.fnst@cn.fujitsu.com>
Message-id: 1462865799-19402-3-git-send-email-xiecl.fnst@cn.fujitsu.com
Reviewed-by: default avatarAlberto Garcia <berto@igalia.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
parent e06018ad

block.c

+4 −4
Original line number Diff line number Diff line
@@ -1174,7 +1174,7 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, 
    return child;

}



static BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,

BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,

                             BlockDriverState *child_bs,

                             const char *child_name,

                             const BdrvChildRole *child_role)

block/quorum.c

+76 −2
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
 */



#include "qemu/osdep.h"

#include "qemu/cutils.h"

#include "block/block_int.h"

#include "qapi/qmp/qbool.h"

#include "qapi/qmp/qdict.h"
@@ -67,6 +68,9 @@ typedef struct QuorumVotes { 
typedef struct BDRVQuorumState {

    BdrvChild **children;  /* children BlockDriverStates */

    int num_children;      /* children count */

    unsigned next_child_index;  /* the index of the next child that should

                                 * be added

                                 */

    int threshold;         /* if less than threshold children reads gave the

                            * same result a quorum error occurs.

                            */
@@ -883,9 +887,9 @@ static int quorum_open(BlockDriverState *bs, QDict *options, int flags, 
        ret = -EINVAL;

        goto exit;

    }

    if (s->num_children < 2) {

    if (s->num_children < 1) {

        error_setg(&local_err,

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

                   "Number of provided children must be 1 or more");

        ret = -EINVAL;

        goto exit;

    }
@@ -949,6 +953,7 @@ static int quorum_open(BlockDriverState *bs, QDict *options, int flags, 


        opened[i] = true;

    }

    s->next_child_index = s->num_children;



    g_free(opened);

    goto exit;
@@ -1005,6 +1010,72 @@ static void quorum_attach_aio_context(BlockDriverState *bs, 
    }

}



static void quorum_add_child(BlockDriverState *bs, BlockDriverState *child_bs,

                             Error **errp)

{

    BDRVQuorumState *s = bs->opaque;

    BdrvChild *child;

    char indexstr[32];

    int ret;



    assert(s->num_children <= INT_MAX / sizeof(BdrvChild *));

    if (s->num_children == INT_MAX / sizeof(BdrvChild *) ||

        s->next_child_index == UINT_MAX) {

        error_setg(errp, "Too many children");

        return;

    }



    ret = snprintf(indexstr, 32, "children.%u", s->next_child_index);

    if (ret < 0 || ret >= 32) {

        error_setg(errp, "cannot generate child name");

        return;

    }

    s->next_child_index++;



    bdrv_drained_begin(bs);



    /* We can safely add the child now */

    bdrv_ref(child_bs);

    child = bdrv_attach_child(bs, child_bs, indexstr, &child_format);

    s->children = g_renew(BdrvChild *, s->children, s->num_children + 1);

    s->children[s->num_children++] = child;



    bdrv_drained_end(bs);

}



static void quorum_del_child(BlockDriverState *bs, BdrvChild *child,

                             Error **errp)

{

    BDRVQuorumState *s = bs->opaque;

    int i;



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

        if (s->children[i] == child) {

            break;

        }

    }



    /* we have checked it in bdrv_del_child() */

    assert(i < s->num_children);



    if (s->num_children <= s->threshold) {

        error_setg(errp,

            "The number of children cannot be lower than the vote threshold %d",

            s->threshold);

        return;

    }



    bdrv_drained_begin(bs);



    /* We can safely remove this child now */

    memmove(&s->children[i], &s->children[i + 1],

            (s->num_children - i - 1) * sizeof(BdrvChild *));

    s->children = g_renew(BdrvChild *, s->children, --s->num_children);

    bdrv_unref_child(bs, child);



    bdrv_drained_end(bs);

}



static void quorum_refresh_filename(BlockDriverState *bs, QDict *options)

{

    BDRVQuorumState *s = bs->opaque;
@@ -1059,6 +1130,9 @@ static BlockDriver bdrv_quorum = { 
    .bdrv_detach_aio_context            = quorum_detach_aio_context,

    .bdrv_attach_aio_context            = quorum_attach_aio_context,



    .bdrv_add_child                     = quorum_add_child,

    .bdrv_del_child                     = quorum_del_child,



    .is_filter                          = true,

    .bdrv_recurse_is_first_non_filter   = quorum_recurse_is_first_non_filter,

};

include/block/block.h

+4 −0
Original line number Diff line number Diff line
@@ -476,6 +476,10 @@ void bdrv_disable_copy_on_read(BlockDriverState *bs); 
void bdrv_ref(BlockDriverState *bs);

void bdrv_unref(BlockDriverState *bs);

void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);

BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,

                             BlockDriverState *child_bs,

                             const char *child_name,

                             const BdrvChildRole *child_role);



bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);

void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);