Commit 61b49e48 authored by Alberto Garcia's avatar Alberto Garcia Committed by Kevin Wolf
Browse files

block: Support streaming to an intermediate layer 



This makes sure that the image we are streaming into is open in
read-write mode during the operation.

Operation blockers are also set in all intermediate nodes, since they
will be removed from the chain afterwards.

Finally, this also unblocks the stream operation in backing files.

Signed-off-by: default avatarAlberto Garcia <berto@igalia.com>
Reviewed-by: default avatarKevin Wolf <kwolf@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent f3ede4b0

block.c

+3 −1
Original line number Diff line number Diff line
@@ -1428,9 +1428,11 @@ void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd) 
            backing_hd->drv ? backing_hd->drv->format_name : "");



    bdrv_op_block_all(backing_hd, bs->backing_blocker);

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

    /* Otherwise we won't be able to commit or stream */

    bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET,

                    bs->backing_blocker);

    bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_STREAM,

                    bs->backing_blocker);

    /*

     * We do backup in 3 ways:

     * 1. drive backup

block/stream.c

+24 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ typedef struct StreamBlockJob { 
    BlockDriverState *base;

    BlockdevOnError on_error;

    char *backing_file_str;

    int bs_flags;

} StreamBlockJob;



static int coroutine_fn stream_populate(BlockBackend *blk,
@@ -81,6 +82,11 @@ static void stream_complete(BlockJob *job, void *opaque) 
        bdrv_set_backing_hd(bs, base);

    }



    /* Reopen the image back in read-only mode if necessary */

    if (s->bs_flags != bdrv_get_flags(bs)) {

        bdrv_reopen(bs, s->bs_flags, NULL);

    }



    g_free(s->backing_file_str);

    block_job_completed(&s->common, data->ret);

    g_free(data);
@@ -220,6 +226,8 @@ void stream_start(const char *job_id, BlockDriverState *bs, 
                  BlockCompletionFunc *cb, void *opaque, Error **errp)

{

    StreamBlockJob *s;

    BlockDriverState *iter;

    int orig_bs_flags;



    s = block_job_create(job_id, &stream_job_driver, bs, speed,

                         cb, opaque, errp);
@@ -227,8 +235,24 @@ void stream_start(const char *job_id, BlockDriverState *bs, 
        return;

    }



    /* Make sure that the image is opened in read-write mode */

    orig_bs_flags = bdrv_get_flags(bs);

    if (!(orig_bs_flags & BDRV_O_RDWR)) {

        if (bdrv_reopen(bs, orig_bs_flags | BDRV_O_RDWR, errp) != 0) {

            block_job_unref(&s->common);

            return;

        }

    }



    /* Block all intermediate nodes between bs and base, because they

     * will disappear from the chain after this operation */

    for (iter = backing_bs(bs); iter && iter != base; iter = backing_bs(iter)) {

        block_job_add_bdrv(&s->common, iter);

    }



    s->base = base;

    s->backing_file_str = g_strdup(backing_file_str);

    s->bs_flags = orig_bs_flags;



    s->on_error = on_error;

    s->common.co = qemu_coroutine_create(stream_run, s);