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[Qemu-devel] [PATCH v2 0/5] Support streaming to an intermediate layer
From: |
Alberto Garcia |
Subject: |
[Qemu-devel] [PATCH v2 0/5] Support streaming to an intermediate layer |
Date: |
Mon, 23 Mar 2015 17:12:47 +0200 |
This is a new version of the patches that add support for streaming
to any intermediate layer. You can check the previous version here:
https://lists.gnu.org/archive/html/qemu-devel/2015-02/msg04116.html
I followed Kevin's idea to put the ownership of the block job directly
on the node that receives the data instead of the root node.
There's a few things that I'm not completely sure of and will
certainly generate some debate, but I decided to send the code anyway
so the actual changes can be seen. Note that this depends on the "Add
bdrv_get_device_or_node_name()" patchset I sent last week.
Here are the changes:
1) The 'top' parameter of block-stream disappears. 'device' also
accepts a node name now, which is used to specify the node where
the data will be written.
2) Block jobs can now be owned by any node. This implies:
- The block-job-* commands now also accept a node name in the
'device' parameter. I decided not to add a separate 'node-name'
parameter, following what we agreed with the 'block-stream'
command.
- The BlockJobInfo type and BLOCK_JOB_* events will report the node
name in the 'device' field if the node does not have a device
name. It seems that we had an agreement for the BlockJobInfo case
so I decided to follow the same approach for these events.
However, in the BLOCK_IMAGE_CORRUPTED case the preferred solution
was to add a new 'node-name' field, so I guess we might want to
do the same here?
- query-block-jobs now searches the whole tree, not just the root
nodes.
3) Operations are blocked in all intermediate nodes during the job. If
we have a chain [A] -> [B] -> [C] -> [D] -> [E] and we stream from
[B] to [E], then [C] and [D] will also be blocked during the job.
Since [C] and [D] will be removed from the chain after the job is
finished I understand that we don't want to perform any operation
with them.
4) As a consequence of 3), op blockers are also checked in all
intermediate nodes (not just in the topmost one) before starting a
streaming operation. I'm currently checking BLOCK_OP_TYPE_STREAM,
but maybe I should use a different op for the intermediate nodes
since what I'm going to do there is removing them from the chain?
I think those are the most important changes. Any feedback is welcome!
Berto
v2:
- The 'block-stream' command does not have a 'node-name' parameter
anymore and reuses 'device' for that purpose.
- Block jobs can now be owned by any intermediate node, and not just
by the ones at the root. query-block-jobs is updated to reflect that
change.
- The 'device' parameter of all 'block-job-*' commands can now take a
node name.
- The BlockJobInfo type and all BLOCK_JOB_* events report the node
name in the 'device' field if the node does not have a device name.
- All intermediate nodes are blocked (and checked for blockers) during
the streaming operation.
Alberto Garcia (5):
block: allow block jobs in any arbitrary node
block: never cancel a streaming job without running stream_complete()
block: Support streaming to an intermediate layer
block: Add QMP support for streaming to an intermediate layer
docs: Document how to stream to an intermediate layer
block.c | 4 +++-
block/mirror.c | 5 +++--
block/stream.c | 47 ++++++++++++++++++++++++++++++++++++++++++-----
blockdev.c | 47 +++++++++++++++++++++++++----------------------
blockjob.c | 17 +++++++++--------
docs/live-block-ops.txt | 32 ++++++++++++++++++++------------
docs/qmp/qmp-events.txt | 8 ++++----
include/qapi/qmp/qerror.h | 3 ---
qapi/block-core.json | 28 ++++++++++++++++------------
9 files changed, 122 insertions(+), 69 deletions(-)
--
2.1.4
- [Qemu-devel] [PATCH v2 0/5] Support streaming to an intermediate layer,
Alberto Garcia <=
- [Qemu-devel] [PATCH 2/5] block: never cancel a streaming job without running stream_complete(), Alberto Garcia, 2015/03/23
- [Qemu-devel] [PATCH 1/5] block: allow block jobs in any arbitrary node, Alberto Garcia, 2015/03/23
- [Qemu-devel] [PATCH 3/5] block: Support streaming to an intermediate layer, Alberto Garcia, 2015/03/23
- [Qemu-devel] [PATCH 5/5] docs: Document how to stream to an intermediate layer, Alberto Garcia, 2015/03/23
- [Qemu-devel] [PATCH 4/5] block: Add QMP support for streaming to an intermediate layer, Alberto Garcia, 2015/03/23