Commit bb00021d authored by Fam Zheng's avatar Fam Zheng Committed by Stefan Hajnoczi
Browse files

block: Split BLOCK_OP_TYPE_COMMIT to BLOCK_OP_TYPE_COMMIT_{SOURCE, TARGET} 



Like BLOCK_OP_TYPE_BACKUP_SOURCE and BLOCK_OP_TYPE_BACKUP_TARGET,
block-commit involves two asymmetric devices.

This change is not user-visible (yet), because commit only works with
device names.

But once we enable backing reference in blockdev-add, or specifying
node-name in block-commit command, we don't want the user to start two
commit jobs on the same backing chain, which will corrupt things because
of the final bdrv_swap.

Before we have per category blockers, splitting this type is still
better.

[Resolved virtio-blk dataplane conflict by replacing
BLOCK_OP_TYPE_COMMIT with both BLOCK_OP_TYPE_COMMIT_{SOURCE, TARGET}.
They are safe since the block job runs in the same AioContext as the
dataplane IOThread.
--Stefan]

Signed-off-by: default avatarFam Zheng <famz@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 095e4fa4

block.c

+3 −3
Original line number Diff line number Diff line
@@ -1200,7 +1200,7 @@ void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd) 


    bdrv_op_block_all(bs->backing_hd, bs->backing_blocker);

    /* Otherwise we won't be able to commit due to check in bdrv_commit */

    bdrv_op_unblock(bs->backing_hd, BLOCK_OP_TYPE_COMMIT,

    bdrv_op_unblock(bs->backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET,

                    bs->backing_blocker);

out:

    bdrv_refresh_limits(bs, NULL);
@@ -2216,8 +2216,8 @@ int bdrv_commit(BlockDriverState *bs) 
        return -ENOTSUP;

    }



    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT, NULL) ||

        bdrv_op_is_blocked(bs->backing_hd, BLOCK_OP_TYPE_COMMIT, NULL)) {

    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, NULL) ||

        bdrv_op_is_blocked(bs->backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET, NULL)) {

        return -EBUSY;

    }

blockdev.c

+5 −1
Original line number Diff line number Diff line
@@ -2218,7 +2218,7 @@ void qmp_block_commit(const char *device, 
    /* drain all i/o before commits */

    bdrv_drain_all();



    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT, errp)) {

    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, errp)) {

        goto out;

    }
@@ -2251,6 +2251,10 @@ void qmp_block_commit(const char *device, 


    assert(bdrv_get_aio_context(base_bs) == aio_context);



    if (bdrv_op_is_blocked(base_bs, BLOCK_OP_TYPE_COMMIT_TARGET, errp)) {

        goto out;

    }



    /* Do not allow attempts to commit an image into itself */

    if (top_bs == base_bs) {

        error_setg(errp, "cannot commit an image into itself");

hw/block/dataplane/virtio-blk.c

+2 −1
Original line number Diff line number Diff line
@@ -198,7 +198,8 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *conf, 
    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_DRIVE_DEL, s->blocker);

    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_BACKUP_SOURCE, s->blocker);

    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_CHANGE, s->blocker);

    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_COMMIT, s->blocker);

    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_COMMIT_SOURCE, s->blocker);

    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_COMMIT_TARGET, s->blocker);

    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_EJECT, s->blocker);

    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT, s->blocker);

    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT, s->blocker);

include/block/block.h

+2 −1
Original line number Diff line number Diff line
@@ -133,7 +133,8 @@ typedef enum BlockOpType { 
    BLOCK_OP_TYPE_BACKUP_SOURCE,

    BLOCK_OP_TYPE_BACKUP_TARGET,

    BLOCK_OP_TYPE_CHANGE,

    BLOCK_OP_TYPE_COMMIT,

    BLOCK_OP_TYPE_COMMIT_SOURCE,

    BLOCK_OP_TYPE_COMMIT_TARGET,

    BLOCK_OP_TYPE_DATAPLANE,

    BLOCK_OP_TYPE_DRIVE_DEL,

    BLOCK_OP_TYPE_EJECT,