Commit ff6ed714 authored by Eric Blake's avatar Eric Blake Committed by Markus Armbruster
Browse files

block: Simplify bdrv_append_temp_snapshot() logic 



Noticed while checking Coccinelle results. Naming a label 'out:'
when it is only used on error paths is weird.  Also, we had some
dead stores to 'ret'.  Meanwhile we know that snapshot_options
is NULL on success and that QDECREF(NULL) is safe.  So merge the
two exit paths into one by careful control over bs_snapshot.

Signed-off-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarMarkus Armbruster <armbru@redhat.com>
Message-Id: <20170427215821.19397-8-eblake@redhat.com>
Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
parent 46f5ac20

block.c

+7 −10
Original line number Diff line number Diff line
@@ -2195,7 +2195,7 @@ static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs, 
    char *tmp_filename = g_malloc0(PATH_MAX + 1);

    int64_t total_size;

    QemuOpts *opts = NULL;

    BlockDriverState *bs_snapshot;

    BlockDriverState *bs_snapshot = NULL;

    Error *local_err = NULL;

    int ret;
@@ -2235,28 +2235,25 @@ static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs, 
    bs_snapshot = bdrv_open(NULL, NULL, snapshot_options, flags, errp);

    snapshot_options = NULL;

    if (!bs_snapshot) {

        ret = -EINVAL;

        goto out;

    }



    /* bdrv_append() consumes a strong reference to bs_snapshot (i.e. it will

     * call bdrv_unref() on it), so in order to be able to return one, we have

     * to increase bs_snapshot's refcount here */

    /* bdrv_append() consumes a strong reference to bs_snapshot

     * (i.e. it will call bdrv_unref() on it) even on error, so in

     * order to be able to return one, we have to increase

     * bs_snapshot's refcount here */

    bdrv_ref(bs_snapshot);

    bdrv_append(bs_snapshot, bs, &local_err);

    if (local_err) {

        error_propagate(errp, local_err);

        ret = -EINVAL;

        bs_snapshot = NULL;

        goto out;

    }



    g_free(tmp_filename);

    return bs_snapshot;



out:

    QDECREF(snapshot_options);

    g_free(tmp_filename);

    return NULL;

    return bs_snapshot;

}



/*