Re: [Qemu-devel] [PATCH v14 7/8] Implement new driver for block replication

[Changlong Xie]

On 01/20/2016 08:04 AM, Eric Blake wrote:
> On 01/13/2016 02:18 AM, Changlong Xie wrote:
> > From: Wen Congyang <address@hidden>
> >
> > Signed-off-by: Wen Congyang <address@hidden>
> > Signed-off-by: zhanghailiang <address@hidden>
> > Signed-off-by: Gonglei <address@hidden>
> > Signed-off-by: Changlong Xie <address@hidden>
> > ---
> >   block/Makefile.objs              |   1 +
> >   block/replication-comm.c         |  66 +++++
> >   block/replication.c              | 590 +++++++++++++++++++++++++++++++++++++++
> >   include/block/replication-comm.h |  50 ++++
> >   qapi/block-core.json             |  13 +
> >   5 files changed, 720 insertions(+)
> >   create mode 100644 block/replication-comm.c
> >   create mode 100644 block/replication.c
> >   create mode 100644 include/block/replication-comm.h
>
> Just a high-level overview, mainly on the user-visible interface and
> things that caught my eye.

Hi eric, thanks for your patience.

> > +++ b/block/replication-comm.c
> > @@ -0,0 +1,66 @@
> > +/*
> > + * Replication Block filter
> > + *
> > + * Copyright (c) 2015 HUAWEI TECHNOLOGIES CO., LTD.
> > + * Copyright (c) 2015 Intel Corporation
> > + * Copyright (c) 2015 FUJITSU LIMITED
>
> Do you want to claim 2016 in any of this?

Will correct all Copyright issues in next version.

> > +
> > +enum {
> > +    BLOCK_REPLICATION_NONE,             /* block replication is not started */
> > +    BLOCK_REPLICATION_RUNNING,          /* block replication is running */
> > +    BLOCK_REPLICATION_FAILOVER,         /* failover is running in background */
> > +    BLOCK_REPLICATION_FAILOVER_FAILED,  /* failover failed*/
>
> Space before */

Will fix this space issue

> > +    BLOCK_REPLICATION_DONE,             /* block replication is done(after 
> > failover) */
> > +};
>
> Should this be an enum type in a .json file?

Since this is just an internal enum that only used in 
block/replication.c, i think we don't need put it in *.json file.

> > +
> > +static int replication_open(BlockDriverState *bs, QDict *options,
> > +                            int flags, Error **errp)
> > +{
>
> > +
> > +fail:
> > +    qemu_opts_del(opts);
> > +    /* propagate error */
> > +    if (local_err) {
> > +        error_propagate(errp, local_err);
> > +    }
>
> It's safe to call error_propagate() unconditionally (you could drop the
> 'if (local_err)').

You're right, i'll fix all relevant issue in my patchset.

> > +static coroutine_fn int replication_co_discard(BlockDriverState *bs,
> > +                                               int64_t sector_num,
> > +                                               int nb_sectors)
> > +{
> > +    BDRVReplicationState *s = bs->opaque;
> > +    int ret;
> > +
> > +    ret = replication_get_io_status(s);
> > +    if (ret < 0) {
> > +        return ret;
> > +    }
> > +
> > +    if (ret == 1) {
> > +        /* It is secondary qemu and failover are running*/
>
> Space before */

Will fix

> > +static void secondary_do_checkpoint(BDRVReplicationState *s, Error **errp)
> > +{
> > +    Error *local_err = NULL;
> > +    int ret;
> > +
> > +    if (!s->secondary_disk->job) {
> > +        error_setg(errp, "Backup job is cancelled unexpectedly");
>
> Maybe s/is/was/

will fix

> > +static void replication_start(BlockReplicationState *brs, ReplicationMode mode,
> > +                              Error **errp)
> > +{
> > +    BlockDriverState *bs = brs->bs;
> > +    BDRVReplicationState *s = brs->bs->opaque;
> > +    int64_t active_length, hidden_length, disk_length;
> > +    AioContext *aio_context;
> > +    Error *local_err = NULL;
> > +
> > +    if (s->replication_state != BLOCK_REPLICATION_NONE) {
> > +        error_setg(errp, "Block replication is running or done");
> > +        return;
> > +    }
> > +
> > +    if (s->mode != mode) {
> > +        error_setg(errp, "The parameter mode's value is invalid, needs %d,"
> > +                   " but receives %d", s->mode, mode);
>
> s/receives/got/

will fix

> > +static void replication_do_checkpoint(BlockReplicationState *brs, Error **errp)
> > +{
> > +    BDRVReplicationState *s = brs->bs->opaque;
> > +
> > +    if (s->replication_state != BLOCK_REPLICATION_RUNNING) {
> > +        error_setg(errp, "Block replication is not running");
> > +        return;
> > +    }
> > +
> > +    if (s->error) {
> > +        error_setg(errp, "I/O error occurs");
>
> s/occurs/occurred/

Will fix

> > +++ b/qapi/block-core.json
> > @@ -1975,6 +1975,19 @@
> >               '*read-pattern': 'QuorumReadPattern' } }
> >
> >   ##
> > +# @ReplicationMode
> > +#
> > +# An enumeration of replication modes.
> > +#
> > +# @primary: Primary mode, the vm's state will be sent to secondary QEMU.
> > +#
> > +# @secondary: Secondary mode, receive the vm's state from primary QEMU.
> > +#
> > +# Since: 2.6
> > +##
> > +{ 'enum' : 'ReplicationMode', 'data' : [ 'primary', 'secondary' ] }
> > +
>
> Interface looks okay.


Thanks
        -Xie

>