From 554b614765090f47d97a20ca6981e17e96515ec1 Mon Sep 17 00:00:00 2001 From: Alberto Garcia Date: Fri, 28 Oct 2016 10:08:11 +0300 Subject: [PATCH] block: Add QMP support for streaming to an intermediate layer This patch makes the 'device' parameter of the 'block-stream' command accept a node name that is not a root node. The presence of this feature can't be directly tested with introspection; soon we'll introduce a 'base-node' parameter whose presence can be checked for this purpose. In addition to that, operation blockers will be checked in all intermediate nodes between the top and the base node. Signed-off-by: Alberto Garcia Signed-off-by: Kevin Wolf --- blockdev.c | 15 +++++++++------ qapi/block-core.json | 13 ++++++++++--- 2 files changed, 19 insertions(+), 9 deletions(-) diff --git a/blockdev.c b/blockdev.c index de5b5f589c..b5d4d6919f 100644 --- a/blockdev.c +++ b/blockdev.c @@ -2937,7 +2937,7 @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device, bool has_on_error, BlockdevOnError on_error, Error **errp) { - BlockDriverState *bs; + BlockDriverState *bs, *iter; BlockDriverState *base_bs = NULL; AioContext *aio_context; Error *local_err = NULL; @@ -2947,7 +2947,7 @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device, on_error = BLOCKDEV_ON_ERROR_REPORT; } - bs = qmp_get_root_bs(device, errp); + bs = bdrv_lookup_bs(device, device, errp); if (!bs) { return; } @@ -2955,10 +2955,6 @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device, aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); - if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_STREAM, errp)) { - goto out; - } - if (has_base) { base_bs = bdrv_find_backing_image(bs, base); if (base_bs == NULL) { @@ -2969,6 +2965,13 @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device, base_name = base; } + /* Check for op blockers in the whole chain between bs and base */ + for (iter = bs; iter && iter != base_bs; iter = backing_bs(iter)) { + if (bdrv_op_is_blocked(iter, BLOCK_OP_TYPE_STREAM, errp)) { + goto out; + } + } + /* if we are streaming the entire chain, the result will have no backing * file, and specifying one is therefore an error */ if (base_bs == NULL && has_backing_file) { diff --git a/qapi/block-core.json b/qapi/block-core.json index 0f2b7032fc..d7a029cfd5 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -1464,6 +1464,13 @@ # with query-block-jobs. The operation can be stopped before it has completed # using the block-job-cancel command. # +# The node that receives the data is called the top image, can be located in +# any part of the chain (but always above the base image; see below) and can be +# specified using its device or node name. Earlier qemu versions only allowed +# 'device' to name the top level node; presence of the 'base-node' parameter +# during introspection can be used as a witness of the enhanced semantics +# of 'device'. +# # If a base file is specified then sectors are not copied from that base file and # its backing chain. When streaming completes the image file will have the base # file as its backing file. This can be used to stream a subset of the backing @@ -1475,12 +1482,12 @@ # @job-id: #optional identifier for the newly-created block job. If # omitted, the device name will be used. (Since 2.7) # -# @device: the device name or node-name of a root node +# @device: the device or node name of the top image # # @base: #optional the common backing file name # -# @backing-file: #optional The backing file string to write into the active -# layer. This filename is not validated. +# @backing-file: #optional The backing file string to write into the top +# image. This filename is not validated. # # If a pathname string is such that it cannot be # resolved by QEMU, that means that subsequent QMP or